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Sample records for key establishment scheme

  1. A Forward Authentication Key Management Scheme for Heterogeneous Sensor Networks

    Directory of Open Access Journals (Sweden)

    Huang Jen-Yan

    2011-01-01

    Full Text Available Key encryption technology is a basic technique for protecting the secrecy of transmitted data among sensor nodes in wireless sensor networks. However, sensor nodes are inherently limited by insufficient hardware resources such as memory capacity and battery lifetime. As a result, few current key management schemes are appropriate for wireless sensor networks. This paper proposes a new key management method that uses dynamic key management schemes for heterogeneous sensor networks. The proposed scheme loads a hash function into the base station, cluster heads, and sensor nodes. The cluster heads and sensor nodes then generate their own keychains to provide forward authentication in case of key changes, security breaches, key changes due to security breaches. The cluster heads and sensor nodes establish pairwise keys to ensure transmission secrecy. The proposed scheme decreases the number of keys required for sensor nodes and cluster heads and is robust to the following attacks: guessing attacks, replay attacks, man-in-the-middle attacks, node capture attacks, and denial-of-service attacks.

  2. Certificateless Key-Insulated Generalized Signcryption Scheme without Bilinear Pairings

    Directory of Open Access Journals (Sweden)

    Caixue Zhou

    2017-01-01

    Full Text Available Generalized signcryption (GSC can be applied as an encryption scheme, a signature scheme, or a signcryption scheme with only one algorithm and one key pair. A key-insulated mechanism can resolve the private key exposure problem. To ensure the security of cloud storage, we introduce the key-insulated mechanism into GSC and propose a concrete scheme without bilinear pairings in the certificateless cryptosystem setting. We provide a formal definition and a security model of certificateless key-insulated GSC. Then, we prove that our scheme is confidential under the computational Diffie-Hellman (CDH assumption and unforgeable under the elliptic curve discrete logarithm (EC-DL assumption. Our scheme also supports both random-access key update and secure key update. Finally, we evaluate the efficiency of our scheme and demonstrate that it is highly efficient. Thus, our scheme is more suitable for users who communicate with the cloud using mobile devices.

  3. Establishing Key Performance Indicators : Case company X

    OpenAIRE

    Singh, Jatinder

    2015-01-01

    The key performance indicators serve as the navigational tools for a business organization to monitor its performance. They enable the management team to take real time decisions to keep organization’s resources aligned to its business strategy to accomplish its strategic objec-tives. This research was conducted to analyse the process of establishing successful key per-formance indicators for a business organization. The research was conducted to recommend key performance indicators developme...

  4. Deducing trapdoor primitives in public key encryption schemes

    Science.gov (United States)

    Pandey, Chandra

    2005-03-01

    Semantic security of public key encryption schemes is often interchangeable with the art of building trapdoors. In the frame of reference of Random Oracle methodology, the "Key Privacy" and "Anonymity" has often been discussed. However to a certain degree the security of most public key encryption schemes is required to be analyzed with formal proofs using one-way functions. This paper evaluates the design of El Gamal and RSA based schemes and attempts to parallelize the trapdoor primitives used in the computation of the cipher text, thereby magnifying the decryption error δp in the above schemes.

  5. Quantum election scheme based on anonymous quantum key distribution

    International Nuclear Information System (INIS)

    Zhou Rui-Rui; Yang Li

    2012-01-01

    An unconditionally secure authority-certified anonymous quantum key distribution scheme using conjugate coding is presented, based on which we construct a quantum election scheme without the help of an entanglement state. We show that this election scheme ensures the completeness, soundness, privacy, eligibility, unreusability, fairness, and verifiability of a large-scale election in which the administrator and counter are semi-honest. This election scheme can work even if there exist loss and errors in quantum channels. In addition, any irregularity in this scheme is sensible. (general)

  6. A secure smart-card based authentication and key agreement scheme for telecare medicine information systems.

    Science.gov (United States)

    Lee, Tian-Fu; Liu, Chuan-Ming

    2013-06-01

    A smart-card based authentication scheme for telecare medicine information systems enables patients, doctors, nurses, health visitors and the medicine information systems to establish a secure communication platform through public networks. Zhu recently presented an improved authentication scheme in order to solve the weakness of the authentication scheme of Wei et al., where the off-line password guessing attacks cannot be resisted. This investigation indicates that the improved scheme of Zhu has some faults such that the authentication scheme cannot execute correctly and is vulnerable to the attack of parallel sessions. Additionally, an enhanced authentication scheme based on the scheme of Zhu is proposed. The enhanced scheme not only avoids the weakness in the original scheme, but also provides users' anonymity and authenticated key agreements for secure data communications.

  7. A robust trust establishment scheme for wireless sensor networks.

    Science.gov (United States)

    Ishmanov, Farruh; Kim, Sung Won; Nam, Seung Yeob

    2015-03-23

    Security techniques like cryptography and authentication can fail to protect a network once a node is compromised. Hence, trust establishment continuously monitors and evaluates node behavior to detect malicious and compromised nodes. However, just like other security schemes, trust establishment is also vulnerable to attack. Moreover, malicious nodes might misbehave intelligently to trick trust establishment schemes. Unfortunately, attack-resistance and robustness issues with trust establishment schemes have not received much attention from the research community. Considering the vulnerability of trust establishment to different attacks and the unique features of sensor nodes in wireless sensor networks, we propose a lightweight and robust trust establishment scheme. The proposed trust scheme is lightweight thanks to a simple trust estimation method. The comprehensiveness and flexibility of the proposed trust estimation scheme make it robust against different types of attack and misbehavior. Performance evaluation under different types of misbehavior and on-off attacks shows that the detection rate of the proposed trust mechanism is higher and more stable compared to other trust mechanisms.

  8. A Robust Trust Establishment Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Farruh Ishmanov

    2015-03-01

    Full Text Available Security techniques like cryptography and authentication can fail to protect a network once a node is compromised. Hence, trust establishment continuously monitors and evaluates node behavior to detect malicious and compromised nodes. However, just like other security schemes, trust establishment is also vulnerable to attack. Moreover, malicious nodes might misbehave intelligently to trick trust establishment schemes. Unfortunately, attack-resistance and robustness issues with trust establishment schemes have not received much attention from the research community. Considering the vulnerability of trust establishment to different attacks and the unique features of sensor nodes in wireless sensor networks, we propose a lightweight and robust trust establishment scheme. The proposed trust scheme is lightweight thanks to a simple trust estimation method. The comprehensiveness and flexibility of the proposed trust estimation scheme make it robust against different types of attack and misbehavior. Performance evaluation under different types of misbehavior and on-off attacks shows that the detection rate of the proposed trust mechanism is higher and more stable compared to other trust mechanisms.

  9. Building Secure Public Key Encryption Scheme from Hidden Field Equations

    Directory of Open Access Journals (Sweden)

    Yuan Ping

    2017-01-01

    Full Text Available Multivariate public key cryptography is a set of cryptographic schemes built from the NP-hardness of solving quadratic equations over finite fields, amongst which the hidden field equations (HFE family of schemes remain the most famous. However, the original HFE scheme was insecure, and the follow-up modifications were shown to be still vulnerable to attacks. In this paper, we propose a new variant of the HFE scheme by considering the special equation x2=x defined over the finite field F3 when x=0,1. We observe that the equation can be used to further destroy the special structure of the underlying central map of the HFE scheme. It is shown that the proposed public key encryption scheme is secure against known attacks including the MinRank attack, the algebraic attacks, and the linearization equations attacks. The proposal gains some advantages over the original HFE scheme with respect to the encryption speed and public key size.

  10. Anticollusion Attack Noninteractive Security Hierarchical Key Agreement Scheme in WHMS

    Directory of Open Access Journals (Sweden)

    Kefei Mao

    2016-01-01

    Full Text Available Wireless Health Monitoring Systems (WHMS have potential to change the way of health care and bring numbers of benefits to patients, physicians, hospitals, and society. However, there are crucial barriers not only to transmit the biometric information but also to protect the privacy and security of the patients’ information. The key agreement between two entities is an essential cryptography operation to clear the barriers. In particular, the noninteractive hierarchical key agreement scheme becomes an attractive direction in WHMS because each sensor node or gateway has limited resources and power. Recently, a noninteractive hierarchical key agreement scheme has been proposed by Kim for WHMS. However, we show that Kim’s cryptographic scheme is vulnerable to the collusion attack if the physicians can be corrupted. Obviously, it is a more practical security condition. Therefore, we proposed an improved key agreement scheme against the attack. Security proof, security analysis, and experimental results demonstrate that our proposed scheme gains enhanced security and more efficiency than Kim’s previous scheme while inheriting its qualities of one-round communication and security properties.

  11. Distributed public key schemes secure against continual leakage

    DEFF Research Database (Denmark)

    Akavia, Adi; Goldwasser, Shafi; Hazay, Carmit

    2012-01-01

    -secure against continual memory leakage. Our DPKE scheme also implies a secure storage system on leaky devices, where a value s can be secretely stored on devices that continually leak information about their internal state to an external attacker. The devices go through a periodic refresh protocol......In this work we study distributed public key schemes secure against continual memory leakage. The secret key will be shared among two computing devices communicating over a public channel, and the decryption operation will be computed by a simple 2-party protocol between the devices. Similarly...... against continual memory leakage, under the Bilinear Decisional Diffie-Hellman and $2$-linear assumptions. Our schemes have the following properties: 1. Our DPKE and DIBE schemes tolerate leakage at all times, including during refresh. During refresh the tolerated leakage is a (1/2-o (1),1)-fraction...

  12. Multi-biometrics based cryptographic key regeneration scheme

    OpenAIRE

    Kanade , Sanjay Ganesh; Petrovska-Delacrétaz , Dijana; Dorizzi , Bernadette

    2009-01-01

    International audience; Biometrics lack revocability and privacy while cryptography cannot detect the user's identity. By obtaining cryptographic keys using biometrics, one can achieve the properties such as revocability, assurance about user's identity, and privacy. In this paper, we propose a multi-biometric based cryptographic key regeneration scheme. Since left and right irises of a person are uncorrelated, we treat them as two independent biometrics and combine in our system. We propose ...

  13. Secure Clustering and Symmetric Key Establishment in Heterogeneous Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Azarderskhsh Reza

    2011-01-01

    Full Text Available Information security in infrastructureless wireless sensor networks (WSNs is one of the most important research challenges. In these networks, sensor nodes are typically sprinkled liberally in the field in order to monitor, gather, disseminate, and provide the sensed data to the command node. Various studies have focused on key establishment schemes in homogeneous WSNs. However, recent research has shown that achieving survivability in WSNs requires a hierarchy and heterogeneous infrastructure. In this paper, to address security issues in the heterogeneous WSNs, we propose a secure clustering scheme along with a deterministic pairwise key management scheme based on public key cryptography. The proposed security mechanism guarantees that any two sensor nodes located in the same cluster and routing path can directly establish a pairwise key without disclosing any information to other nodes. Through security performance evaluation, it is shown that the proposed scheme guarantees node-to-node authentication, high resiliency against node capture, and minimum memory space requirement.

  14. A Secure Trust Establishment Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Farruh Ishmanov

    2014-01-01

    Full Text Available Trust establishment is an important tool to improve cooperation and enhance security in wireless sensor networks. The core of trust establishment is trust estimation. If a trust estimation method is not robust against attack and misbehavior, the trust values produced will be meaningless, and system performance will be degraded. We present a novel trust estimation method that is robust against on-off attacks and persistent malicious behavior. Moreover, in order to aggregate recommendations securely, we propose using a modified one-step M-estimator scheme. The novelty of the proposed scheme arises from combining past misbehavior with current status in a comprehensive way. Specifically, we introduce an aggregated misbehavior component in trust estimation, which assists in detecting an on-off attack and persistent malicious behavior. In order to determine the current status of the node, we employ previous trust values and current measured misbehavior components. These components are combined to obtain a robust trust value. Theoretical analyses and evaluation results show that our scheme performs better than other trust schemes in terms of detecting an on-off attack and persistent misbehavior.

  15. Security enhanced anonymous multiserver authenticated key agreement scheme using smart cards and biometrics.

    Science.gov (United States)

    Choi, Younsung; Nam, Junghyun; Lee, Donghoon; Kim, Jiye; Jung, Jaewook; Won, Dongho

    2014-01-01

    An anonymous user authentication scheme allows a user, who wants to access a remote application server, to achieve mutual authentication and session key establishment with the server in an anonymous manner. To enhance the security of such authentication schemes, recent researches combined user's biometrics with a password. However, these authentication schemes are designed for single server environment. So when a user wants to access different application servers, the user has to register many times. To solve this problem, Chuang and Chen proposed an anonymous multiserver authenticated key agreement scheme using smart cards together with passwords and biometrics. Chuang and Chen claimed that their scheme not only supports multiple servers but also achieves various security requirements. However, we show that this scheme is vulnerable to a masquerade attack, a smart card attack, a user impersonation attack, and a DoS attack and does not achieve perfect forward secrecy. We also propose a security enhanced anonymous multiserver authenticated key agreement scheme which addresses all the weaknesses identified in Chuang and Chen's scheme.

  16. Security Enhanced Anonymous Multiserver Authenticated Key Agreement Scheme Using Smart Cards and Biometrics

    Directory of Open Access Journals (Sweden)

    Younsung Choi

    2014-01-01

    Full Text Available An anonymous user authentication scheme allows a user, who wants to access a remote application server, to achieve mutual authentication and session key establishment with the server in an anonymous manner. To enhance the security of such authentication schemes, recent researches combined user’s biometrics with a password. However, these authentication schemes are designed for single server environment. So when a user wants to access different application servers, the user has to register many times. To solve this problem, Chuang and Chen proposed an anonymous multiserver authenticated key agreement scheme using smart cards together with passwords and biometrics. Chuang and Chen claimed that their scheme not only supports multiple servers but also achieves various security requirements. However, we show that this scheme is vulnerable to a masquerade attack, a smart card attack, a user impersonation attack, and a DoS attack and does not achieve perfect forward secrecy. We also propose a security enhanced anonymous multiserver authenticated key agreement scheme which addresses all the weaknesses identified in Chuang and Chen’s scheme.

  17. Key Management Scheme Based on Route Planning of Mobile Sink in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2016-01-01

    Full Text Available In many wireless sensor network application scenarios the key management scheme with a Mobile Sink (MS should be fully investigated. This paper proposes a key management scheme based on dynamic clustering and optimal-routing choice of MS. The concept of Traveling Salesman Problem with Neighbor areas (TSPN in dynamic clustering for data exchange is proposed, and the selection probability is used in MS route planning. The proposed scheme extends static key management to dynamic key management by considering the dynamic clustering and mobility of MSs, which can effectively balance the total energy consumption during the activities. Considering the different resources available to the member nodes and sink node, the session key between cluster head and MS is established by modified an ECC encryption with Diffie-Hellman key exchange (ECDH algorithm and the session key between member node and cluster head is built with a binary symmetric polynomial. By analyzing the security of data storage, data transfer and the mechanism of dynamic key management, the proposed scheme has more advantages to help improve the resilience of the key management system of the network on the premise of satisfying higher connectivity and storage efficiency.

  18. Key Management Scheme Based on Route Planning of Mobile Sink in Wireless Sensor Networks.

    Science.gov (United States)

    Zhang, Ying; Liang, Jixing; Zheng, Bingxin; Jiang, Shengming; Chen, Wei

    2016-01-29

    In many wireless sensor network application scenarios the key management scheme with a Mobile Sink (MS) should be fully investigated. This paper proposes a key management scheme based on dynamic clustering and optimal-routing choice of MS. The concept of Traveling Salesman Problem with Neighbor areas (TSPN) in dynamic clustering for data exchange is proposed, and the selection probability is used in MS route planning. The proposed scheme extends static key management to dynamic key management by considering the dynamic clustering and mobility of MSs, which can effectively balance the total energy consumption during the activities. Considering the different resources available to the member nodes and sink node, the session key between cluster head and MS is established by modified an ECC encryption with Diffie-Hellman key exchange (ECDH) algorithm and the session key between member node and cluster head is built with a binary symmetric polynomial. By analyzing the security of data storage, data transfer and the mechanism of dynamic key management, the proposed scheme has more advantages to help improve the resilience of the key management system of the network on the premise of satisfying higher connectivity and storage efficiency.

  19. Extended KCI attack against two-party key establishment protocols

    NARCIS (Netherlands)

    Tang, Qiang; Chen, Liqun

    2011-01-01

    We introduce an extended Key Compromise Impersonation (KCI) attack against two-party key establishment protocols, where an adversary has access to both long-term and ephemeral secrets of a victim. Such an attack poses serious threats to both key authentication and key confirmation properties of a

  20. Post-quantum attacks on key distribution schemes in the presence of weakly stochastic sources

    International Nuclear Information System (INIS)

    Al–Safi, S W; Wilmott, C M

    2015-01-01

    It has been established that the security of quantum key distribution protocols can be severely compromised were one to permit an eavesdropper to possess a very limited knowledge of the random sources used between the communicating parties. While such knowledge should always be expected in realistic experimental conditions, the result itself opened a new line of research to fully account for real-world weak randomness threats to quantum cryptography. Here we expand of this novel idea by describing a key distribution scheme that is provably secure against general attacks by a post-quantum adversary. We then discuss possible security consequences for such schemes under the assumption of weak randomness. (paper)

  1. Understanding security failures of two authentication and key agreement schemes for telecare medicine information systems.

    Science.gov (United States)

    Mishra, Dheerendra

    2015-03-01

    Smart card based authentication and key agreement schemes for telecare medicine information systems (TMIS) enable doctors, nurses, patients and health visitors to use smart cards for secure login to medical information systems. In recent years, several authentication and key agreement schemes have been proposed to present secure and efficient solution for TMIS. Most of the existing authentication schemes for TMIS have either higher computation overhead or are vulnerable to attacks. To reduce the computational overhead and enhance the security, Lee recently proposed an authentication and key agreement scheme using chaotic maps for TMIS. Xu et al. also proposed a password based authentication and key agreement scheme for TMIS using elliptic curve cryptography. Both the schemes provide better efficiency from the conventional public key cryptography based schemes. These schemes are important as they present an efficient solution for TMIS. We analyze the security of both Lee's scheme and Xu et al.'s schemes. Unfortunately, we identify that both the schemes are vulnerable to denial of service attack. To understand the security failures of these cryptographic schemes which are the key of patching existing schemes and designing future schemes, we demonstrate the security loopholes of Lee's scheme and Xu et al.'s scheme in this paper.

  2. An Authenticated Key Agreement Scheme Based on Cyclic Automorphism Subgroups of Random Orders

    Directory of Open Access Journals (Sweden)

    Yang Jun

    2017-01-01

    Full Text Available Group-based cryptography is viewed as a modern cryptographic candidate solution to blocking quantum computer attacks, and key exchange protocols on the Internet are one of the primitives to ensure the security of communication. In 2016 Habeeb et al proposed a “textbook” key exchange protocol based on the semidirect product of two groups, which is insecure for use in real-world applications. In this paper, after discarding the unnecessary disguising notion of semidirect product in the protocol, we establish a simplified yet enhanced authenticated key agreement scheme based on cyclic automorphism subgroups of random orders by making hybrid use of certificates and symmetric-key encryption as challenge-and-responses in the public-key setting. Its passive security is formally analyzed, which is relative to the cryptographic hardness assumption of a computational number-theoretic problem. Cryptanalysis of this scheme shows that it is secure against the intruder-in-the-middle attack even in the worst case of compromising the signatures, and provides explicit key confirmation to both parties.

  3. Establishment of water quality classification scheme: a case study of ...

    African Journals Online (AJOL)

    A water quality classification scheme based on 11 routinely measured physicochemical variables has been developed for the Calabar River Estuary. The variables considered include water temperature, pH. Eh, DO, DO saturation, BOD5, COD, TSS, turbidity, NH4-N and electrical conductivity. Classification of water source ...

  4. Practical scheme to share a secret key through a quantum channel with a 27.6% bit error rate

    International Nuclear Information System (INIS)

    Chau, H.F.

    2002-01-01

    A secret key shared through quantum key distribution between two cooperative players is secure against any eavesdropping attack allowed by the laws of physics. Yet, such a key can be established only when the quantum channel error rate due to eavesdropping or imperfect apparatus is low. Here, a practical quantum key distribution scheme by making use of an adaptive privacy amplification procedure with two-way classical communication is reported. Then, it is proven that the scheme generates a secret key whenever the bit error rate of the quantum channel is less than 0.5-0.1√(5)≅27.6%, thereby making it the most error resistant scheme known to date

  5. Tamper-proof secret image-sharing scheme for identifying cheated secret keys and shared images

    Science.gov (United States)

    Chen, Chien-Chang; Liu, Chong-An

    2013-01-01

    A (t,n) secret image-sharing scheme shares a secret image to n participants, and the t users recover the image. During the recovery procedure of a conventional secret image-sharing scheme, cheaters may use counterfeit secret keys or modified shared images to cheat other users' secret keys and shared images. A cheated secret key or shared image leads to an incorrect secret image. Unfortunately, the cheater cannot be identified. We present an exponent and modulus-based scheme to provide a tamper-proof secret image-sharing scheme for identifying cheaters on secret keys or shared images. The proposed scheme allows users to securely select their secret key. This assignment can be performed over networks. Modulus results of each shared image is calculated to recognize cheaters of a shared image. Experimental results indicate that the proposed scheme is excellent at identifying cheated secret keys and shared images.

  6. Trading scheme 'key' to low-carbon economy

    International Nuclear Information System (INIS)

    2006-01-01

    Federal Opposition Leader Kim Beazley has emphasised the importance of getting the economics of environmental policy right by introducing market-based mechanisms for pricing emissions. 'Market-based mechanisms such as emissions trading are central to moving to a low-carbon economy,' he said in his latest blueprint. 'A functioning carbon market will deliver a price signal, so there is a long-term incentive to cut emissions further, and a mechanism for trading, so that energy can be allocated efficiently in the economy. It will also encourage greater private investment in clean energy technology.' Mr Beazley said the new market would also reward the many companies who were already adapting to a carbon-constrained world. 'This includes those global companies in Australia that already operate in emissions trading markets overseas. An effective price signal for carbon in Australia will allow these companies to benefit directly from their good corporate citizenship and long-term vision.' Mr Beazley has committed a federal Labor government to work with state governments and business to establish the national trading scheme. He also criticised the Federal Government for refusing to ratify the Kyoto Protocol, which he argued excluded Australian businesses from participating in the emerging global carbon trade. This made it harder for businesses to break into the market for cleaner production technologies overseas. While again admitting Kyoto was not perfect, Mr Beazley said ratification would see Australia part of what would potentially be 'the biggest market in the world by 2020'. He said the recent Asia Pacific Climate Change Pact was a positive step but was not an alternative to Kyoto. 'Above all, it has no economic mechanisms to drive further change. 'Without ratifying Kyoto some of our businesses are missing out on effective participation in international schemes that offer substantial financial rewards for greenhouse gas reductions. 'By ratifying Kyoto and adopting

  7. Dynamic Symmetric Key Mobile Commerce Scheme Based on Self-Verified Mechanism

    Directory of Open Access Journals (Sweden)

    Jiachen Yang

    2014-01-01

    Full Text Available In terms of the security and efficiency of mobile e-commerce, the authors summarized the advantages and disadvantages of several related schemes, especially the self-verified mobile payment scheme based on the elliptic curve cryptosystem (ECC and then proposed a new type of dynamic symmetric key mobile commerce scheme based on self-verified mechanism. The authors analyzed the basic algorithm based on self-verified mechanisms and detailed the complete transaction process of the proposed scheme. The authors analyzed the payment scheme based on the security and high efficiency index. The analysis shows that the proposed scheme not only meets the high efficiency of mobile electronic payment premise, but also takes the security into account. The user confirmation mechanism at the end of the proposed scheme further strengthens the security of the proposed scheme. In brief, the proposed scheme is more efficient and practical than most of the existing schemes.

  8. Password-based authenticated key exchange scheme using smart card

    Science.gov (United States)

    Liu, Hui; Zhong, Shaojun

    2013-03-01

    A protocol that allows any two entities to negotiate a shared session key is commonly called a key exchange protocol. If the protocol provides a function to authenticate each other, we call the protocol authenticated key exchange protocol (AKE). Password authentication key exchange (PAKE) is the AKE protocol in which the two entities share a humanmemorable password. Most of current PAKE relies on the existence of a public key infrastructure, which sometime is impossible for a certain environments such as low computational device due to the computation overhead. In this paper, we propose password-based authenticated key exchange using smart card. Compared to previous PAKE, our protocol is more efficient because our protocol is based on ECC. Thereby, the proposed protocol can be well applied to low computation device.

  9. Secure networking quantum key distribution schemes with Greenberger-Horne-Zeilinger states

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Ying; Shi, Ronghua [School of Information Science and Engineering, Central South University, Changsha 410083 (China); Zeng, Guihua [Department of Electronic Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)], E-mail: sdguoying@gmail.com, E-mail: rhshi@mail.edu.com, E-mail: ghzeng@sjtu.edu.cn

    2010-04-15

    A novel approach to quantum cryptography to be called NQKD, networking quantum key distribution, has been developed for secure quantum communication schemes on the basis of the complementary relations of entanglement Greenberger-Horne-Zeilinger (GHZ) triplet states. One scheme distributes the private key among legal participants in a probabilistic manner, while another transmits the deterministic message with some certainty. Some decoy photons are employed for preventing a potential eavesdropper from attacking quantum channels. The present schemes are efficient as there exists an elegant method for key distributions. The security of the proposed schemes is exactly guaranteed by the entanglement of the GHZ quantum system, which is illustrated in security analysis.

  10. Secure networking quantum key distribution schemes with Greenberger-Horne-Zeilinger states

    International Nuclear Information System (INIS)

    Guo, Ying; Shi, Ronghua; Zeng, Guihua

    2010-01-01

    A novel approach to quantum cryptography to be called NQKD, networking quantum key distribution, has been developed for secure quantum communication schemes on the basis of the complementary relations of entanglement Greenberger-Horne-Zeilinger (GHZ) triplet states. One scheme distributes the private key among legal participants in a probabilistic manner, while another transmits the deterministic message with some certainty. Some decoy photons are employed for preventing a potential eavesdropper from attacking quantum channels. The present schemes are efficient as there exists an elegant method for key distributions. The security of the proposed schemes is exactly guaranteed by the entanglement of the GHZ quantum system, which is illustrated in security analysis.

  11. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme.

    Directory of Open Access Journals (Sweden)

    Chengqi Wang

    Full Text Available With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.'s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks.

  12. Robust biometrics based authentication and key agreement scheme for multi-server environments using smart cards.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Yang, Xing; Yang, Yixian

    2015-01-01

    Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.'s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes.

  13. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme

    Science.gov (United States)

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.’s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks. PMID:26866606

  14. Robust biometrics based authentication and key agreement scheme for multi-server environments using smart cards.

    Directory of Open Access Journals (Sweden)

    Yanrong Lu

    Full Text Available Biometrics authenticated schemes using smart cards have attracted much attention in multi-server environments. Several schemes of this type where proposed in the past. However, many of them were found to have some design flaws. This paper concentrates on the security weaknesses of the three-factor authentication scheme by Mishra et al. After careful analysis, we find their scheme does not really resist replay attack while failing to provide an efficient password change phase. We further propose an improvement of Mishra et al.'s scheme with the purpose of preventing the security threats of their scheme. We demonstrate the proposed scheme is given to strong authentication against several attacks including attacks shown in the original scheme. In addition, we compare the performance and functionality with other multi-server authenticated key schemes.

  15. Cryptanalysis and Improvement of a Biometric-Based Multi-Server Authentication and Key Agreement Scheme.

    Science.gov (United States)

    Wang, Chengqi; Zhang, Xiao; Zheng, Zhiming

    2016-01-01

    With the security requirements of networks, biometrics authenticated schemes which are applied in the multi-server environment come to be more crucial and widely deployed. In this paper, we propose a novel biometric-based multi-server authentication and key agreement scheme which is based on the cryptanalysis of Mishra et al.'s scheme. The informal and formal security analysis of our scheme are given, which demonstrate that our scheme satisfies the desirable security requirements. The presented scheme provides a variety of significant functionalities, in which some features are not considered in the most of existing authentication schemes, such as, user revocation or re-registration and biometric information protection. Compared with several related schemes, our scheme has more secure properties and lower computation cost. It is obviously more appropriate for practical applications in the remote distributed networks.

  16. A Key Establishment Protocol for RFID User in IPTV Environment

    Science.gov (United States)

    Jeong, Yoon-Su; Kim, Yong-Tae; Sohn, Jae-Min; Park, Gil-Cheol; Lee, Sang-Ho

    In recent years, the usage of IPTV (Internet Protocol Television) has been increased. The reason is a technological convergence of broadcasting and telecommunication delivering interactive applications and multimedia content through high speed Internet connections. The main critical point of IPTV security requirements is subscriber authentication. That is, IPTV service should have the capability to identify the subscribers to prohibit illegal access. Currently, IPTV service does not provide a sound authentication mechanism to verify the identity of its wireless users (or devices). This paper focuses on a lightweight authentication and key establishment protocol based on the use of hash functions. The proposed approach provides effective authentication for a mobile user with a RFID tag whose authentication information is communicated back and forth with the IPTV authentication server via IPTV set-top box (STB). That is, the proposed protocol generates user's authentication information that is a bundle of two public keys derived from hashing user's private keys and RFID tag's session identifier, and adds 1bit to this bundled information for subscriber's information confidentiality before passing it to the authentication server.

  17. A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

    Science.gov (United States)

    Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

    2013-01-01

    A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

  18. Two-Factor User Authentication with Key Agreement Scheme Based on Elliptic Curve Cryptosystem

    Directory of Open Access Journals (Sweden)

    Juan Qu

    2014-01-01

    Full Text Available A password authentication scheme using smart card is called two-factor authentication scheme. Two-factor authentication scheme is the most accepted and commonly used mechanism that provides the authorized users a secure and efficient method for accessing resources over insecure communication channel. Up to now, various two-factor user authentication schemes have been proposed. However, most of them are vulnerable to smart card loss attack, offline password guessing attack, impersonation attack, and so on. In this paper, we design a password remote user authentication with key agreement scheme using elliptic curve cryptosystem. Security analysis shows that the proposed scheme has high level of security. Moreover, the proposed scheme is more practical and secure in contrast to some related schemes.

  19. An Improved and Secure Anonymous Biometric-Based User Authentication with Key Agreement Scheme for the Integrated EPR Information System.

    Science.gov (United States)

    Jung, Jaewook; Kang, Dongwoo; Lee, Donghoon; Won, Dongho

    2017-01-01

    Nowadays, many hospitals and medical institutes employ an authentication protocol within electronic patient records (EPR) services in order to provide protected electronic transactions in e-medicine systems. In order to establish efficient and robust health care services, numerous studies have been carried out on authentication protocols. Recently, Li et al. proposed a user authenticated key agreement scheme according to EPR information systems, arguing that their scheme is able to resist various types of attacks and preserve diverse security properties. However, this scheme possesses critical vulnerabilities. First, the scheme cannot prevent off-line password guessing attacks and server spoofing attack, and cannot preserve user identity. Second, there is no password verification process with the failure to identify the correct password at the beginning of the login phase. Third, the mechanism of password change is incompetent, in that it induces inefficient communication in communicating with the server to change a user password. Therefore, we suggest an upgraded version of the user authenticated key agreement scheme that provides enhanced security. Our security and performance analysis shows that compared to other related schemes, our scheme not only improves the security level, but also ensures efficiency.

  20. An Improved and Secure Anonymous Biometric-Based User Authentication with Key Agreement Scheme for the Integrated EPR Information System.

    Directory of Open Access Journals (Sweden)

    Jaewook Jung

    Full Text Available Nowadays, many hospitals and medical institutes employ an authentication protocol within electronic patient records (EPR services in order to provide protected electronic transactions in e-medicine systems. In order to establish efficient and robust health care services, numerous studies have been carried out on authentication protocols. Recently, Li et al. proposed a user authenticated key agreement scheme according to EPR information systems, arguing that their scheme is able to resist various types of attacks and preserve diverse security properties. However, this scheme possesses critical vulnerabilities. First, the scheme cannot prevent off-line password guessing attacks and server spoofing attack, and cannot preserve user identity. Second, there is no password verification process with the failure to identify the correct password at the beginning of the login phase. Third, the mechanism of password change is incompetent, in that it induces inefficient communication in communicating with the server to change a user password. Therefore, we suggest an upgraded version of the user authenticated key agreement scheme that provides enhanced security. Our security and performance analysis shows that compared to other related schemes, our scheme not only improves the security level, but also ensures efficiency.

  1. An Improved and Secure Anonymous Biometric-Based User Authentication with Key Agreement Scheme for the Integrated EPR Information System

    Science.gov (United States)

    Kang, Dongwoo; Lee, Donghoon; Won, Dongho

    2017-01-01

    Nowadays, many hospitals and medical institutes employ an authentication protocol within electronic patient records (EPR) services in order to provide protected electronic transactions in e-medicine systems. In order to establish efficient and robust health care services, numerous studies have been carried out on authentication protocols. Recently, Li et al. proposed a user authenticated key agreement scheme according to EPR information systems, arguing that their scheme is able to resist various types of attacks and preserve diverse security properties. However, this scheme possesses critical vulnerabilities. First, the scheme cannot prevent off-line password guessing attacks and server spoofing attack, and cannot preserve user identity. Second, there is no password verification process with the failure to identify the correct password at the beginning of the login phase. Third, the mechanism of password change is incompetent, in that it induces inefficient communication in communicating with the server to change a user password. Therefore, we suggest an upgraded version of the user authenticated key agreement scheme that provides enhanced security. Our security and performance analysis shows that compared to other related schemes, our scheme not only improves the security level, but also ensures efficiency. PMID:28046075

  2. A Secure Dynamic Identity and Chaotic Maps Based User Authentication and Key Agreement Scheme for e-Healthcare Systems.

    Science.gov (United States)

    Li, Chun-Ta; Lee, Cheng-Chi; Weng, Chi-Yao; Chen, Song-Jhih

    2016-11-01

    Secure user authentication schemes in many e-Healthcare applications try to prevent unauthorized users from intruding the e-Healthcare systems and a remote user and a medical server can establish session keys for securing the subsequent communications. However, many schemes does not mask the users' identity information while constructing a login session between two or more parties, even though personal privacy of users is a significant topic for e-Healthcare systems. In order to preserve personal privacy of users, dynamic identity based authentication schemes are hiding user's real identity during the process of network communications and only the medical server knows login user's identity. In addition, most of the existing dynamic identity based authentication schemes ignore the inputs verification during login condition and this flaw may subject to inefficiency in the case of incorrect inputs in the login phase. Regarding the use of secure authentication mechanisms for e-Healthcare systems, this paper presents a new dynamic identity and chaotic maps based authentication scheme and a secure data protection approach is employed in every session to prevent illegal intrusions. The proposed scheme can not only quickly detect incorrect inputs during the phases of login and password change but also can invalidate the future use of a lost/stolen smart card. Compared the functionality and efficiency with other authentication schemes recently, the proposed scheme satisfies desirable security attributes and maintains acceptable efficiency in terms of the computational overheads for e-Healthcare systems.

  3. Key management schemes using routing information frames in secure wireless sensor networks

    Science.gov (United States)

    Kamaev, V. A.; Finogeev, A. G.; Finogeev, A. A.; Parygin, D. S.

    2017-01-01

    The article considers the problems and objectives of key management for data encryption in wireless sensor networks (WSN) of SCADA systems. The structure of the key information in the ZigBee network and methods of keys obtaining are discussed. The use of a hybrid key management schemes is most suitable for WSN. The session symmetric key is used to encrypt the sensor data, asymmetric keys are used to encrypt the session key transmitted from the routing information. Three algorithms of hybrid key management using routing information frames determined by routing methods and the WSN topology are presented.

  4. A Privacy Protection User Authentication and Key Agreement Scheme Tailored for the Internet of Things Environment: PriAuth

    Directory of Open Access Journals (Sweden)

    Yuwen Chen

    2017-01-01

    Full Text Available In a wearable sensor-based deployment, sensors are placed over the patient to monitor their body health parameters. Continuous physiological information monitored by wearable sensors helps doctors have a better diagnostic and a suitable treatment. When doctors want to access the patient’s sensor data remotely via network, the patient will authenticate the identity of the doctor first, and then they will negotiate a key for further communication. Many lightweight schemes have been proposed to enable a mutual authentication and key establishment between the two parties with the help of a gateway node, but most of these schemes cannot enable identity confidentiality. Besides, the shared key is also known by the gateway, which means the patient’s sensor data could be leaked to the gateway. In PriAuth, identities are encrypted to guarantee confidentiality. Additionally, Elliptic Curve Diffie–Hellman (ECDH key exchange protocol has been adopted to ensure the secrecy of the key, avoiding the gateway access to it. Besides, only hash and XOR computations are adopted because of the computability and power constraints of the wearable sensors. The proposed scheme has been validated by BAN logic and AVISPA, and the results show the scheme has been proven as secure.

  5. Three-factor anonymous authentication and key agreement scheme for Telecare Medicine Information Systems.

    Science.gov (United States)

    Arshad, Hamed; Nikooghadam, Morteza

    2014-12-01

    Nowadays, with comprehensive employment of the internet, healthcare delivery services is provided remotely by telecare medicine information systems (TMISs). A secure mechanism for authentication and key agreement is one of the most important security requirements for TMISs. Recently, Tan proposed a user anonymity preserving three-factor authentication scheme for TMIS. The present paper shows that Tan's scheme is vulnerable to replay attacks and Denial-of-Service attacks. In order to overcome these security flaws, a new and efficient three-factor anonymous authentication and key agreement scheme for TMIS is proposed. Security and performance analysis shows superiority of the proposed scheme in comparison with previously proposed schemes that are related to security of TMISs.

  6. Key-Insulated Undetachable Digital Signature Scheme and Solution for Secure Mobile Agents in Electronic Commerce

    Directory of Open Access Journals (Sweden)

    Yang Shi

    2016-01-01

    Full Text Available Considering the security of both the customers’ hosts and the eShops’ servers, we introduce the idea of a key-insulated undetachable digital signature, enabling mobile agents to generate undetachable digital signatures on remote hosts with the key-insulated property of the original signer’s signing key. From the theoretical perspective, we provide the formal definition and security notion of a key-insulated undetachable digital signature. From the practical perspective, we propose a concrete scheme to secure mobile agents in electronic commerce. The scheme is mainly focused on protecting the signing key from leakage and preventing the misuse of the signature algorithm on malicious servers. Agents do not carry the signing key when they generate digital signatures on behalf of the original signer, so the key is protected on remote servers. Furthermore, if a hacker gains the signing key of the original signer, the hacker is still unable to forge a signature for any time period other than the key being accessed. In addition, the encrypted function is combined with the original signer’s requirement to prevent the misuse of signing algorithm. The scheme is constructed on gap Diffie–Hellman groups with provable security, and the performance testing indicates that the scheme is efficient.

  7. Towards Public Key Encryption Scheme Supporting Equality Test with Fine-Grained Authorization

    NARCIS (Netherlands)

    Tang, Qiang

    2011-01-01

    In this paper we investigate a new category of public key encryption schemes which supports equality test between ciphertexts. With this new primitive, two users, who possess their own public/private key pairs, can issue token(s) to a proxy to authorize it to perform equality test between their

  8. Collaboration: the Key to Establishing Community Networks in Regional Australia

    Directory of Open Access Journals (Sweden)

    Wal Taylor

    2002-01-01

    Full Text Available Despite the promise of community involvement, cohesion and empowerment offered by local community networks (CN using Internet Technologies, few communities in regional Australia have been able to demonstrate sustainable and vibrant CN which demonstrate increased social, cultural or self-reliance capital. The Faculty of Informatics and Communication at Central Queensland University (CQU and a local council have established a formal alliance to establish the COIN (Community Informatics projects to research issues around this topic. This paper presents the initial findings from this work and draws conclusions for possible comparison with other international experience. The research focuses attention on community understanding and cohesion, local government priorities in a community with relatively low diffusion of the Internet and the competing demands in a regional university between traditional service provision in an increasingly competitive market and the needs of establishing outreach research for altruistic, industry establishment and commercial rationale.

  9. An Improved Dynamic ID-Based Remote User Authentication with Key Agreement Scheme

    Directory of Open Access Journals (Sweden)

    Juan Qu

    2013-01-01

    Full Text Available In recent years, several dynamic ID-based remote user authentication schemes have been proposed. In 2012, Wen and Li proposed a dynamic ID-based remote user authentication with key agreement scheme. They claimed that their scheme can resist impersonation attack and insider attack and provide anonymity for the users. However, we will show that Wen and Li's scheme cannot withstand insider attack and forward secrecy, does not provide anonymity for the users, and inefficiency for error password login. In this paper, we propose a novel ECC-based remote user authentication scheme which is immune to various known types of attack and is more secure and practical for mobile clients.

  10. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-06-08

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas's currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs.

  11. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2016-01-01

    WSNs (Wireless sensor networks) are nowadays viewed as a vital portion of the IoTs (Internet of Things). Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement) enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas’s currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham) logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications) to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs. PMID:27338382

  12. An Energy Efficient Mutual Authentication and Key Agreement Scheme Preserving Anonymity for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yanrong Lu

    2016-06-01

    Full Text Available WSNs (Wireless sensor networks are nowadays viewed as a vital portion of the IoTs (Internet of Things. Security is a significant issue in WSNs, especially in resource-constrained environments. AKA (Authentication and key agreement enhances the security of WSNs against adversaries attempting to get sensitive sensor data. Various AKA schemes have been developed for verifying the legitimate users of a WSN. Firstly, we scrutinize Amin-Biswas’s currently scheme and demonstrate the major security loopholes in their works. Next, we propose a lightweight AKA scheme, using symmetric key cryptography based on smart card, which is resilient against all well known security attacks. Furthermore, we prove the scheme accomplishes mutual handshake and session key agreement property securely between the participates involved under BAN (Burrows, Abadi and Needham logic. Moreover, formal security analysis and simulations are also conducted using AVISPA(Automated Validation of Internet Security Protocols and Applications to show that our scheme is secure against active and passive attacks. Additionally, performance analysis shows that our proposed scheme is secure and efficient to apply for resource-constrained WSNs.

  13. Physical Layer Secret-Key Generation Scheme for Transportation Security Sensor Network.

    Science.gov (United States)

    Yang, Bin; Zhang, Jianfeng

    2017-06-28

    Wireless Sensor Networks (WSNs) are widely used in different disciplines, including transportation systems, agriculture field environment monitoring, healthcare systems, and industrial monitoring. The security challenge of the wireless communication link between sensor nodes is critical in WSNs. In this paper, we propose a new physical layer secret-key generation scheme for transportation security sensor network. The scheme is based on the cooperation of all the sensor nodes, thus avoiding the key distribution process, which increases the security of the system. Different passive and active attack models are analyzed in this paper. We also prove that when the cooperative node number is large enough, even when the eavesdropper is equipped with multiple antennas, the secret-key is still secure. Numerical results are performed to show the efficiency of the proposed scheme.

  14. Secret-Key-Aided Scheme for Securing Untrusted DF Relaying Networks

    KAUST Repository

    Shafie, Ahmed El

    2017-06-12

    This paper proposes a new scheme to secure the transmissions in an untrusted decode-and-forward (DF) relaying network. A legitimate source node, Alice, sends her data to a legitimate destination node, Bob, with the aid of an untrusted DF relay node, Charlie. To secure the transmissions from Charlie during relaying time slots, each data codeword is secured using a secret-key codeword that has been previously shared between Alice and Bob during the perfectly secured time slots (i.e., when the channel secrecy rate is positive). The secret-key bits exchanged between Alice and Bob are stored in a finite-length buffer and are used to secure data transmission whenever needed. We model the secret-key buffer as a queueing system and analyze its Markov chain. Our numerical results show the gains of our proposed scheme relative to benchmarks. Moreover, the proposed scheme achieves an upper bound on the secure throughput.

  15. Secret-Key-Aided Scheme for Securing Untrusted DF Relaying Networks

    KAUST Repository

    Shafie, Ahmed El; Salem, Ahmed Sultan; Mabrouk, Asma; Tourki, Kamel; Al-Dhahir, Naofal

    2017-01-01

    This paper proposes a new scheme to secure the transmissions in an untrusted decode-and-forward (DF) relaying network. A legitimate source node, Alice, sends her data to a legitimate destination node, Bob, with the aid of an untrusted DF relay node, Charlie. To secure the transmissions from Charlie during relaying time slots, each data codeword is secured using a secret-key codeword that has been previously shared between Alice and Bob during the perfectly secured time slots (i.e., when the channel secrecy rate is positive). The secret-key bits exchanged between Alice and Bob are stored in a finite-length buffer and are used to secure data transmission whenever needed. We model the secret-key buffer as a queueing system and analyze its Markov chain. Our numerical results show the gains of our proposed scheme relative to benchmarks. Moreover, the proposed scheme achieves an upper bound on the secure throughput.

  16. Key Management Schemes for Peer-to-Peer Multimedia Streaming Overlay Networks

    Science.gov (United States)

    Naranjo, J. A. M.; López-Ramos, J. A.; Casado, L. G.

    Key distribution for multimedia live streaming peer-to-peer overlay networks is a field still in its childhood stage. A scheme designed for networks of this kind must seek security and efficiency while keeping in mind the following restrictions: limited bandwidth, continuous playing, great audience size and clients churn. This paper introduces two novel schemes that allow a trade-off between security and efficiency by allowing to dynamically vary the number of levels used in the key hierarchy. These changes are motivated by great variations in audience size, and initiated by decision of the Key Server. Additionally, a comparative study of both is presented, focusing on security and audience size. Results show that larger key hierarchies can supply bigger audiences, but offer less security against statistical attacks. The opposite happens for shorter key hierarchies.

  17. Differential on-on keying: A robust non-coherent digital modulation scheme

    KAUST Repository

    Kaddoum, Georges

    2015-05-01

    A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

  18. Differential on-on keying: A robust non-coherent digital modulation scheme

    KAUST Repository

    Kaddoum, Georges; Ahmed, Mohammed F. A.; Al-Naffouri, Tareq Y.

    2015-01-01

    A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

  19. A secure chaotic maps and smart cards based password authentication and key agreement scheme with user anonymity for telecare medicine information systems.

    Science.gov (United States)

    Li, Chun-Ta; Lee, Cheng-Chi; Weng, Chi-Yao

    2014-09-01

    Telecare medicine information system (TMIS) is widely used for providing a convenient and efficient communicating platform between patients at home and physicians at medical centers or home health care (HHC) organizations. To ensure patient privacy, in 2013, Hao et al. proposed a chaotic map based authentication scheme with user anonymity for TMIS. Later, Lee showed that Hao et al.'s scheme is in no provision for providing fairness in session key establishment and gave an efficient user authentication and key agreement scheme using smart cards, in which only few hashing and Chebyshev chaotic map operations are required. In addition, Jiang et al. discussed that Hao et al.'s scheme can not resist stolen smart card attack and they further presented an improved scheme which attempts to repair the security pitfalls found in Hao et al.'s scheme. In this paper, we found that both Lee's and Jiang et al.'s authentication schemes have a serious security problem in that a registered user's secret parameters may be intentionally exposed to many non-registered users and this problem causing the service misuse attack. Therefore, we propose a slight modification on Lee's scheme to prevent the shortcomings. Compared with previous schemes, our improved scheme not only inherits the advantages of Lee's and Jiang et al.'s authentication schemes for TMIS but also remedies the serious security weakness of not being able to withstand service misuse attack.

  20. A Dual Key-Based Activation Scheme for Secure LoRaWAN

    Directory of Open Access Journals (Sweden)

    Jaehyu Kim

    2017-01-01

    Full Text Available With the advent of the Internet of Things (IoT era, we are experiencing rapid technological progress. Billions of devices are connected to each other, and our homes, cities, hospitals, and schools are getting smarter and smarter. However, to realize the IoT, several challenging issues such as connecting resource-constrained devices to the Internet must be resolved. Recently introduced Low Power Wide Area Network (LPWAN technologies have been devised to resolve this issue. Among many LPWAN candidates, the Long Range (LoRa is one of the most promising technologies. The Long Range Wide Area Network (LoRaWAN is a communication protocol for LoRa that provides basic security mechanisms. However, some security loopholes exist in LoRaWAN’s key update and session key generation. In this paper, we propose a dual key-based activation scheme for LoRaWAN. It resolves the problem of key updates not being fully supported. In addition, our scheme facilitates each layer in generating its own session key directly, which ensures the independence of all layers. Real-world experimental results compared with the original scheme show that the proposed scheme is totally feasible in terms of delay and battery consumption.

  1. Authenticated Diffie-Hellman Key Agreement Scheme that Protects Client Anonymity and Achieves Half-Forward Secrecy

    Directory of Open Access Journals (Sweden)

    Hung-Yu Chien

    2015-01-01

    Full Text Available Authenticated Diffie-Hellman key agreement (D-H key is the de facto building block for establishing secure session keys in many security systems. Regarding the computations of authenticated D-H key agreement, the operation of modular exponentiation is the most expensive computation, which incurs a heavy loading on those clients where either their computational capacities or their batteries are limited and precious. As client’s privacy is a big concern in several e-commerce applications, it is desirable to extend authenticated D-H key agreement to protect client’s identity privacy. This paper proposes a new problem: the modified elliptic curves computational Diffie-Hellman problem (MECDHP and proves that the MECDHP is as hard as the conventional elliptic curves computational Diffie-Hellman problem (ECDHP. Based on the MECDHP, we propose an authenticated D-H key agreement scheme which greatly improves client computational efficiency and protects client’s anonymity from outsiders. This new scheme is attractive to those applications where the clients need identity protection and lightweight computation.

  2. A Lightweight Authentication and Key Management Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Danyang Qin

    2016-01-01

    Full Text Available Security problem is one of the most popular research fields in wireless sensor networks for both the application requirement and the resource-constrained essence. An effective and lightweight Authentication and Key Management Scheme (AKMS is proposed in this paper to solve the problem of malicious nodes occurring in the process of networking and to offer a high level of security with low cost. For the condition that the mobile sensor nodes need to be authenticated, the keys in AKMS will be dynamically generated and adopted for security protection. Even when the keys are being compromised or captured, the attackers can neither use the previous keys nor misuse the authenticated nodes to cheat. Simulation results show that the proposed scheme provides more efficient security with less energy consumption for wireless sensor networks especially with mobile sensors.

  3. A novel authentication scheme using self-certified public keys for telecare medical information systems.

    Science.gov (United States)

    Guo, Dianli; Wen, Qiaoyan; Li, Wenmin; Zhang, Hua; Jin, Zhengping

    2015-06-01

    Telecare medical information systems (TMIS), with the explosive growth of communication technology and physiological monitoring devices, are applied increasingly to enable and support healthcare delivery services. In order to safeguard patients' privacy and tackle the illegal access, authentication schemes for TMIS have been investigated and designed by many researchers. Many of them are promising for adoption in practice, nevertheless, they still have security flaws. In this paper, we propose a novel remote authentication scheme for TMIS using self-certified public keys, which is formally secure in the ID-mBJM model. Besides, the proposed scheme has better computational efficiency. Compared to the related schemes, our protocol is more practical for telemedicine system.

  4. A new two-code keying scheme for SAC-OCDMA systems enabling bipolar encoding

    Science.gov (United States)

    Al-Khafaji, Hamza M. R.; Ngah, Razali; Aljunid, S. A.; Rahman, T. A.

    2015-03-01

    In this paper, we propose a new two-code keying scheme for enabling bipolar encoding in a high-rate spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) system. The mathematical formulations are derived for the signal-to-noise ratio and bit-error rate (BER) of SAC-OCDMA system based on the suggested scheme using multi-diagonal (MD) code. Performance analyses are assessed considering the effects of phase-induced intensity noise, as well as shot and thermal noises in photodetectors. The numerical results demonstrated that the proposed scheme exhibits an enhanced BER performance compared to the existing unipolar encoding with direct detection technique. Furthermore, the performance improvement afforded by this scheme is verified using simulation experiments.

  5. An Enhanced Secure Identity-Based Certificateless Public Key Authentication Scheme for Vehicular Sensor Networks

    Science.gov (United States)

    Li, Congcong; Zhang, Xi; Wang, Haiping; Li, Dongfeng

    2018-01-01

    Vehicular sensor networks have been widely applied in intelligent traffic systems in recent years. Because of the specificity of vehicular sensor networks, they require an enhanced, secure and efficient authentication scheme. Existing authentication protocols are vulnerable to some problems, such as a high computational overhead with certificate distribution and revocation, strong reliance on tamper-proof devices, limited scalability when building many secure channels, and an inability to detect hardware tampering attacks. In this paper, an improved authentication scheme using certificateless public key cryptography is proposed to address these problems. A security analysis of our scheme shows that our protocol provides an enhanced secure anonymous authentication, which is resilient against major security threats. Furthermore, the proposed scheme reduces the incidence of node compromise and replication attacks. The scheme also provides a malicious-node detection and warning mechanism, which can quickly identify compromised static nodes and immediately alert the administrative department. With performance evaluations, the scheme can obtain better trade-offs between security and efficiency than the well-known available schemes. PMID:29324719

  6. An Enhanced Secure Identity-Based Certificateless Public Key Authentication Scheme for Vehicular Sensor Networks.

    Science.gov (United States)

    Li, Congcong; Zhang, Xi; Wang, Haiping; Li, Dongfeng

    2018-01-11

    Vehicular sensor networks have been widely applied in intelligent traffic systems in recent years. Because of the specificity of vehicular sensor networks, they require an enhanced, secure and efficient authentication scheme. Existing authentication protocols are vulnerable to some problems, such as a high computational overhead with certificate distribution and revocation, strong reliance on tamper-proof devices, limited scalability when building many secure channels, and an inability to detect hardware tampering attacks. In this paper, an improved authentication scheme using certificateless public key cryptography is proposed to address these problems. A security analysis of our scheme shows that our protocol provides an enhanced secure anonymous authentication, which is resilient against major security threats. Furthermore, the proposed scheme reduces the incidence of node compromise and replication attacks. The scheme also provides a malicious-node detection and warning mechanism, which can quickly identify compromised static nodes and immediately alert the administrative department. With performance evaluations, the scheme can obtain better trade-offs between security and efficiency than the well-known available schemes.

  7. Efficient Anonymous Authenticated Key Agreement Scheme for Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Tong Li

    2017-01-01

    Full Text Available Wireless body area networks (WBANs are widely used in telemedicine, which can be utilized for real-time patients monitoring and home health-care. The sensor nodes in WBANs collect the client’s physiological data and transmit it to the medical center. However, the clients’ personal information is sensitive and there are many security threats in the extra-body communication. Therefore, the security and privacy of client’s physiological data need to be ensured. Many authentication protocols for WBANs have been proposed in recent years. However, the existing protocols fail to consider the key update phase. In this paper, we propose an efficient authenticated key agreement scheme for WBANs and add the key update phase to enhance the security of the proposed scheme. In addition, session keys are generated during the registration phase and kept secretly, thus reducing computation cost in the authentication phase. The performance analysis demonstrates that our scheme is more efficient than the currently popular related schemes.

  8. KALwEN+: Practical Key Management Schemes for Gossip-Based Wireless Medical Sensor Networks

    NARCIS (Netherlands)

    Gong, Zheng; Tang, Qiang; Law, Y.W.; Chen, Hongyang; Lai, X.; Yung, M.

    2010-01-01

    The constrained resources of sensors restrict the design of a key management scheme for wireless sensor networks (WSNs). In this work, we first formalize the security model of ALwEN, which is a gossip-based wireless medical sensor network (WMSN) for ambient assisted living. Our security model

  9. VLSI IMPLEMENTATION OF NOVEL ROUND KEYS GENERATION SCHEME FOR CRYPTOGRAPHY APPLICATIONS BY ERROR CONTROL ALGORITHM

    Directory of Open Access Journals (Sweden)

    B. SENTHILKUMAR

    2015-05-01

    Full Text Available A novel implementation of code based cryptography (Cryptocoding technique for multi-layer key distribution scheme is presented. VLSI chip is designed for storing information on generation of round keys. New algorithm is developed for reduced key size with optimal performance. Error Control Algorithm is employed for both generation of round keys and diffusion of non-linearity among them. Two new functions for bit inversion and its reversal are developed for cryptocoding. Probability of retrieving original key from any other round keys is reduced by diffusing nonlinear selective bit inversions on round keys. Randomized selective bit inversions are done on equal length of key bits by Round Constant Feedback Shift Register within the error correction limits of chosen code. Complexity of retrieving the original key from any other round keys is increased by optimal hardware usage. Proposed design is simulated and synthesized using VHDL coding for Spartan3E FPGA and results are shown. Comparative analysis is done between 128 bit Advanced Encryption Standard round keys and proposed round keys for showing security strength of proposed algorithm. This paper concludes that chip based multi-layer key distribution of proposed algorithm is an enhanced solution to the existing threats on cryptography algorithms.

  10. On the Security of a Two-Factor Authentication and Key Agreement Scheme for Telecare Medicine Information Systems.

    Science.gov (United States)

    Arshad, Hamed; Teymoori, Vahid; Nikooghadam, Morteza; Abbassi, Hassan

    2015-08-01

    Telecare medicine information systems (TMISs) aim to deliver appropriate healthcare services in an efficient and secure manner to patients. A secure mechanism for authentication and key agreement is required to provide proper security in these systems. Recently, Bin Muhaya demonstrated some security weaknesses of Zhu's authentication and key agreement scheme and proposed a security enhanced authentication and key agreement scheme for TMISs. However, we show that Bin Muhaya's scheme is vulnerable to off-line password guessing attacks and does not provide perfect forward secrecy. Furthermore, in order to overcome the mentioned weaknesses, we propose a new two-factor anonymous authentication and key agreement scheme using the elliptic curve cryptosystem. Security and performance analyses demonstrate that the proposed scheme not only overcomes the weaknesses of Bin Muhaya's scheme, but also is about 2.73 times faster than Bin Muhaya's scheme.

  11. A New Quantum Key Distribution Scheme Based on Frequency and Time Coding

    International Nuclear Information System (INIS)

    Chang-Hua, Zhu; Chang-Xing, Pei; Dong-Xiao, Quan; Jing-Liang, Gao; Nan, Chen; Yun-Hui, Yi

    2010-01-01

    A new scheme of quantum key distribution (QKD) using frequency and time coding is proposed, in which the security is based on the frequency-time uncertainty relation. In this scheme, the binary information sequence is encoded randomly on either the central frequency or the time delay of the optical pulse at the sender. The central frequency of the single photon pulse is set as ω 1 for bit 0 and set as ω 2 for bit 1 when frequency coding is selected. However, the single photon pulse is not delayed for bit 0 and is delayed in τ for 1 when time coding is selected. At the receiver, either the frequency or the time delay of the pulse is measured randomly, and the final key is obtained after basis comparison, data reconciliation and privacy amplification. With the proposed method, the effect of the noise in the fiber channel and environment on the QKD system can be reduced effectively

  12. Ubi-RKE: A Rhythm Key Based Encryption Scheme for Ubiquitous Devices

    Directory of Open Access Journals (Sweden)

    Jae Dong Lee

    2014-01-01

    Full Text Available As intelligent ubiquitous devices become more popular, security threats targeting them are increasing; security is seen as one of the major challenges of the ubiquitous computing. Now a days, applying ubiquitous computing in number of fields for human safety and convenience was immensely increased in recent years. The popularity of the technology is rising day by day, and hence the security is becoming the main focused point with the advent and rising popularity of the applications. In particular, the number of wireless networks based on ubiquitous devices has increased rapidly; these devices support transmission for many types of data traffic. The convenient portability of ubiquitous devices makes them vulnerable to security threats, such as loss, theft, data modification, and wiretapping. Developers and users should seriously consider employing data encryption to protect data from such vulnerabilities. In this paper, we propose a Rhythm Key based Encryption scheme for ubiquitous devices (Ubi-RKE. The concept of Rhythm Key based Encryption has been applied to numerous real world applications in different domains. It provides key memorability and secure encryption through user touching rhythm on ubiquitous devices. Our proposed scheme is more efficient for users than existing schemes, by providing a strong cipher.

  13. Key factors for the implementation of successful, stand-alone village electrification schemes in Peru

    Science.gov (United States)

    Sanchez-Campos, Teodoro

    The hypothesis of this work is that there are social, financial, technical, managerial institutional and political key factors that may either support or prevent the success of small stand alone energy systems in rural areas. This research work aims at contributing to the identification of such factors and study their relevance to the performance and sustainability of stand alone energy systems in rural areas; to meet its purpose, a wide range of literature was reviewed including rural electrification programmes and projects, research and development projects on access to electricity in rural areas, impact studies and others, and a field research survey was done the Andes and Upper Jungle regions in Peru. Nineteen possible critical factors were identified, thirteen with relevance at the local context (the community or village), and six with relevance at the national (or wider) context. From literature review it was found that the possible local critical factors were relevant only to four categories of factors instead of the six considered initially (i.e. social, financial, technological and managerial): the other two categories, political and institutional were found to be more relevant to the national context, therefore those were included in the group of possible critical factors of wider context. A series of questionnaires were designed to collect field data information, which was later used to analyse and establish the relation of each identified factor with the success of the systems studied. The survey research was implemented in 14 villages, 7 with small diesel sets and 7 with small hydropower schemes, all spread in the Andes and Upper Jungle of Peru, which were carefully selected to be representative of regions with isolated stand alone systems and with different socioeconomic background. Out of the 13 possible critical factors of local context, it was found that only 3 are really critical, the others are important but not critical; one of them (technical

  14. On distributed key distribution centers and unconditionally secure proactive verifiable secret sharing schemes based on general access structure

    NARCIS (Netherlands)

    Nikov, V.S.; Nikova, S.I.; Preneel, B.; Vandewalle, J.; Menezes, A.; Sarkar, P.

    2002-01-01

    A Key Distribution Center of a network is a server enabling private communications within groups of users. A Distributed Key Distribution Center is a set of servers that jointly realizes a Key Distribution Center. In this paper we build a robust Distributed Key Distribution Center Scheme secure

  15. A key heterogeneous structure of fractal networks based on inverse renormalization scheme

    Science.gov (United States)

    Bai, Yanan; Huang, Ning; Sun, Lina

    2018-06-01

    Self-similarity property of complex networks was found by the application of renormalization group theory. Based on this theory, network topologies can be classified into universality classes in the space of configurations. In return, through inverse renormalization scheme, a given primitive structure can grow into a pure fractal network, then adding different types of shortcuts, it exhibits different characteristics of complex networks. However, the effect of primitive structure on networks structural property has received less attention. In this paper, we introduce a degree variance index to measure the dispersion of nodes degree in the primitive structure, and investigate the effect of the primitive structure on network structural property quantified by network efficiency. Numerical simulations and theoretical analysis show a primitive structure is a key heterogeneous structure of generated networks based on inverse renormalization scheme, whether or not adding shortcuts, and the network efficiency is positively correlated with degree variance of the primitive structure.

  16. Implementation of a european directive establishing a negotiable CO2 emissions trading scheme

    International Nuclear Information System (INIS)

    Coussy, P.

    2003-01-01

    Approved on July 22, 2003, European Directive 87/2003/EC establishes a scheme for the trading of greenhouse gas emissions allowances. Before the market comes into effect on January 1, 2005, industrialists will have to account for a new financial asset in planning development strategy: the CO 2 allowance. Each Member State is currently developing a climate plan that includes the allocation of CO 2 emissions allowances to industrial installations. It will not be possible to exceed these allowances without incurring a financial penalty. (author)

  17. Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes.

    Science.gov (United States)

    Guo, Xi; Wang, Min; Wang, Lu; Wang, Yao; Chen, Tingting; Wu, Pan; Chen, Min; Liu, Bin; Feng, Lu

    2018-01-01

    Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes . A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes , providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes , providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen.

  18. An Efficient Key-Policy Attribute-Based Encryption Scheme with Constant Ciphertext Length

    Directory of Open Access Journals (Sweden)

    Changji Wang

    2013-01-01

    Full Text Available There is an acceleration of adoption of cloud computing among enterprises. However, moving the infrastructure and sensitive data from trusted domain of the data owner to public cloud will pose severe security and privacy risks. Attribute-based encryption (ABE is a new cryptographic primitive which provides a promising tool for addressing the problem of secure and fine-grained data sharing and decentralized access control. Key-policy attribute-based encryption (KP-ABE is an important type of ABE, which enables senders to encrypt messages under a set of attributes and private keys are associated with access structures that specify which ciphertexts the key holder will be allowed to decrypt. In most existing KP-ABE scheme, the ciphertext size grows linearly with the number of attributes embedded in ciphertext. In this paper, we propose a new KP-ABE construction with constant ciphertext size. In our construction, the access policy can be expressed as any monotone access structure. Meanwhile, the ciphertext size is independent of the number of ciphertext attributes, and the number of bilinear pairing evaluations is reduced to a constant. We prove that our scheme is semantically secure in the selective-set model based on the general Diffie-Hellman exponent assumption.

  19. A Cross-Layer Key Management Scheme for MIPv6 Fast Handover over IEEE 802.11 Wireless LAN

    Directory of Open Access Journals (Sweden)

    Chang-Seop Park

    2015-01-01

    Full Text Available A new key management and security scheme is proposed to integrate Layer Two (L2 and Layer Three (L3 keys for secure and fast Mobile IPv6 handover over IEEE 802.11 Wireless Local Area Network (WLAN. Unlike the original IEEE 802.11-based Mobile IPv6 Fast Handover (FMIPv6 that requires time-consuming IEEE 802.1x-based Extensible Authentication Protocol (EAP authentication on each L3 handover, the newly proposed key management and security scheme requires only one 802.1x-EAP regardless of how many L3 handovers occur. Therefore, the proposed scheme reduces the handover latency that results from a lengthy 802.1x-based EAP. The proposed key management and security scheme is extensively analyzed in terms of security and performance, and the proposed security scheme is shown to be more secure than those that were previously proposed.

  20. Efficient and Security Enhanced Anonymous Authentication with Key Agreement Scheme in Wireless Sensor Networks.

    Science.gov (United States)

    Jung, Jaewook; Moon, Jongho; Lee, Donghoon; Won, Dongho

    2017-03-21

    At present, users can utilize an authenticated key agreement protocol in a Wireless Sensor Network (WSN) to securely obtain desired information, and numerous studies have investigated authentication techniques to construct efficient, robust WSNs. Chang et al. recently presented an authenticated key agreement mechanism for WSNs and claimed that their authentication mechanism can both prevent various types of attacks, as well as preserve security properties. However, we have discovered that Chang et al's method possesses some security weaknesses. First, their mechanism cannot guarantee protection against a password guessing attack, user impersonation attack or session key compromise. Second, the mechanism results in a high load on the gateway node because the gateway node should always maintain the verifier tables. Third, there is no session key verification process in the authentication phase. To this end, we describe how the previously-stated weaknesses occur and propose a security-enhanced version for WSNs. We present a detailed analysis of the security and performance of our authenticated key agreement mechanism, which not only enhances security compared to that of related schemes, but also takes efficiency into consideration.

  1. An efficient chaotic maps-based authentication and key agreement scheme using smartcards for telecare medicine information systems.

    Science.gov (United States)

    Lee, Tian-Fu

    2013-12-01

    A smartcard-based authentication and key agreement scheme for telecare medicine information systems enables patients, doctors, nurses and health visitors to use smartcards for secure login to medical information systems. Authorized users can then efficiently access remote services provided by the medicine information systems through public networks. Guo and Chang recently improved the efficiency of a smartcard authentication and key agreement scheme by using chaotic maps. Later, Hao et al. reported that the scheme developed by Guo and Chang had two weaknesses: inability to provide anonymity and inefficient double secrets. Therefore, Hao et al. proposed an authentication scheme for telecare medicine information systems that solved these weaknesses and improved performance. However, a limitation in both schemes is their violation of the contributory property of key agreements. This investigation discusses these weaknesses and proposes a new smartcard-based authentication and key agreement scheme that uses chaotic maps for telecare medicine information systems. Compared to conventional schemes, the proposed scheme provides fewer weaknesses, better security, and more efficiency.

  2. European Society of Gastrointestinal Endoscopy - Establishing the key unanswered research questions within gastrointestinal endoscopy

    DEFF Research Database (Denmark)

    Rees, Colin J; Ngu, Wee Sing; Regula, Jaroslaw

    2016-01-01

    Background and study aim: Gastrointestinal endoscopy is a rapidly evolving research field. The European Society of Gastrointestinal Endoscopy (ESGE) plays a key role in shaping opinion and endoscopy activity throughout Europe and further afield. Establishing key unanswered questions within the fi...

  3. Establishing an external quality assessment scheme for point-of-care international normalized ratio in Thailand.

    Science.gov (United States)

    Tientadakul, P; Chuntarut, A

    2015-08-01

    Effective warfarin therapy management has gained national interest, resulting in the increased use of point-of-care testing (POCT) for international normalized ratio (INR). External quality assessment (EQA) is recommended to ensure quality of the testing. CoaguChek XS and CoaguChek XS Plus are the only commonly available POCT INR monitors in Thailand. Therefore, Thailand NEQAS for Blood Coagulation initiated the scheme for POCT INR in 2013, including only hospitals using these devices. Questionnaires were sent to the hospitals, enquiring about their interest in EQA participation. Two surveys were distributed; each included five certified European Concerted Action on Anticoagulation (ECAA) INR plasma sets. Unsatisfactory performance was indicated by a 15% deviation from the certified mean INR value. There were 156 hospitals using the devices. Thirty-five hospitals responded to the questionnaires. Medical personnel undertaking POCT INR were limited to laboratory staff in 29 (83%) of these centers, and 31 hospitals actually participated. The medians of results from participants were the same or nearly the same as the certified mean INRs. External quality assessment for POCT INR in Thailand is feasible using the ECAA plasmas as control materials. The results therefore appear encouraging to other developing countries to establish their own EQA schemes. © 2014 John Wiley & Sons Ltd.

  4. Establishing the long-term fuel management scheme using point reactivity model

    International Nuclear Information System (INIS)

    Park, Yong-Soo; Kim, Jae-Hak; Lee, Young-Ouk; Song, Jae-Woong; Zee, Sung-Kyun

    1994-01-01

    A new approach to establish the long-term fuel management scheme is presented in this paper. The point reactivity model is used to predict the core average reactivity. An attempt to calculate batchwise power fraction is introduced through the two-dimensional nodal power algorithm based on the modified one-group diffusion equation and the number of fuel assemblies on the core periphery. Suggested is an empirical formula to estimate the radial leakage reactivity with ripe core design experience reflected. This approach predicts the cycle lengths and the discharge burnups of individual fuel batches up to an equilibrium core when the proper input data such as batch enrichment, batch size, type and content of burnable poison and reloading strategies are given. Eight benchmark calculations demonstrate that the new approach used in this study is reasonably accurate and highly efficient for the purpose of scoping calculation when compared with design code predictions. (author)

  5. An adaptive secret key-directed cryptographic scheme for secure transmission in wireless sensor networks

    International Nuclear Information System (INIS)

    Muhammad, K.; Jan, Z.; Khan, Z

    2015-01-01

    Wireless Sensor Networks (WSNs) are memory and bandwidth limited networks whose main goals are to maximize the network lifetime and minimize the energy consumption and transmission cost. To achieve these goals, different techniques of compression and clustering have been used. However, security is an open and major issue in WSNs for which different approaches are used, both in centralized and distributed WSNs' environments. This paper presents an adaptive cryptographic scheme for secure transmission of various sensitive parameters, sensed by wireless sensors to the fusion center for further processing in WSNs such as military networks. The proposed method encrypts the sensitive captured data of sensor nodes using various encryption procedures (bitxor operation, bits shuffling, and secret key based encryption) and then sends it to the fusion center. At the fusion center, the received encrypted data is decrypted for taking further necessary actions. The experimental results with complexity analysis, validate the effectiveness and feasibility of the proposed method in terms of security in WSNs. (author)

  6. Digital chaos-masked optical encryption scheme enhanced by two-dimensional key space

    Science.gov (United States)

    Liu, Ling; Xiao, Shilin; Zhang, Lu; Bi, Meihua; Zhang, Yunhao; Fang, Jiafei; Hu, Weisheng

    2017-09-01

    A digital chaos-masked optical encryption scheme is proposed and demonstrated. The transmitted signal is completely masked by interference chaotic noise in both bandwidth and amplitude with analog method via dual-drive Mach-Zehnder modulator (DDMZM), making the encrypted signal analog, noise-like and unrecoverable by post-processing techniques. The decryption process requires precise matches of both the amplitude and phase between the cancellation and interference chaotic noises, which provide a large two-dimensional key space with the help of optical interference cancellation technology. For 10-Gb/s 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal over the maximum transmission distance of 80 km without dispersion compensation or inline amplifier, the tolerable mismatch ranges of amplitude and phase/delay at the forward error correction (FEC) threshold of 3.8×10-3 are 0.44 dB and 0.08 ns respectively.

  7. An Anonymous User Authentication and Key Agreement Scheme Based on a Symmetric Cryptosystem in Wireless Sensor Networks.

    Science.gov (United States)

    Jung, Jaewook; Kim, Jiye; Choi, Younsung; Won, Dongho

    2016-08-16

    In wireless sensor networks (WSNs), a registered user can login to the network and use a user authentication protocol to access data collected from the sensor nodes. Since WSNs are typically deployed in unattended environments and sensor nodes have limited resources, many researchers have made considerable efforts to design a secure and efficient user authentication process. Recently, Chen et al. proposed a secure user authentication scheme using symmetric key techniques for WSNs. They claim that their scheme assures high efficiency and security against different types of attacks. After careful analysis, however, we find that Chen et al.'s scheme is still vulnerable to smart card loss attack and is susceptible to denial of service attack, since it is invalid for verification to simply compare an entered ID and a stored ID in smart card. In addition, we also observe that their scheme cannot preserve user anonymity. Furthermore, their scheme cannot quickly detect an incorrect password during login phase, and this flaw wastes both communication and computational overheads. In this paper, we describe how these attacks work, and propose an enhanced anonymous user authentication and key agreement scheme based on a symmetric cryptosystem in WSNs to address all of the aforementioned vulnerabilities in Chen et al.'s scheme. Our analysis shows that the proposed scheme improves the level of security, and is also more efficient relative to other related schemes.

  8. An Anonymous User Authentication and Key Agreement Scheme Based on a Symmetric Cryptosystem in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jaewook Jung

    2016-08-01

    Full Text Available In wireless sensor networks (WSNs, a registered user can login to the network and use a user authentication protocol to access data collected from the sensor nodes. Since WSNs are typically deployed in unattended environments and sensor nodes have limited resources, many researchers have made considerable efforts to design a secure and efficient user authentication process. Recently, Chen et al. proposed a secure user authentication scheme using symmetric key techniques for WSNs. They claim that their scheme assures high efficiency and security against different types of attacks. After careful analysis, however, we find that Chen et al.’s scheme is still vulnerable to smart card loss attack and is susceptible to denial of service attack, since it is invalid for verification to simply compare an entered ID and a stored ID in smart card. In addition, we also observe that their scheme cannot preserve user anonymity. Furthermore, their scheme cannot quickly detect an incorrect password during login phase, and this flaw wastes both communication and computational overheads. In this paper, we describe how these attacks work, and propose an enhanced anonymous user authentication and key agreement scheme based on a symmetric cryptosystem in WSNs to address all of the aforementioned vulnerabilities in Chen et al.’s scheme. Our analysis shows that the proposed scheme improves the level of security, and is also more efficient relative to other related schemes.

  9. Cryptanalysis and improvement of a biometrics-based authentication and key agreement scheme for multi-server environments.

    Science.gov (United States)

    Yang, Li; Zheng, Zhiming

    2018-01-01

    According to advancements in the wireless technologies, study of biometrics-based multi-server authenticated key agreement schemes has acquired a lot of momentum. Recently, Wang et al. presented a three-factor authentication protocol with key agreement and claimed that their scheme was resistant to several prominent attacks. Unfortunately, this paper indicates that their protocol is still vulnerable to the user impersonation attack, privileged insider attack and server spoofing attack. Furthermore, their protocol cannot provide the perfect forward secrecy. As a remedy of these aforementioned problems, we propose a biometrics-based authentication and key agreement scheme for multi-server environments. Compared with various related schemes, our protocol achieves the stronger security and provides more functionality properties. Besides, the proposed protocol shows the satisfactory performances in respect of storage requirement, communication overhead and computational cost. Thus, our protocol is suitable for expert systems and other multi-server architectures. Consequently, the proposed protocol is more appropriate in the distributed networks.

  10. A Key Pre-Distribution Scheme Based on µ-PBIBD for Enhancing Resilience in Wireless Sensor Networks.

    Science.gov (United States)

    Yuan, Qi; Ma, Chunguang; Yu, Haitao; Bian, Xuefen

    2018-05-12

    Many key pre-distribution (KPD) schemes based on combinatorial design were proposed for secure communication of wireless sensor networks (WSNs). Due to complexity of constructing the combinatorial design, it is infeasible to generate key rings using the corresponding combinatorial design in large scale deployment of WSNs. In this paper, we present a definition of new combinatorial design, termed “µ-partially balanced incomplete block design (µ-PBIBD)”, which is a refinement of partially balanced incomplete block design (PBIBD), and then describe a 2-D construction of µ-PBIBD which is mapped to KPD in WSNs. Our approach is of simple construction which provides a strong key connectivity and a poor network resilience. To improve the network resilience of KPD based on 2-D µ-PBIBD, we propose a KPD scheme based on 3-D Ex-µ-PBIBD which is a construction of µ-PBIBD from 2-D space to 3-D space. Ex-µ-PBIBD KPD scheme improves network scalability and resilience while has better key connectivity. Theoretical analysis and comparison with the related schemes show that key pre-distribution scheme based on Ex-µ-PBIBD provides high network resilience and better key scalability, while it achieves a trade-off between network resilience and network connectivity.

  11. Design of a Secure Authentication and Key Agreement Scheme Preserving User Privacy Usable in Telecare Medicine Information Systems.

    Science.gov (United States)

    Arshad, Hamed; Rasoolzadegan, Abbas

    2016-11-01

    Authentication and key agreement schemes play a very important role in enhancing the level of security of telecare medicine information systems (TMISs). Recently, Amin and Biswas demonstrated that the authentication scheme proposed by Giri et al. is vulnerable to off-line password guessing attacks and privileged insider attacks and also does not provide user anonymity. They also proposed an improved authentication scheme, claiming that it resists various security attacks. However, this paper demonstrates that Amin and Biswas's scheme is defenseless against off-line password guessing attacks and replay attacks and also does not provide perfect forward secrecy. This paper also shows that Giri et al.'s scheme not only suffers from the weaknesses pointed out by Amin and Biswas, but it also is vulnerable to replay attacks and does not provide perfect forward secrecy. Moreover, this paper proposes a novel authentication and key agreement scheme to overcome the mentioned weaknesses. Security and performance analyses show that the proposed scheme not only overcomes the mentioned security weaknesses, but also is more efficient than the previous schemes.

  12. Secure anonymity-preserving password-based user authentication and session key agreement scheme for telecare medicine information systems.

    Science.gov (United States)

    Sutrala, Anil Kumar; Das, Ashok Kumar; Odelu, Vanga; Wazid, Mohammad; Kumari, Saru

    2016-10-01

    Information and communication and technology (ICT) has changed the entire paradigm of society. ICT facilitates people to use medical services over the Internet, thereby reducing the travel cost, hospitalization cost and time to a greater extent. Recent advancements in Telecare Medicine Information System (TMIS) facilitate users/patients to access medical services over the Internet by gaining health monitoring facilities at home. Amin and Biswas recently proposed a RSA-based user authentication and session key agreement protocol usable for TMIS, which is an improvement over Giri et al.'s RSA-based user authentication scheme for TMIS. In this paper, we show that though Amin-Biswas's scheme considerably improves the security drawbacks of Giri et al.'s scheme, their scheme has security weaknesses as it suffers from attacks such as privileged insider attack, user impersonation attack, replay attack and also offline password guessing attack. A new RSA-based user authentication scheme for TMIS is proposed, which overcomes the security pitfalls of Amin-Biswas's scheme and also preserves user anonymity property. The careful formal security analysis using the two widely accepted Burrows-Abadi-Needham (BAN) logic and the random oracle models is done. Moreover, the informal security analysis of the scheme is also done. These security analyses show the robustness of our new scheme against the various known attacks as well as attacks found in Amin-Biswas's scheme. The simulation of the proposed scheme using the widely accepted Automated Validation of Internet Security Protocols and Applications (AVISPA) tool is also done. We present a new user authentication and session key agreement scheme for TMIS, which fixes the mentioned security pitfalls found in Amin-Biswas's scheme, and we also show that the proposed scheme provides better security than other existing schemes through the rigorous security analysis and verification tool. Furthermore, we present the formal security

  13. A secure effective dynamic group password-based authenticated key agreement scheme for the integrated EPR information system

    Directory of Open Access Journals (Sweden)

    Vanga Odelu

    2016-01-01

    Full Text Available With the rapid growth of the Internet, a lot of electronic patient records (EPRs have been developed for e-medicine systems. The security and privacy issues of EPRs are important for the patients in order to understand how the hospitals control the use of their personal information, such as name, address, e-mail, medical records, etc. of a particular patient. Recently, Lee et al. proposed a simple group password-based authenticated key agreement protocol for the integrated EPR information system (SGPAKE. However, in this paper, we show that Lee et al.’s protocol is vulnerable to the off-line weak password guessing attack and as a result, their scheme does not provide users’ privacy. To withstand this security weakness found in Lee et al.’s scheme, we aim to propose an effective dynamic group password-based authenticated key exchange scheme for the integrated EPR information system, which retains the original merits of Lee et al.’s scheme. Through the informal and formal security analysis, we show that our scheme provides users’ privacy, perfect forward security and known-key security, and also protects online and offline password guessing attacks. Furthermore, our scheme efficiently supports the dynamic group password-based authenticated key agreement for the integrated EPR information system. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool and show that our scheme is secure against passive and active attacks.

  14. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards.

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user's management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.'s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.'s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.'s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties.

  15. An Improvement of Robust Biometrics-Based Authentication and Key Agreement Scheme for Multi-Server Environments Using Smart Cards

    Science.gov (United States)

    Moon, Jongho; Choi, Younsung; Jung, Jaewook; Won, Dongho

    2015-01-01

    In multi-server environments, user authentication is a very important issue because it provides the authorization that enables users to access their data and services; furthermore, remote user authentication schemes for multi-server environments have solved the problem that has arisen from user’s management of different identities and passwords. For this reason, numerous user authentication schemes that are designed for multi-server environments have been proposed over recent years. In 2015, Lu et al. improved upon Mishra et al.’s scheme, claiming that their remote user authentication scheme is more secure and practical; however, we found that Lu et al.’s scheme is still insecure and incorrect. In this paper, we demonstrate that Lu et al.’s scheme is vulnerable to outsider attack and user impersonation attack, and we propose a new biometrics-based scheme for authentication and key agreement that can be used in multi-server environments; then, we show that our proposed scheme is more secure and supports the required security properties. PMID:26709702

  16. A Secure and Robust User Authenticated Key Agreement Scheme for Hierarchical Multi-medical Server Environment in TMIS.

    Science.gov (United States)

    Das, Ashok Kumar; Odelu, Vanga; Goswami, Adrijit

    2015-09-01

    The telecare medicine information system (TMIS) helps the patients to gain the health monitoring facility at home and access medical services over the Internet of mobile networks. Recently, Amin and Biswas presented a smart card based user authentication and key agreement security protocol usable for TMIS system using the cryptographic one-way hash function and biohashing function, and claimed that their scheme is secure against all possible attacks. Though their scheme is efficient due to usage of one-way hash function, we show that their scheme has several security pitfalls and design flaws, such as (1) it fails to protect privileged-insider attack, (2) it fails to protect strong replay attack, (3) it fails to protect strong man-in-the-middle attack, (4) it has design flaw in user registration phase, (5) it has design flaw in login phase, (6) it has design flaw in password change phase, (7) it lacks of supporting biometric update phase, and (8) it has flaws in formal security analysis. In order to withstand these security pitfalls and design flaws, we aim to propose a secure and robust user authenticated key agreement scheme for the hierarchical multi-server environment suitable in TMIS using the cryptographic one-way hash function and fuzzy extractor. Through the rigorous security analysis including the formal security analysis using the widely-accepted Burrows-Abadi-Needham (BAN) logic, the formal security analysis under the random oracle model and the informal security analysis, we show that our scheme is secure against possible known attacks. Furthermore, we simulate our scheme using the most-widely accepted and used Automated Validation of Internet Security Protocols and Applications (AVISPA) tool. The simulation results show that our scheme is also secure. Our scheme is more efficient in computation and communication as compared to Amin-Biswas's scheme and other related schemes. In addition, our scheme supports extra functionality features as compared to

  17. An Advanced Temporal Credential-Based Security Scheme with Mutual Authentication and Key Agreement for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Chun-Ta Li

    2013-07-01

    Full Text Available Wireless sensor networks (WSNs can be quickly and randomly deployed in any harsh and unattended environment and only authorized users are allowed to access reliable sensor nodes in WSNs with the aid of gateways (GWNs. Secure authentication models among the users, the sensor nodes and GWN are important research issues for ensuring communication security and data privacy in WSNs. In 2013, Xue et al. proposed a temporal-credential-based mutual authentication and key agreement scheme for WSNs. However, in this paper, we point out that Xue et al.’s scheme cannot resist stolen-verifier, insider, off-line password guessing, smart card lost problem and many logged-in users’ attacks and these security weaknesses make the scheme inapplicable to practical WSN applications. To tackle these problems, we suggest a simple countermeasure to prevent proposed attacks while the other merits of Xue et al.’s authentication scheme are left unchanged.

  18. An advanced temporal credential-based security scheme with mutual authentication and key agreement for wireless sensor networks.

    Science.gov (United States)

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi

    2013-07-24

    Wireless sensor networks (WSNs) can be quickly and randomly deployed in any harsh and unattended environment and only authorized users are allowed to access reliable sensor nodes in WSNs with the aid of gateways (GWNs). Secure authentication models among the users, the sensor nodes and GWN are important research issues for ensuring communication security and data privacy in WSNs. In 2013, Xue et al. proposed a temporal-credential-based mutual authentication and key agreement scheme for WSNs. However, in this paper, we point out that Xue et al.'s scheme cannot resist stolen-verifier, insider, off-line password guessing, smart card lost problem and many logged-in users' attacks and these security weaknesses make the scheme inapplicable to practical WSN applications. To tackle these problems, we suggest a simple countermeasure to prevent proposed attacks while the other merits of Xue et al.'s authentication scheme are left unchanged.

  19. A Secure Key Establishment Protocol for ZigBee Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    2009-01-01

    ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4’s physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist....... In particular we show that the End-to-End Application Key Establishment Protocol is flawed and we propose a secure protocol instead. We do so by using formal verification techniques based on static program analysis and process algebras. We present a way of using formal methods in wireless network security......, and propose a secure key establishment protocol for ZigBee networks....

  20. Cryptanalysis and improvement of a biometrics-based authentication and key agreement scheme for multi-server environments

    Science.gov (United States)

    Zheng, Zhiming

    2018-01-01

    According to advancements in the wireless technologies, study of biometrics-based multi-server authenticated key agreement schemes has acquired a lot of momentum. Recently, Wang et al. presented a three-factor authentication protocol with key agreement and claimed that their scheme was resistant to several prominent attacks. Unfortunately, this paper indicates that their protocol is still vulnerable to the user impersonation attack, privileged insider attack and server spoofing attack. Furthermore, their protocol cannot provide the perfect forward secrecy. As a remedy of these aforementioned problems, we propose a biometrics-based authentication and key agreement scheme for multi-server environments. Compared with various related schemes, our protocol achieves the stronger security and provides more functionality properties. Besides, the proposed protocol shows the satisfactory performances in respect of storage requirement, communication overhead and computational cost. Thus, our protocol is suitable for expert systems and other multi-server architectures. Consequently, the proposed protocol is more appropriate in the distributed networks. PMID:29534085

  1. A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting.

    Science.gov (United States)

    Lin, Tsung-Hung; Tsung, Chen-Kun; Lee, Tian-Fu; Wang, Zeng-Bo

    2017-12-03

    The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA). PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE) proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie-Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions.

  2. A Round-Efficient Authenticated Key Agreement Scheme Based on Extended Chaotic Maps for Group Cloud Meeting

    Directory of Open Access Journals (Sweden)

    Tsung-Hung Lin

    2017-12-01

    Full Text Available The security is a critical issue for business purposes. For example, the cloud meeting must consider strong security to maintain the communication privacy. Considering the scenario with cloud meeting, we apply extended chaotic map to present passwordless group authentication key agreement, termed as Passwordless Group Authentication Key Agreement (PL-GAKA. PL-GAKA improves the computation efficiency for the simple group password-based authenticated key agreement (SGPAKE proposed by Lee et al. in terms of computing the session key. Since the extended chaotic map has equivalent security level to the Diffie–Hellman key exchange scheme applied by SGPAKE, the security of PL-GAKA is not sacrificed when improving the computation efficiency. Moreover, PL-GAKA is a passwordless scheme, so the password maintenance is not necessary. Short-term authentication is considered, hence the communication security is stronger than other protocols by dynamically generating session key in each cloud meeting. In our analysis, we first prove that each meeting member can get the correct information during the meeting. We analyze common security issues for the proposed PL-GAKA in terms of session key security, mutual authentication, perfect forward security, and data integrity. Moreover, we also demonstrate that communicating in PL-GAKA is secure when suffering replay attacks, impersonation attacks, privileged insider attacks, and stolen-verifier attacks. Eventually, an overall comparison is given to show the performance between PL-GAKA, SGPAKE and related solutions.

  3. Biometrics based key management of double random phase encoding scheme using error control codes

    Science.gov (United States)

    Saini, Nirmala; Sinha, Aloka

    2013-08-01

    In this paper, an optical security system has been proposed in which key of the double random phase encoding technique is linked to the biometrics of the user to make it user specific. The error in recognition due to the biometric variation is corrected by encoding the key using the BCH code. A user specific shuffling key is used to increase the separation between genuine and impostor Hamming distance distribution. This shuffling key is then further secured using the RSA public key encryption to enhance the security of the system. XOR operation is performed between the encoded key and the feature vector obtained from the biometrics. The RSA encoded shuffling key and the data obtained from the XOR operation are stored into a token. The main advantage of the present technique is that the key retrieval is possible only in the simultaneous presence of the token and the biometrics of the user which not only authenticates the presence of the original input but also secures the key of the system. Computational experiments showed the effectiveness of the proposed technique for key retrieval in the decryption process by using the live biometrics of the user.

  4. A Robust SRAM-PUF Key Generation Scheme Based on Polar Codes

    OpenAIRE

    Chen, Bin; Ignatenko, Tanya; Willems, Frans M. J.; Maes, Roel; van der Sluis, Erik; Selimis, Georgios

    2017-01-01

    Physical unclonable functions (PUFs) are relatively new security primitives used for device authentication and device-specific secret key generation. In this paper we focus on SRAM-PUFs. The SRAM-PUFs enjoy uniqueness and randomness properties stemming from the intrinsic randomness of SRAM memory cells, which is a result of manufacturing variations. This randomness can be translated into the cryptographic keys thus avoiding the need to store and manage the device cryptographic keys. Therefore...

  5. Autonomy and Financial Sources, Key Factors in the Performance of Health Insurance Scheme: Case of Albania

    Directory of Open Access Journals (Sweden)

    Enkelejda Avdi

    2013-12-01

    Full Text Available Autonomy of public health insurance scheme comprises political, financial, organizational, normative and contractual aspects. The paper analyses the role and position of a health insurance scheme (HIS within the overall healthcare system in Albania, the relationship to all other institutions, stakeholders and actors. By analyesing published literature and collected data through secondary sources, the paper focuses on financial autonomy, which refers first of all to a certain level of budgetary independence regarding source generation and spending on health services. For assuring effective and efficient performance of the single payer for health care services in Albania, need effective changes in the legislation do take into account the various levels of autonomy mentioned above.

  6. Identity Establishment and Capability Based Access Control (IECAC) Scheme for Internet of Things

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Anggorojati, Bayu; Prasad, Neeli R.

    2012-01-01

    Internet of Things (IoT) become discretionary part of everyday life and could befall a threat if security is not considered before deployment. Authentication and access control in IoT is equally important to establish secure communication between devices. To protect IoT from man in middle, replay...... and denial of service attacks, the concept of capability for access control is introduced. This paper presents Identity establishment and capability based access control (IECAC) protocol using ECC (Elliptical Curve Cryptography) for IoT along with protocol evaluation, which protect against the aforementioned...

  7. 77 FR 23425 - Revisions of Boundaries, Regulations and Zoning Scheme for Florida Keys National Marine Sanctuary...

    Science.gov (United States)

    2012-04-19

    .... Increase abundance and condition of selected key species including corals, queen conch, long spined sea..., Rooms 165 C and D, 2295 Victoria Ave., Fort Myers, FL 33901. Consultation Under National Historic...

  8. A key distribution scheme using elliptic curve cryptography in wireless sensor networks

    CSIR Research Space (South Africa)

    Louw, J

    2016-12-01

    Full Text Available Wireless sensor networks (WSNs) have become increasingly popular in many applications across a broad range of fields. Securing WSNs poses unique challenges mainly due to their resource constraints. Traditional public key cryptography (PKC...

  9. What are key determinants of hospital admissions, readmission rate and day case rate within the South African medical schemes population?

    Directory of Open Access Journals (Sweden)

    Nondumiso Gugu Khumalo

    2012-06-01

    Full Text Available  BACKGROUND: In South Africa, private hospitals absorb a high proportion of the total health expenditure on private health care. Between 2008-2010 private hospital expenditure which includes ward fees, theatre fees, consumables, medicines and per diem arrangements consumed between 40.5% and 40.9% of the total benefits paid by medical schemes from the risk pool, whilst in-hospital managed care fees ranged between 1.8% and 2.8% for the equivalent years.OBJECTIVE: The aim of this paper is to highlight key factors contributing to utilisation of hospital services within the medical schemes population and to recommend “appropriate” and cost effective strategies on hospital utilisation management.METHODS: A cross sectional survey informed by retrospective analysis of quantitative data was used. Researchers also triangulated quantitative data with systematic review of literature.RESULTS: The results show that demographic indicators such as age profile, dependency ratio, pensioner ratio and prevalence of chronic conditions are not the only key factors influencing hospital admissions, but rather the effectiveness of each medical scheme in containing hospital admissions is also influenced by available technical capacity on utilisation review and audit as well as the managed care methodology including the philosophy underpinning benefit option design.CONCLUSION: This study highlights the importance of “value based” managed care programs linked to benefit option design in health care utilisation management. The choice of one managed care program over the other often leads to tradeoffs whereby unintended consequences emanate. Medical schemes are therefore encouraged to continuously review their managed care programs to ensure value for money as well as better access and health outcomes.http://dx.doi.org/10.7175/fe.v13i2.207

  10. An Anonymous Mutual Authenticated Key Agreement Scheme for Wearable Sensors in Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Chien-Ming Chen

    2018-07-01

    Full Text Available The advancement of Wireless Body Area Networks (WBAN have led to significant progress in medical and health care systems. However, such networks still suffer from major security and privacy threats, especially for the data collected in medical or health care applications. Lack of security and existence of anonymous communication in WBAN brings about the operation failure of these networks. Recently, Li et al. proposed a lightweight protocol for wearable sensors in wireless body area networks. In their paper, the authors claimed that the protocol may provide anonymous mutual authentication and resist against various types of attacks. This study shows that such a protocol is still vulnerable to three types of attacks, i.e., the offline identity guessing attack, the sensor node impersonation attack and the hub node spoofing attack. We then present a secure scheme that addresses these problems, and retains similar efficiency in wireless sensors nodes and mobile phones.

  11. Independent attacks in imperfect settings: A case for a two-way quantum key distribution scheme

    International Nuclear Information System (INIS)

    Shaari, J.S.; Bahari, Iskandar

    2010-01-01

    We review the study on a two-way quantum key distribution protocol given imperfect settings through a simple analysis of a toy model and show that it can outperform a BB84 setup. We provide the sufficient condition for this as a ratio of optimal intensities for the protocols.

  12. A robust SRAM-PUF key generation scheme based on polar codes

    NARCIS (Netherlands)

    Chen, Bin; Ignatenko, Tanya; Willems, Frans M.J.; Maes, Roel; van der Sluis, Erik; Selimis, Georgios

    2017-01-01

    Physical unclonable functions (PUFs) are relatively new security primitives used for device authentication and device-specific secret key generation. In this paper we focus on SRAM- PUFs. The SRAM-PUFs enjoy uniqueness and randomness properties stemming from the intrinsic randomness of SRAM memory

  13. Establishment on the classification scheme for the Evaluation System of the Decommissioning Information and Data

    International Nuclear Information System (INIS)

    Park, S. K.; Ji, Y. H.; Chung, U. S.

    2010-01-01

    According to the requirement, the items for the evaluation system were distinguished with the understanding of the code and it's value, the relation of the technology and it's problems, the relation with the systematical structure of the DECOMMIS-I and its' advantages and disadvantages. The detailed data model (the connection with entities) was structured as of the Information and data on the evaluation items. The ERD(Entity Relationship Diagram) on the characterization was set up. The conceptual modeling (the prototyping) which be on the base of these all result was established

  14. An Energy-Efficient Secure Routing and Key Management Scheme for Mobile Sinks in Wireless Sensor Networks Using Deployment Knowledge

    Directory of Open Access Journals (Sweden)

    Le Xuan Hung

    2008-12-01

    Full Text Available For many sensor network applications such as military or homeland security, it is essential for users (sinks to access the sensor network while they are moving. Sink mobility brings new challenges to secure routing in large-scale sensor networks. Previous studies on sink mobility have mainly focused on efficiency and effectiveness of data dissemination without security consideration. Also, studies and experiences have shown that considering security during design time is the best way to provide security for sensor network routing. This paper presents an energy-efficient secure routing and key management for mobile sinks in sensor networks, called SCODEplus. It is a significant extension of our previous study in five aspects: (1 Key management scheme and routing protocol are considered during design time to increase security and efficiency; (2 The network topology is organized in a hexagonal plane which supports more efficiency than previous square-grid topology; (3 The key management scheme can eliminate the impacts of node compromise attacks on links between non-compromised nodes; (4 Sensor node deployment is based on Gaussian distribution which is more realistic than uniform distribution; (5 No GPS or like is required to provide sensor node location information. Our security analysis demonstrates that the proposed scheme can defend against common attacks in sensor networks including node compromise attacks, replay attacks, selective forwarding attacks, sinkhole and wormhole, Sybil attacks, HELLO flood attacks. Both mathematical and simulation-based performance evaluation show that the SCODEplus significantly reduces the communication overhead, energy consumption, packet delivery latency while it always delivers more than 97 percent of packets successfully.

  15. Applicability of DUKPT Key Management Scheme to Cloud Wallet and other Mobile Payments

    OpenAIRE

    Saha, Amal; Sanyal, Sugata

    2014-01-01

    After discussing the concept of DUKPT based symmetric encryption key management (e.g., for 3DES) and definition of cloud or remote wallet, the paper analyses applicability of DUKPT to different use cases like mobile banking, NFC payment using EMV contactless card and mobile based EMV card emulation, web browser based transaction and cloud or remote wallet. Cloud wallet is an emerging payment method and is gaining momentum very fast. Anticipating that the wallet product managers and security s...

  16. A Scenario-Based Protocol Checker for Public-Key Authentication Scheme

    Science.gov (United States)

    Saito, Takamichi

    Security protocol provides communication security for the internet. One of the important features of it is authentication with key exchange. Its correctness is a requirement of the whole of the communication security. In this paper, we introduce three attack models realized as their attack scenarios, and provide an authentication-protocol checker for applying three attack-scenarios based on the models. We also utilize it to check two popular security protocols: Secure SHell (SSH) and Secure Socket Layer/Transport Layer Security (SSL/TLS).

  17. An improved and effective secure password-based authentication and key agreement scheme using smart cards for the telecare medicine information system.

    Science.gov (United States)

    Das, Ashok Kumar; Bruhadeshwar, Bezawada

    2013-10-01

    Recently Lee and Liu proposed an efficient password based authentication and key agreement scheme using smart card for the telecare medicine information system [J. Med. Syst. (2013) 37:9933]. In this paper, we show that though their scheme is efficient, their scheme still has two security weaknesses such as (1) it has design flaws in authentication phase and (2) it has design flaws in password change phase. In order to withstand these flaws found in Lee-Liu's scheme, we propose an improvement of their scheme. Our improved scheme keeps also the original merits of Lee-Liu's scheme. We show that our scheme is efficient as compared to Lee-Liu's scheme. Further, through the security analysis, we show that our scheme is secure against possible known attacks. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to show that our scheme is secure against passive and active attacks.

  18. Cryptanalysis and Enhancement of Anonymity Preserving Remote User Mutual Authentication and Session Key Agreement Scheme for E-Health Care Systems.

    Science.gov (United States)

    Amin, Ruhul; Islam, S K Hafizul; Biswas, G P; Khan, Muhammad Khurram; Li, Xiong

    2015-11-01

    The E-health care systems employ IT infrastructure for maximizing health care resources utilization as well as providing flexible opportunities to the remote patient. Therefore, transmission of medical data over any public networks is necessary in health care system. Note that patient authentication including secure data transmission in e-health care system is critical issue. Although several user authentication schemes for accessing remote services are available, their security analysis show that none of them are free from relevant security attacks. We reviewed Das et al.'s scheme and demonstrated their scheme lacks proper protection against several security attacks such as user anonymity, off-line password guessing attack, smart card theft attack, user impersonation attack, server impersonation attack, session key discloser attack. In order to overcome the mentioned security pitfalls, this paper proposes an anonymity preserving remote patient authentication scheme usable in E-health care systems. We then validated the security of the proposed scheme using BAN logic that ensures secure mutual authentication and session key agreement. We also presented the experimental results of the proposed scheme using AVISPA software and the results ensure that our scheme is secure under OFMC and CL-AtSe models. Moreover, resilience of relevant security attacks has been proved through both formal and informal security analysis. The performance analysis and comparison with other schemes are also made, and it has been found that the proposed scheme overcomes the security drawbacks of the Das et al.'s scheme and additionally achieves extra security requirements.

  19. Does the operations of the National Health Insurance Scheme (NHIS) in Ghana align with the goals of Primary Health Care? Perspectives of key stakeholders in northern Ghana.

    Science.gov (United States)

    Awoonor-Williams, John Koku; Tindana, Paulina; Dalinjong, Philip Ayizem; Nartey, Harry; Akazili, James

    2016-09-05

    In 2005, the World Health Assembly (WHA) of the World Health Organization (WHO) urged member states to aim at achieving affordable universal coverage and access to key promotive, preventive, curative, rehabilitative and palliative health interventions for all their citizens on the basis of equity and solidarity. Since then, some African countries, including Ghana, have taken steps to introduce national health insurance reforms as one of the key strategies towards achieving universal health coverage (UHC). The aim of this study was to get a better understanding of how Ghana's health insurance institutions interact with stakeholders and other health sector programmes in promoting primary health care (PHC). Specifically, the study identified the key areas of misalignment between the operations of the NHIS and that of PHC. Using qualitative and survey methods, this study involved interviews with various stakeholders in six selected districts in the Upper East region of Ghana. The key stakeholders included the National Health Insurance Authority (NHIA), district coordinators of the National Health Insurance Schemes (NHIS), the Ghana Health Service (GHS) and District Health Management Teams (DHMTs) who supervise the district hospitals, health centers/clinics and the Community-based Health and Planning Services (CHPS) compounds as well as other public and private PHC providers. A stakeholders' workshop was organized to validate the preliminary results which provided a platform for stakeholders to deliberate on the key areas of misalignment especially, and to elicit additional information, ideas and responses, comments and recommendations from respondents for the achievement of the goals of UHC and PHC. The key areas of misalignments identified during this pilot study included: delays in reimbursements of claims for services provided by health care providers, which serves as a disincentive for service providers to support the NHIS; inadequate coordination among

  20. Predicting establishment of non-native fishes in Greece: identifying key features

    Directory of Open Access Journals (Sweden)

    Christos Gkenas

    2015-11-01

    Full Text Available Non-native fishes are known to cause economic damage to human society and are considered a major threat to biodiversity loss in freshwater ecosystems. The growing concern about these impacts has driven to an investigation of the biological traits that facilitate the establishment of non-native fish. However, invalid assessment in choosing the appropriate statistical model can lead researchers to ambiguous conclusions. Here, we present a comprehensive comparison of traditional and alternative statistical methods for predicting fish invasions using logistic regression, classification trees, multicorrespondence analysis and random forest analysis to determine characteristics of successful and failed non-native fishes in Hellenic Peninsula through establishment. We defined fifteen categorical predictor variables with biological relevance and measures of human interest. Our study showed that accuracy differed according to the model and the number of factors considered. Among all the models tested, random forest and logistic regression performed best, although all approaches predicted non-native fish establishment with moderate to excellent results. Detailed evaluation among the models corresponded with differences in variables importance, with three biological variables (parental care, distance from nearest native source and maximum size and two variables of human interest (prior invasion success and propagule pressure being important in predicting establishment. The analyzed statistical methods presented have a high predictive power and can be used as a risk assessment tool to prevent future freshwater fish invasions in this region with an imperiled fish fauna.

  1. Bleeding risk in 'real world' patients with atrial fibrillation: comparison of two established bleeding prediction schemes in a nationwide cohort

    DEFF Research Database (Denmark)

    Olesen, J B; Lip, G Y H; Hansen, P R

    2011-01-01

    Oral anticoagulation (OAC) in patients with atrial fibrillation (AF) is a double-edged sword, because it decreases the risk of stroke at the cost of an increased risk of bleeding. We compared the performance of a new bleeding prediction scheme, HAS-BLED, with an older bleeding prediction scheme...

  2. The practicalities and pitfalls of establishing a policy-relevant and cost-effective soil biological monitoring scheme

    NARCIS (Netherlands)

    Faber, J.H.; Creamer, R.E.; Mulder, C.; Römbke, J.; Rutgers, M.; Sousa, J.P.; Stone, D.; Griffiths, B.S.

    2013-01-01

    A large number of biological indicators have been proposed over the years for assessing soil quality. Although many of those have been applied in monitoring schemes across Europe, no consensus exists on the extent to which these indicators might perform best and how monitoring schemes can be further

  3. Establishment of key grid-connected performance index system for integrated PV-ES system

    Science.gov (United States)

    Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

    2016-08-01

    In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

  4. Establishing Baseline Key Ecological Functions of Fish and Wildlife for Subbasin Planning, Final Report 2001.

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, Thomas A.

    2001-08-01

    As we strive to manage the Columbia River Basin for its sustainable, productive, and diverse ecosystems, we are, in fact, managing these systems to provide an a array of ecological functions upon which these systems are based. These ecological functions avail themselves as an important tool with which to assess our historical and current habitat conditions, as well as proposed future or ideal conditions under differing management scenarios. So what are key ecological functions (KEFs) and which ones are involved? Key ecological functions refer to the major ecological roles played by an organism in its ecosystem that can affect environmental conditions for themselves or other species, or that directly influences other organisms (Marcot and Vander Heyden 2001). Currently, 111 KEFs are identified for fish and wildlife species as a result of Task 1 of this project. Even though the assessment phase of this project encompasses the entire Columbia River Basin, only a subset of KEFs (58) that are associated with the lotic systems, which includes 7 anadromous fish, 20 co-occurring resident fish, and 137 wildlife species linked to salmon are addressed. Since the basin has not be systematically surveyed for each fish and wildlife species, baseline conditions for each KEF are determined by developing basin-wide species range maps using the following information: wildlife-habitat type associations, county and ecoprovince occurrence, literature (like individual state atlases), and expert peer review. This approach produced a set of species range maps that depict a species potential for occurrence given the current or historic conditions. It is this potential occurrence that serves as a baseline condition to determine the key ecological functions. The results offer a framework and a set of baseline assessments that can be done with existing databases. Thus, allowing resource managers the ability to assess future management activities against this norm and guide their activities in

  5. Establishing baseline key ecological functions of fish and wildlife for subbasin planning, final report 2001.; FINAL

    International Nuclear Information System (INIS)

    O'Neil, Thomas A.

    2001-01-01

    As we strive to manage the Columbia River Basin for its sustainable, productive, and diverse ecosystems, we are, in fact, managing these systems to provide an a array of ecological functions upon which these systems are based. These ecological functions avail themselves as an important tool with which to assess our historical and current habitat conditions, as well as proposed future or ideal conditions under differing management scenarios. So what are key ecological functions (KEFs) and which ones are involved? Key ecological functions refer to the major ecological roles played by an organism in its ecosystem that can affect environmental conditions for themselves or other species, or that directly influences other organisms (Marcot and Vander Heyden 2001). Currently, 111 KEFs are identified for fish and wildlife species as a result of Task 1 of this project. Even though the assessment phase of this project encompasses the entire Columbia River Basin, only a subset of KEFs (58) that are associated with the lotic systems, which includes 7 anadromous fish, 20 co-occurring resident fish, and 137 wildlife species linked to salmon are addressed. Since the basin has not be systematically surveyed for each fish and wildlife species, baseline conditions for each KEF are determined by developing basin-wide species range maps using the following information: wildlife-habitat type associations, county and ecoprovince occurrence, literature (like individual state atlases), and expert peer review. This approach produced a set of species range maps that depict a species potential for occurrence given the current or historic conditions. It is this potential occurrence that serves as a baseline condition to determine the key ecological functions. The results offer a framework and a set of baseline assessments that can be done with existing databases. Thus, allowing resource managers the ability to assess future management activities against this norm and guide their activities in

  6. A Hash Based Remote User Authentication and Authenticated Key Agreement Scheme for the Integrated EPR Information System.

    Science.gov (United States)

    Li, Chun-Ta; Weng, Chi-Yao; Lee, Cheng-Chi; Wang, Chun-Cheng

    2015-11-01

    To protect patient privacy and ensure authorized access to remote medical services, many remote user authentication schemes for the integrated electronic patient record (EPR) information system have been proposed in the literature. In a recent paper, Das proposed a hash based remote user authentication scheme using passwords and smart cards for the integrated EPR information system, and claimed that the proposed scheme could resist various passive and active attacks. However, in this paper, we found that Das's authentication scheme is still vulnerable to modification and user duplication attacks. Thereafter we propose a secure and efficient authentication scheme for the integrated EPR information system based on lightweight hash function and bitwise exclusive-or (XOR) operations. The security proof and performance analysis show our new scheme is well-suited to adoption in remote medical healthcare services.

  7. Establishing key components of yoga interventions for musculoskeletal conditions: a Delphi survey

    Science.gov (United States)

    2014-01-01

    Background Evidence suggests yoga is a safe and effective intervention for the management of physical and psychosocial symptoms associated with musculoskeletal conditions. However, heterogeneity in the components and reporting of clinical yoga trials impedes both the generalization of study results and the replication of study protocols. The aim of this Delphi survey was to address these issues of heterogeneity, by developing a list of recommendations of key components for the design and reporting of yoga interventions for musculoskeletal conditions. Methods Recognised experts involved in the design, conduct, and teaching of yoga for musculoskeletal conditions were identified from a systematic review, and invited to contribute to the Delphi survey. Forty-one of the 58 experts contacted, representing six countries, agreed to participate. A three-round Delphi was conducted via electronic surveys. Round 1 presented an open-ended question, allowing panellists to individually identify components they considered key to the design and reporting of yoga interventions for musculoskeletal conditions. Thematic analysis of Round 1 identified items for quantitative rating in Round 2; items not reaching consensus were forwarded to Round 3 for re-rating. Results Thirty-six panellists (36/41; 88%) completed the three rounds of the Delphi survey. Panellists provided 348 comments to the Round 1 question. These comments were reduced to 49 items, grouped under five themes, for rating in subsequent rounds. A priori group consensus of ≥80% was reached on 28 items related to five themes concerning defining the yoga intervention, types of yoga practices to include in an intervention, delivery of the yoga protocol, domains of outcome measures, and reporting of yoga interventions for musculoskeletal conditions. Additionally, a priori consensus of ≥50% was reached on five items relating to minimum values for intervention parameters. Conclusions Expert consensus has provided a non

  8. Analysis of the key issues in establishing the Russian-based high technological companies

    Directory of Open Access Journals (Sweden)

    V. G. Zinov

    2016-01-01

    Full Text Available The article analyses the reasons that prevent a competitive export-oriented Russian domestic development of the robot surgical complex from being industrially prototyped and serially released for the domestic and global market. The development is completed within the framework of a «priority project» which was also highlighted as of significant importance in the Forecast analysis of the scientific-technological development of Russia for the period of up until 2030 and in the road maps of the National technological initiative and other strategic documents. The project was financed by nearly all development funds and institutes in Russia. A conclusion is drawn that the key reason behind the significant increase in a life span of a high-tech market product is the absence of a target setting and a programme of coordinated actions from committed ministries and governmental agencies, as well as the lack of a large high tech company in Russia, capable of producing in industrial volumes the export-oriented products and ensure their global sales.

  9. Evaluation of the condensation potential of hydrocarbon fluids in the national gas pipeline system; establishing of adequate operational schemes

    International Nuclear Information System (INIS)

    Pineda Gomez, Cesar Augusto; Arenas Mantilla, Oscar Armando; Santos Santos, Nicolas

    2007-01-01

    (Reglamento Unico de Transporte - RUT) established by CREG (CREG, 1999); section four presents the recommended set up of adequate work schemes required lo guarantee the non-existence of hydrocarbon fluid due condensation in the evaluated system

  10. Establishing strategic energy assessment indicators for Zimbabwe: A key to improving electrical energy efficiency

    Science.gov (United States)

    Goto, Felix

    In Zimbabwe, there is still very little realization of the potential of demand side management (DSM) to increase industrial energy efficiency. Without clear guidelines that indicate the most economic energy efficiency strategies to implement, it is difficult for industry to easily evaluate the benefits of energy assessments. This research focused on establishing and evaluating indicators that guide correct implementation of energy assessments into Zimbabwean industry. This quantitative and qualitative study used a theoretic approach to develop indicators that identified industrial subsectors that should be targeted for DSM interventions. This may bring about reduction in energy demand in high power consuming Zimbabwean industrial companies, which were compared with energy utility performances of similar industrial companies in countries located in other parts of the world. This research used pattern-matching, categorical aggregation, and stochastic frontier regression analysis for data analysis. In maximizing electrical efficiency, the implications of this study may be used by individual companies in Zimbabwe to perform energy efficiency self-diagnoses, operational efficiency evaluations, and capital resource justifications. From a societal perspective, this study may benefit Zimbabwe because it provides opportunities for the alleviation of both shortages in power supply and the capital constraints of building new generating capacity. This study will also benefit ordinary Zimbabweans by lowering energy costs and providing reliable power. This promotes sustainable economic growth and lowers the need for foreign currency to import power.

  11. A no-key-exchange secure image sharing scheme based on Shamir's three-pass cryptography protocol and the multiple-parameter fractional Fourier transform.

    Science.gov (United States)

    Lang, Jun

    2012-01-30

    In this paper, we propose a novel secure image sharing scheme based on Shamir's three-pass protocol and the multiple-parameter fractional Fourier transform (MPFRFT), which can safely exchange information with no advance distribution of either secret keys or public keys between users. The image is encrypted directly by the MPFRFT spectrum without the use of phase keys, and information can be shared by transmitting the encrypted image (or message) three times between users. Numerical simulation results are given to verify the performance of the proposed algorithm.

  12. Critical analysis of the Bennett-Riedel attack on secure cryptographic key distributions via the Kirchhoff-Law-Johnson-noise scheme.

    Directory of Open Access Journals (Sweden)

    Laszlo B Kish

    Full Text Available Recently, Bennett and Riedel (BR (http://arxiv.org/abs/1303.7435v1 argued that thermodynamics is not essential in the Kirchhoff-law-Johnson-noise (KLJN classical physical cryptographic exchange method in an effort to disprove the security of the KLJN scheme. They attempted to demonstrate this by introducing a dissipation-free deterministic key exchange method with two batteries and two switches. In the present paper, we first show that BR's scheme is unphysical and that some elements of its assumptions violate basic protocols of secure communication. All our analyses are based on a technically unlimited Eve with infinitely accurate and fast measurements limited only by the laws of physics and statistics. For non-ideal situations and at active (invasive attacks, the uncertainly principle between measurement duration and statistical errors makes it impossible for Eve to extract the key regardless of the accuracy or speed of her measurements. To show that thermodynamics and noise are essential for the security, we crack the BR system with 100% success via passive attacks, in ten different ways, and demonstrate that the same cracking methods do not function for the KLJN scheme that employs Johnson noise to provide security underpinned by the Second Law of Thermodynamics. We also present a critical analysis of some other claims by BR; for example, we prove that their equations for describing zero security do not apply to the KLJN scheme. Finally we give mathematical security proofs for each BR-attack against the KLJN scheme and conclude that the information theoretic (unconditional security of the KLJN method has not been successfully challenged.

  13. Critical analysis of the Bennett-Riedel attack on secure cryptographic key distributions via the Kirchhoff-Law-Johnson-noise scheme.

    Science.gov (United States)

    Kish, Laszlo B; Abbott, Derek; Granqvist, Claes G

    2013-01-01

    Recently, Bennett and Riedel (BR) (http://arxiv.org/abs/1303.7435v1) argued that thermodynamics is not essential in the Kirchhoff-law-Johnson-noise (KLJN) classical physical cryptographic exchange method in an effort to disprove the security of the KLJN scheme. They attempted to demonstrate this by introducing a dissipation-free deterministic key exchange method with two batteries and two switches. In the present paper, we first show that BR's scheme is unphysical and that some elements of its assumptions violate basic protocols of secure communication. All our analyses are based on a technically unlimited Eve with infinitely accurate and fast measurements limited only by the laws of physics and statistics. For non-ideal situations and at active (invasive) attacks, the uncertainly principle between measurement duration and statistical errors makes it impossible for Eve to extract the key regardless of the accuracy or speed of her measurements. To show that thermodynamics and noise are essential for the security, we crack the BR system with 100% success via passive attacks, in ten different ways, and demonstrate that the same cracking methods do not function for the KLJN scheme that employs Johnson noise to provide security underpinned by the Second Law of Thermodynamics. We also present a critical analysis of some other claims by BR; for example, we prove that their equations for describing zero security do not apply to the KLJN scheme. Finally we give mathematical security proofs for each BR-attack against the KLJN scheme and conclude that the information theoretic (unconditional) security of the KLJN method has not been successfully challenged.

  14. Analysis of ISO/IEC 17025 for establishment of KOLAS (Korea Laboratory Accreditation Scheme) quality assurance system

    International Nuclear Information System (INIS)

    Nam, Ji Hee

    2000-12-01

    Besides one existent accredited lab, radioactive material chemical analysis lab, five test laboratories and two calibration labs are under plan to acquire the accreditation from KOLAS. But the current Quality Manual was developed according to ISO Guide 25 that was superceded by ISO/IEC 17025. Since it is tailored to the radioactive material chemical analysis lab, a number of requirements of the Manual are not applicable to the labs other than radioactive material chemical analysis lab. Through the analysis of ISO/IEC 17025, a model of quality system was established which is not only consistent with ISO/IEC 17025 but reflective of the KAERI's situation

  15. A reliable user authentication and key agreement scheme for Web-based Hospital-acquired Infection Surveillance Information System.

    Science.gov (United States)

    Wu, Zhen-Yu; Tseng, Yi-Ju; Chung, Yufang; Chen, Yee-Chun; Lai, Feipei

    2012-08-01

    With the rapid development of the Internet, both digitization and electronic orientation are required on various applications in the daily life. For hospital-acquired infection control, a Web-based Hospital-acquired Infection Surveillance System was implemented. Clinical data from different hospitals and systems were collected and analyzed. The hospital-acquired infection screening rules in this system utilized this information to detect different patterns of defined hospital-acquired infection. Moreover, these data were integrated into the user interface of a signal entry point to assist physicians and healthcare providers in making decisions. Based on Service-Oriented Architecture, web-service techniques which were suitable for integrating heterogeneous platforms, protocols, and applications, were used. In summary, this system simplifies the workflow of hospital infection control and improves the healthcare quality. However, it is probable for attackers to intercept the process of data transmission or access to the user interface. To tackle the illegal access and to prevent the information from being stolen during transmission over the insecure Internet, a password-based user authentication scheme is proposed for information integrity.

  16. On the “Cracking” Scheme in the Paper “A Directional Coupler Attack Against the Kish Key Distribution System” by Gunn, Allison and Abbott

    Directory of Open Access Journals (Sweden)

    Chen Hsien-Pu

    2014-08-01

    Full Text Available Recently, Gunn, Allison and Abbott (GAA [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014 1450016] that GAA’s mathematical model is unphysical. Here we analyze GAA’s cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010], while it offers no information in the case of a lossy cable. We also investigate GAA’s claim to be experimentally capable of distinguishing—using statistics over a few correlation times only—the distributions of two Gaussian noises with a relative variance difference of less than 10-8. Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA’s assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the timederivative nature of GAA’s scheme which tends to enhance all of these artifacts.

  17. Establishing and evaluating the key functions of an interactive systems framework using an assets-getting to outcomes intervention.

    Science.gov (United States)

    Chinman, Matthew; Acosta, Joie; Ebener, Patricia; Q Burkhart; Clifford, Michael; Corsello, Maryann; Duffey, Tim; Hunter, Sarah; Jones, Margaret; Lahti, Michel; Malone, Patrick S; Paddock, Susan; Phillips, Andrea; Savell, Susan; Scales, Peter C; Tellett-Royce, Nancy

    2012-12-01

    Community practitioners can face difficulty in achieving outcomes demonstrated by prevention science. Building a community practitioner's prevention capacity-the knowledge and skills needed to conduct critical prevention practices-could improve the quality of prevention and its outcomes. The purpose of this article is to: (1) describe how an intervention called Assets-Getting To Outcomes (AGTO) was used to establish the key functions of the ISF and present early lessons learned from that intervention's first 6 months and (2) examine whether there is an empirical relationship between practitioner capacity at the individual level and the performance of prevention at the program level-a relationship predicted by the ISF but untested. The article describes an operationalization of the ISF in the context of a five-year randomized controlled efficacy trial that combines two complementary models designed to build capacity: Getting To Outcomes (GTO) and Developmental Assets. The trial compares programs and individual practitioners from six community-based coalitions using AGTO with programs and practitioners from six similar coalitions that are not. In this article, we primarily focus on what the ISF calls innovation specific capacity and discuss how the combined AGTO innovation structures and uses feedback about its capacity-building activities, which can serve as a model for implementing the ISF. Focus group discussions used to gather lessons learned from the first 6 months of the AGTO intervention suggest that while the ISF may have been conceptualized as three distinct systems, in practice they are less distinct. Findings from the baseline wave of data collection of individual capacity and program performance suggest that practitioner capacity predicts, in part, performance of prevention programs. Empirically linking practitioner capacity and performance of prevention provides empirical support for both the ISF and AGTO.

  18. Proof-of-principle experimental realization of a qubit-like qudit-based quantum key distribution scheme

    Science.gov (United States)

    Wang, Shuang; Yin, Zhen-Qiang; Chau, H. F.; Chen, Wei; Wang, Chao; Guo, Guang-Can; Han, Zheng-Fu

    2018-04-01

    In comparison to qubit-based protocols, qudit-based quantum key distribution ones generally allow two cooperative parties to share unconditionally secure keys under a higher channel noise. However, it is very hard to prepare and measure the required quantum states in qudit-based protocols in general. One exception is the recently proposed highly error tolerant qudit-based protocol known as the Chau15 (Chau 2015 Phys. Rev. A 92 062324). Remarkably, the state preparation and measurement in this protocol can be done relatively easily since the required states are phase encoded almost like the diagonal basis states of a qubit. Here we report the first proof-of-principle demonstration of the Chau15 protocol. One highlight of our experiment is that its post-processing is based on practical one-way manner, while the original proposal in Chau (2015 Phys. Rev. A 92 062324) relies on complicated two-way post-processing, which is a great challenge in experiment. In addition, by manipulating time-bin qudit and measurement with a variable delay interferometer, our realization is extensible to qudit with high-dimensionality and confirms the experimental feasibility of the Chau15 protocol.

  19. Design of a hybrid reconfigurable Software Defined Radio transceiver based on frequency shift keying using multiple encoding schemes

    Directory of Open Access Journals (Sweden)

    Nikhil Marriwala

    2016-03-01

    The aim of this paper was to analyze Frequency Shift Keying (FSK Transceiver built using Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW and to measure the reduction in data errors in the presence of Forward Error Correction (FEC channel coding algorithms namely the Convolution and the Turbo Codes. Through this design a graphical representation of Bit Error Rate (BER vs Eb/N0 where (Eb is Energy per bit and (N0 is Spectral noise density has been given in the presence of Additive White Gaussian Noise (AWGN introduced in the channel. FSK is widely used for data transmission over band pass channels; hence, we have chosen FSK for the implementation of SDR. The SDR transceiver module designed has been fully implemented and has the ability to navigate over a wide range of frequencies with programmable channel bandwidth and modulation characteristics. We are able to build an interactive FSK based SDR transceiver in a shorter time with the use of LabVIEW. The outputs achieved show a low BER for very high data rates in the presence of AWGN noise.

  20. Mitigation of Control Channel Jamming via Combinatorial Key Distribution

    Science.gov (United States)

    Falahati, Abolfazl; Azarafrooz, Mahdi

    The problem of countering control channel jamming against internal adversaries in wireless ad hoc networks is addressed. Using combinatorial key distribution, a new method to secure the control channel access is introduced. This method, utilizes the established keys in the key establishment phase to hide the location of control channels without the need for a secure BS. This is in obtained by combination of a collision free one-way function and a combinatorial key establishment method. The proposed scheme can be considered as a special case of the ALOHA random access schemes which uses the common established keys as its seeds to generate the pattern of transmission.

  1. Analysis of Transcription Factors Key for Mouse Pancreatic Development Establishes NKX2-2 and MNX1 Mutations as Causes of Neonatal Diabetes in Man

    Science.gov (United States)

    Flanagan, Sarah E.; De Franco, Elisa; Lango Allen, Hana; Zerah, Michele; Abdul-Rasoul, Majedah M.; Edge, Julie A.; Stewart, Helen; Alamiri, Elham; Hussain, Khalid; Wallis, Sam; de Vries, Liat; Rubio-Cabezas, Oscar; Houghton, Jayne A.L.; Edghill, Emma L.; Patch, Ann-Marie; Ellard, Sian; Hattersley, Andrew T.

    2014-01-01

    Summary Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development. PMID:24411943

  2. Establishing sustainable performance-based incentive schemes: views of rural health workers from qualitative research in three sub-Saharan African countries.

    Science.gov (United States)

    Yé, M; Aninanya, G A; Sié, A; Kakoko, D C V; Chatio, S; Kagoné, M; Prytherch, H; Loukanova, S; Williams, J E; Sauerborn, R

    2014-01-01

    Performance-based incentives (PBIs) are currently receiving attention as a strategy for improving the quality of care that health providers deliver. Experiences from several African countries have shown that PBIs can trigger improvements, particularly in the area of maternal and neonatal health. The involvement of health workers in deciding how their performance should be measured is recommended. Only limited information is available about how such schemes can be made sustainable. This study explored the types of PBIs that rural health workers suggested, their ideas regarding the management and sustainability of such schemes, and their views on which indicators best lend themselves to the monitoring of performance. In this article the authors reported the findings from a cross-country survey conducted in Burkina Faso, Ghana and Tanzania. The study was exploratory with qualitative methodology. In-depth interviews were conducted with 29 maternal and neonatal healthcare providers, four district health managers and two policy makers (total 35 respondents) from one district in each of the three countries. The respondents were purposively selected from six peripheral health facilities. Care was taken to include providers who had a management role. By also including respondents from district and policy level a comparison of perspectives from different levels of the health system was facilitated. The data that was collected was coded and analysed with support of NVivo v8 software. The most frequently suggested PBIs amongst the respondents in Burkina Faso were training with per-diems, bonuses and recognition of work done. The respondents in Tanzania favoured training with per-diems, as well as payment of overtime, and timely promotion. The respondents in Ghana also called for training, including paid study leave, payment of overtime and recognition schemes for health workers or facilities. Respondents in the three countries supported the mobilisation of local resources to

  3. Secure and Efficient Anonymous Authentication Scheme in Global Mobility Networks

    Directory of Open Access Journals (Sweden)

    Jun-Sub Kim

    2013-01-01

    Full Text Available In 2012, Mun et al. pointed out that Wu et al.’s scheme failed to achieve user anonymity and perfect forward secrecy and disclosed the passwords of legitimate users. And they proposed a new enhancement for anonymous authentication scheme. However, their proposed scheme has vulnerabilities that are susceptible to replay attack and man-in-the-middle attack. It also incurs a high overhead in the database. In this paper, we examine the vulnerabilities in the existing schemes and the computational overhead incurred in the database. We then propose a secure and efficient anonymous authentication scheme for roaming service in global mobility network. Our proposed scheme is secure against various attacks, provides mutual authentication and session key establishment, and incurs less computational overhead in the database than Mun et al.'s scheme.

  4. Does the operations of the National Health Insurance Scheme (NHIS) in Ghana align with the goals of Primary Health Care? Perspectives of key stakeholders in northern Ghana

    OpenAIRE

    Awoonor-Williams, John Koku; Tindana, Paulina; Dalinjong, Philip Ayizem; Nartey, Harry; Akazili, James

    2016-01-01

    Background In 2005, the World Health Assembly (WHA) of the World Health Organization (WHO) urged member states to aim at achieving affordable universal coverage and access to key promotive, preventive, curative, rehabilitative and palliative health interventions for all their citizens on the basis of equity and solidarity. Since then, some African countries, including Ghana, have taken steps to introduce national health insurance reforms as one of the key strategies towards achieving universa...

  5. Round one of the Adelaide and Meath Hospital/Trinity College Colorectal Cancer Screening Programme: programme report and analysis based on established international key performance indices.

    LENUS (Irish Health Repository)

    McNamara, D

    2012-02-01

    BACKGROUND: In Ireland, colorectal cancer (CRC) is the second most frequently diagnosed cancer in men, after prostate cancer, and the second most frequently diagnosed cancer in women, after breast cancer. By 2020, the number of new cases diagnosed annually in Ireland is projected to have increased by 79% in men and 56% in women. Organised screening for CRC is already underway or is in the process of being rolled out in several European countries, either at a regional or national level. The Adelaide and Meath Hospital\\/ Trinity College Dublin Colorectal Cancer Screening Programme (TTC-CRC-SP) is Ireland\\'s first pilot population based bowel screening programme. METHOD: Based on a biennial test model the pilot aimed to assess the accuracy of FIT and to evaluate the whole programme based on established international key performance indices. RESULTS: To date 9,993 individuals aged 50-74 years have been invited to participate in the TTC-CRC-SP with over 5,000 FIT\\'s analysed. Overall uptake was 51% and FIT positivity was 10%. The programme has undertaken over 400 screening colonoscopies and detected 154 precancerous adenomas and 38 cancerous lesions. CONCLUSIONS: The first round of The Adelaide and Meath Hospital Tallaght\\/Trinity College Dublin Colorectal Cancer Screening Programme has been highly successful and confirmed that there is an advantage for FIT based two stage bowel cancer screening programmes.

  6. Key performance indicators score (KPIs-score) based on clinical and laboratorial parameters can establish benchmarks for internal quality control in an ART program.

    Science.gov (United States)

    Franco, José G; Petersen, Claudia G; Mauri, Ana L; Vagnini, Laura D; Renzi, Adriana; Petersen, Bruna; Mattila, M C; Comar, Vanessa A; Ricci, Juliana; Dieamant, Felipe; Oliveira, João Batista A; Baruffi, Ricardo L R

    2017-06-01

    KPIs have been employed for internal quality control (IQC) in ART. However, clinical KPIs (C-KPIs) such as age, AMH and number of oocytes collected are never added to laboratory KPIs (L-KPIs), such as fertilization rate and morphological quality of the embryos for analysis, even though the final endpoint is the evaluation of clinical pregnancy rates. This paper analyzed if a KPIs-score strategy with clinical and laboratorial parameters could be used to establish benchmarks for IQC in ART cycles. In this prospective cohort study, 280 patients (36.4±4.3years) underwent ART. The total KPIs-score was obtained by the analysis of age, AMH (AMH Gen II ELISA/pre-mixing modified, Beckman Coulter Inc.), number of metaphase-II oocytes, fertilization rates and morphological quality of the embryonic lot. The total KPIs-score (C-KPIs+L-KPIs) was correlated with the presence or absence of clinical pregnancy. The relationship between the C-KPIs and L-KPIs scores was analyzed to establish quality standards, to increase the performance of clinical and laboratorial processes in ART. The logistic regression model (LRM), with respect to pregnancy and total KPIs-score (280 patients/102 clinical pregnancies), yielded an odds ratio of 1.24 (95%CI = 1.16-1.32). There was also a significant difference (pclinical pregnancies (total KPIs-score=20.4±3.7) and the group without clinical pregnancies (total KPIs-score=15.9±5). Clinical pregnancy probabilities (CPP) can be obtained using the LRM (prediction key) with the total KPIs-score as a predictor variable. The mean C-KPIs and L-KPIs scores obtained in the pregnancy group were 11.9±2.9 and 8.5±1.7, respectively. Routinely, in all cases where the C-KPIs score was ≥9, after the procedure, the L-KPIs score obtained was ≤6, a revision of the laboratory procedure was performed to assess quality standards. This total KPIs-score could set up benchmarks for clinical pregnancy. Moreover, IQC can use C-KPIs and L-KPIs scores to detect problems

  7. Key Recovery Attacks on Recent Authenticated Ciphers

    DEFF Research Database (Denmark)

    Bogdanov, Andrey; Dobraunig, Christoph; Eichlseder, Maria

    2014-01-01

    In this paper, we cryptanalyze three authenticated ciphers: AVALANCHE, Calico, and RBS. While the former two are contestants in the ongoing international CAESAR competition for authenticated encryption schemes, the latter has recently been proposed for lightweight applications such as RFID systems...... and wireless networks. All these schemes use well-established and secure components such as the AES, Grain-like NFSRs, ChaCha and SipHash as their building blocks. However, we discover key recovery attacks for all three designs, featuring square-root complexities. Using a key collision technique, we can...

  8. RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity

    Directory of Open Access Journals (Sweden)

    Elias Abdou

    2017-05-01

    Full Text Available For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original “in vitro model of persistence” consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL, were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work

  9. Robust and Efficient Authentication Scheme for Session Initiation Protocol

    Directory of Open Access Journals (Sweden)

    Yanrong Lu

    2015-01-01

    Full Text Available The session initiation protocol (SIP is a powerful application-layer protocol which is used as a signaling one for establishing, modifying, and terminating sessions among participants. Authentication is becoming an increasingly crucial issue when a user asks to access SIP services. Hitherto, many authentication schemes have been proposed to enhance the security of SIP. In 2014, Arshad and Nikooghadam proposed an enhanced authentication and key agreement scheme for SIP and claimed that their scheme could withstand various attacks. However, in this paper, we show that Arshad and Nikooghadam’s authentication scheme is still susceptible to key-compromise impersonation and trace attacks and does not provide proper mutual authentication. To conquer the flaws, we propose a secure and efficient ECC-based authentication scheme for SIP. Through the informal and formal security analyses, we demonstrate that our scheme is resilient to possible known attacks including the attacks found in Arshad et al.’s scheme. In addition, the performance analysis shows that our scheme has similar or better efficiency in comparison with other existing ECC-based authentication schemes for SIP.

  10. Lower and Upper Bounds for Deniable Public-Key Encryption

    DEFF Research Database (Denmark)

    Bendlin, Rikke; Nielsen, Jesper Buus; Nordholt, Peter Sebastian

    2011-01-01

    the parties to change their internal state to make it look like a given ciphertext decrypts to a message different from what it really decrypts to. Deniable encryption was in this way introduced to allow to deny a message exchange and hence combat coercion. Depending on which parties can be coerced...... that it is impossible to construct a non-interactive bi-deniable public-key encryption scheme with better than polynomial security. Specifically, we give an explicit bound relating the security of the scheme to how efficient the scheme is in terms of key size. Our impossibility result establishes a lower bound...

  11. Two-Dimensional Key Table-Based Group Key Distribution in Advanced Metering Infrastructure

    Directory of Open Access Journals (Sweden)

    Woong Go

    2014-01-01

    Full Text Available A smart grid provides two-way communication by using the information and communication technology. In order to establish two-way communication, the advanced metering infrastructure (AMI is used in the smart grid as the core infrastructure. This infrastructure consists of smart meters, data collection units, maintenance data management systems, and so on. However, potential security problems of the AMI increase owing to the application of the public network. This is because the transmitted information is electricity consumption data for charging. Thus, in order to establish a secure connection to transmit electricity consumption data, encryption is necessary, for which key distribution is required. Further, a group key is more efficient than a pairwise key in the hierarchical structure of the AMI. Therefore, we propose a group key distribution scheme using a two-dimensional key table through the analysis result of the sensor network group key distribution scheme. The proposed scheme has three phases: group key predistribution, selection of group key generation element, and generation of group key.

  12. The QKD network: model and routing scheme

    Science.gov (United States)

    Yang, Chao; Zhang, Hongqi; Su, Jinhai

    2017-11-01

    Quantum key distribution (QKD) technology can establish unconditional secure keys between two communicating parties. Although this technology has some inherent constraints, such as the distance and point-to-point mode limits, building a QKD network with multiple point-to-point QKD devices can overcome these constraints. Considering the development level of current technology, the trust relaying QKD network is the first choice to build a practical QKD network. However, the previous research didn't address a routing method on the trust relaying QKD network in detail. This paper focuses on the routing issues, builds a model of the trust relaying QKD network for easily analysing and understanding this network, and proposes a dynamical routing scheme for this network. From the viewpoint of designing a dynamical routing scheme in classical network, the proposed scheme consists of three components: a Hello protocol helping share the network topology information, a routing algorithm to select a set of suitable paths and establish the routing table and a link state update mechanism helping keep the routing table newly. Experiments and evaluation demonstrates the validity and effectiveness of the proposed routing scheme.

  13. Manet key management via Mobile Ficlke Key protocol (MFK ...

    African Journals Online (AJOL)

    Manet key management via Mobile Ficlke Key protocol (MFK) ... Journal of Fundamental and Applied Sciences. Journal Home · ABOUT THIS JOURNAL ... No Abstract. Keywords: MANET; key management scheme; simulation environment ...

  14. A full quantum network scheme

    International Nuclear Information System (INIS)

    Ma Hai-Qiang; Wei Ke-Jin; Yang Jian-Hui; Li Rui-Xue; Zhu Wu

    2014-01-01

    We present a full quantum network scheme using a modified BB84 protocol. Unlike other quantum network schemes, it allows quantum keys to be distributed between two arbitrary users with the help of an intermediary detecting user. Moreover, it has good expansibility and prevents all potential attacks using loopholes in a detector, so it is more practical to apply. Because the fiber birefringence effects are automatically compensated, the scheme is distinctly stable in principle and in experiment. The simple components for every user make our scheme easier for many applications. The experimental results demonstrate the stability and feasibility of this scheme. (general)

  15. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation.......This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  16. Quantum key management

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard John; Thrasher, James Thomas; Nordholt, Jane Elizabeth

    2016-11-29

    Innovations for quantum key management harness quantum communications to form a cryptography system within a public key infrastructure framework. In example implementations, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a Merkle signature scheme (using Winternitz one-time digital signatures or other one-time digital signatures, and Merkle hash trees) to constitute a cryptography system. More generally, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a hash-based signature scheme. This provides a secure way to identify, authenticate, verify, and exchange secret cryptographic keys. Features of the quantum key management innovations further include secure enrollment of users with a registration authority, as well as credential checking and revocation with a certificate authority, where the registration authority and/or certificate authority can be part of the same system as a trusted authority for quantum key distribution.

  17. Establishing a library of resources to help people understand key concepts in assessing treatment claims—The “Critical thinking and Appraisal Resource Library” (CARL)

    Science.gov (United States)

    Chalmers, Iain; Atkinson, Patricia; Badenoch, Douglas; Oxman, Andrew D.; Austvoll-Dahlgren, Astrid; Nordheim, Lena; Krause, L. Kendall; Schwartz, Lisa M.; Woloshin, Steven; Burls, Amanda; Mosconi, Paola; Hoffmann, Tammy; Cusack, Leila; Albarqouni, Loai; Glasziou, Paul

    2017-01-01

    Background People are frequently confronted with untrustworthy claims about the effects of treatments. Uncritical acceptance of these claims can lead to poor, and sometimes dangerous, treatment decisions, and wasted time and money. Resources to help people learn to think critically about treatment claims are scarce, and they are widely scattered. Furthermore, very few learning-resources have been assessed to see if they improve knowledge and behavior. Objectives Our objectives were to develop the Critical thinking and Appraisal Resource Library (CARL). This library was to be in the form of a database containing learning resources for those who are responsible for encouraging critical thinking about treatment claims, and was to be made available online. We wished to include resources for groups we identified as ‘intermediaries’ of knowledge, i.e. teachers of schoolchildren, undergraduates and graduates, for example those teaching evidence-based medicine, or those communicating treatment claims to the public. In selecting resources, we wished to draw particular attention to those resources that had been formally evaluated, for example, by the creators of the resource or independent research groups. Methods CARL was populated with learning-resources identified from a variety of sources—two previously developed but unmaintained inventories; systematic reviews of learning-interventions; online and database searches; and recommendations by members of the project group and its advisors. The learning-resources in CARL were organised by ‘Key Concepts’ needed to judge the trustworthiness of treatment claims, and were made available online by the James Lind Initiative in Testing Treatments interactive (TTi) English (www.testingtreatments.org/category/learning-resources).TTi English also incorporated the database of Key Concepts and the Claim Evaluation Tools developed through the Informed Healthcare Choices (IHC) project (informedhealthchoices.org). Results We have

  18. Establishing a library of resources to help people understand key concepts in assessing treatment claims-The "Critical thinking and Appraisal Resource Library" (CARL).

    Science.gov (United States)

    Castle, John C; Chalmers, Iain; Atkinson, Patricia; Badenoch, Douglas; Oxman, Andrew D; Austvoll-Dahlgren, Astrid; Nordheim, Lena; Krause, L Kendall; Schwartz, Lisa M; Woloshin, Steven; Burls, Amanda; Mosconi, Paola; Hoffmann, Tammy; Cusack, Leila; Albarqouni, Loai; Glasziou, Paul

    2017-01-01

    People are frequently confronted with untrustworthy claims about the effects of treatments. Uncritical acceptance of these claims can lead to poor, and sometimes dangerous, treatment decisions, and wasted time and money. Resources to help people learn to think critically about treatment claims are scarce, and they are widely scattered. Furthermore, very few learning-resources have been assessed to see if they improve knowledge and behavior. Our objectives were to develop the Critical thinking and Appraisal Resource Library (CARL). This library was to be in the form of a database containing learning resources for those who are responsible for encouraging critical thinking about treatment claims, and was to be made available online. We wished to include resources for groups we identified as 'intermediaries' of knowledge, i.e. teachers of schoolchildren, undergraduates and graduates, for example those teaching evidence-based medicine, or those communicating treatment claims to the public. In selecting resources, we wished to draw particular attention to those resources that had been formally evaluated, for example, by the creators of the resource or independent research groups. CARL was populated with learning-resources identified from a variety of sources-two previously developed but unmaintained inventories; systematic reviews of learning-interventions; online and database searches; and recommendations by members of the project group and its advisors. The learning-resources in CARL were organised by 'Key Concepts' needed to judge the trustworthiness of treatment claims, and were made available online by the James Lind Initiative in Testing Treatments interactive (TTi) English (www.testingtreatments.org/category/learning-resources).TTi English also incorporated the database of Key Concepts and the Claim Evaluation Tools developed through the Informed Healthcare Choices (IHC) project (informedhealthchoices.org). We have created a database of resources called CARL

  19. Get the Basics Right: A Description of the Key Priorities for Establishing a Neonatal Service in a Resource-Limited Setting in Cambodia.

    Science.gov (United States)

    Fox-Lewis, Shivani; Genasci Smith, Wyatt; Lor, Vary; McKellar, Gregor; Phal, Chea; Fox-Lewis, Andrew; Turner, Paul; Neou, Leakhena; Turner, Claudia

    2018-05-28

    Worldwide, reduction in under-five mortality has not sufficiently included neonates, who represent 45% of deaths in children of age under five years. The least progress has been observed in resource-limited settings. This mixed methods study conducted at a Cambodian non-governmental paediatric hospital described the key priorities of the ongoing neonatal service. Routinely collected data from the hospital and microbiology databases included the number of admissions, discharges and deaths and the number of cases of bacteraemias (2011-2016). Semi-structured interviews with the management staff explored the essential features of the service. There were 2127 neonatal admissions and 247 deaths. The incidence of facility-based neonatal mortality decreased by 81%. Bacteraemic healthcare-associated infections decreased by 68%. A dedicated area for neonatal care was perceived as crucial, allowing better infection control and delivery of staff training. In this hospital, the neonatal service prioritized basic measures, particularly, having a dedicated neonatal area. Facility-based mortality and bacteraemic healthcare-associated infections decreased.

  20. Establishing Key Performance Indicators [KPIs] and Their Importance for the Surgical Management of Inflammatory Bowel Disease-Results From a Pan-European, Delphi Consensus Study.

    Science.gov (United States)

    Morar, Pritesh S; Hollingshead, James; Bemelman, Willem; Sevdalis, Nick; Pinkney, Thomas; Wilson, Graeme; Dunlop, Malcolm; Davies, R Justin; Guy, Richard; Fearnhead, Nicola; Brown, Steven; Warusavitarne, Janindra; Edwards, Cathryn; Faiz, Omar

    2017-10-27

    Key performance indicators [KPIs] exist across a range of areas in medicine. They help to monitor outcomes, reduce variation, and drive up standards across services. KPIs exist for inflammatory bowel disease [IBD] care, but none specifically cover inflammatory bowel disease [IBD] surgical service provision. This was a consensus-based study using a panel of expert IBD clinicians from across Europe. Items were developed and fed through a Delphi process to achieve consensus. Items were ranked on a Likert scale from 1 [not important] to 5 [very important]. Consensus was defined when the inter quartile range was ≤ 1, and items with a median score > 3 were considered for inclusion. A panel of 21 experts [14 surgeons and 7 gastroenterologists] was recruited. Consensus was achieved on procedure-specific KPIs for ileocaecal and perianal surgery for Crohn's disease, [N = 10] with themes relating to morbidity [N = 7], multidisciplinary input [N = 2], and quality of life [N = 1]; and for subtotal colectomy, proctocolectomy and ileoanal pouch surgery for ulcerative colitis [N = 11], with themes relating to mortality [N = 2], morbidity [N = 8], and service provision [N = 1]. Consensus was also achieved for measures of the quality of IBD surgical service provision and quality assurance in IBD surgery. This study has provided measurable KPIs for the provision of surgical services in IBD. These indicators cover IBD surgery in general, the governance and structures of the surgical services, and separate indicators for specific subareas of surgery. Monitoring of IBD services with these KPIs may reduce variation across services and improve quality. Copyright © 2017 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com

  1. An enhanced biometric authentication scheme for telecare medicine information systems with nonce using chaotic hash function.

    Science.gov (United States)

    Das, Ashok Kumar; Goswami, Adrijit

    2014-06-01

    Recently, Awasthi and Srivastava proposed a novel biometric remote user authentication scheme for the telecare medicine information system (TMIS) with nonce. Their scheme is very efficient as it is based on efficient chaotic one-way hash function and bitwise XOR operations. In this paper, we first analyze Awasthi-Srivastava's scheme and then show that their scheme has several drawbacks: (1) incorrect password change phase, (2) fails to preserve user anonymity property, (3) fails to establish a secret session key beween a legal user and the server, (4) fails to protect strong replay attack, and (5) lacks rigorous formal security analysis. We then a propose a novel and secure biometric-based remote user authentication scheme in order to withstand the security flaw found in Awasthi-Srivastava's scheme and enhance the features required for an idle user authentication scheme. Through the rigorous informal and formal security analysis, we show that our scheme is secure against possible known attacks. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool and show that our scheme is secure against passive and active attacks, including the replay and man-in-the-middle attacks. Our scheme is also efficient as compared to Awasthi-Srivastava's scheme.

  2. Tradable schemes

    NARCIS (Netherlands)

    J.K. Hoogland (Jiri); C.D.D. Neumann

    2000-01-01

    textabstractIn this article we present a new approach to the numerical valuation of derivative securities. The method is based on our previous work where we formulated the theory of pricing in terms of tradables. The basic idea is to fit a finite difference scheme to exact solutions of the pricing

  3. Security Analysis and Improvement of an Anonymous Authentication Scheme for Roaming Services

    Directory of Open Access Journals (Sweden)

    Youngsook Lee

    2014-01-01

    Full Text Available An anonymous authentication scheme for roaming services in global mobility networks allows a mobile user visiting a foreign network to achieve mutual authentication and session key establishment with the foreign-network operator in an anonymous manner. In this work, we revisit He et al.’s anonymous authentication scheme for roaming services and present previously unpublished security weaknesses in the scheme: (1 it fails to provide user anonymity against any third party as well as the foreign agent, (2 it cannot protect the passwords of mobile users due to its vulnerability to an offline dictionary attack, and (3 it does not achieve session-key security against a man-in-the-middle attack. We also show how the security weaknesses of He et al.’s scheme can be addressed without degrading the efficiency of the scheme.

  4. Cost Comparison Among Provable Data Possession Schemes

    Science.gov (United States)

    2016-03-01

    of Acronyms and Abbreviations AE authenticated encryption AWS Amazon Web Services CIO Chief Information Officer DISA Defense Information Systems Agency...the number of possible challenges, H be a cryptographic hash function, AE be an authenticated encryption scheme, f be a keyed pseudo-random function...key kenc R←− Kenc for symmetric encryption scheme Enc, and a random HMAC key kmac R←− Kmac. The secret key is sk = 〈kenc, kmac〉 and public key is pk

  5. Quantum dense key distribution

    International Nuclear Information System (INIS)

    Degiovanni, I.P.; Ruo Berchera, I.; Castelletto, S.; Rastello, M.L.; Bovino, F.A.; Colla, A.M.; Castagnoli, G.

    2004-01-01

    This paper proposes a protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than the Bennet-Brassard 1984 protocol. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility

  6. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  7. QIM blind video watermarking scheme based on Wavelet transform and principal component analysis

    Directory of Open Access Journals (Sweden)

    Nisreen I. Yassin

    2014-12-01

    Full Text Available In this paper, a blind scheme for digital video watermarking is proposed. The security of the scheme is established by using one secret key in the retrieval of the watermark. Discrete Wavelet Transform (DWT is applied on each video frame decomposing it into a number of sub-bands. Maximum entropy blocks are selected and transformed using Principal Component Analysis (PCA. Quantization Index Modulation (QIM is used to quantize the maximum coefficient of the PCA blocks of each sub-band. Then, the watermark is embedded into the selected suitable quantizer values. The proposed scheme is tested using a number of video sequences. Experimental results show high imperceptibility. The computed average PSNR exceeds 45 dB. Finally, the scheme is applied on two medical videos. The proposed scheme shows high robustness against several attacks such as JPEG coding, Gaussian noise addition, histogram equalization, gamma correction, and contrast adjustment in both cases of regular videos and medical videos.

  8. Signature scheme based on bilinear pairs

    Science.gov (United States)

    Tong, Rui Y.; Geng, Yong J.

    2013-03-01

    An identity-based signature scheme is proposed by using bilinear pairs technology. The scheme uses user's identity information as public key such as email address, IP address, telephone number so that it erases the cost of forming and managing public key infrastructure and avoids the problem of user private generating center generating forgery signature by using CL-PKC framework to generate user's private key.

  9. An Improved and Secure Biometric Authentication Scheme for Telecare Medicine Information Systems Based on Elliptic Curve Cryptography.

    Science.gov (United States)

    Chaudhry, Shehzad Ashraf; Mahmood, Khalid; Naqvi, Husnain; Khan, Muhammad Khurram

    2015-11-01

    Telecare medicine information system (TMIS) offers the patients convenient and expedite healthcare services remotely anywhere. Patient security and privacy has emerged as key issues during remote access because of underlying open architecture. An authentication scheme can verify patient's as well as TMIS server's legitimacy during remote healthcare services. To achieve security and privacy a number of authentication schemes have been proposed. Very recently Lu et al. (J. Med. Syst. 39(3):1-8, 2015) proposed a biometric based three factor authentication scheme for TMIS to confiscate the vulnerabilities of Arshad et al.'s (J. Med. Syst. 38(12):136, 2014) scheme. Further, they emphasized the robustness of their scheme against several attacks. However, in this paper we establish that Lu et al.'s scheme is vulnerable to numerous attacks including (1) Patient anonymity violation attack, (2) Patient impersonation attack, and (3) TMIS server impersonation attack. Furthermore, their scheme does not provide patient untraceability. We then, propose an improvement of Lu et al.'s scheme. We have analyzed the security of improved scheme using popular automated tool ProVerif. The proposed scheme while retaining the plusses of Lu et al.'s scheme is also robust against known attacks.

  10. A Novel Iris Segmentation Scheme

    Directory of Open Access Journals (Sweden)

    Chen-Chung Liu

    2014-01-01

    Full Text Available One of the key steps in the iris recognition system is the accurate iris segmentation from its surrounding noises including pupil, sclera, eyelashes, and eyebrows of a captured eye-image. This paper presents a novel iris segmentation scheme which utilizes the orientation matching transform to outline the outer and inner iris boundaries initially. It then employs Delogne-Kåsa circle fitting (instead of the traditional Hough transform to further eliminate the outlier points to extract a more precise iris area from an eye-image. In the extracted iris region, the proposed scheme further utilizes the differences in the intensity and positional characteristics of the iris, eyelid, and eyelashes to detect and delete these noises. The scheme is then applied on iris image database, UBIRIS.v1. The experimental results show that the presented scheme provides a more effective and efficient iris segmentation than other conventional methods.

  11. Robust Multiparty Quantum Secret Key Sharing Over Two Collective-Noise Channels via Three-Photon Mixed States

    International Nuclear Information System (INIS)

    Wang Zhangyin; Yuan Hao; Gao Gan; Shi Shouhua

    2006-01-01

    We present a robust (n,n)-threshold scheme for multiparty quantum secret sharing of key over two collective-noise channels (i.e., the collective dephasing channel and the collective rotating channel) via three-photon mixed states. In our scheme, only if all the sharers collaborate together can they establish a joint key with the message sender and extract the secret message from the sender's encrypted message. This scheme can be implemented using only a Bell singlet, a one-qubit state and polarization identification of single photon, so it is completely feasible according to the present-day technique.

  12. Symmetric autocompensating quantum key distribution

    Science.gov (United States)

    Walton, Zachary D.; Sergienko, Alexander V.; Levitin, Lev B.; Saleh, Bahaa E. A.; Teich, Malvin C.

    2004-08-01

    We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and time-bin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We show that both the polarization and the time-bin schemes may be implemented with existing technology. The new schemes are related to previously described schemes by the concept of advanced waves.

  13. Group key management

    Energy Technology Data Exchange (ETDEWEB)

    Dunigan, T.; Cao, C.

    1997-08-01

    This report describes an architecture and implementation for doing group key management over a data communications network. The architecture describes a protocol for establishing a shared encryption key among an authenticated and authorized collection of network entities. Group access requires one or more authorization certificates. The implementation includes a simple public key and certificate infrastructure. Multicast is used for some of the key management messages. An application programming interface multiplexes key management and user application messages. An implementation using the new IP security protocols is postulated. The architecture is compared with other group key management proposals, and the performance and the limitations of the implementation are described.

  14. A concept model for learning: An attempt to define a proper relations scheme between instruction, learning and to establish the dynamics of learning in relation to modern political concepts as study-fairness.

    NARCIS (Netherlands)

    Min, F.B.M.; Vos, Henk; Kommers, Petrus A.M.; van Dijkum, C.; van Dijkum, C.

    2000-01-01

    For years, it has been attempted within educational science to establish the process of learning. A lot is known about instruction, but as to learning and acquiring knowledge and insight, we still know very little. A lot of research is conducted on methods of instruction, but very little on learning

  15. Resonance ionization scheme development for europium

    Energy Technology Data Exchange (ETDEWEB)

    Chrysalidis, K., E-mail: katerina.chrysalidis@cern.ch; Goodacre, T. Day; Fedosseev, V. N.; Marsh, B. A. [CERN (Switzerland); Naubereit, P. [Johannes Gutenberg-Universität, Institiut für Physik (Germany); Rothe, S.; Seiffert, C. [CERN (Switzerland); Kron, T.; Wendt, K. [Johannes Gutenberg-Universität, Institiut für Physik (Germany)

    2017-11-15

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  16. A novel secret image sharing scheme based on chaotic system

    Science.gov (United States)

    Li, Li; Abd El-Latif, Ahmed A.; Wang, Chuanjun; Li, Qiong; Niu, Xiamu

    2012-04-01

    In this paper, we propose a new secret image sharing scheme based on chaotic system and Shamir's method. The new scheme protects the shadow images with confidentiality and loss-tolerance simultaneously. In the new scheme, we generate the key sequence based on chaotic system and then encrypt the original image during the sharing phase. Experimental results and analysis of the proposed scheme demonstrate a better performance than other schemes and confirm a high probability to resist brute force attack.

  17. A New Quantum Communication Scheme by Using Bell States

    International Nuclear Information System (INIS)

    Cao Haijing; Chen Jing; Song Heshan

    2006-01-01

    A new quantum communication scheme based on entanglement swapping is presented. Simplified calculation symbols are adopted to realize the process. Quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme. Two legitimate communicators can secretly share four certain key bits and four random key bits via three EPR pairs (quantum channels).

  18. Secure key distribution by swapping quantum entanglement

    International Nuclear Information System (INIS)

    Song, Daegene

    2004-01-01

    We report two key distribution schemes achieved by swapping quantum entanglement. Using two Bell states, two bits of secret key can be shared between two distant parties that play symmetric and equal roles. We also address eavesdropping attacks against the schemes

  19. A new access scheme in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    GU Xue-lin; YAN Wei; TIAN Hui; ZHANG Ping

    2006-01-01

    This article presents a dynamic random access scheme for orthogonal frequency division multiple access (OFDMA) systems. The key features of the proposed scheme are:it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes,and it can adjust the number of random access channels in a media access control (MAC) frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.

  20. Quantum signature scheme for known quantum messages

    International Nuclear Information System (INIS)

    Kim, Taewan; Lee, Hyang-Sook

    2015-01-01

    When we want to sign a quantum message that we create, we can use arbitrated quantum signature schemes which are possible to sign for not only known quantum messages but also unknown quantum messages. However, since the arbitrated quantum signature schemes need the help of a trusted arbitrator in each verification of the signature, it is known that the schemes are not convenient in practical use. If we consider only known quantum messages such as the above situation, there can exist a quantum signature scheme with more efficient structure. In this paper, we present a new quantum signature scheme for known quantum messages without the help of an arbitrator. Differing from arbitrated quantum signature schemes based on the quantum one-time pad with the symmetric key, since our scheme is based on quantum public-key cryptosystems, the validity of the signature can be verified by a receiver without the help of an arbitrator. Moreover, we show that our scheme provides the functions of quantum message integrity, user authentication and non-repudiation of the origin as in digital signature schemes. (paper)

  1. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

    The key attribute of a Fault Tolerant Control (FTC) system is its ability to maintain overall system stability and acceptable performance in the face of faults and failures within the feedback system. In this book Integral Sliding Mode (ISM) Control Allocation (CA) schemes for FTC are described, which have the potential to maintain close to nominal fault-free performance (for the entire system response), in the face of actuator faults and even complete failures of certain actuators. Broadly an ISM controller based around a model of the plant with the aim of creating a nonlinear fault tolerant feedback controller whose closed-loop performance is established during the design process. The second approach involves retro-fitting an ISM scheme to an existing feedback controller to introduce fault tolerance. This may be advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. A high fidelity benchmark model of a large transport aircraft is u...

  2. A secure and efficient uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care.

    Science.gov (United States)

    Das, Ashok Kumar; Goswami, Adrijit

    2013-06-01

    Connected health care has several applications including telecare medicine information system, personally controlled health records system, and patient monitoring. In such applications, user authentication can ensure the legality of patients. In user authentication for such applications, only the legal user/patient himself/herself is allowed to access the remote server, and no one can trace him/her according to transmitted data. Chang et al. proposed a uniqueness-and-anonymity-preserving remote user authentication scheme for connected health care (Chang et al., J Med Syst 37:9902, 2013). Their scheme uses the user's personal biometrics along with his/her password with the help of the smart card. The user's biometrics is verified using BioHashing. Their scheme is efficient due to usage of one-way hash function and exclusive-or (XOR) operations. In this paper, we show that though their scheme is very efficient, their scheme has several security weaknesses such as (1) it has design flaws in login and authentication phases, (2) it has design flaws in password change phase, (3) it fails to protect privileged insider attack, (4) it fails to protect the man-in-the middle attack, and (5) it fails to provide proper authentication. In order to remedy these security weaknesses in Chang et al.'s scheme, we propose an improvement of their scheme while retaining the original merit of their scheme. We show that our scheme is efficient as compared to Chang et al.'s scheme. Through the security analysis, we show that our scheme is secure against possible attacks. Further, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to ensure that our scheme is secure against passive and active attacks. In addition, after successful authentication between the user and the server, they establish a secret session key shared between them for future secure communication.

  3. On the diversity-multiplexing tradeoff of secret-key agreement over multiple-antenna channels

    KAUST Repository

    Zorgui, Marwen

    2014-09-01

    We consider secret-key agreement with public discussion over Rayleigh fading quasi-static channels. First, the secret-key diversity gain and the secret-key multiplexing gain are defined. Then, the secret-key diversity multiplexing tradeoff (DMT) is established. The eavesdropper is shown to \\'steal\\' only transmit antennas. We show that likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information (CSI) at the transmitter (CSI-T). This insensitivity of secret-key DMT toward CSI-T highlights a fundamental difference between secret-key agreement and the wiretap channel whose secret DMT depends crucially on CSI-T. Several secret-key DMT-achieving schemes are presented in case of full CSI-T.

  4. On the diversity-multiplexing tradeoff of secret-key agreement over multiple-antenna channels

    KAUST Repository

    Zorgui, Marwen; Rezki, Zouheir; Alomair, Basel; Alouini, Mohamed-Slim

    2014-01-01

    We consider secret-key agreement with public discussion over Rayleigh fading quasi-static channels. First, the secret-key diversity gain and the secret-key multiplexing gain are defined. Then, the secret-key diversity multiplexing tradeoff (DMT) is established. The eavesdropper is shown to 'steal' only transmit antennas. We show that likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information (CSI) at the transmitter (CSI-T). This insensitivity of secret-key DMT toward CSI-T highlights a fundamental difference between secret-key agreement and the wiretap channel whose secret DMT depends crucially on CSI-T. Several secret-key DMT-achieving schemes are presented in case of full CSI-T.

  5. Finite Boltzmann schemes

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the

  6. A combined spectrum sensing and OFDM demodulation scheme

    NARCIS (Netherlands)

    Heskamp, M.; Slump, Cornelis H.

    2009-01-01

    In this paper we propose a combined signaling and spectrum sensing scheme for cognitive radio that can detect in-band primary users while the networks own signal is active. The signaling scheme uses OFDM with phase shift keying modulated sub-carriers, and the detection scheme measures the deviation

  7. Quantum Watermarking Scheme Based on INEQR

    Science.gov (United States)

    Zhou, Ri-Gui; Zhou, Yang; Zhu, Changming; Wei, Lai; Zhang, Xiafen; Ian, Hou

    2018-04-01

    Quantum watermarking technology protects copyright by embedding invisible quantum signal in quantum multimedia data. In this paper, a watermarking scheme based on INEQR was presented. Firstly, the watermark image is extended to achieve the requirement of embedding carrier image. Secondly, the swap and XOR operation is used on the processed pixels. Since there is only one bit per pixel, XOR operation can achieve the effect of simple encryption. Thirdly, both the watermark image extraction and embedding operations are described, where the key image, swap operation and LSB algorithm are used. When the embedding is made, the binary image key is changed. It means that the watermark has been embedded. Of course, if the watermark image is extracted, the key's state need detected. When key's state is |1>, this extraction operation is carried out. Finally, for validation of the proposed scheme, both the Signal-to-noise ratio (PSNR) and the security of the scheme are analyzed.

  8. Generalization of binary tensor product schemes depends upon four parameters

    International Nuclear Information System (INIS)

    Bashir, R.; Bari, M.; Mustafa, G.

    2018-01-01

    This article deals with general formulae of parametric and non parametric bivariate subdivision scheme with four parameters. By assigning specific values to those parameters we get some special cases of existing tensor product schemes as well as a new proposed scheme. The behavior of schemes produced by the general formulae is interpolating, approximating and relaxed. Approximating bivariate subdivision schemes produce some other surfaces as compared to interpolating bivariate subdivision schemes. Polynomial reproduction and polynomial generation are desirable properties of subdivision schemes. Capability of polynomial reproduction and polynomial generation is strongly connected with smoothness, sum rules, convergence and approximation order. We also calculate the polynomial generation and polynomial reproduction of 9-point bivariate approximating subdivision scheme. Comparison of polynomial reproduction, polynomial generation and continuity of existing and proposed schemes has also been established. Some numerical examples are also presented to show the behavior of bivariate schemes. (author)

  9. Experimental aspects of deterministic secure quantum key distribution

    Energy Technology Data Exchange (ETDEWEB)

    Walenta, Nino; Korn, Dietmar; Puhlmann, Dirk; Felbinger, Timo; Hoffmann, Holger; Ostermeyer, Martin [Universitaet Potsdam (Germany). Institut fuer Physik; Bostroem, Kim [Universitaet Muenster (Germany)

    2008-07-01

    Most common protocols for quantum key distribution (QKD) use non-deterministic algorithms to establish a shared key. But deterministic implementations can allow for higher net key transfer rates and eavesdropping detection rates. The Ping-Pong coding scheme by Bostroem and Felbinger[1] employs deterministic information encoding in entangled states with its characteristic quantum channel from Bob to Alice and back to Bob. Based on a table-top implementation of this protocol with polarization-entangled photons fundamental advantages as well as practical issues like transmission losses, photon storage and requirements for progress towards longer transmission distances are discussed and compared to non-deterministic protocols. Modifications of common protocols towards a deterministic quantum key distribution are addressed.

  10. An authentication scheme for secure access to healthcare services.

    Science.gov (United States)

    Khan, Muhammad Khurram; Kumari, Saru

    2013-08-01

    Last few decades have witnessed boom in the development of information and communication technologies. Health-sector has also been benefitted with this advancement. To ensure secure access to healthcare services some user authentication mechanisms have been proposed. In 2012, Wei et al. proposed a user authentication scheme for telecare medical information system (TMIS). Recently, Zhu pointed out offline password guessing attack on Wei et al.'s scheme and proposed an improved scheme. In this article, we analyze both of these schemes for their effectiveness in TMIS. We show that Wei et al.'s scheme and its improvement proposed by Zhu fail to achieve some important characteristics necessary for secure user authentication. We find that security problems of Wei et al.'s scheme stick with Zhu's scheme; like undetectable online password guessing attack, inefficacy of password change phase, traceability of user's stolen/lost smart card and denial-of-service threat. We also identify that Wei et al.'s scheme lacks forward secrecy and Zhu's scheme lacks session key between user and healthcare server. We therefore propose an authentication scheme for TMIS with forward secrecy which preserves the confidentiality of air messages even if master secret key of healthcare server is compromised. Our scheme retains advantages of Wei et al.'s scheme and Zhu's scheme, and offers additional security. The security analysis and comparison results show the enhanced suitability of our scheme for TMIS.

  11. A Spatial Domain Quantum Watermarking Scheme

    International Nuclear Information System (INIS)

    Wei Zhan-Hong; Chen Xiu-Bo; Niu Xin-Xin; Yang Yi-Xian; Xu Shu-Jiang

    2016-01-01

    This paper presents a spatial domain quantum watermarking scheme. For a quantum watermarking scheme, a feasible quantum circuit is a key to achieve it. This paper gives a feasible quantum circuit for the presented scheme. In order to give the quantum circuit, a new quantum multi-control rotation gate, which can be achieved with quantum basic gates, is designed. With this quantum circuit, our scheme can arbitrarily control the embedding position of watermark images on carrier images with the aid of auxiliary qubits. Besides reversely acting the given quantum circuit, the paper gives another watermark extracting algorithm based on quantum measurements. Moreover, this paper also gives a new quantum image scrambling method and its quantum circuit. Differ from other quantum watermarking schemes, all given quantum circuits can be implemented with basic quantum gates. Moreover, the scheme is a spatial domain watermarking scheme, and is not based on any transform algorithm on quantum images. Meanwhile, it can make sure the watermark be secure even though the watermark has been found. With the given quantum circuit, this paper implements simulation experiments for the presented scheme. The experimental result shows that the scheme does well in the visual quality and the embedding capacity. (paper)

  12. A Digital Signature Scheme Based on MST3 Cryptosystems

    Directory of Open Access Journals (Sweden)

    Haibo Hong

    2014-01-01

    Full Text Available As special types of factorization of finite groups, logarithmic signature and cover have been used as the main components of cryptographic keys for secret key cryptosystems such as PGM and public key cryptosystems like MST1, MST2, and MST3. Recently, Svaba et. al proposed a revised MST3 encryption scheme with greater security. Meanwhile, they put forward an idea of constructing signature schemes on the basis of logarithmic signatures and random covers. In this paper, we firstly design a secure digital signature scheme based on logarithmic signatures and random covers. In order to complete the task, we devise a new encryption scheme based on MST3 cryptosystems.

  13. Color encryption scheme based on adapted quantum logistic map

    Science.gov (United States)

    Zaghloul, Alaa; Zhang, Tiejun; Amin, Mohamed; Abd El-Latif, Ahmed A.

    2014-04-01

    This paper presents a new color image encryption scheme based on quantum chaotic system. In this scheme, a new encryption scheme is accomplished by generating an intermediate chaotic key stream with the help of quantum chaotic logistic map. Then, each pixel is encrypted by the cipher value of the previous pixel and the adapted quantum logistic map. The results show that the proposed scheme has adequate security for the confidentiality of color images.

  14. Quantum Communication Scheme Using Non-symmetric Quantum Channel

    International Nuclear Information System (INIS)

    Cao Haijing; Chen Zhonghua; Song Heshan

    2008-01-01

    A theoretical quantum communication scheme based on entanglement swapping and superdense coding is proposed with a 3-dimensional Bell state and 2-dimensional Bell state function as quantum channel. quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme. The scheme is secure and has high source capacity. At last, we generalize the quantum communication scheme to d-dimensional quantum channel

  15. Establishment of a genotyping scheme for Coxiella burnetii.

    NARCIS (Netherlands)

    Svraka, Sanela; Toman, Rudolf; Skultety, Ludovit; Slaba, Katarina; Homan, Wieger L

    2006-01-01

    Coxiella burnetii is the causative agent of Q fever. The bacterium is highly infectious and is classified as a category B biological weapon. The tools of molecular biology are of utmost importance in a rapid and unambiguous identification of C. burnetii in naturally occurring Q fever outbreaks, or

  16. Current use of impact models for agri-environment schemes and potential for improvements of policy design and assessment.

    Science.gov (United States)

    Primdahl, Jørgen; Vesterager, Jens Peter; Finn, John A; Vlahos, George; Kristensen, Lone; Vejre, Henrik

    2010-06-01

    Agri-Environment Schemes (AES) to maintain or promote environmentally-friendly farming practices were implemented on about 25% of all agricultural land in the EU by 2002. This article analyses and discusses the actual and potential use of impact models in supporting the design, implementation and evaluation of AES. Impact models identify and establish the causal relationships between policy objectives and policy outcomes. We review and discuss the role of impact models at different stages in the AES policy process, and present results from a survey of impact models underlying 60 agri-environmental schemes in seven EU member states. We distinguished among three categories of impact models (quantitative, qualitative or common sense), depending on the degree of evidence in the formal scheme description, additional documents, or key person interviews. The categories of impact models used mainly depended on whether scheme objectives were related to natural resources, biodiversity or landscape. A higher proportion of schemes dealing with natural resources (primarily water) were based on quantitative impact models, compared to those concerned with biodiversity or landscape. Schemes explicitly targeted either on particular parts of individual farms or specific areas tended to be based more on quantitative impact models compared to whole-farm schemes and broad, horizontal schemes. We conclude that increased and better use of impact models has significant potential to improve efficiency and effectiveness of AES. (c) 2009 Elsevier Ltd. All rights reserved.

  17. Quantum Encryption Minimising Key Leakage under Known Plaintext Attacks

    DEFF Research Database (Denmark)

    Pedersen, Thomas Brochmann

    2006-01-01

    , or interactive encryption schemes, where the interaction does not need to occur online. In our model we show that the amount of key leaked under a known plaintext attack can be made arbitrarily small even in non-interactive encryption schemes. We also give an encryption scheme where eavesdropping can be detected....... In this encryption scheme the entire key can be safely recycled when no eavesdropping is detected....

  18. Scheme Program Documentation Tools

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2004-01-01

    are separate and intended for different documentation purposes they are related to each other in several ways. Both tools are based on XML languages for tool setup and for documentation authoring. In addition, both tools rely on the LAML framework which---in a systematic way---makes an XML language available...... as named functions in Scheme. Finally, the Scheme Elucidator is able to integrate SchemeDoc resources as part of an internal documentation resource....

  19. Symmetric Key Authentication Services Revisited

    NARCIS (Netherlands)

    Crispo, B.; Popescu, B.C.; Tanenbaum, A.S.

    2004-01-01

    Most of the symmetric key authentication schemes deployed today are based on principles introduced by Needham and Schroeder [15] more than twenty years ago. However, since then, the computing environment has evolved from a LAN-based client-server world to include new paradigms, including wide area

  20. Navigators’ Behavior in Traffic Separation Schemes

    Directory of Open Access Journals (Sweden)

    Zbigniew Pietrzykowski

    2015-03-01

    Full Text Available One of the areas of decision support in the navigational ship conduct process is a Traffic Separation Scheme. TSSs are established in areas with high traffic density, often near the shore and in port approaches. The main purpose of these schemes is to improve maritime safety by channeling vessel traffic into streams. Traffic regulations as well as ships behavior in real conditions in chosen TSSs have been analyzed in order to develop decision support algorithms.

  1. Extensible router for a quantum key distribution network

    International Nuclear Information System (INIS)

    Zhang Tao; Mo Xiaofan; Han Zhengfu; Guo Guangcan

    2008-01-01

    Building a quantum key distribution network is crucial for practical quantum cryptography. We present a scheme to build a star topology quantum key distribution network based on wavelength division multiplexing which, with current technology, can connect at least a hundred users. With the scheme, a 4-user demonstration network was built up and key exchanges were performed

  2. Security and efficiency data sharing scheme for cloud storage

    International Nuclear Information System (INIS)

    Han, Ke; Li, Qingbo; Deng, Zhongliang

    2016-01-01

    With the adoption and diffusion of data sharing paradigm in cloud storage, there have been increasing demands and concerns for shared data security. Ciphertext Policy Attribute-Based Encryption (CP-ABE) is becoming a promising cryptographic solution to the security problem of shared data in cloud storage. However due to key escrow, backward security and inefficiency problems, existing CP-ABE schemes cannot be directly applied to cloud storage system. In this paper, an effective and secure access control scheme for shared data is proposed to solve those problems. The proposed scheme refines the security of existing CP-ABE based schemes. Specifically, key escrow and conclusion problem are addressed by dividing key generation center into several distributed semi-trusted parts. Moreover, secrecy revocation algorithm is proposed to address not only back secrecy but efficient problem in existing CP-ABE based scheme. Furthermore, security and performance analyses indicate that the proposed scheme is both secure and efficient for cloud storage.

  3. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    J. Goutsias (John); H.J.A.M. Heijmans (Henk)

    1998-01-01

    textabstract[PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis

  4. Adaptive protection scheme

    Directory of Open Access Journals (Sweden)

    R. Sitharthan

    2016-09-01

    Full Text Available This paper aims at modelling an electronically coupled distributed energy resource with an adaptive protection scheme. The electronically coupled distributed energy resource is a microgrid framework formed by coupling the renewable energy source electronically. Further, the proposed adaptive protection scheme provides a suitable protection to the microgrid for various fault conditions irrespective of the operating mode of the microgrid: namely, grid connected mode and islanded mode. The outstanding aspect of the developed adaptive protection scheme is that it monitors the microgrid and instantly updates relay fault current according to the variations that occur in the system. The proposed adaptive protection scheme also employs auto reclosures, through which the proposed adaptive protection scheme recovers faster from the fault and thereby increases the consistency of the microgrid. The effectiveness of the proposed adaptive protection is studied through the time domain simulations carried out in the PSCAD⧹EMTDC software environment.

  5. Key Distribution and Changing Key Cryptosystem Based on Phase Retrieval Algorithm and RSA Public-Key Algorithm

    Directory of Open Access Journals (Sweden)

    Tieyu Zhao

    2015-01-01

    Full Text Available The optical image encryption has attracted more and more researchers’ attention, and the various encryption schemes have been proposed. In existing optical cryptosystem, the phase functions or images are usually used as the encryption keys, and it is difficult that the traditional public-key algorithm (such as RSA, ECC, etc. is used to complete large numerical key transfer. In this paper, we propose a key distribution scheme based on the phase retrieval algorithm and the RSA public-key algorithm, which solves the problem for the key distribution in optical image encryption system. Furthermore, we also propose a novel image encryption system based on the key distribution principle. In the system, the different keys can be used in every encryption process, which greatly improves the security of the system.

  6. An Efficient V2I Authentication Scheme for VANETs

    Directory of Open Access Journals (Sweden)

    Yousheng Zhou

    2018-01-01

    Full Text Available The advent of intelligent transportation system has a crucial impact on the traffic safety and efficiency. To cope with security issues such as spoofing attack and forgery attack, many authentication schemes for vehicular ad hoc networks (VANETs have been developed, which are based on the hypothesis that secret keys are kept perfectly secure. However, key exposure is inevitable on account of the openness of VANET environment. To address this problem, key insulation is introduced in our proposed scheme. With a helper device, vehicles could periodically update their own secret keys. In this way, the forward and backward secrecy has been achieved. In addition, the elliptic curve operations have been integrated to improve the performance. The random oracle model is adopted to prove the security of the proposed scheme, and the experiment has been conducted to demonstrate the comparison between our scheme and the existing similar schemes.

  7. Efficient multiparty quantum-secret-sharing schemes

    International Nuclear Information System (INIS)

    Xiao Li; Deng Fuguo; Long Guilu; Pan Jianwei

    2004-01-01

    In this work, we generalize the quantum-secret-sharing scheme of Hillery, Buzek, and Berthiaume [Phys. Rev. A 59, 1829 (1999)] into arbitrary multiparties. Explicit expressions for the shared secret bit is given. It is shown that in the Hillery-Buzek-Berthiaume quantum-secret-sharing scheme the secret information is shared in the parity of binary strings formed by the measured outcomes of the participants. In addition, we have increased the efficiency of the quantum-secret-sharing scheme by generalizing two techniques from quantum key distribution. The favored-measuring-basis quantum-secret-sharing scheme is developed from the Lo-Chau-Ardehali technique [H. K. Lo, H. F. Chau, and M. Ardehali, e-print quant-ph/0011056] where all the participants choose their measuring-basis asymmetrically, and the measuring-basis-encrypted quantum-secret-sharing scheme is developed from the Hwang-Koh-Han technique [W. Y. Hwang, I. G. Koh, and Y. D. Han, Phys. Lett. A 244, 489 (1998)] where all participants choose their measuring basis according to a control key. Both schemes are asymptotically 100% in efficiency, hence nearly all the Greenberger-Horne-Zeilinger states in a quantum-secret-sharing process are used to generate shared secret information

  8. A group signature scheme based on quantum teleportation

    International Nuclear Information System (INIS)

    Wen Xiaojun; Tian Yuan; Ji Liping; Niu Xiamu

    2010-01-01

    In this paper, we present a group signature scheme using quantum teleportation. Different from classical group signature and current quantum signature schemes, which could only deliver either group signature or unconditional security, our scheme guarantees both by adopting quantum key preparation, quantum encryption algorithm and quantum teleportation. Security analysis proved that our scheme has the characteristics of group signature, non-counterfeit, non-disavowal, blindness and traceability. Our quantum group signature scheme has a foreseeable application in the e-payment system, e-government, e-business, etc.

  9. A group signature scheme based on quantum teleportation

    Energy Technology Data Exchange (ETDEWEB)

    Wen Xiaojun; Tian Yuan; Ji Liping; Niu Xiamu, E-mail: wxjun36@gmail.co [Information Countermeasure Technique Research Institute, Harbin Institute of Technology, Harbin 150001 (China)

    2010-05-01

    In this paper, we present a group signature scheme using quantum teleportation. Different from classical group signature and current quantum signature schemes, which could only deliver either group signature or unconditional security, our scheme guarantees both by adopting quantum key preparation, quantum encryption algorithm and quantum teleportation. Security analysis proved that our scheme has the characteristics of group signature, non-counterfeit, non-disavowal, blindness and traceability. Our quantum group signature scheme has a foreseeable application in the e-payment system, e-government, e-business, etc.

  10. Threshold Signature Schemes Application

    Directory of Open Access Journals (Sweden)

    Anastasiya Victorovna Beresneva

    2015-10-01

    Full Text Available This work is devoted to an investigation of threshold signature schemes. The systematization of the threshold signature schemes was done, cryptographic constructions based on interpolation Lagrange polynomial, elliptic curves and bilinear pairings were examined. Different methods of generation and verification of threshold signatures were explored, the availability of practical usage of threshold schemes in mobile agents, Internet banking and e-currency was shown. The topics of further investigation were given and it could reduce a level of counterfeit electronic documents signed by a group of users.

  11. Chaotic image encryption based on running-key related to plaintext.

    Science.gov (United States)

    Guanghui, Cao; Kai, Hu; Yizhi, Zhang; Jun, Zhou; Xing, Zhang

    2014-01-01

    In the field of chaotic image encryption, the algorithm based on correlating key with plaintext has become a new developing direction. However, for this kind of algorithm, some shortcomings in resistance to reconstruction attack, efficient utilization of chaotic resource, and reducing dynamical degradation of digital chaos are found. In order to solve these problems and further enhance the security of encryption algorithm, based on disturbance and feedback mechanism, we present a new image encryption scheme. In the running-key generation stage, by successively disturbing chaotic stream with cipher-text, the relation of running-key to plaintext is established, reconstruction attack is avoided, effective use of chaotic resource is guaranteed, and dynamical degradation of digital chaos is minimized. In the image encryption stage, by introducing random-feedback mechanism, the difficulty of breaking this scheme is increased. Comparing with the-state-of-the-art algorithms, our scheme exhibits good properties such as large key space, long key period, and extreme sensitivity to the initial key and plaintext. Therefore, it can resist brute-force, reconstruction attack, and differential attack.

  12. Chaotic Image Encryption Based on Running-Key Related to Plaintext

    Directory of Open Access Journals (Sweden)

    Cao Guanghui

    2014-01-01

    Full Text Available In the field of chaotic image encryption, the algorithm based on correlating key with plaintext has become a new developing direction. However, for this kind of algorithm, some shortcomings in resistance to reconstruction attack, efficient utilization of chaotic resource, and reducing dynamical degradation of digital chaos are found. In order to solve these problems and further enhance the security of encryption algorithm, based on disturbance and feedback mechanism, we present a new image encryption scheme. In the running-key generation stage, by successively disturbing chaotic stream with cipher-text, the relation of running-key to plaintext is established, reconstruction attack is avoided, effective use of chaotic resource is guaranteed, and dynamical degradation of digital chaos is minimized. In the image encryption stage, by introducing random-feedback mechanism, the difficulty of breaking this scheme is increased. Comparing with the-state-of-the-art algorithms, our scheme exhibits good properties such as large key space, long key period, and extreme sensitivity to the initial key and plaintext. Therefore, it can resist brute-force, reconstruction attack, and differential attack.

  13. Symmetric weak ternary quantum homomorphic encryption schemes

    Science.gov (United States)

    Wang, Yuqi; She, Kun; Luo, Qingbin; Yang, Fan; Zhao, Chao

    2016-03-01

    Based on a ternary quantum logic circuit, four symmetric weak ternary quantum homomorphic encryption (QHE) schemes were proposed. First, for a one-qutrit rotation gate, a QHE scheme was constructed. Second, in view of the synthesis of a general 3 × 3 unitary transformation, another one-qutrit QHE scheme was proposed. Third, according to the one-qutrit scheme, the two-qutrit QHE scheme about generalized controlled X (GCX(m,n)) gate was constructed and further generalized to the n-qutrit unitary matrix case. Finally, the security of these schemes was analyzed in two respects. It can be concluded that the attacker can correctly guess the encryption key with a maximum probability pk = 1/33n, thus it can better protect the privacy of users’ data. Moreover, these schemes can be well integrated into the future quantum remote server architecture, and thus the computational security of the users’ private quantum information can be well protected in a distributed computing environment.

  14. Ponzi scheme diffusion in complex networks

    Science.gov (United States)

    Zhu, Anding; Fu, Peihua; Zhang, Qinghe; Chen, Zhenyue

    2017-08-01

    Ponzi schemes taking the form of Internet-based financial schemes have been negatively affecting China's economy for the last two years. Because there is currently a lack of modeling research on Ponzi scheme diffusion within social networks yet, we develop a potential-investor-divestor (PID) model to investigate the diffusion dynamics of Ponzi scheme in both homogeneous and inhomogeneous networks. Our simulation study of artificial and real Facebook social networks shows that the structure of investor networks does indeed affect the characteristics of dynamics. Both the average degree of distribution and the power-law degree of distribution will reduce the spreading critical threshold and will speed up the rate of diffusion. A high speed of diffusion is the key to alleviating the interest burden and improving the financial outcomes for the Ponzi scheme operator. The zero-crossing point of fund flux function we introduce proves to be a feasible index for reflecting the fast-worsening situation of fiscal instability and predicting the forthcoming collapse. The faster the scheme diffuses, the higher a peak it will reach and the sooner it will collapse. We should keep a vigilant eye on the harm of Ponzi scheme diffusion through modern social networks.

  15. The ultimate security bounds of quantum key distribution protocols

    International Nuclear Information System (INIS)

    Nikolopoulos, G.M.; Alber, G.

    2005-01-01

    Full text: Quantum key distribution (QKD) protocols exploit quantum correlations in order to establish a secure key between two legitimate users. Recent work on QKD has revealed a remarkable link between quantum and secret correlations. In this talk we report on recent results concerning the ultimate upper security bounds of various QKD schemes (i.e., the maximal disturbance up to which the two legitimate users share quantum correlations) under the assumption of general coherent attacks. In particular, we derive an analytic expression for the ultimate upper security bound of QKD schemes that use two mutually unbiased bases. As long as the two legitimate users focus on the sifted key and treat each pair of data independently during the post processing, our results are valid for arbitrary dimensions of the information carriers. The bound we have derived is well below the predictions of optimal cloning machines. The possibility of extraction of a secret key beyond entanglement distillation is also discussed. In the case of qutrits we argue that any eavesdropping strategy is equivalent to a symmetric one. For higher dimensions, however, such equivalence is generally no longer valid. (author)

  16. Anonymity-Preserving Public-Key Encryption

    DEFF Research Database (Denmark)

    Kohlweiss, Markulf; Maurer, Ueli; Onete, Cristina

    2013-01-01

    security properties have been proposed. We investigate constructions as well as limitations for preserving receiver anonymity when using public-key encryption (PKE). We use the constructive cryptography approach by Maurer and Renner and interpret cryptographic schemes as constructions of a certain ideal...... literature (IND-CCA, key-privacy, weak robustness). We also show that a desirable stronger variant, preventing the adversary from selective ”trial-deliveries” of messages, is unfortunately unachievable by any PKE scheme, no matter how strong. The constructive approach makes the guarantees achieved...... by applying a cryptographic scheme explicit in the constructed (ideal) resource; this specifies the exact requirements for the applicability of a cryptographic scheme in a given context. It also allows to decide which of the existing security properties of such a cryptographic scheme are adequate...

  17. Comparison is key.

    Science.gov (United States)

    Stone, Mark H; Stenner, A Jackson

    2014-01-01

    Several concepts from Georg Rasch's last papers are discussed. The key one is comparison because Rasch considered the method of comparison fundamental to science. From the role of comparison stems scientific inference made operational by a properly developed frame of reference producing specific objectivity. The exact specifications Rasch outlined for making comparisons are explicated from quotes, and the role of causality derived from making comparisons is also examined. Understanding causality has implications for what can and cannot be produced via Rasch measurement. His simple examples were instructive, but the implications are far reaching upon first establishing the key role of comparison.

  18. Improvement of One Quantum Encryption Scheme

    Science.gov (United States)

    Cao, Zhengjun; Liu, Lihua

    2012-01-01

    Zhou et al. proposed a quantum encryption scheme based on quantum computation in 2006 [N. Zhou et al., Physica A362 (2006) 305]. Each qubit of the ciphertext is constrained to two pairs of conjugate states. So, its implementation is feasible with the existing technology. But it is inefficient since it entails six key bits to encrypt one message bit, and the resulting ciphertext for one message bit consists of three qubits. In addition, its security cannot be directly reduced to the well-known BB84 protocol. In this paper, we improve it using the technique developed in BB84 protocol. The new scheme entails only two key bits to encrypt one message bit. The resulting ciphertext is just composed of two qubits. It saves about a half cost without the loss of security. Moreover, the new scheme is probabilistic instead of deterministic.

  19. Establishment of the National Nuclear Regulatory Portal (NNRP) as the key element of the Global Nuclear Safety and Security Network and Regulatory Network (GNSSN/RegNet) for sharing of nuclear safety information and knowledge among the Global Expert Community

    International Nuclear Information System (INIS)

    Kuvshinnikov, A.V.

    2011-01-01

    The Global Nuclear Safety and Security Network (GNSSN) implements the concept of the Global Nuclear Safety and Security Framework (GNSSF) as outlined in INSAG 21. This is the framework of instruments and resources for achieving and maintaining worldwide a high level of safety and security at nuclear facilities and activities as stated in SF-1 and supporting safety standards or recommendations such as INSAG-12. National efforts are and should be augmented by the activities of a variety of international enterprises that facilitate safety and security. The IAEA standard GS-R-3 requires that information and knowledge is managed as a resource. Further strengthening of GNSSN in particular regulatory networking as intended by GNSSN/RegNet has to be based on current national priorities, on existing regional and thematic networks and on the established mechanisms of international co-operation as presented for example on the websites of the IAEA or the OECD-NEA. Current design and operation of RegNet are flexible enough to accommodate differences in national and international approaches and practices and to facilitate exchange and cooperation on regulatory matters. The main role of GNSSN/RegNet is sharing knowledge and bringing people together to enhance and promote nuclear safety and security. The objectives of GNSSN/RegNet: enhancing safety and security by international cooperation, sharing information and best practices, enabling adequate access to relevant safety and security information and promoting the dissemination of this information, implementing active collaboration in the relevant areas related to safety and security, such as joint projects, peer reviews, enabling synergies among existing networks and initiatives, informing the public on the relevant safety and security areas and the related international collaboration. In the RegNet part of the GNSSN exist the National Nuclear Regulatory Portal (NNRP) which is on one hand a part of the global RegNet and on the

  20. CSR schemes in agribusiness

    DEFF Research Database (Denmark)

    Pötz, Katharina Anna; Haas, Rainer; Balzarova, Michaela

    2013-01-01

    of schemes that can be categorized on focus areas, scales, mechanisms, origins, types and commitment levels. Research limitations/implications – The findings contribute to conceptual and empirical research on existing models to compare and analyse CSR standards. Sampling technique and depth of analysis limit......Purpose – The rise of CSR followed a demand for CSR standards and guidelines. In a sector already characterized by a large number of standards, the authors seek to ask what CSR schemes apply to agribusiness, and how they can be systematically compared and analysed. Design....../methodology/approach – Following a deductive-inductive approach the authors develop a model to compare and analyse CSR schemes based on existing studies and on coding qualitative data on 216 CSR schemes. Findings – The authors confirm that CSR standards and guidelines have entered agribusiness and identify a complex landscape...

  1. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  2. Evaluating statistical cloud schemes

    OpenAIRE

    Grützun, Verena; Quaas, Johannes; Morcrette , Cyril J.; Ament, Felix

    2015-01-01

    Statistical cloud schemes with prognostic probability distribution functions have become more important in atmospheric modeling, especially since they are in principle scale adaptive and capture cloud physics in more detail. While in theory the schemes have a great potential, their accuracy is still questionable. High-resolution three-dimensional observational data of water vapor and cloud water, which could be used for testing them, are missing. We explore the potential of ground-based re...

  3. Gamma spectrometry; level schemes

    International Nuclear Information System (INIS)

    Blachot, J.; Bocquet, J.P.; Monnand, E.; Schussler, F.

    1977-01-01

    The research presented dealt with: a new beta emitter, isomer of 131 Sn; the 136 I levels fed through the radioactive decay of 136 Te (20.9s); the A=145 chain (β decay of Ba, La and Ce, and level schemes for 145 La, 145 Ce, 145 Pr); the A=47 chain (La and Ce, β decay, and the level schemes of 147 Ce and 147 Pr) [fr

  4. Scheme of energy utilities

    International Nuclear Information System (INIS)

    2002-04-01

    This scheme defines the objectives relative to the renewable energies and the rational use of the energy in the framework of the national energy policy. It evaluates the needs and the potentialities of the regions and preconizes the actions between the government and the territorial organizations. The document is presented in four parts: the situation, the stakes and forecasts; the possible actions for new measures; the scheme management and the regional contributions analysis. (A.L.B.)

  5. A Polynomial Subset-Based Efficient Multi-Party Key Management System for Lightweight Device Networks.

    Science.gov (United States)

    Mahmood, Zahid; Ning, Huansheng; Ghafoor, AtaUllah

    2017-03-24

    Wireless Sensor Networks (WSNs) consist of lightweight devices to measure sensitive data that are highly vulnerable to security attacks due to their constrained resources. In a similar manner, the internet-based lightweight devices used in the Internet of Things (IoT) are facing severe security and privacy issues because of the direct accessibility of devices due to their connection to the internet. Complex and resource-intensive security schemes are infeasible and reduce the network lifetime. In this regard, we have explored the polynomial distribution-based key establishment schemes and identified an issue that the resultant polynomial value is either storage intensive or infeasible when large values are multiplied. It becomes more costly when these polynomials are regenerated dynamically after each node join or leave operation and whenever key is refreshed. To reduce the computation, we have proposed an Efficient Key Management (EKM) scheme for multiparty communication-based scenarios. The proposed session key management protocol is established by applying a symmetric polynomial for group members, and the group head acts as a responsible node. The polynomial generation method uses security credentials and secure hash function. Symmetric cryptographic parameters are efficient in computation, communication, and the storage required. The security justification of the proposed scheme has been completed by using Rubin logic, which guarantees that the protocol attains mutual validation and session key agreement property strongly among the participating entities. Simulation scenarios are performed using NS 2.35 to validate the results for storage, communication, latency, energy, and polynomial calculation costs during authentication, session key generation, node migration, secure joining, and leaving phases. EKM is efficient regarding storage, computation, and communication overhead and can protect WSN-based IoT infrastructure.

  6. Key issues

    International Nuclear Information System (INIS)

    Cook, N.G.W.

    1980-01-01

    Successful modeling of the thermo-mechanical and hydrochemical behavior of radioactive waste repositories in hard rock is possible in principle. Because such predictions lie outside the realm of experience, their adequacy depends entirely upon a thorough understanding of three fundamental questions: an understanding of the chemical and physical processess that determine the behavior of rock and all its complexities; accurate and realistic numerical models of the geologic media within which a repository may be built; and sufficient in-situ data covering the entire geologic region affected by, or effecting the behavior of a repository. At present sufficient is known to be able to identify most of those areas which require further attention. These areas extend all the way from a complete understanding of the chemical and physical processes determining the behavior of rock through to the exploration mapping and testing that must be done during the development of any potential repository. Many of the techniques, laboratory equipment, field instrumentation, and numerical methods needed to accomplish this do not exist at present. Therefore it is necessary to accept that a major investment in scientific research is required to generate this information over the next few years. The spectrum of scientific and engineering activities is wide extending from laboratory measurements through the development of numerical models to the measurement of data in-situ, but there is every prospect that sufficient can be done to resolve these key issues. However, to do so requires overt recognition of the many gaps which exist in our knowledge and abilities today, and of the need to bridge these gaps and of the significant costs involved in doing so

  7. Optimal placement of combined heat and power scheme (cogeneration): application to an ethylbenzene plant

    International Nuclear Information System (INIS)

    Zainuddin Abd Manan; Lim Fang Yee

    2001-01-01

    Combined heat and power (CHP) scheme, also known as cogeneration is widely accepted as a highly efficient energy saving measure, particularly in medium to large scale chemical process plants. To date, CHP application is well established in the developed countries. The advantage of a CHP scheme for a chemical plant is two-fold: (i) drastically cut down on the electricity bill from on-site power generation (ii) to save the fuel bills through recovery of the quality waste heat from power generation for process heating. In order to be effective, a CHP scheme must be placed at the right temperature level in the context of the overall process. Failure to do so might render a CHP venture worthless. This paper discusses the procedure for an effective implementation of a CHP scheme. An ethylbenzene process is used as a case study. A key visualization tool known as the grand composite curves is used to provide an overall picture of the process heat source and heat sink profiles. The grand composite curve, which is generated based on the first principles of Pinch Analysis enables the CHP scheme to be optimally placed within the overall process scenario. (Author)

  8. Signature Schemes Secure against Hard-to-Invert Leakage

    DEFF Research Database (Denmark)

    Faust, Sebastian; Hazay, Carmit; Nielsen, Jesper Buus

    2012-01-01

    of the secret key. As a second contribution, we construct a signature scheme that achieves security for random messages assuming that the adversary is given a polynomial-time hard to invert function. Here, polynomial-hardness is required even when given the entire public-key – so called weak auxiliary input......-theoretically reveal the entire secret key. In this work, we propose the first constructions of digital signature schemes that are secure in the auxiliary input model. Our main contribution is a digital signature scheme that is secure against chosen message attacks when given an exponentially hard-to-invert function...... security. We show that such signature schemes readily give us auxiliary input secure identification schemes...

  9. Analysis and improvement for the performance of Baptista's cryptographic scheme

    International Nuclear Information System (INIS)

    Wei Jun; Liao Xiaofeng; Wong, K.W.; Zhou Tsing; Deng Yigui

    2006-01-01

    Based on Baptista's chaotic cryptosystem, we propose a secure and robust chaotic cryptographic scheme after investigating the problems found in this cryptosystem as well as its variants. In this proposed scheme, a subkey array generated from the key and the plaintext is adopted to enhance the security. Some methods are introduced to increase the efficiency. Theoretical analyses and numerical simulations indicate that the proposed scheme is secure and efficient for practical use

  10. Semi-quantum communication: protocols for key agreement, controlled secure direct communication and dialogue

    Science.gov (United States)

    Shukla, Chitra; Thapliyal, Kishore; Pathak, Anirban

    2017-12-01

    Semi-quantum protocols that allow some of the users to remain classical are proposed for a large class of problems associated with secure communication and secure multiparty computation. Specifically, first-time semi-quantum protocols are proposed for key agreement, controlled deterministic secure communication and dialogue, and it is shown that the semi-quantum protocols for controlled deterministic secure communication and dialogue can be reduced to semi-quantum protocols for e-commerce and private comparison (socialist millionaire problem), respectively. Complementing with the earlier proposed semi-quantum schemes for key distribution, secret sharing and deterministic secure communication, set of schemes proposed here and subsequent discussions have established that almost every secure communication and computation tasks that can be performed using fully quantum protocols can also be performed in semi-quantum manner. Some of the proposed schemes are completely orthogonal-state-based, and thus, fundamentally different from the existing semi-quantum schemes that are conjugate coding-based. Security, efficiency and applicability of the proposed schemes have been discussed with appropriate importance.

  11. Performance investigation of advanced adsorption desalination cycle with condenser-evaporator heat recovery scheme

    KAUST Repository

    Thu, Kyaw; Kim, Youngdeuk; Myat, Aung; Chakraborty, Anutosh; Ng, K. C.

    2013-01-01

    Energy or heat recovery schemes are keys for the performance improvement of any heat-activated cycles such as the absorption and adsorption cycles. We present two innovative heat recovery schemes between the condensing and evaporating units

  12. J-PAKE: Authenticated Key Exchange without PKI

    Science.gov (United States)

    Hao, Feng; Ryan, Peter

    Password Authenticated Key Exchange (PAKE) is one of the important topics in cryptography. It aims to address a practical security problem: how to establish secure communication between two parties solely based on a shared password without requiring a Public Key Infrastructure (PKI). After more than a decade of extensive research in this field, there have been several PAKE protocols available. The EKE and SPEKE schemes are perhaps the two most notable examples. Both techniques are however patented. In this paper, we review these techniques in detail and summarize various theoretical and practical weaknesses. In addition, we present a new PAKE solution called J-PAKE. Our strategy is to depend on well-established primitives such as the Zero-Knowledge Proof (ZKP). So far, almost all of the past solutions have avoided using ZKP for the concern on efficiency. We demonstrate how to effectively integrate the ZKP into the protocol design and meanwhile achieve good efficiency. Our protocol has comparable computational efficiency to the EKE and SPEKE schemes with clear advantages on security.

  13. Towards Symbolic Encryption Schemes

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.; Zenner, Erik

    2012-01-01

    , namely an authenticated encryption scheme that is secure under chosen ciphertext attack. Therefore, many reasonable encryption schemes, such as AES in the CBC or CFB mode, are not among the implementation options. In this paper, we report new attacks on CBC and CFB based implementations of the well......Symbolic encryption, in the style of Dolev-Yao models, is ubiquitous in formal security models. In its common use, encryption on a whole message is specified as a single monolithic block. From a cryptographic perspective, however, this may require a resource-intensive cryptographic algorithm......-known Needham-Schroeder and Denning-Sacco protocols. To avoid such problems, we advocate the use of refined notions of symbolic encryption that have natural correspondence to standard cryptographic encryption schemes....

  14. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  15. Network-based Arbitrated Quantum Signature Scheme with Graph State

    Science.gov (United States)

    Ma, Hongling; Li, Fei; Mao, Ningyi; Wang, Yijun; Guo, Ying

    2017-08-01

    Implementing an arbitrated quantum signature(QAS) through complex networks is an interesting cryptography technology in the literature. In this paper, we propose an arbitrated quantum signature for the multi-user-involved networks, whose topological structures are established by the encoded graph state. The determinative transmission of the shared keys, is enabled by the appropriate stabilizers performed on the graph state. The implementation of this scheme depends on the deterministic distribution of the multi-user-shared graph state on which the encoded message can be processed in signing and verifying phases. There are four parties involved, the signatory Alice, the verifier Bob, the arbitrator Trent and Dealer who assists the legal participants in the signature generation and verification. The security is guaranteed by the entanglement of the encoded graph state which is cooperatively prepared by legal participants in complex quantum networks.

  16. Single-quadrature continuous-variable quantum key distribution

    DEFF Research Database (Denmark)

    Gehring, Tobias; Jacobsen, Christian Scheffmann; Andersen, Ulrik Lund

    2016-01-01

    Most continuous-variable quantum key distribution schemes are based on the Gaussian modulation of coherent states followed by continuous quadrature detection using homodyne detectors. In all previous schemes, the Gaussian modulation has been carried out in conjugate quadratures thus requiring two...... commercialization of continuous-variable quantum key distribution, provided that the low noise requirement can be achieved....

  17. Quantum attack-resistent certificateless multi-receiver signcryption scheme.

    Directory of Open Access Journals (Sweden)

    Huixian Li

    Full Text Available The existing certificateless signcryption schemes were designed mainly based on the traditional public key cryptography, in which the security relies on the hard problems, such as factor decomposition and discrete logarithm. However, these problems will be easily solved by the quantum computing. So the existing certificateless signcryption schemes are vulnerable to the quantum attack. Multivariate public key cryptography (MPKC, which can resist the quantum attack, is one of the alternative solutions to guarantee the security of communications in the post-quantum age. Motivated by these concerns, we proposed a new construction of the certificateless multi-receiver signcryption scheme (CLMSC based on MPKC. The new scheme inherits the security of MPKC, which can withstand the quantum attack. Multivariate quadratic polynomial operations, which have lower computation complexity than bilinear pairing operations, are employed in signcrypting a message for a certain number of receivers in our scheme. Security analysis shows that our scheme is a secure MPKC-based scheme. We proved its security under the hardness of the Multivariate Quadratic (MQ problem and its unforgeability under the Isomorphism of Polynomials (IP assumption in the random oracle model. The analysis results show that our scheme also has the security properties of non-repudiation, perfect forward secrecy, perfect backward secrecy and public verifiability. Compared with the existing schemes in terms of computation complexity and ciphertext length, our scheme is more efficient, which makes it suitable for terminals with low computation capacity like smart cards.

  18. New analytic unitarization schemes

    International Nuclear Information System (INIS)

    Cudell, J.-R.; Predazzi, E.; Selyugin, O. V.

    2009-01-01

    We consider two well-known classes of unitarization of Born amplitudes of hadron elastic scattering. The standard class, which saturates at the black-disk limit includes the standard eikonal representation, while the other class, which goes beyond the black-disk limit to reach the full unitarity circle, includes the U matrix. It is shown that the basic properties of these schemes are independent of the functional form used for the unitarization, and that U matrix and eikonal schemes can be extended to have similar properties. A common form of unitarization is proposed interpolating between both classes. The correspondence with different nonlinear equations are also briefly examined.

  19. A Secure and Efficient Certificateless Short Signature Scheme

    Directory of Open Access Journals (Sweden)

    Lin Cheng

    2013-07-01

    Full Text Available Certificateless public key cryptography combines advantage of traditional public key cryptography and identity-based public key cryptography as it avoids usage of certificates and resolves the key escrow problem. In 2007, Huang et al. classified adversaries against certificateless signatures according to their attack power into normal, strong and super adversaries (ordered by their attack power. In this paper, we propose a new certificateless short signature scheme and prove that it is secure against both of the super type I and the super type II adversaries. Our new scheme not only achieves the strongest security level but also has the shortest signature length (one group element. Compared with the other short certificateless signature schemes which have a similar security level, our new scheme has less operation cost.

  20. Diffie-Hellman Key Based Authentication in Proxy Mobile IPv6

    Directory of Open Access Journals (Sweden)

    HyunGon Kim

    2010-01-01

    Full Text Available Wireless communication service providers have been showing strong interest in Proxy Mobile IPv6 for providing network-based IP mobility management. This could be a prominent way to support IP mobility to mobile nodes, because Proxy Mobile IPv6 requires minimal functionalities on the mobile node. While several extensions for Proxy Mobile IPv6 are being developed in the Internet Engineering Task Force, there has been little attentions paid to developing efficient authentication mechanisms. An authentication scheme for a mobility protocol must protect signaling messages against various security threats, e.g., session stealing attack, intercept attack by redirection, replay attack, and key exposure, while minimizing authentication latency. In this paper, we propose a Diffie-Hellman key based authentication scheme that utilizes the low layer signaling to exchange Diffie-Hellman variables and allows mobility service provisioning entities to exchange mobile node's profile and ongoing sessions securely. By utilizing the low layer signaling and context transfer between relevant nodes, the proposed authentication scheme minimizes authentication latency when the mobile node moves across different networks. In addition, thanks to the use of the Diffie-Hellman key agreement, pre-established security associations between mobility service provisioning entities are not required in the proposed authentication scheme so that network scalability in an operationally efficient manner is ensured. To ascertain its feasibility, security analysis and performance analysis are presented.

  1. A Classification Scheme for Literary Characters

    Directory of Open Access Journals (Sweden)

    Matthew Berry

    2017-10-01

    Full Text Available There is no established classification scheme for literary characters in narrative theory short of generic categories like protagonist vs. antagonist or round vs. flat. This is so despite the ubiquity of stock characters that recur across media, cultures, and historical time periods. We present here a proposal of a systematic psychological scheme for classifying characters from the literary and dramatic fields based on a modification of the Thomas-Kilmann (TK Conflict Mode Instrument used in applied studies of personality. The TK scheme classifies personality along the two orthogonal dimensions of assertiveness and cooperativeness. To examine the validity of a modified version of this scheme, we had 142 participants provide personality ratings for 40 characters using two of the Big Five personality traits as well as assertiveness and cooperativeness from the TK scheme. The results showed that assertiveness and cooperativeness were orthogonal dimensions, thereby supporting the validity of using a modified version of TK’s two-dimensional scheme for classifying characters.

  2. Method for adding nodes to a quantum key distribution system

    Science.gov (United States)

    Grice, Warren P

    2015-02-24

    An improved quantum key distribution (QKD) system and method are provided. The system and method introduce new clients at intermediate points along a quantum channel, where any two clients can establish a secret key without the need for a secret meeting between the clients. The new clients perform operations on photons as they pass through nodes in the quantum channel, and participate in a non-secret protocol that is amended to include the new clients. The system and method significantly increase the number of clients that can be supported by a conventional QKD system, with only a modest increase in cost. The system and method are compatible with a variety of QKD schemes, including polarization, time-bin, continuous variable and entanglement QKD.

  3. Four-state discrimination scheme beyond the heterodyne limit

    DEFF Research Database (Denmark)

    Muller, C. R.; Castaneda, Mario A. Usuga; Wittmann, C.

    2012-01-01

    We propose and experimentally demonstrate a hybrid discrimination scheme for the quadrature phase shift keying protocol, which outperforms heterodyne detection for any signal power. The discrimination is composed of a quadrature measurement, feed forward and photon detection.......We propose and experimentally demonstrate a hybrid discrimination scheme for the quadrature phase shift keying protocol, which outperforms heterodyne detection for any signal power. The discrimination is composed of a quadrature measurement, feed forward and photon detection....

  4. 4. Payment Schemes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 2. Electronic Commerce - Payment Schemes. V Rajaraman. Series Article Volume 6 Issue 2 February 2001 pp 6-13. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/006/02/0006-0013 ...

  5. Contract saving schemes

    NARCIS (Netherlands)

    Ronald, R.; Smith, S.J.; Elsinga, M.; Eng, O.S.; Fox O'Mahony, L.; Wachter, S.

    2012-01-01

    Contractual saving schemes for housing are institutionalised savings programmes normally linked to rights to loans for home purchase. They are diverse types as they have been developed differently in each national context, but normally fall into categories of open, closed, compulsory, and ‘free

  6. Alternative reprocessing schemes evaluation

    International Nuclear Information System (INIS)

    1979-02-01

    This paper reviews the parameters which determine the inaccessibility of the plutonium in reprocessing plants. Among the various parameters, the physical and chemical characteristics of the materials, the various processing schemes and the confinement are considered. The emphasis is placed on that latter parameter, and the advantages of an increased confinement in the socalled PIPEX reprocessing plant type are presented

  7. Introduction to association schemes

    NARCIS (Netherlands)

    Seidel, J.J.

    1991-01-01

    The present paper gives an introduction to the theory of association schemes, following Bose-Mesner (1959), Biggs (1974), Delsarte (1973), Bannai-Ito (1984) and Brouwer-Cohen-Neumaier (1989). Apart from definitions and many examples, also several proofs and some problems are included. The paragraphs

  8. Reaction schemes of immunoanalysis

    International Nuclear Information System (INIS)

    Delaage, M.; Barbet, J.

    1991-01-01

    The authors apply a general theory for multiple equilibria to the reaction schemes of immunoanalysis, competition and sandwich. This approach allows the manufacturer to optimize the system and provide the user with interpolation functions for the standard curve and its first derivative as well, thus giving access to variance [fr

  9. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...... competitive insurance; this situation turns out to be at least as good as either of the alternatives...

  10. A study on different thermodynamic cycle schemes coupled with a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Qu, Xinhe; Yang, Xiaoyong; Wang, Jie

    2017-01-01

    Highlights: • The features of three different power generation schemes, including closed Brayton cycle, non-reheating combined cycle and reheating combined cycle, coupled with high temperature gas-cooled reactor (HTGR) were investigated and compared. • The effects and mechanism of reactor core outlet temperature, compression ratio and other key parameters over cycle characteristics were analyzed by the thermodynamic models.. • It is found that reheated combined cycle has the highest efficiency. Reactor outlet temperature and main steam parameters are key factors to improve the cycle’s performance. - Abstract: With gradual increase in reactor outlet temperature, the efficient power conversion technology has become one of developing trends of (very) high temperature gas-cooled reactors (HTGRs). In this paper, different cycle power generation schemes for HTGRs were systematically studied. Physical and mathematical models were established for these three cycle schemes: closed Brayton cycle, simple combined cycle, and reheated combined cycle. The effects and mechanism of key parameters such as reactor core outlet temperature, reactor core inlet temperature and compression ratio on the features of these cycles were analyzed. Then, optimization results were given with engineering restrictive conditions, including pinch point temperature differences. Results revealed that within the temperature range of HTGRs (700–900 °C), the reheated combined cycle had the highest efficiency, while the simple combined cycle had the lowest efficiency (900 °C). The efficiencies of the closed Brayton cycle, simple combined cycle and reheated combined cycle are 49.5%, 46.6% and 50.1%, respectively. These results provide insights on the different schemes of these cycles, and reveal the effects of key parameters on performance of these cycles. It could be helpful to understand and develop a combined cycle coupled with a high temperature reactor in the future.

  11. FPGA BASED HARDWARE KEY FOR TEMPORAL ENCRYPTION

    Directory of Open Access Journals (Sweden)

    B. Lakshmi

    2010-09-01

    Full Text Available In this paper, a novel encryption scheme with time based key technique on an FPGA is presented. Time based key technique ensures right key to be entered at right time and hence, vulnerability of encryption through brute force attack is eliminated. Presently available encryption systems, suffer from Brute force attack and in such a case, the time taken for breaking a code depends on the system used for cryptanalysis. The proposed scheme provides an effective method in which the time is taken as the second dimension of the key so that the same system can defend against brute force attack more vigorously. In the proposed scheme, the key is rotated continuously and four bits are drawn from the key with their concatenated value representing the delay the system has to wait. This forms the time based key concept. Also the key based function selection from a pool of functions enhances the confusion and diffusion to defend against linear and differential attacks while the time factor inclusion makes the brute force attack nearly impossible. In the proposed scheme, the key scheduler is implemented on FPGA that generates the right key at right time intervals which is then connected to a NIOS – II processor (a virtual microcontroller which is brought out from Altera FPGA that communicates with the keys to the personal computer through JTAG (Joint Test Action Group communication and the computer is used to perform encryption (or decryption. In this case the FPGA serves as hardware key (dongle for data encryption (or decryption.

  12. Near-optimal labeling schemes for nearest common ancestors

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Bistrup Halvorsen, Esben; Larsen, Kasper Green

    2014-01-01

    and Korman (STOC'10) established that labels in ancestor labeling schemes have size log n + Θ(log log n), our new lower bound separates ancestor and NCA labeling schemes. Our upper bound improves the 10 log n upper bound by Alstrup, Gavoille, Kaplan and Rauhe (TOCS'04), and our theoretical result even...

  13. How update schemes influence crowd simulations

    International Nuclear Information System (INIS)

    Seitz, Michael J; Köster, Gerta

    2014-01-01

    Time discretization is a key modeling aspect of dynamic computer simulations. In current pedestrian motion models based on discrete events, e.g. cellular automata and the Optimal Steps Model, fixed-order sequential updates and shuffle updates are prevalent. We propose to use event-driven updates that process events in the order they occur, and thus better match natural movement. In addition, we present a parallel update with collision detection and resolution for situations where computational speed is crucial. Two simulation studies serve to demonstrate the practical impact of the choice of update scheme. Not only do density-speed relations differ, but there is a statistically significant effect on evacuation times. Fixed-order sequential and random shuffle updates with a short update period come close to event-driven updates. The parallel update scheme overestimates evacuation times. All schemes can be employed for arbitrary simulation models with discrete events, such as car traffic or animal behavior. (paper)

  14. Yellow light for green scheme

    International Nuclear Information System (INIS)

    Morch, Stein

    2004-01-01

    The article asserts that there could be an investment boom for wind, hydro and bio power in a common Norwegian-Swedish market scheme for green certificates. The Swedish authorities are ready, and the Norwegian government is preparing a report to the Norwegian Parliament. What are the ambitions of Norway, and will hydro power be included? A green certificate market common to more countries have never before been established and requires the solution of many challenging problems. In Sweden, certificate support is expected to promote primarily bioenergy, wind power and small-scale hydro power. In Norway there is an evident potential for wind power, and more hydro power can be developed if desired

  15. A Key Management Method for Cryptographically Enforced Access Control

    NARCIS (Netherlands)

    Zych, Anna; Petkovic, Milan; Jonker, Willem; Fernández-Medina, Eduardo; Yagüe, Mariemma I.

    Cryptographic enforcement of access control mechanisms relies on encrypting protected data with the keys stored by authorized users. This approach poses the problem of the distribution of secret keys. In this paper, a key management scheme is presented where each user stores a single key and is

  16. Efficient key management for cryptographically enforced access control

    NARCIS (Netherlands)

    Zych, Anna; Petkovic, Milan; Jonker, Willem

    Cryptographic enforcement of access control mechanisms relies on encrypting protected data with the keys stored by authorized users. This approach poses the problem of the distribution of secret keys. In this paper, a key management scheme is presented where each user stores a single key and is

  17. Wind power and market integration, comparative study of financing schemes

    International Nuclear Information System (INIS)

    2013-10-01

    The financing scheme of renewable energies is a key factor for their development pace and cost. As some countries like France, Germany or Spain have chosen a Feed-in Tariff (FiT) scheme, there are in fact four possible financing schemes: FiT, ex-post prime, ex-ante prime, and quotas (green certificates). A market convergence is then supposed to meet two main objectives: the control of market distortions related to wind energy development, and the optimization of wind energy production with respect to market signals. The authors analyse the underlying economic challenges and the ability of financing schemes to meet these objectives within a short term horizon (2015). They present the different financing schemes, analyse the impact of three key economic factors (market distortion, production optimization, financing costs)

  18. On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Wang Daoshun

    2010-01-01

    Full Text Available Abstract Traditional Secret Sharing (SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing (VSS schemes decode the secret without computation, but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing (Prob.VSS schemes for a binary image use only one subpixel to share the secret image; however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes, VSS schemes, and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert (transform a -SS scheme to a -VSS scheme for greyscale images. The generation of the shadow images (shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation, as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images, measured by average contrast, is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale -SS scheme to a more general case of greyscale -VSS scheme.

  19. Atomic Weapons Establishment Bill [Money

    International Nuclear Information System (INIS)

    Bennett, A.F.; Cryer, Bob; Carlisle, Kenneth; Dean, Paul.

    1990-01-01

    The debate concerns the authorisation of payment of the money required to reorganise the atomic weapons establishment in the United Kingdom provided for in the Atomic Weapons Establishment Bill in progress through Parliament. In the Bill the contractorisation of the establishment is recommended and some sort of Government owned company operated scheme set up. The debate lasted about half an hour and is reported verbatim. The issues raised concerned the actual sums likely to be incurred in the formation of a Company to carry out the designated activities of the Bill. These are connected with the research, development, production or maintenance of nuclear devices and the premises needed. The government spokesman suggested the sums required to support the Bill would not be large and the resolution was agreed to without a vote. (UK)

  20. The Victorian government`s clean technology incentive scheme

    Energy Technology Data Exchange (ETDEWEB)

    Connor, M.A. [Melbourne Univ., Parkville, VIC (Australia). Dept. of Chemical Engineering; Reeve, D. [Environment Protection Authority, Melbourne, VIC (Australia)

    1993-12-31

    Over the past decade environment policies have placed increasing emphasis on waste minimization and cleaner production techniques. The Environment Protection Authority in Victoria, Australia, has sought to encourage waste minimization by establishing a Clean Technology Incentive Scheme. The Scheme was established in 1988 and since then 35 offers of loans have been made. Results to date are encouraging. In this work, case studies of three especially successful projects are presented. 2 refs.

  1. The Victorian government`s clean technology incentive scheme

    Energy Technology Data Exchange (ETDEWEB)

    Connor, M A [Melbourne Univ., Parkville, VIC (Australia). Dept. of Chemical Engineering; Reeve, D [Environment Protection Authority, Melbourne, VIC (Australia)

    1994-12-31

    Over the past decade environment policies have placed increasing emphasis on waste minimization and cleaner production techniques. The Environment Protection Authority in Victoria, Australia, has sought to encourage waste minimization by establishing a Clean Technology Incentive Scheme. The Scheme was established in 1988 and since then 35 offers of loans have been made. Results to date are encouraging. In this work, case studies of three especially successful projects are presented. 2 refs.

  2. Smooth Phase Interpolated Keying

    Science.gov (United States)

    Borah, Deva K.

    2007-01-01

    Smooth phase interpolated keying (SPIK) is an improved method of computing smooth phase-modulation waveforms for radio communication systems that convey digital information. SPIK is applicable to a variety of phase-shift-keying (PSK) modulation schemes, including quaternary PSK (QPSK), octonary PSK (8PSK), and 16PSK. In comparison with a related prior method, SPIK offers advantages of better performance and less complexity of implementation. In a PSK scheme, the underlying information waveform that one seeks to convey consists of discrete rectangular steps, but the spectral width of such a waveform is excessive for practical radio communication. Therefore, the problem is to smooth the step phase waveform in such a manner as to maintain power and bandwidth efficiency without incurring an unacceptably large error rate and without introducing undesired variations in the amplitude of the affected radio signal. Although the ideal constellation of PSK phasor points does not cause amplitude variations, filtering of the modulation waveform (in which, typically, a rectangular pulse is converted to a square-root raised cosine pulse) causes amplitude fluctuations. If a power-efficient nonlinear amplifier is used in the radio communication system, the fluctuating-amplitude signal can undergo significant spectral regrowth, thus compromising the bandwidth efficiency of the system. In the related prior method, one seeks to solve the problem in a procedure that comprises two major steps: phase-value generation and phase interpolation. SPIK follows the two-step approach of the related prior method, but the details of the steps are different. In the phase-value-generation step, the phase values of symbols in the PSK constellation are determined by a phase function that is said to be maximally smooth and that is chosen to minimize the spectral spread of the modulated signal. In this step, the constellation is divided into two groups by assigning, to information symbols, phase values

  3. Quality Index Method (QIM) scheme developed for farmed Atlantic salmon ( Salmo salar )

    DEFF Research Database (Denmark)

    Sveinsdóttir, K.; Hyldig, Grethe; Martinsdóttir, E.

    2003-01-01

    The aim of the study was to develop 'Quality Index Method (QIM) scheme for raw, farmed Atlantic salmon (Salmo salar) and to evaluate the scheme. in a shelf life study. QIM is based on the evaluation of key parameters in the deterioration of seafood's. Demerit points are assigned to selected...... parameters according to their importance and a Quality Index (QI) is established by cumulating the resulting scores. The maximum storage time in ice was determined with Quantitative Descriptive Analysis (QDA) of the salmon after cooking and found to be 20-21 days. This was used as a reference to enable...... prediction of the remaining storage time of raw salmon in ice with QIM. The calculated QI evolved linearly with storage time in ice (QI=0.82x (days in ice)+0.18, R-2=0.97). Individual salmon varied in QI within each storage day. However, the multivariate analysis (PLS1) demonstrated that storage time could...

  4. Text analysis of MEDLINE for discovering functional relationships among genes: evaluation of keyword extraction weighting schemes.

    Science.gov (United States)

    Liu, Ying; Navathe, Shamkant B; Pivoshenko, Alex; Dasigi, Venu G; Dingledine, Ray; Ciliax, Brian J

    2006-01-01

    One of the key challenges of microarray studies is to derive biological insights from the gene-expression patterns. Clustering genes by functional keyword association can provide direct information about the functional links among genes. However, the quality of the keyword lists significantly affects the clustering results. We compared two keyword weighting schemes: normalised z-score and term frequency-inverse document frequency (TFIDF). Two gene sets were tested to evaluate the effectiveness of the weighting schemes for keyword extraction for gene clustering. Using established measures of cluster quality, the results produced from TFIDF-weighted keywords outperformed those produced from normalised z-score weighted keywords. The optimised algorithms should be useful for partitioning genes from microarray lists into functionally discrete clusters.

  5. Selectively strippable paint schemes

    Science.gov (United States)

    Stein, R.; Thumm, D.; Blackford, Roger W.

    1993-03-01

    In order to meet the requirements of more environmentally acceptable paint stripping processes many different removal methods are under evaluation. These new processes can be divided into mechanical and chemical methods. ICI has developed a paint scheme with intermediate coat and fluid resistant polyurethane topcoat which can be stripped chemically in a short period of time with methylene chloride free and phenol free paint strippers.

  6. A continuous variable quantum deterministic key distribution based on two-mode squeezed states

    International Nuclear Information System (INIS)

    Gong, Li-Hua; Song, Han-Chong; Liu, Ye; Zhou, Nan-Run; He, Chao-Sheng

    2014-01-01

    The distribution of deterministic keys is of significance in personal communications, but the existing continuous variable quantum key distribution protocols can only generate random keys. By exploiting the entanglement properties of two-mode squeezed states, a continuous variable quantum deterministic key distribution (CVQDKD) scheme is presented for handing over the pre-determined key to the intended receiver. The security of the CVQDKD scheme is analyzed in detail from the perspective of information theory. It shows that the scheme can securely and effectively transfer pre-determined keys under ideal conditions. The proposed scheme can resist both the entanglement and beam splitter attacks under a relatively high channel transmission efficiency. (paper)

  7. Scalable Nonlinear Compact Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debojyoti [Argonne National Lab. (ANL), Argonne, IL (United States); Constantinescu, Emil M. [Univ. of Chicago, IL (United States); Brown, Jed [Univ. of Colorado, Boulder, CO (United States)

    2014-04-01

    In this work, we focus on compact schemes resulting in tridiagonal systems of equations, specifically the fifth-order CRWENO scheme. We propose a scalable implementation of the nonlinear compact schemes by implementing a parallel tridiagonal solver based on the partitioning/substructuring approach. We use an iterative solver for the reduced system of equations; however, we solve this system to machine zero accuracy to ensure that no parallelization errors are introduced. It is possible to achieve machine-zero convergence with few iterations because of the diagonal dominance of the system. The number of iterations is specified a priori instead of a norm-based exit criterion, and collective communications are avoided. The overall algorithm thus involves only point-to-point communication between neighboring processors. Our implementation of the tridiagonal solver differs from and avoids the drawbacks of past efforts in the following ways: it introduces no parallelization-related approximations (multiprocessor solutions are exactly identical to uniprocessor ones), it involves minimal communication, the mathematical complexity is similar to that of the Thomas algorithm on a single processor, and it does not require any communication and computation scheduling.

  8. A digital memories based user authentication scheme with privacy preservation.

    Directory of Open Access Journals (Sweden)

    JunLiang Liu

    Full Text Available The traditional username/password or PIN based authentication scheme, which still remains the most popular form of authentication, has been proved insecure, unmemorable and vulnerable to guessing, dictionary attack, key-logger, shoulder-surfing and social engineering. Based on this, a large number of new alternative methods have recently been proposed. However, most of them rely on users being able to accurately recall complex and unmemorable information or using extra hardware (such as a USB Key, which makes authentication more difficult and confusing. In this paper, we propose a Digital Memories based user authentication scheme adopting homomorphic encryption and a public key encryption design which can protect users' privacy effectively, prevent tracking and provide multi-level security in an Internet & IoT environment. Also, we prove the superior reliability and security of our scheme compared to other schemes and present a performance analysis and promising evaluation results.

  9. Securing information using optically generated biometric keys

    Science.gov (United States)

    Verma, Gaurav; Sinha, Aloka

    2016-11-01

    In this paper, we present a new technique to obtain biometric keys by using the fingerprint of a person for an optical image encryption system. The key generation scheme uses the fingerprint biometric information in terms of the amplitude mask (AM) and the phase mask (PM) of the reconstructed fingerprint image that is implemented using the digital holographic technique. Statistical tests have been conducted to check the randomness of the fingerprint PM key that enables its usage as an image encryption key. To explore the utility of the generated biometric keys, an optical image encryption system has been further demonstrated based on the phase retrieval algorithm and the double random phase encoding scheme in which keys for the encryption are used as the AM and the PM key. The advantage associated with the proposed scheme is that the biometric keys’ retrieval requires the simultaneous presence of the fingerprint hologram and the correct knowledge of the reconstruction parameters at the decryption stage, which not only verifies the authenticity of the person but also protects the valuable fingerprint biometric features of the keys. Numerical results are carried out to prove the feasibility and the effectiveness of the proposed encryption system.

  10. Short-term incentive schemes for hospital managers

    Directory of Open Access Journals (Sweden)

    Lucas Malambe

    2013-10-01

    Full Text Available Orientation: Short-term incentives, considered to be an extrinsic motivation, are commonly used to motivate performance. This study explored hospital managers’ perceptions of short term incentives in maximising performance and retention. Research purpose: The study explored the experiences, views and perceptions of private hospital managers in South Africa regarding the use of short-term incentives to maximise performance and retention, as well as the applicability of the findings to public hospitals. Motivation for the study: Whilst there is an established link between performance reward schemes and organisational performance, there is little understanding of the effects of short term incentives on the performance and retention of hospital managers within the South African context. Research design, approach, and method: The study used a qualitative research design: interviews were conducted with a purposive sample of 19 hospital managers, and a thematic content analysis was performed. Main findings: Short-term incentives may not be the primary motivator for hospital managers, but they do play a critical role in sustaining motivation. Participants indicated that these schemes could also be applicable to public hospitals. Practical/managerial implications: Hospital managers are inclined to be more motivated by intrinsic than extrinsic factors. However, hospital managers (as middle managers also seem to be motivated by short-term incentives. A combination of intrinsic and extrinsic motivators should thus be used to maximise performance and retention. Contribution/value-add: Whilst the study sought to explore hospital managers’ perceptions of short-term incentives, it also found that an adequate balance between internal and external motivators is key to implementing an effective short-term incentive scheme.

  11. NAGRADATA. Code key. Geology

    International Nuclear Information System (INIS)

    Mueller, W.H.; Schneider, B.; Staeuble, J.

    1984-01-01

    This reference manual provides users of the NAGRADATA system with comprehensive keys to the coding/decoding of geological and technical information to be stored in or retreaved from the databank. Emphasis has been placed on input data coding. When data is retreaved the translation into plain language of stored coded information is done automatically by computer. Three keys each, list the complete set of currently defined codes for the NAGRADATA system, namely codes with appropriate definitions, arranged: 1. according to subject matter (thematically) 2. the codes listed alphabetically and 3. the definitions listed alphabetically. Additional explanation is provided for the proper application of the codes and the logic behind the creation of new codes to be used within the NAGRADATA system. NAGRADATA makes use of codes instead of plain language for data storage; this offers the following advantages: speed of data processing, mainly data retrieval, economies of storage memory requirements, the standardisation of terminology. The nature of this thesaurian type 'key to codes' makes it impossible to either establish a final form or to cover the entire spectrum of requirements. Therefore, this first issue of codes to NAGRADATA must be considered to represent the current state of progress of a living system and future editions will be issued in a loose leave ringbook system which can be updated by an organised (updating) service. (author)

  12. ESCAP mobile training scheme.

    Science.gov (United States)

    Yasas, F M

    1977-01-01

    In response to a United Nations resolution, the Mobile Training Scheme (MTS) was set up to provide training to the trainers of national cadres engaged in frontline and supervisory tasks in social welfare and rural development. The training is innovative in its being based on an analysis of field realities. The MTS team consisted of a leader, an expert on teaching methods and materials, and an expert on action research and evaluation. The country's trainers from different departments were sent to villages to work for a short period and to report their problems in fulfilling their roles. From these grass roots experiences, they made an analysis of the job, determining what knowledge, attitude and skills it required. Analysis of daily incidents and problems were used to produce indigenous teaching materials drawn from actual field practice. How to consider the problems encountered through government structures for policy making and decisions was also learned. Tasks of the students were to identify the skills needed for role performance by job analysis, daily diaries and project histories; to analyze the particular community by village profiles; to produce indigenous teaching materials; and to practice the role skills by actual role performance. The MTS scheme was tried in Nepal in 1974-75; 3 training programs trained 25 trainers and 51 frontline workers; indigenous teaching materials were created; technical papers written; and consultations were provided. In Afghanistan the scheme was used in 1975-76; 45 participants completed the training; seminars were held; and an ongoing Council was created. It is hoped that the training program will be expanded to other countries.

  13. Detector decoy quantum key distribution

    International Nuclear Information System (INIS)

    Moroder, Tobias; Luetkenhaus, Norbert; Curty, Marcos

    2009-01-01

    Photon number resolving detectors can enhance the performance of many practical quantum cryptographic setups. In this paper, we employ a simple method to estimate the statistics provided by such a photon number resolving detector using only a threshold detector together with a variable attenuator. This idea is similar in spirit to that of the decoy state technique, and is especially suited to those scenarios where only a few parameters of the photon number statistics of the incoming signals have to be estimated. As an illustration of the potential applicability of the method in quantum communication protocols, we use it to prove security of an entanglement-based quantum key distribution scheme with an untrusted source without the need for a squash model and by solely using this extra idea. In this sense, this detector decoy method can be seen as a different conceptual approach to adapt a single-photon security proof to its physical, full optical implementation. We show that in this scenario, the legitimate users can now even discard the double click events from the raw key data without compromising the security of the scheme, and we present simulations on the performance of the BB84 and the 6-state quantum key distribution protocols.

  14. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  15. Succesful labelling schemes

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2001-01-01

    . In the spring of 2001 MAPP carried out an extensive consumer study with special emphasis on the Nordic environmentally friendly label 'the swan'. The purpose was to find out how much consumers actually know and use various labelling schemes. 869 households were contacted and asked to fill in a questionnaire...... it into consideration when I go shopping. The respondent was asked to pick the most suitable answer, which described her use of each label. 29% - also called 'the labelling blind' - responded that they basically only knew the recycling label and the Government controlled organic label 'Ø-mærket'. Another segment of 6...

  16. Scheme of stepmotor control

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Karyshev, Yu.Ya.

    1982-01-01

    A 6-cycle scheme of step motor is described. The block-diagram and the basic circuit of the step motor control are presented. The step motor control comprises a pulse shaper, electronic commutator and power amplifiers. The step motor supply from 6-cycle electronic commutator provides for higher reliability and accuracy than from 3-cycle commutator. The control of step motor work is realised by the program given by the external source of control signals. Time-dependent diagrams for step motor control are presented. The specifications of the step-motor is given

  17. Finite key analysis in quantum cryptography

    International Nuclear Information System (INIS)

    Meyer, T.

    2007-01-01

    In view of experimental realization of quantum key distribution schemes, the study of their efficiency becomes as important as the proof of their security. The latter is the subject of most of the theoretical work about quantum key distribution, and many important results such as the proof of unconditional security have been obtained. The efficiency and also the robustness of quantum key distribution protocols against noise can be measured by figures of merit such as the secret key rate (the fraction of input signals that make it into the key) and the threshold quantum bit error rate (the maximal error rate such that one can still create a secret key). It is important to determine these quantities because they tell us whether a certain quantum key distribution scheme can be used at all in a given situation and if so, how many secret key bits it can generate in a given time. However, these figures of merit are usually derived under the ''infinite key limit'' assumption, that is, one assumes that an infinite number of quantum states are send and that all sub-protocols of the scheme (in particular privacy amplification) are carried out on these infinitely large blocks. Such an assumption usually eases the analysis, but also leads to (potentially) too optimistic values for the quantities in question. In this thesis, we are explicitly avoiding the infinite key limit for the analysis of the privacy amplification step, which plays the most important role in a quantum key distribution scheme. We still assume that an optimal error correction code is applied and we do not take into account any statistical errors that might occur in the parameter estimation step. Renner and coworkers derived an explicit formula for the obtainable key rate in terms of Renyi entropies of the quantum states describing Alice's, Bob's, and Eve's systems. This results serves as a starting point for our analysis, and we derive an algorithm that efficiently computes the obtainable key rate for any

  18. Breaking a chaos-noise-based secure communication scheme

    Science.gov (United States)

    Li, Shujun; Álvarez, Gonzalo; Chen, Guanrong; Mou, Xuanqin

    2005-03-01

    This paper studies the security of a secure communication scheme based on two discrete-time intermittently chaotic systems synchronized via a common random driving signal. Some security defects of the scheme are revealed: 1) The key space can be remarkably reduced; 2) the decryption is insensitive to the mismatch of the secret key; 3) the key-generation process is insecure against known/chosen-plaintext attacks. The first two defects mean that the scheme is not secure enough against brute-force attacks, and the third one means that an attacker can easily break the cryptosystem by approximately estimating the secret key once he has a chance to access a fragment of the generated keystream. Yet it remains to be clarified if intermittent chaos could be used for designing secure chaotic cryptosystems.

  19. Packet reversed packet combining scheme

    International Nuclear Information System (INIS)

    Bhunia, C.T.

    2006-07-01

    The packet combining scheme is a well defined simple error correction scheme with erroneous copies at the receiver. It offers higher throughput combined with ARQ protocols in networks than that of basic ARQ protocols. But packet combining scheme fails to correct errors when the errors occur in the same bit locations of two erroneous copies. In the present work, we propose a scheme that will correct error if the errors occur at the same bit location of the erroneous copies. The proposed scheme when combined with ARQ protocol will offer higher throughput. (author)

  20. Secure image retrieval with multiple keys

    Science.gov (United States)

    Liang, Haihua; Zhang, Xinpeng; Wei, Qiuhan; Cheng, Hang

    2018-03-01

    This article proposes a secure image retrieval scheme under a multiuser scenario. In this scheme, the owner first encrypts and uploads images and their corresponding features to the cloud; then, the user submits the encrypted feature of the query image to the cloud; next, the cloud compares the encrypted features and returns encrypted images with similar content to the user. To find the nearest neighbor in the encrypted features, an encryption with multiple keys is proposed, in which the query feature of each user is encrypted by his/her own key. To improve the key security and space utilization, global optimization and Gaussian distribution are, respectively, employed to generate multiple keys. The experiments show that the proposed encryption can provide effective and secure image retrieval for each user and ensure confidentiality of the query feature of each user.

  1. Enhanced Two-Factor Authentication and Key Agreement Using Dynamic Identities in Wireless Sensor Networks.

    Science.gov (United States)

    Chang, I-Pin; Lee, Tian-Fu; Lin, Tsung-Hung; Liu, Chuan-Ming

    2015-11-30

    Key agreements that use only password authentication are convenient in communication networks, but these key agreement schemes often fail to resist possible attacks, and therefore provide poor security compared with some other authentication schemes. To increase security, many authentication and key agreement schemes use smartcard authentication in addition to passwords. Thus, two-factor authentication and key agreement schemes using smartcards and passwords are widely adopted in many applications. Vaidya et al. recently presented a two-factor authentication and key agreement scheme for wireless sensor networks (WSNs). Kim et al. observed that the Vaidya et al. scheme fails to resist gateway node bypassing and user impersonation attacks, and then proposed an improved scheme for WSNs. This study analyzes the weaknesses of the two-factor authentication and key agreement scheme of Kim et al., which include vulnerability to impersonation attacks, lost smartcard attacks and man-in-the-middle attacks, violation of session key security, and failure to protect user privacy. An efficient and secure authentication and key agreement scheme for WSNs based on the scheme of Kim et al. is then proposed. The proposed scheme not only solves the weaknesses of previous approaches, but also increases security requirements while maintaining low computational cost.

  2. Verifier-based three-party authentication schemes using extended chaotic maps for data exchange in telecare medicine information systems.

    Science.gov (United States)

    Lee, Tian-Fu

    2014-12-01

    Telecare medicine information systems provide a communicating platform for accessing remote medical resources through public networks, and help health care workers and medical personnel to rapidly making correct clinical decisions and treatments. An authentication scheme for data exchange in telecare medicine information systems enables legal users in hospitals and medical institutes to establish a secure channel and exchange electronic medical records or electronic health records securely and efficiently. This investigation develops an efficient and secure verified-based three-party authentication scheme by using extended chaotic maps for data exchange in telecare medicine information systems. The proposed scheme does not require server's public keys and avoids time-consuming modular exponential computations and scalar multiplications on elliptic curve used in previous related approaches. Additionally, the proposed scheme is proven secure in the random oracle model, and realizes the lower bounds of messages and rounds in communications. Compared to related verified-based approaches, the proposed scheme not only possesses higher security, but also has lower computational cost and fewer transmissions. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Pressure correction schemes for compressible flows

    International Nuclear Information System (INIS)

    Kheriji, W.

    2011-01-01

    This thesis is concerned with the development of semi-implicit fractional step schemes, for the compressible Navier-Stokes equations; these schemes are part of the class of the pressure correction methods. The chosen spatial discretization is staggered: non conforming mixed finite elements (Crouzeix-Raviart or Rannacher-Turek) or the classic MA C scheme. An upwind finite volume discretization of the mass balance guarantees the positivity of the density. The positivity of the internal energy is obtained by discretizing the internal energy balance by an upwind finite volume scheme and b y coupling the discrete internal energy balance with the pressure correction step. A special finite volume discretization on dual cells is performed for the convection term in the momentum balance equation, and a renormalisation step for the pressure is added to the algorithm; this ensures the control in time of the integral of the total energy over the domain. All these a priori estimates imply the existence of a discrete solution by a topological degree argument. The application of this scheme to Euler equations raises an additional difficulty. Indeed, obtaining correct shocks requires the scheme to be consistent with the total energy balance, property which we obtain as follows. First of all, a local discrete kinetic energy balance is established; it contains source terms winch we somehow compensate in the internal energy balance. The kinetic and internal energy equations are associated with the dual and primal meshes respectively, and thus cannot be added to obtain a total energy balance; its continuous counterpart is however recovered at the limit: if we suppose that a sequence of discrete solutions converges when the space and time steps tend to 0, we indeed show, in 1D at least, that the limit satisfies a weak form of the equation. These theoretical results are comforted by numerical tests. Similar results are obtained for the baro-tropic Navier-Stokes equations. (author)

  4. Forcing scheme in pseudopotential lattice Boltzmann model for multiphase flows.

    Science.gov (United States)

    Li, Q; Luo, K H; Li, X J

    2012-07-01

    The pseudopotential lattice Boltzmann (LB) model is a widely used multiphase model in the LB community. In this model, an interaction force, which is usually implemented via a forcing scheme, is employed to mimic the molecular interactions that cause phase segregation. The forcing scheme is therefore expected to play an important role in the pseudoepotential LB model. In this paper, we aim to address some key issues about forcing schemes in the pseudopotential LB model. First, theoretical and numerical analyses will be made for Shan-Chen's forcing scheme [Shan and Chen, Phys. Rev. E 47, 1815 (1993)] and the exact-difference-method forcing scheme [Kupershtokh et al., Comput. Math. Appl. 58, 965 (2009)]. The nature of these two schemes and their recovered macroscopic equations will be shown. Second, through a theoretical analysis, we will reveal the physics behind the phenomenon that different forcing schemes exhibit different performances in the pseudopotential LB model. Moreover, based on the analysis, we will present an improved forcing scheme and numerically demonstrate that the improved scheme can be treated as an alternative approach to achieving thermodynamic consistency in the pseudopotential LB model.

  5. Secure Hybrid Encryption from Weakened Key Encapsulation

    NARCIS (Netherlands)

    D. Hofheinz (Dennis); E. Kiltz (Eike); A. Menezes

    2007-01-01

    textabstractWe put forward a new paradigm for building hybrid encryption schemes from constrained chosen-ciphertext secure (CCCA) key-encapsulation mechanisms (KEMs) plus authenticated symmetric encryption. Constrained chosen-ciphertext security is a new security notion for KEMs that we propose. It

  6. Two-level schemes for the advection equation

    Science.gov (United States)

    Vabishchevich, Petr N.

    2018-06-01

    The advection equation is the basis for mathematical models of continuum mechanics. In the approximate solution of nonstationary problems it is necessary to inherit main properties of the conservatism and monotonicity of the solution. In this paper, the advection equation is written in the symmetric form, where the advection operator is the half-sum of advection operators in conservative (divergent) and non-conservative (characteristic) forms. The advection operator is skew-symmetric. Standard finite element approximations in space are used. The standard explicit two-level scheme for the advection equation is absolutely unstable. New conditionally stable regularized schemes are constructed, on the basis of the general theory of stability (well-posedness) of operator-difference schemes, the stability conditions of the explicit Lax-Wendroff scheme are established. Unconditionally stable and conservative schemes are implicit schemes of the second (Crank-Nicolson scheme) and fourth order. The conditionally stable implicit Lax-Wendroff scheme is constructed. The accuracy of the investigated explicit and implicit two-level schemes for an approximate solution of the advection equation is illustrated by the numerical results of a model two-dimensional problem.

  7. Security of helper data Schemes for SRAM-PUF in multiple enrollment scenarios

    NARCIS (Netherlands)

    Kusters, C.J.; Ignatenko, T.; Maes, R.; van der Sluis, E.; Selimis, G.; Willems, F.M.J.

    2017-01-01

    Fuzzy commitment and syndrome-based schemes are two well-known helper data schemes used to bind and generate, respectively, a secret key to/from SRAM-PUF observations. To allow the decoder to reconstruct this secret key from a new (verification) observation of an SRAM-PUF, an encoder has to generate

  8. The Diversity-Multiplexing Tradeoff of Secret-Key Agreement over Multiple-Antenna Channels

    KAUST Repository

    Zorgui, Marwen

    2015-10-26

    We study the problem of secret-key agreement between two legitimate parties, Alice and Bob, in presence an of eavesdropper Eve. There is a public channel with unlimited capacity that is available to the legitimate parties and is also observed by Eve. Our focus is on Rayleigh fading quasi-static channels. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge of their channels. We study the system in the high-power regime. First, we define the secret-key diversity gain and the secret-key multiplexing gain. Second, we establish the secret-key diversity multiplexing tradeoff (DMT) under no channel state information (CSI) at the transmitter (CSI-T). The eavesdropper is shown to “steal” only transmit antennas. We show that, likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information at the transmitter. This insensitivity of secret-key DMT toward CSI-T features a fundamental difference between secret-key agreement and the wiretap channel, in which secret DMT depends heavily on CSI-T. Finally, we present several secret-key DMT-achieving schemes in case of full CSI-T. We argue that secret DMT-achieving schemes are also key DMT-achieving. Moreover, we show formally that artificial noise (AN), likewise zero-forcing (ZF), is DMT-achieving. We also show that the public feedback channel improves the outage performance without having any effect on the DMT.

  9. The Diversity-Multiplexing Tradeoff of Secret-Key Agreement over Multiple-Antenna Channels

    KAUST Repository

    Zorgui, Marwen; Rezki, Zouheir; Alomair, Basel; Alouini, Mohamed-Slim

    2015-01-01

    We study the problem of secret-key agreement between two legitimate parties, Alice and Bob, in presence an of eavesdropper Eve. There is a public channel with unlimited capacity that is available to the legitimate parties and is also observed by Eve. Our focus is on Rayleigh fading quasi-static channels. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge of their channels. We study the system in the high-power regime. First, we define the secret-key diversity gain and the secret-key multiplexing gain. Second, we establish the secret-key diversity multiplexing tradeoff (DMT) under no channel state information (CSI) at the transmitter (CSI-T). The eavesdropper is shown to “steal” only transmit antennas. We show that, likewise the DMT without secrecy constraint, the secret-key DMT is the same either with or without full channel state information at the transmitter. This insensitivity of secret-key DMT toward CSI-T features a fundamental difference between secret-key agreement and the wiretap channel, in which secret DMT depends heavily on CSI-T. Finally, we present several secret-key DMT-achieving schemes in case of full CSI-T. We argue that secret DMT-achieving schemes are also key DMT-achieving. Moreover, we show formally that artificial noise (AN), likewise zero-forcing (ZF), is DMT-achieving. We also show that the public feedback channel improves the outage performance without having any effect on the DMT.

  10. Communication key using delay times in time-delayed chaos synchronization

    International Nuclear Information System (INIS)

    Kim, Chil-Min; Kye, Won-Ho; Rim, Sunghwan; Lee, Soo-Young

    2004-01-01

    We propose an efficient key scheme, which can generate a great number of communication keys, for communication using chaos synchronization. We have attained the keys from delay times of time-delay coupled chaotic systems. We explain the scheme and the efficiency by coupling Henon and logistic maps and illustrate them by coupling Navier-Stokes and Lorenz equations as a continuous system

  11. Efficient biometric authenticated key agreements based on extended chaotic maps for telecare medicine information systems.

    Science.gov (United States)

    Lou, Der-Chyuan; Lee, Tian-Fu; Lin, Tsung-Hung

    2015-05-01

    Authenticated key agreements for telecare medicine information systems provide patients, doctors, nurses and health visitors with accessing medical information systems and getting remote services efficiently and conveniently through an open network. In order to have higher security, many authenticated key agreement schemes appended biometric keys to realize identification except for using passwords and smartcards. Due to too many transmissions and computational costs, these authenticated key agreement schemes are inefficient in communication and computation. This investigation develops two secure and efficient authenticated key agreement schemes for telecare medicine information systems by using biometric key and extended chaotic maps. One scheme is synchronization-based, while the other nonce-based. Compared to related approaches, the proposed schemes not only retain the same security properties with previous schemes, but also provide users with privacy protection and have fewer transmissions and lower computational cost.

  12. Performance comparison of binary modulation schemes for visible light communication

    KAUST Repository

    Park, Kihong

    2015-09-11

    In this paper, we investigate the power spectral density of several binary modulation schemes including variable on-off keying, variable pulse position modulation, and pulse dual slope modulation which were previously proposed for visible light communication with dimming control. We also propose a novel slope-based modulation called differential chip slope modulation (DCSM) and develop a chip-based hard-decision receiver to demodulate the resulting signal, detect the chip sequence, and decode the input bit sequence. We show that the DCSM scheme can exploit spectrum density more efficiently than the reference schemes while providing an error rate performance comparable to them. © 2015 IEEE.

  13. An efficient quantum scheme for Private Set Intersection

    Science.gov (United States)

    Shi, Run-hua; Mu, Yi; Zhong, Hong; Cui, Jie; Zhang, Shun

    2016-01-01

    Private Set Intersection allows a client to privately compute set intersection with the collaboration of the server, which is one of the most fundamental and key problems within the multiparty collaborative computation of protecting the privacy of the parties. In this paper, we first present a cheat-sensitive quantum scheme for Private Set Intersection. Compared with classical schemes, our scheme has lower communication complexity, which is independent of the size of the server's set. Therefore, it is very suitable for big data services in Cloud or large-scale client-server networks.

  14. Comparative evaluation of remote maintenance schemes for fusion DEMO reactor

    Energy Technology Data Exchange (ETDEWEB)

    Utoh, Hiroyasu, E-mail: uto.hiroyasu@jaea.go.jp; Tobita, Kenji; Someya, Youji; Asakura, Nobuyuki; Sakamoto, Yoshiteru; Hoshino, Kazuo; Nakamura, Makoto

    2015-10-15

    Highlights: • Various remote maintenance schemes for DEMO were comparatively assessed based on requirements for DEMO remote maintenance. • The banana shape segment transport using all vertical maintenance ports would be more probable DEMO reactor maintenance scheme. • The key engineering issues are in-vessel transferring mechanism of segment, pipe connection and conducting shell design for plasma vertical stability. - Abstract: Maintenance schemes are one of the critical issues in DEMO design, significantly affecting the configuration of in-vessel components, the size of toroidal field (TF) coil, the arrangement of poloidal field (PF) coils, reactor building, hot cell and so forth. Therefore, the maintenance schemes should satisfy many design requirements and criteria to assure reliable and safe plant operation and to attain reasonable plant availability. The plant availability depends on reliability of remote maintenance scheme, inspection of pipe connection and plasma operation. In this paper, various remote maintenance schemes for DEMO were comparatively assessed based on requirements for DEMO remote maintenance. From the view points of the reliability of inspection on hot cell, TF coil size, stored energy of PF coil and portability of segment, the banana shape segment transport using all vertical maintenance ports would be more probable DEMO reactor maintenance scheme, and it has key engineering issues such as in-vessel transferring mechanism of segment, pipe connection and conducting shell design for plasma vertical stability.

  15. Comparative evaluation of remote maintenance schemes for fusion DEMO reactor

    International Nuclear Information System (INIS)

    Utoh, Hiroyasu; Tobita, Kenji; Someya, Youji; Asakura, Nobuyuki; Sakamoto, Yoshiteru; Hoshino, Kazuo; Nakamura, Makoto

    2015-01-01

    Highlights: • Various remote maintenance schemes for DEMO were comparatively assessed based on requirements for DEMO remote maintenance. • The banana shape segment transport using all vertical maintenance ports would be more probable DEMO reactor maintenance scheme. • The key engineering issues are in-vessel transferring mechanism of segment, pipe connection and conducting shell design for plasma vertical stability. - Abstract: Maintenance schemes are one of the critical issues in DEMO design, significantly affecting the configuration of in-vessel components, the size of toroidal field (TF) coil, the arrangement of poloidal field (PF) coils, reactor building, hot cell and so forth. Therefore, the maintenance schemes should satisfy many design requirements and criteria to assure reliable and safe plant operation and to attain reasonable plant availability. The plant availability depends on reliability of remote maintenance scheme, inspection of pipe connection and plasma operation. In this paper, various remote maintenance schemes for DEMO were comparatively assessed based on requirements for DEMO remote maintenance. From the view points of the reliability of inspection on hot cell, TF coil size, stored energy of PF coil and portability of segment, the banana shape segment transport using all vertical maintenance ports would be more probable DEMO reactor maintenance scheme, and it has key engineering issues such as in-vessel transferring mechanism of segment, pipe connection and conducting shell design for plasma vertical stability.

  16. Modified Aggressive Packet Combining Scheme

    International Nuclear Information System (INIS)

    Bhunia, C.T.

    2010-06-01

    In this letter, a few schemes are presented to improve the performance of aggressive packet combining scheme (APC). To combat error in computer/data communication networks, ARQ (Automatic Repeat Request) techniques are used. Several modifications to improve the performance of ARQ are suggested by recent research and are found in literature. The important modifications are majority packet combining scheme (MjPC proposed by Wicker), packet combining scheme (PC proposed by Chakraborty), modified packet combining scheme (MPC proposed by Bhunia), and packet reversed packet combining (PRPC proposed by Bhunia) scheme. These modifications are appropriate for improving throughput of conventional ARQ protocols. Leung proposed an idea of APC for error control in wireless networks with the basic objective of error control in uplink wireless data network. We suggest a few modifications of APC to improve its performance in terms of higher throughput, lower delay and higher error correction capability. (author)

  17. Transmission usage cost allocation schemes

    International Nuclear Information System (INIS)

    Abou El Ela, A.A.; El-Sehiemy, R.A.

    2009-01-01

    This paper presents different suggested transmission usage cost allocation (TCA) schemes to the system individuals. Different independent system operator (ISO) visions are presented using the proportional rata and flow-based TCA methods. There are two proposed flow-based TCA schemes (FTCA). The first FTCA scheme generalizes the equivalent bilateral exchanges (EBE) concepts for lossy networks through two-stage procedure. The second FTCA scheme is based on the modified sensitivity factors (MSF). These factors are developed from the actual measurements of power flows in transmission lines and the power injections at different buses. The proposed schemes exhibit desirable apportioning properties and are easy to implement and understand. Case studies for different loading conditions are carried out to show the capability of the proposed schemes for solving the TCA problem. (author)

  18. Precoded generalized space shift keying for indoor visible light communications

    KAUST Repository

    Kadampot, Ishaque Ashar; Park, Kihong; Alouini, Mohamed-Slim

    2014-01-01

    We consider a visible light communication system with 2 transmit light emitting diodes (LED) and nr receive photodiodes. An optical generalized space shift keying modulation scheme is considered for the transmission of bits where each LED can

  19. a Thtee-Dimensional Variational Assimilation Scheme for Satellite Aod

    Science.gov (United States)

    Liang, Y.; Zang, Z.; You, W.

    2018-04-01

    A three-dimensional variational data assimilation scheme is designed for satellite AOD based on the IMPROVE (Interagency Monitoring of Protected Visual Environments) equation. The observation operator that simulates AOD from the control variables is established by the IMPROVE equation. All of the 16 control variables in the assimilation scheme are the mass concentrations of aerosol species from the Model for Simulation Aerosol Interactions and Chemistry scheme, so as to take advantage of this scheme in providing comprehensive analyses of species concentrations and size distributions as well as be calculating efficiently. The assimilation scheme can save computational resources as the IMPROVE equation is a quadratic equation. A single-point observation experiment shows that the information from the single-point AOD is effectively spread horizontally and vertically.

  20. Delay and cost performance analysis of the diffie-hellman key exchange protocol in opportunistic mobile networks

    Science.gov (United States)

    Soelistijanto, B.; Muliadi, V.

    2018-03-01

    Diffie-Hellman (DH) provides an efficient key exchange system by reducing the number of cryptographic keys distributed in the network. In this method, a node broadcasts a single public key to all nodes in the network, and in turn each peer uses this key to establish a shared secret key which then can be utilized to encrypt and decrypt traffic between the peer and the given node. In this paper, we evaluate the key transfer delay and cost performance of DH in opportunistic mobile networks, a specific scenario of MANETs where complete end-to-end paths rarely exist between sources and destinations; consequently, the end-to-end delays in these networks are much greater than typical MANETs. Simulation results, driven by a random node movement model and real human mobility traces, showed that DH outperforms a typical key distribution scheme based on the RSA algorithm in terms of key transfer delay, measured by average key convergence time; however, DH performs as well as the benchmark in terms of key transfer cost, evaluated by total key (copies) forwards.

  1. VerSAMI: Versatile and Scalable key management for Smart Grid AMI systems

    OpenAIRE

    Benmalek , Mourad; Challal , Yacine; Derhab , Abdelouahid; Bouabdallah , Abdelmadjid

    2018-01-01

    International audience; In this paper, we propose four new key management schemes for Advanced Metering Infrastructure (AMI) to secure data communications in the Smart Grid (SG). The schemes are based on individual and batch rekeying operations using a novel multi-group key graph structure, are also versatile in the sense that they can support broadcast, unicast, as well as multicast communications. Security analysis shows that our schemes satisfy key management security properties. Furthermo...

  2. Privacy protection schemes for fingerprint recognition systems

    Science.gov (United States)

    Marasco, Emanuela; Cukic, Bojan

    2015-05-01

    The deployment of fingerprint recognition systems has always raised concerns related to personal privacy. A fingerprint is permanently associated with an individual and, generally, it cannot be reset if compromised in one application. Given that fingerprints are not a secret, potential misuses besides personal recognition represent privacy threats and may lead to public distrust. Privacy mechanisms control access to personal information and limit the likelihood of intrusions. In this paper, image- and feature-level schemes for privacy protection in fingerprint recognition systems are reviewed. Storing only key features of a biometric signature can reduce the likelihood of biometric data being used for unintended purposes. In biometric cryptosystems and biometric-based key release, the biometric component verifies the identity of the user, while the cryptographic key protects the communication channel. Transformation-based approaches only a transformed version of the original biometric signature is stored. Different applications can use different transforms. Matching is performed in the transformed domain which enable the preservation of low error rates. Since such templates do not reveal information about individuals, they are referred to as cancelable templates. A compromised template can be re-issued using a different transform. At image-level, de-identification schemes can remove identifiers disclosed for objectives unrelated to the original purpose, while permitting other authorized uses of personal information. Fingerprint images can be de-identified by, for example, mixing fingerprints or removing gender signature. In both cases, degradation of matching performance is minimized.

  3. Exclusion from the Health Insurance Scheme

    CERN Multimedia

    2003-01-01

    A CERN pensioner, member of the Organization's Health Insurance Scheme (CHIS), recently provided fake documents in support of claims for medical expenses, in order to receive unjustified reimbursement from the CHIS. The Administrator of the CHIS, UNIQA, suspected a case of fraud: Accordingly, an investigation and interview of the person concerned was carried out and brought the Organization to the conclusion that fraud had actually taken place. Consequently and in accordance with Article VIII 3.12 of the CHIS Rules, it was decided to exclude this member permanently from the CHIS. The Organization takes the opportunity to remind Scheme members that any fraud or attempt to fraud established within the framework of the CHIS exposes them to: - disciplinary action, according to the Staff Rules and Regulations, for CERN members of the personnel; - definitive exclusion from the CHIS for members affiliated on a voluntary basis. Human Resources Division Tel. 73635

  4. Three state quantum key distribution for small keys

    International Nuclear Information System (INIS)

    Batuwantudawe, J.; Boileau, J.-C.

    2005-01-01

    Full text: Quantum key distribution (QKD) protocols allow two parties, Alice and Bob, to establish secure keys. The most well-known protocol is BB84, using four distinct states. Recently, Phoenix et al. proposed a three state protocol. We explain the protocol and discuss its security proof. The three state protocol also has an interesting structure that allows for errors estimation from the inconclusive results (i.e.. where Alice and Bob choose different bases). This eliminates the need for sampling, potentially useful when qubits are limited. We discuss the effectiveness of this approach compared to BB84 for the case where a good error estimate is required. (author)

  5. A joint asymmetric watermarking and image encryption scheme

    Science.gov (United States)

    Boato, G.; Conotter, V.; De Natale, F. G. B.; Fontanari, C.

    2008-02-01

    Here we introduce a novel watermarking paradigm designed to be both asymmetric, i.e., involving a private key for embedding and a public key for detection, and commutative with a suitable encryption scheme, allowing both to cipher watermarked data and to mark encrypted data without interphering with the detection process. In order to demonstrate the effectiveness of the above principles, we present an explicit example where the watermarking part, based on elementary linear algebra, and the encryption part, exploiting a secret random permutation, are integrated in a commutative scheme.

  6. Matrix Encryption Scheme

    Directory of Open Access Journals (Sweden)

    Abdelhakim Chillali

    2017-05-01

    Full Text Available In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. In this work, we proposed a new problem applicable to the public key cryptography, based on the Matrices, called “Matrix discrete logarithm problem”, it uses certain elements formed by matrices whose coefficients are elements in a finite field. We have constructed an abelian group and, for the cryptographic part in this unreliable group, we then perform the computation corresponding to the algebraic equations, Returning the encrypted result to a receiver. Upon receipt of the result, the receiver can retrieve the sender’s clear message by performing the inverse calculation.

  7. Fine-Grained Forward-Secure Signature Schemes without Random Oracles

    DEFF Research Database (Denmark)

    Camenisch, Jan; Koprowski, Maciej

    2006-01-01

    We propose the concept of fine-grained forward-secure signature schemes. Such signature schemes not only provide nonrepudiation w.r.t. past time periods the way ordinary forward-secure signature schemes do but, in addition, allow the signer to specify which signatures of the current time period...... remain valid when revoking the public key. This is an important advantage if the signer produces many signatures per time period as otherwise the signer would have to re-issue those signatures (and possibly re-negotiate the respective messages) with a new key.Apart from a formal model for fine......-grained forward-secure signature schemes, we present practical schemes and prove them secure under the strong RSA assumption only, i.e., we do not resort to the random oracle model to prove security. As a side-result, we provide an ordinary forward-secure scheme whose key-update time is significantly smaller than...

  8. A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks.

    Science.gov (United States)

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-07-14

    The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes.

  9. New Financing Schemes of Public Infrastructure

    Directory of Open Access Journals (Sweden)

    Ignacio de la Riva

    2017-01-01

    Full Text Available Public works procurements and concessions are traditional legal techniques used to shape the financing of public infrastructure. Fiscal constraints faced by public administrations at the end of the 20th century, and the subsequent increase of private participation in the provision of public goods and services, encouraged the development of new legal schemes allowing a higher degree of private investment in public infrastructure; such as Public Private Partnerships, project finance, securitizations, the shadow toll, turn-key agreements, public leasing and public trusts.

  10. Coordinated renewable energy support schemes

    DEFF Research Database (Denmark)

    Morthorst, P.E.; Jensen, S.G.

    2006-01-01

    . The first example covers countries with regional power markets that also regionalise their support schemes, the second countries with separate national power markets that regionalise their support schemes. The main findings indicate that the almost ideal situation exists if the region prior to regionalising...

  11. CANONICAL BACKWARD DIFFERENTIATION SCHEMES FOR ...

    African Journals Online (AJOL)

    This paper describes a new nonlinear backward differentiation schemes for the numerical solution of nonlinear initial value problems of first order ordinary differential equations. The schemes are based on rational interpolation obtained from canonical polynomials. They are A-stable. The test problems show that they give ...

  12. Key distillation in quantum cryptography

    Science.gov (United States)

    Slutsky, Boris Aron

    1998-11-01

    Quantum cryptography is a technique which permits two parties to communicate over an open channel and establish a shared sequence of bits known only to themselves. This task, provably impossible in classical cryptography, is accomplished by encoding the data on quantum particles and harnessing their unique properties. It is believed that no eavesdropping attack consistent with the laws of quantum theory can compromise the secret data unknowingly to the legitimate users of the channel. Any attempt by a hostile actor to monitor the data carrying particles while in transit reveals itself through transmission errors it must inevitably introduce. Unfortunately, in practice a communication is not free of errors even when no eavesdropping is present. Key distillation is a technique that permits the parties to overcome this difficulty and establish a secret key despite channel defects, under the assumption that every particle is handled independently from other particles by the enemy. In the present work, key distillation is described and its various aspects are studied. A relationship is derived between the average error rate resulting from an eavesdropping attack and the amount of information obtained by the attacker. Formal definition is developed of the security of the final key. The net throughput of secret bits in a quantum cryptosystem employing key distillation is assessed. An overview of quantum cryptographic protocols and related information theoretical results is also given.

  13. Key China Energy Statistics 2012

    Energy Technology Data Exchange (ETDEWEB)

    Levine, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fridley, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fino-Chen, Cecilia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-05-01

    The China Energy Group at Lawrence Berkeley National Laboratory (LBNL) was established in 1988. Over the years the Group has gained recognition as an authoritative source of China energy statistics through the publication of its China Energy Databook (CED). The Group has published seven editions to date of the CED (http://china.lbl.gov/research/chinaenergy-databook). This handbook summarizes key statistics from the CED and is expressly modeled on the International Energy Agency’s “Key World Energy Statistics” series of publications. The handbook contains timely, clearly-presented data on the supply, transformation, and consumption of all major energy sources.

  14. Key China Energy Statistics 2011

    Energy Technology Data Exchange (ETDEWEB)

    Levine, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fridley, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Hongyou [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fino-Chen, Cecilia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-01-15

    The China Energy Group at Lawrence Berkeley National Laboratory (LBNL) was established in 1988. Over the years the Group has gained recognition as an authoritative source of China energy statistics through the publication of its China Energy Databook (CED). In 2008 the Group published the Seventh Edition of the CED (http://china.lbl.gov/research/chinaenergy-databook). This handbook summarizes key statistics from the CED and is expressly modeled on the International Energy Agency’s “Key World Energy Statistics” series of publications. The handbook contains timely, clearly-presented data on the supply, transformation, and consumption of all major energy sources.

  15. Construction of a knowledge classification scheme for sharing and usage of knowledge

    International Nuclear Information System (INIS)

    Yoo, Jae Bok; Oh, Jeong Hoon; Lee, Ji Ho; Ko, Young Chul

    2003-12-01

    To efficiently share knowledge among our members on the basis of knowledge management system, first of all, we need to systematically design the knowledge classification scheme that we can classify these knowledge well. The objective of this project is to construct the most suitable knowledge classification scheme that all of us can share them in Korea Atomic Energy Research Institute(KAERI). To construct the knowledge classification scheme all over the our organization, we established a few principles to design it and examined related many classification schemes. And we carried out 3 steps to complete the best desirable KAERI's knowledge classification scheme, that is, 1) the step to design a draft of the knowledge classification scheme, 2) the step to revise a draft of the knowledge classification scheme, 3) the step to verify the revised scheme and to decide its scheme. The scheme completed as a results of this project is consisted of total 218 items, that is, sections of 8 items, classes of 43 items and sub-classes of 167 items. We expect that the knowledge classification scheme designed as the results of this project can be played an important role as the frame to share knowledge among our members when we introduce knowledge management system in our organization. In addition, we expect that methods to design its scheme as well as this scheme itself can be applied when design a knowledge classification scheme at the other R and D institutes and enterprises

  16. Boudot's Range-Bounded Commitment Scheme Revisited

    Science.gov (United States)

    Cao, Zhengjun; Liu, Lihua

    Checking whether a committed integer lies in a specific interval has many cryptographic applications. In Eurocrypt'98, Chan et al. proposed an instantiation (CFT Proof). Based on CFT, Boudot presented a popular range-bounded commitment scheme in Eurocrypt'2000. Both CFT Proof and Boudot Proof are based on the encryption E(x, r)=g^xh^r mod n, where n is an RSA modulus whose factorization is unknown by the prover. They did not use a single base as usual. Thus an increase in cost occurs. In this paper, we show that it suffices to adopt a single base. The cost of the modified Boudot Proof is about half of that of the original scheme. Moreover, the key restriction in the original scheme, i.e., both the discrete logarithm of g in base h and the discrete logarithm of h in base g are unknown by the prover, which is a potential menace to the Boudot Proof, is definitely removed.

  17. Numerical Schemes for Rough Parabolic Equations

    Energy Technology Data Exchange (ETDEWEB)

    Deya, Aurelien, E-mail: deya@iecn.u-nancy.fr [Universite de Nancy 1, Institut Elie Cartan Nancy (France)

    2012-04-15

    This paper is devoted to the study of numerical approximation schemes for a class of parabolic equations on (0,1) perturbed by a non-linear rough signal. It is the continuation of Deya (Electron. J. Probab. 16:1489-1518, 2011) and Deya et al. (Probab. Theory Relat. Fields, to appear), where the existence and uniqueness of a solution has been established. The approach combines rough paths methods with standard considerations on discretizing stochastic PDEs. The results apply to a geometric 2-rough path, which covers the case of the multidimensional fractional Brownian motion with Hurst index H>1/3.

  18. Information Security Scheme Based on Computational Temporal Ghost Imaging.

    Science.gov (United States)

    Jiang, Shan; Wang, Yurong; Long, Tao; Meng, Xiangfeng; Yang, Xiulun; Shu, Rong; Sun, Baoqing

    2017-08-09

    An information security scheme based on computational temporal ghost imaging is proposed. A sequence of independent 2D random binary patterns are used as encryption key to multiply with the 1D data stream. The cipher text is obtained by summing the weighted encryption key. The decryption process can be realized by correlation measurement between the encrypted information and the encryption key. Due to the instinct high-level randomness of the key, the security of this method is greatly guaranteed. The feasibility of this method and robustness against both occlusion and additional noise attacks are discussed with simulation, respectively.

  19. Image encryption using fingerprint as key based on phase retrieval algorithm and public key cryptography

    Science.gov (United States)

    Zhao, Tieyu; Ran, Qiwen; Yuan, Lin; Chi, Yingying; Ma, Jing

    2015-09-01

    In this paper, a novel image encryption system with fingerprint used as a secret key is proposed based on the phase retrieval algorithm and RSA public key algorithm. In the system, the encryption keys include the fingerprint and the public key of RSA algorithm, while the decryption keys are the fingerprint and the private key of RSA algorithm. If the users share the fingerprint, then the system will meet the basic agreement of asymmetric cryptography. The system is also applicable for the information authentication. The fingerprint as secret key is used in both the encryption and decryption processes so that the receiver can identify the authenticity of the ciphertext by using the fingerprint in decryption process. Finally, the simulation results show the validity of the encryption scheme and the high robustness against attacks based on the phase retrieval technique.

  20. Key management issue in SCADA networks: A review

    Directory of Open Access Journals (Sweden)

    Abdalhossein Rezai

    2017-02-01

    Full Text Available Supervisory Control And Data Acquisition (SCADA networks have a vital role in Critical Infrastructures (CIs such as public transports, power generation systems, gas, water and oil industries, so that there are concerns on security issues in these networks. The utilized Remote Terminal Units (RTUs and Intelligence Electronic Devices (IEDs in these networks have resource limitations, which make security applications a challenging issue. Efficient key management schemes are required besides lightweight ciphers for securing the SCADA communications. Many key management schemes have been developed to address the tradeoff between SCADA constrain and security, but which scheme is the most effective is still debatable. This paper presents a review of the existing key management schemes in SCADA networks, which provides directions for further researches in this field.

  1. hybrid modulation scheme fo rid modulation scheme fo dulation

    African Journals Online (AJOL)

    eobe

    control technique is done through simulations and ex control technique .... HYBRID MODULATION SCHEME FOR CASCADED H-BRIDGE INVERTER CELLS. C. I. Odeh ..... and OR operations. Referring to ... MATLAB/SIMULINK environment.

  2. Revocable Key-Aggregate Cryptosystem for Data Sharing in Cloud

    Directory of Open Access Journals (Sweden)

    Qingqing Gan

    2017-01-01

    Full Text Available With the rapid development of network and storage technology, cloud storage has become a new service mode, while data sharing and user revocation are important functions in the cloud storage. Therefore, according to the characteristics of cloud storage, a revocable key-aggregate encryption scheme is put forward based on subset-cover framework. The proposed scheme not only has the key-aggregate characteristics, which greatly simplifies the user’s key management, but also can revoke user access permissions, realizing the flexible and effective access control. When user revocation occurs, it allows cloud server to update the ciphertext so that revoked users can not have access to the new ciphertext, while nonrevoked users do not need to update their private keys. In addition, a verification mechanism is provided in the proposed scheme, which can verify the updated ciphertext and ensure that the user revocation is performed correctly. Compared with the existing schemes, this scheme can not only reduce the cost of key management and storage, but also realize user revocation and achieve user’s access control efficiently. Finally, the proposed scheme can be proved to be selective chosen-plaintext security in the standard model.

  3. A New Proxy Electronic Voting Scheme Achieved by Six-Particle Entangled States

    Science.gov (United States)

    Cao, Hai-Jing; Ding, Li-Yuan; Jiang, Xiu-Li; Li, Peng-Fei

    2018-03-01

    In this paper, we use quantum proxy signature to construct a new secret electronic voting scheme. In our scheme, six particles entangled states function as quantum channels. The voter Alice, the Vote Management Center Bob, the scrutineer Charlie only perform two particles measurements on the Bell bases to realize the electronic voting process. So the scheme reduces the technical difficulty and increases operation efficiency. We use quantum key distribution and one-time pad to guarantee its unconditional security. The significant advantage of our scheme is that transmitted information capacity is twice as much as the capacity of other schemes.

  4. How Governance Regimes Shape the Implementation of Water Reuse Schemes

    Directory of Open Access Journals (Sweden)

    Jos Frijns

    2016-12-01

    Full Text Available The governance dimensions of water reuse scheme development and operation, such as policies and regulatory frameworks, and public involvement and stakeholder collaboration, can serve to both facilitate and constrain wider adoption of water reuse practices. This paper explores the significance and underlying structure of the key governance challenges facing the water reuse sector in Europe. It presents empirical evidence from interviews and focus group sessions conducted at four water reuse schemes: an indirect potable reuse scheme at Torreele (Belgium, the urban reuse of treated municipal wastewater at the London Olympic Park (United Kingdom and at Sabadell (Spain, and the reuse of agro-industrial effluent for irrigation at Capitanata (Italy. The findings underscore the importance of clarity in policy arrangements around water reuse, as well as of the financial competitiveness of reuse projects compared to alternative water supply options. Operators of water reuse schemes expressed a preference for water quality standards, which focus on appropriateness for use rather than over-emphasise the waters’ origin so that unnecessary treatment and costs can be avoided. Positive public support was widely acknowledged as an important factor in the success or failure of water reuse schemes. We conclude that constructive institutional relationships underpin many of the challenges faced by reuse scheme operators and that greater emphasis should be given to building confidence and gaining trust in water service providers through early identification of how governance regimes shape the viability of new schemes.

  5. Modular Connector Keying Concept

    Science.gov (United States)

    Ishman, Scott; Dukes, Scott; Warnica, Gary; Conrad, Guy; Senigla, Steven

    2013-01-01

    For panel-mount-type connectors, keying is usually "built-in" to the connector body, necessitating different part numbers for each key arrangement. This is costly for jobs that require small quantities. This invention was driven to provide a cost savings and to reduce documentation of individual parts. The keys are removable and configurable in up to 16 combinations. Since the key parts are separate from the connector body, a common design can be used for the plug, receptacle, and key parts. The keying can then be set at the next higher assembly.

  6. An emerging equilibrium in the EU emissions trading scheme

    International Nuclear Information System (INIS)

    Bredin, Don; Muckley, Cal

    2011-01-01

    The European Union's Emissions Trading Scheme (ETS) is the key policy instrument of the European Commission's Climate Change Program aimed at reducing greenhouse gas emissions to eight percent below 1990 levels by 2012. A critically important element of the EU ETS is the establishment of a market determined price for EU allowances. This article examines the extent to which several theoretically founded factors including, economic growth, energy prices and weather conditions determine the expected prices of the European Union CO 2 allowances during the 2005 through to the 2009 period. The novel aspect of our study is that we examine heavily traded futures instruments that have an expiry date in Phase 2 of the EU ETS. Our study adopts both static and recursive versions of the Johansen multivariate cointegration likelihood ratio test as well as a variation on this test with a view to controlling for time varying volatility effects. Our results are indicative of a new pricing regime emerging in Phase 2 and point to a maturing market driven by the fundamentals. These results are valuable both for traders of EU allowances and for those policy makers seeking to improve the design of the European Union ETS.

  7. Good governance for pension schemes

    CERN Document Server

    Thornton, Paul

    2011-01-01

    Regulatory and market developments have transformed the way in which UK private sector pension schemes operate. This has increased demands on trustees and advisors and the trusteeship governance model must evolve in order to remain fit for purpose. This volume brings together leading practitioners to provide an overview of what today constitutes good governance for pension schemes, from both a legal and a practical perspective. It provides the reader with an appreciation of the distinctive characteristics of UK occupational pension schemes, how they sit within the capital markets and their social and fiduciary responsibilities. Providing a holistic analysis of pension risk, both from the trustee and the corporate perspective, the essays cover the crucial role of the employer covenant, financing and investment risk, developments in longevity risk hedging and insurance de-risking, and best practice scheme administration.

  8. Optimum RA reactor fuelling scheme

    International Nuclear Information System (INIS)

    Strugar, P.; Nikolic, V.

    1965-10-01

    Ideal reactor refueling scheme can be achieved only by continuous fuel elements movement in the core, which is not possible, and thus approximations are applied. One of the possible approximations is discontinuous movement of fuel elements groups in radial direction. This enables higher burnup especially if axial exchange is possible. Analysis of refueling schemes in the RA reactor core and schemes with mixing the fresh and used fuel elements show that 30% higher burnup can be achieved by applying mixing, and even 40% if reactivity due to decrease in experimental space is taken into account. Up to now, mean burnup of 4400 MWd/t has been achieved, and the proposed fueling scheme with reduction of experimental space could achieve mean burnup of 6300 MWd/t which means about 25 Mwd/t per fuel channel [sr

  9. Numerical schemes for explosion hazards

    International Nuclear Information System (INIS)

    Therme, Nicolas

    2015-01-01

    In nuclear facilities, internal or external explosions can cause confinement breaches and radioactive materials release in the environment. Hence, modeling such phenomena is crucial for safety matters. Blast waves resulting from explosions are modeled by the system of Euler equations for compressible flows, whereas Navier-Stokes equations with reactive source terms and level set techniques are used to simulate the propagation of flame front during the deflagration phase. The purpose of this thesis is to contribute to the creation of efficient numerical schemes to solve these complex models. The work presented here focuses on two major aspects: first, the development of consistent schemes for the Euler equations, then the buildup of reliable schemes for the front propagation. In both cases, explicit in time schemes are used, but we also introduce a pressure correction scheme for the Euler equations. Staggered discretization is used in space. It is based on the internal energy formulation of the Euler system, which insures its positivity and avoids tedious discretization of the total energy over staggered grids. A discrete kinetic energy balance is derived from the scheme and a source term is added in the discrete internal energy balance equation to preserve the exact total energy balance at the limit. High order methods of MUSCL type are used in the discrete convective operators, based solely on material velocity. They lead to positivity of density and internal energy under CFL conditions. This ensures that the total energy cannot grow and we can furthermore derive a discrete entropy inequality. Under stability assumptions of the discrete L8 and BV norms of the scheme's solutions one can prove that a sequence of converging discrete solutions necessarily converges towards the weak solution of the Euler system. Besides it satisfies a weak entropy inequality at the limit. Concerning the front propagation, we transform the flame front evolution equation (the so called

  10. Breakdown of NpNn scheme in very heavy nuclei

    International Nuclear Information System (INIS)

    Varshney, A.K.; Singh, M.; Kumar, Rajesh; Gupta, K.K.; Gupta, D.K.

    2016-01-01

    The proton neutron interaction has been considered the key ingredient in the development of configuration mixing, collectivity and ultimately deformation in atomic nuclei for over five decades. Phenomenologically, the correlation of the integrated valance p - n interaction with the onset of collectivity and deformation has been described in terms of NpNn scheme

  11. EFFECTIVE SCHEMES OF FINANCING MERGERS AND ACQUISITIONS OF INTERNATIONAL CORPORATIONS

    Directory of Open Access Journals (Sweden)

    Vladimir Momot

    2013-10-01

    Full Text Available The article considers the question of a choice of the optimum scheme of financing mergers and acquisitions (M&As in the environment of international corporations. Methods and ways of financing integration transactions are considered and key factors and system processes of realization of these transactions are defined.

  12. Breeding schemes in reindeer husbandry

    Directory of Open Access Journals (Sweden)

    Lars Rönnegård

    2003-04-01

    Full Text Available The objective of the paper was to investigate annual genetic gain from selection (G, and the influence of selection on the inbreeding effective population size (Ne, for different possible breeding schemes within a reindeer herding district. The breeding schemes were analysed for different proportions of the population within a herding district included in the selection programme. Two different breeding schemes were analysed: an open nucleus scheme where males mix and mate between owner flocks, and a closed nucleus scheme where the males in non-selected owner flocks are culled to maximise G in the whole population. The theory of expected long-term genetic contributions was used and maternal effects were included in the analyses. Realistic parameter values were used for the population, modelled with 5000 reindeer in the population and a sex ratio of 14 adult females per male. The standard deviation of calf weights was 4.1 kg. Four different situations were explored and the results showed: 1. When the population was randomly culled, Ne equalled 2400. 2. When the whole population was selected on calf weights, Ne equalled 1700 and the total annual genetic gain (direct + maternal in calf weight was 0.42 kg. 3. For the open nucleus scheme, G increased monotonically from 0 to 0.42 kg as the proportion of the population included in the selection programme increased from 0 to 1.0, and Ne decreased correspondingly from 2400 to 1700. 4. In the closed nucleus scheme the lowest value of Ne was 1300. For a given proportion of the population included in the selection programme, the difference in G between a closed nucleus scheme and an open one was up to 0.13 kg. We conclude that for mass selection based on calf weights in herding districts with 2000 animals or more, there are no risks of inbreeding effects caused by selection.

  13. Integrating a Trust Framework with a Distributed Certificate Validation Scheme for MANETs

    Directory of Open Access Journals (Sweden)

    Marias Giannis F

    2006-01-01

    Full Text Available Many trust establishment solutions in mobile ad hoc networks (MANETs rely on public key certificates. Therefore, they should be accompanied by an efficient mechanism for certificate revocation and validation. Ad hoc distributed OCSP for trust (ADOPT is a lightweight, distributed, on-demand scheme based on cached OCSP responses, which provides certificate status information to the nodes of a MANET. In this paper we discuss the ADOPT scheme and issues on its deployment over MANETs. We present some possible threats to ADOPT and suggest the use of a trust assessment and establishment framework, named ad hoc trust framework (ATF, to support ADOPT's robustness and efficiency. ADOPT is deployed as a trust-aware application that provides feedback to ATF, which calculates the trustworthiness of the peer nodes' functions and helps ADOPT to improve its performance by rapidly locating valid certificate status information. Moreover, we introduce the TrustSpan algorithm to reduce the overhead that ATF produces, and the TrustPath algorithm to identify and use trusted routes for propagating sensitive information, such as third parties' accusations. Simulation results show that ATF adds limited overhead compared to its efficiency in detecting and isolating malicious and selfish nodes. ADOPT's reliability is increased, since it can rapidly locate a legitimate response by using information provided by ATF.

  14. Quantum key distribution without alternative measurements

    CERN Document Server

    Cabello, A

    2000-01-01

    Entanglement swapping between Einstein-Podolsky-Rosen (EPR) pairs can be used to generate the same sequence of random bits in two remote places. A quantum key distribution protocol based on this idea is described. The scheme exhibits the following features. (a) It does not require that Alice and Bob choose between alternative measurements, therefore improving the rate of generated bits by transmitted qubit. (b) It allows Alice and Bob to generate a key of arbitrary length using a single quantum system (three EPR pairs), instead of a long sequence of them. (c) Detecting Eve requires the comparison of fewer bits. (d) Entanglement is an essential ingredient. The scheme assumes reliable measurements of the Bell operator. (20 refs).

  15. Asynchronous Channel-Hopping Scheme under Jamming Attacks

    Directory of Open Access Journals (Sweden)

    Yongchul Kim

    2018-01-01

    Full Text Available Cognitive radio networks (CRNs are considered an attractive technology to mitigate inefficiency in the usage of licensed spectrum. CRNs allow the secondary users (SUs to access the unused licensed spectrum and use a blind rendezvous process to establish communication links between SUs. In particular, quorum-based channel-hopping (CH schemes have been studied recently to provide guaranteed blind rendezvous in decentralized CRNs without using global time synchronization. However, these schemes remain vulnerable to jamming attacks. In this paper, we first analyze the limitations of quorum-based rendezvous schemes called asynchronous channel hopping (ACH. Then, we introduce a novel sequence sensing jamming attack (SSJA model in which a sophisticated jammer can dramatically reduce the rendezvous success rates of ACH schemes. In addition, we propose a fast and robust asynchronous rendezvous scheme (FRARS that can significantly enhance robustness under jamming attacks. Our numerical results demonstrate that the performance of the proposed scheme vastly outperforms the ACH scheme when there are security concerns about a sequence sensing jammer.

  16. A Secure and Scalable Data Communication Scheme in Smart Grids

    Directory of Open Access Journals (Sweden)

    Chunqiang Hu

    2018-01-01

    Full Text Available The concept of smart grid gained tremendous attention among researchers and utility providers in recent years. How to establish a secure communication among smart meters, utility companies, and the service providers is a challenging issue. In this paper, we present a communication architecture for smart grids and propose a scheme to guarantee the security and privacy of data communications among smart meters, utility companies, and data repositories by employing decentralized attribute based encryption. The architecture is highly scalable, which employs an access control Linear Secret Sharing Scheme (LSSS matrix to achieve a role-based access control. The security analysis demonstrated that the scheme ensures security and privacy. The performance analysis shows that the scheme is efficient in terms of computational cost.

  17. Password Authenticated Key Exchange and Protected Password Change Protocols

    Directory of Open Access Journals (Sweden)

    Ting-Yi Chang

    2017-07-01

    Full Text Available In this paper, we propose new password authenticated key exchange (PAKE and protected password change (PPC protocols without any symmetric or public-key cryptosystems. The security of the proposed protocols is based on the computational Diffie-Hellman assumption in the random oracle model. The proposed scheme can resist both forgery server and denial of service attacks.

  18. Quantum Key Distribution Using Four-Qubit W State

    International Nuclear Information System (INIS)

    Cai Haijing; Song Heshan

    2006-01-01

    A new theoretical quantum key distribution scheme based on entanglement swapping is proposed, where four-qubit symmetric W state functions as quantum channel. It is shown that two legitimate users can secretly share a series of key bits by using Bell-state measurements and classical communication.

  19. Key Recovery Using Noised Secret Sharing with Discounts over Large Clouds

    OpenAIRE

    JAJODIA , Sushil; Litwin , Witold; Schwarz , Thomas

    2013-01-01

    Encryption key loss problem is the Achilles's heel of cryptography. Key escrow helps, but favors disclosures. Schemes for recoverable encryption keys through noised secret sharing alleviate the dilemma. Key owner escrows a specifically encrypted backup. The recovery needs a large cloud. Cloud cost, money trail should rarefy illegal attempts. We now propose noised secret sharing schemes supporting discounts. The recovery request with discount code lowers the recovery complexity, easily by orde...

  20. Biometry, the safe key

    Directory of Open Access Journals (Sweden)

    María Fraile-Hurtado

    2010-12-01

    Full Text Available Biometry is the next step in authentication, why do not we take this stepforward in our communication security systems? Keys are the main disadvantage in the cryptography, what if we were our own key?

  1. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  2. Public Key Cryptography.

    Science.gov (United States)

    Tapson, Frank

    1996-01-01

    Describes public key cryptography, also known as RSA, which is a system using two keys, one used to put a message into cipher and another used to decipher the message. Presents examples using small prime numbers. (MKR)

  3. Key Management Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides a secure environment to research and develop advanced electronic key management and networked key distribution technologies for the Navy and DoD....

  4. Public Key Infrastructure Study

    National Research Council Canada - National Science Library

    Berkovits, Shimshon

    1994-01-01

    The National Institute of Standards and Technology (NIST) has tasked The MITRE Corporation to study the alternatives for automated management of public keys and of the associated public key certificates for the Federal Government...

  5. Bit-Oriented Quantum Public-Key Cryptosystem Based on Bell States

    Science.gov (United States)

    Wu, WanQing; Cai, QingYu; Zhang, HuanGuo; Liang, XiaoYan

    2018-06-01

    Quantum public key encryption system provides information confidentiality using quantum mechanics. This paper presents a quantum public key cryptosystem ( Q P K C) based on the Bell states. By H o l e v o' s theorem, the presented scheme provides the security of the secret key using one-wayness during the QPKC. While the QPKC scheme is information theoretic security under chosen plaintext attack ( C P A). Finally some important features of presented QPKC scheme can be compared with other QPKC scheme.

  6. An optimized encoding method for secure key distribution by swapping quantum entanglement and its extension

    International Nuclear Information System (INIS)

    Gao Gan

    2015-01-01

    Song [Song D 2004 Phys. Rev. A 69 034301] first proposed two key distribution schemes with the symmetry feature. We find that, in the schemes, the private channels which Alice and Bob publicly announce the initial Bell state or the measurement result through are not needed in discovering keys, and Song’s encoding methods do not arrive at the optimization. Here, an optimized encoding method is given so that the efficiencies of Song’s schemes are improved by 7/3 times. Interestingly, this optimized encoding method can be extended to the key distribution scheme composed of generalized Bell states. (paper)

  7. An efficient three-party password-based key agreement protocol using extended chaotic maps

    International Nuclear Information System (INIS)

    Shu Jian

    2015-01-01

    Three-party password-based key agreement protocols allow two users to authenticate each other via a public channel and establish a session key with the aid of a trusted server. Recently, Farash et al. [Farash M S, Attari M A 2014 “An efficient and provably secure three-party password-based authenticated key exchange protocol based on Chebyshev chaotic maps”, Nonlinear Dynamics 77(7): 399–411] proposed a three-party key agreement protocol by using the extended chaotic maps. They claimed that their protocol could achieve strong security. In the present paper, we analyze Farash et al.’s protocol and point out that this protocol is vulnerable to off-line password guessing attack and suffers communication burden. To handle the issue, we propose an efficient three-party password-based key agreement protocol using extended chaotic maps, which uses neither symmetric cryptosystems nor the server’s public key. Compared with the relevant schemes, our protocol provides better performance in terms of computation and communication. Therefore, it is suitable for practical applications. (paper)

  8. The Key Lake project

    International Nuclear Information System (INIS)

    1991-01-01

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  9. Establishment Registration & Device Listing

    Data.gov (United States)

    U.S. Department of Health & Human Services — This searchable database contains establishments (engaged in the manufacture, preparation, propagation, compounding, assembly, or processing of medical devices...

  10. A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

    International Nuclear Information System (INIS)

    Zhang Xiaohong; Min Lequan

    2005-01-01

    Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color (RGB) digital image secure communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin, and decrypts the ciphertext. The scheme can encrypt and decrypt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security.

  11. Finite key analysis in quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.

    2007-10-31

    In view of experimental realization of quantum key distribution schemes, the study of their efficiency becomes as important as the proof of their security. The latter is the subject of most of the theoretical work about quantum key distribution, and many important results such as the proof of unconditional security have been obtained. The efficiency and also the robustness of quantum key distribution protocols against noise can be measured by figures of merit such as the secret key rate (the fraction of input signals that make it into the key) and the threshold quantum bit error rate (the maximal error rate such that one can still create a secret key). It is important to determine these quantities because they tell us whether a certain quantum key distribution scheme can be used at all in a given situation and if so, how many secret key bits it can generate in a given time. However, these figures of merit are usually derived under the ''infinite key limit'' assumption, that is, one assumes that an infinite number of quantum states are send and that all sub-protocols of the scheme (in particular privacy amplification) are carried out on these infinitely large blocks. Such an assumption usually eases the analysis, but also leads to (potentially) too optimistic values for the quantities in question. In this thesis, we are explicitly avoiding the infinite key limit for the analysis of the privacy amplification step, which plays the most important role in a quantum key distribution scheme. We still assume that an optimal error correction code is applied and we do not take into account any statistical errors that might occur in the parameter estimation step. Renner and coworkers derived an explicit formula for the obtainable key rate in terms of Renyi entropies of the quantum states describing Alice's, Bob's, and Eve's systems. This results serves as a starting point for our analysis, and we derive an algorithm that efficiently computes

  12. LOCKS AND KEYS SERVICE

    CERN Multimedia

    Locks and Keys Service

    2002-01-01

    The Locks and Keys service (ST/FM) will move from building 55 to building 570 from the 2nd August to the 9th August 2002 included. During this period the service will be closed. Only in case of extreme urgency please call the 164550. Starting from Monday, 12th August, the Locks and Keys Service will continue to follow the activities related to office keys (keys and locks) and will provide the keys for furniture. The service is open from 8h30 to 12h00 and from 13h00 to 17h30. We remind you that your divisional correspondents can help you in the execution of the procedures. We thank you for your comprehension and we remain at your service to help you in solving all the matters related to keys for offices and furniture. Locks and Keys Service - ST Division - FM Group

  13. Modeling and performance analysis of an improved movement-based location management scheme for packet-switched mobile communication systems.

    Science.gov (United States)

    Chung, Yun Won; Kwon, Jae Kyun; Park, Suwon

    2014-01-01

    One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds.

  14. Arbitrated quantum signature scheme based on χ-type entangled states

    International Nuclear Information System (INIS)

    Zuo, Huijuan; Huang, Wei; Qin, Sujuan

    2013-01-01

    An arbitrated quantum signature scheme, which is mainly applied in electronic-payment systems, is proposed and investigated. The χ-type entangled states are used for quantum key distribution and quantum signature in this protocol. Compared with previous quantum signature schemes which also utilize χ-type entangled states, the proposed scheme provides higher efficiency. Finally, we also analyze its security under various kinds of attacks. (paper)

  15. Development of the Latvian scheme for energy auditing of buildings and inspection of boilers and air-conditioning systems. Final report institutional set-up

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-12-01

    To implement EU directive 93/76/EEC on reduction of carbon dioxide emission by increasing energy efficiency and EU directive 2002/91/EC on building energy efficiency, Latvia must establish and institutional scheme and define all the organisations involved. From a general perspective the institutional scheme must as a minimum include the following four key players: the administrator, the operating unit, the auditors or independent experts, and finally the client. Furthermore, institutions dealing with financing of energy efficiency improvement activities, training and certification of experts, information about auditing and energy efficiency etc. need to be involved. At present there is no governmental or private Latvian organisation that could fully rearrange and assume the duties of an energy audit scheme secretariat. It is therefore recommended initially to place the secretariat as a separate, new unit within the Ministry of Economy, financed by the Ministry of Economy, with the intention of establishing at a later stage (after e.g. 5 years) a separate, new agency, an Energy Efficiency Agency partly financed by the incomes from the energy audit and boiler inspection schemes. The Secretariat should, both in its initial phase and later, assign the tasks of training, information campaigns, quality assurance and evaluation to external organisations. (BA)

  16. Complex of Key Instruments of Management of Operation Activity of a Small Business Trade Enterprise

    Directory of Open Access Journals (Sweden)

    Serdyuk Vira M.

    2013-11-01

    Full Text Available The article offers a complex of key instruments of management of operation activity of a small business trade enterprise, including: 1 budgeting of operation activity; 2 its accounting by norms and deviations from them; 3 monitoring of operational activity of an enterprise, which envisages analysis of revealed deviations. The article shows the most efficient way of realisation and practical use of the presented concept – application of the “standard-cost” scheme within the framework of which the following tasks are solved: 1 budgeting of income from operational activity; 2 establishment of standards of costs; 3 accumulation of data on factual income and expenditures; 4 analysis of deviations and reporting; and 5 introduction of necessary amendments. The article also offers an imitation model of analysis of dynamics of trade processes, which allows detection of key spheres of management of operation activity of a small trade enterprise and principles of carrying out an efficient and well thought over financial policy.

  17. Data-derived symbol synchronization of MASK and QASK signals. [Multilevel and Quadrature Amplitude Shift Keying

    Science.gov (United States)

    Simon, M. K.

    1975-01-01

    Much has been said in the literature regarding the problem of establishing symbol synchronization in binary baseband digital communication systems. By comparison, the literature contains little information relating to the extraction of symbol sync from multilevel baseband data. With the recent interest in multilevel amplitude-shift keying (MASK) and quadrature amplitude-shift keying (QASK) as signaling techniques for multilevel digital communications systems, the problem of providing symbol synchronization in the receivers of such systems becomes paramount. This paper presents a technique for extracting symbol sync from a MASK or QASK signal which has been transmitted over an infinite-bandwidth white Gaussian noise channel. The scheme is essentially a generalization of the data transition tracking loop (DTTL) which has heretofore been used in PSK systems. The performance of the loop is analyzed in terms of its mean-squared symbol sync jitter and its effects on the data detection process in MASK and QASK systems.

  18. Designing synchronization schemes for chaotic fractional-order unified systems

    International Nuclear Information System (INIS)

    Wang Junwei; Zhang Yanbin

    2006-01-01

    Synchronization in chaotic fractional-order differential systems is studied both theoretically and numerically. Two schemes are designed to achieve chaos synchronization of so-called unified chaotic systems and the corresponding numerical algorithms are established. Some sufficient conditions on synchronization are also derived based on the Laplace transformation theory. Computer simulations are used for demonstration

  19. The Spanish external quality assessment scheme for lead in blood.

    Science.gov (United States)

    Marcuello, D

    1996-01-01

    In 1985 the Instituto Nacional de Seguridad e Higiene en el Trabajo (INSHT) established the "Programa Interlaboratorios de Control de Calidad de Plomo en Sangre (PICC-PbS)". The operation of this scheme is explained, criteria for evaluation of laboratory performance are defined and some results obtained are reviewed.

  20. Evaluation of Rajiv Aarogyasri Health Insurance Scheme in Andrha ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    In 2007, out-of-pocket expenditures accounted for 90% of total private expenditure on healthcare in India. The cost of coping with serious disease can be ruinous for families living below the poverty line. The Rajiv Aarogyasri Health Insurance Scheme was established in Andrha Pradesh to mitigate catastrophic healthcare ...

  1. Participation in the National Health Insurance Scheme Among ...

    African Journals Online (AJOL)

    Background: The National Health Insurance Scheme was established under Act 35 of 1999 by the Federal Government of Nigeria and is aimed at providing easy access to health care for all Nigerians at an affordable cost through various prepayment systems. It is totally committed to achieving universal coverage and ...

  2. Employment and Training Schemes for Rural Youth: Learning from Experience.

    Science.gov (United States)

    Phan-Thuy, N.

    1985-01-01

    Over the past two decades a number of African and Asian governments have experimented with various types of youth mobilization or employment and training schemes in trying to cope with rural youth unemployment. A critical appraisal is made of some of these in an attempt to establish criteria that productive employment programs for rural youth…

  3. An efficient and provable secure revocable identity-based encryption scheme.

    Directory of Open Access Journals (Sweden)

    Changji Wang

    Full Text Available Revocation functionality is necessary and crucial to identity-based cryptosystems. Revocable identity-based encryption (RIBE has attracted a lot of attention in recent years, many RIBE schemes have been proposed in the literature but shown to be either insecure or inefficient. In this paper, we propose a new scalable RIBE scheme with decryption key exposure resilience by combining Lewko and Waters' identity-based encryption scheme and complete subtree method, and prove our RIBE scheme to be semantically secure using dual system encryption methodology. Compared to existing scalable and semantically secure RIBE schemes, our proposed RIBE scheme is more efficient in term of ciphertext size, public parameters size and decryption cost at price of a little looser security reduction. To the best of our knowledge, this is the first construction of scalable and semantically secure RIBE scheme with constant size public system parameters.

  4. An improved biometrics-based authentication scheme for telecare medical information systems.

    Science.gov (United States)

    Guo, Dianli; Wen, Qiaoyan; Li, Wenmin; Zhang, Hua; Jin, Zhengping

    2015-03-01

    Telecare medical information system (TMIS) offers healthcare delivery services and patients can acquire their desired medical services conveniently through public networks. The protection of patients' privacy and data confidentiality are significant. Very recently, Mishra et al. proposed a biometrics-based authentication scheme for telecare medical information system. Their scheme can protect user privacy and is believed to resist a range of network attacks. In this paper, we analyze Mishra et al.'s scheme and identify that their scheme is insecure to against known session key attack and impersonation attack. Thereby, we present a modified biometrics-based authentication scheme for TMIS to eliminate the aforementioned faults. Besides, we demonstrate the completeness of the proposed scheme through BAN-logic. Compared to the related schemes, our protocol can provide stronger security and it is more practical.

  5. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  6. Nonlinear secret image sharing scheme.

    Science.gov (United States)

    Shin, Sang-Ho; Lee, Gil-Je; Yoo, Kee-Young

    2014-01-01

    Over the past decade, most of secret image sharing schemes have been proposed by using Shamir's technique. It is based on a linear combination polynomial arithmetic. Although Shamir's technique based secret image sharing schemes are efficient and scalable for various environments, there exists a security threat such as Tompa-Woll attack. Renvall and Ding proposed a new secret sharing technique based on nonlinear combination polynomial arithmetic in order to solve this threat. It is hard to apply to the secret image sharing. In this paper, we propose a (t, n)-threshold nonlinear secret image sharing scheme with steganography concept. In order to achieve a suitable and secure secret image sharing scheme, we adapt a modified LSB embedding technique with XOR Boolean algebra operation, define a new variable m, and change a range of prime p in sharing procedure. In order to evaluate efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB) and 1.74t⌈log2 m⌉ bit-per-pixel (bpp), respectively.

  7. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  8. Partial Key Grouping: Load-Balanced Partitioning of Distributed Streams

    OpenAIRE

    Nasir, Muhammad Anis Uddin; Morales, Gianmarco De Francisci; Garcia-Soriano, David; Kourtellis, Nicolas; Serafini, Marco

    2015-01-01

    We study the problem of load balancing in distributed stream processing engines, which is exacerbated in the presence of skew. We introduce PARTIAL KEY GROUPING (PKG), a new stream partitioning scheme that adapts the classical “power of two choices” to a distributed streaming setting by leveraging two novel techniques: key splitting and local load estimation. In so doing, it achieves better load balancing than key grouping while being more scalable than shuffle grouping. We test PKG on severa...

  9. Small Private Key PKS on an Embedded Microprocessor

    OpenAIRE

    Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

    2014-01-01

    Multivariate quadratic (MQ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor...

  10. A Remote User Authentication Scheme with Anonymity for Mobile Devices

    Directory of Open Access Journals (Sweden)

    Soobok Shin

    2012-04-01

    Full Text Available With the rapid growth of information technologies, mobile devices have been utilized in a variety of services such as e-commerce. When a remote server provides such e-commerce services to a user, it must verify the legitimacy of the user over an insecure communication channel. Therefore, remote user authentication has been widely deployed to verify the legitimacy of remote user login requests using mobile devices like smart cards. In this paper we propose a smart card-based authentication scheme that provides both user anonymity and mutual authentication between a remote server and a user. The proposed authentication scheme is a simple and efficient system applicable to the limited resource and low computing performance of the smart card. The proposed scheme provides not only resilience to potential attacks in the smart card-based authentication scheme, but also secure authentication functions. A smart card performs a simple one-way hash function, the operations of exclusive-or and concatenation in the authentication phase of the proposed scheme. The proposed scheme also provides user anonymity using a dynamic identity and key agreement, and secure password change.

  11. Time-and-ID-Based Proxy Reencryption Scheme

    Directory of Open Access Journals (Sweden)

    Kambombo Mtonga

    2014-01-01

    Full Text Available Time- and ID-based proxy reencryption scheme is proposed in this paper in which a type-based proxy reencryption enables the delegator to implement fine-grained policies with one key pair without any additional trust on the proxy. However, in some applications, the time within which the data was sampled or collected is very critical. In such applications, for example, healthcare and criminal investigations, the delegatee may be interested in only some of the messages with some types sampled within some time bound instead of the entire subset. Hence, in order to carter for such situations, in this paper, we propose a time-and-identity-based proxy reencryption scheme that takes into account the time within which the data was collected as a factor to consider when categorizing data in addition to its type. Our scheme is based on Boneh and Boyen identity-based scheme (BB-IBE and Matsuo’s proxy reencryption scheme for identity-based encryption (IBE to IBE. We prove that our scheme is semantically secure in the standard model.

  12. Unequal error control scheme for dimmable visible light communication systems

    Science.gov (United States)

    Deng, Keyan; Yuan, Lei; Wan, Yi; Li, Huaan

    2017-01-01

    Visible light communication (VLC), which has the advantages of a very large bandwidth, high security, and freedom from license-related restrictions and electromagnetic-interference, has attracted much interest. Because a VLC system simultaneously performs illumination and communication functions, dimming control, efficiency, and reliable transmission are significant and challenging issues of such systems. In this paper, we propose a novel unequal error control (UEC) scheme in which expanding window fountain (EWF) codes in an on-off keying (OOK)-based VLC system are used to support different dimming target values. To evaluate the performance of the scheme for various dimming target values, we apply it to H.264 scalable video coding bitstreams in a VLC system. The results of the simulations that are performed using additive white Gaussian noises (AWGNs) with different signal-to-noise ratios (SNRs) are used to compare the performance of the proposed scheme for various dimming target values. It is found that the proposed UEC scheme enables earlier base layer recovery compared to the use of the equal error control (EEC) scheme for different dimming target values and therefore afford robust transmission for scalable video multicast over optical wireless channels. This is because of the unequal error protection (UEP) and unequal recovery time (URT) of the EWF code in the proposed scheme.

  13. Certificateless short sequential and broadcast multisignature schemes using elliptic curve bilinear pairings

    Directory of Open Access Journals (Sweden)

    SK Hafizul Islam

    2014-01-01

    Full Text Available Several certificateless short signature and multisignature schemes based on traditional public key infrastructure (PKI or identity-based cryptosystem (IBC have been proposed in the literature; however, no certificateless short sequential (or serial multisignature (CL-SSMS or short broadcast (or parallel multisignature (CL-SBMS schemes have been proposed. In this paper, we propose two such new CL-SSMS and CL-SBMS schemes based on elliptic curve bilinear pairing. Like any certificateless public key cryptosystem (CL-PKC, the proposed schemes are free from the public key certificate management burden and the private key escrow problem as found in PKI- and IBC-based cryptosystems, respectively. In addition, the requirements of the expected security level and the fixed length signature with constant verification time have been achieved in our schemes. The schemes are communication efficient as the length of the multisignature is equivalent to a single elliptic curve point and thus become the shortest possible multisignature scheme. The proposed schemes are then suitable for communication systems having resource constrained devices such as PDAs, mobile phones, RFID chips, and sensors where the communication bandwidth, battery life, computing power and storage space are limited.

  14. Renewing membership in three community-based health insurance schemes in rural India

    NARCIS (Netherlands)

    P. Panda (Pradeep); A. Chakraborty (Arpita); W.A. Raza (Wameq); A.S. Bedi (Arjun Singh)

    2015-01-01

    textabstractLow renewal rate is a key challenge facing the sustainability of Community-based Health Insurance (CBHI) schemes. While there is a large literature on initial enrolment into such schemes, there is limited evidence on the factors that impede renewal. This paper uses longitudinal data to

  15. A new Identity Based Encryption (IBE) scheme using extended Chebyshev polynomial over finite fields Zp

    International Nuclear Information System (INIS)

    Benasser Algehawi, Mohammed; Samsudin, Azman

    2010-01-01

    We present a method to extract key pairs needed for the Identity Based Encryption (IBE) scheme from extended Chebyshev polynomial over finite fields Z p . Our proposed scheme relies on the hard problem and the bilinear property of the extended Chebyshev polynomial over Z p . The proposed system is applicable, secure, and reliable.

  16. Butterfly Encryption Scheme for Resource-Constrained Wireless Networks

    Directory of Open Access Journals (Sweden)

    Raghav V. Sampangi

    2015-09-01

    Full Text Available Resource-constrained wireless networks are emerging networks such as Radio Frequency Identification (RFID and Wireless Body Area Networks (WBAN that might have restrictions on the available resources and the computations that can be performed. These emerging technologies are increasing in popularity, particularly in defence, anti-counterfeiting, logistics and medical applications, and in consumer applications with growing popularity of the Internet of Things. With communication over wireless channels, it is essential to focus attention on securing data. In this paper, we present an encryption scheme called Butterfly encryption scheme. We first discuss a seed update mechanism for pseudorandom number generators (PRNG, and employ this technique to generate keys and authentication parameters for resource-constrained wireless networks. Our scheme is lightweight, as in it requires less resource when implemented and offers high security through increased unpredictability, owing to continuously changing parameters. Our work focuses on accomplishing high security through simplicity and reuse. We evaluate our encryption scheme using simulation, key similarity assessment, key sequence randomness assessment, protocol analysis and security analysis.

  17. Butterfly Encryption Scheme for Resource-Constrained Wireless Networks.

    Science.gov (United States)

    Sampangi, Raghav V; Sampalli, Srinivas

    2015-09-15

    Resource-constrained wireless networks are emerging networks such as Radio Frequency Identification (RFID) and Wireless Body Area Networks (WBAN) that might have restrictions on the available resources and the computations that can be performed. These emerging technologies are increasing in popularity, particularly in defence, anti-counterfeiting, logistics and medical applications, and in consumer applications with growing popularity of the Internet of Things. With communication over wireless channels, it is essential to focus attention on securing data. In this paper, we present an encryption scheme called Butterfly encryption scheme. We first discuss a seed update mechanism for pseudorandom number generators (PRNG), and employ this technique to generate keys and authentication parameters for resource-constrained wireless networks. Our scheme is lightweight, as in it requires less resource when implemented and offers high security through increased unpredictability, owing to continuously changing parameters. Our work focuses on accomplishing high security through simplicity and reuse. We evaluate our encryption scheme using simulation, key similarity assessment, key sequence randomness assessment, protocol analysis and security analysis.

  18. A provably-secure ECC-based authentication scheme for wireless sensor networks.

    Science.gov (United States)

    Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

    2014-11-06

    A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes.

  19. A Provably-Secure ECC-Based Authentication Scheme for Wireless Sensor Networks

    Science.gov (United States)

    Nam, Junghyun; Kim, Moonseong; Paik, Juryon; Lee, Youngsook; Won, Dongho

    2014-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme) is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000). Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC), and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure) schemes. PMID:25384009

  20. A Provably-Secure ECC-Based Authentication Scheme for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Junghyun Nam

    2014-11-01

    Full Text Available A smart-card-based user authentication scheme for wireless sensor networks (in short, a SUA-WSN scheme is designed to restrict access to the sensor data only to users who are in possession of both a smart card and the corresponding password. While a significant number of SUA-WSN schemes have been suggested in recent years, their intended security properties lack formal definitions and proofs in a widely-accepted model. One consequence is that SUA-WSN schemes insecure against various attacks have proliferated. In this paper, we devise a security model for the analysis of SUA-WSN schemes by extending the widely-accepted model of Bellare, Pointcheval and Rogaway (2000. Our model provides formal definitions of authenticated key exchange and user anonymity while capturing side-channel attacks, as well as other common attacks. We also propose a new SUA-WSN scheme based on elliptic curve cryptography (ECC, and prove its security properties in our extended model. To the best of our knowledge, our proposed scheme is the first SUA-WSN scheme that provably achieves both authenticated key exchange and user anonymity. Our scheme is also computationally competitive with other ECC-based (non-provably secure schemes.

  1. Non-interactive and Reusable Non-malleable Commitment Schemes

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Groth, Jens

    2003-01-01

    version based on the strong RSA assumption. For UC commitments, we show that existence of a UC commitment scheme in the CRS model (interactive or not) implies key exchange and - for a uniform reference string - even implies oblivious transfer. This indicates that UC commitment is a strictly stronger...... primitive than NM. Finally, we show that our strong RSA based construction can be used to improve the most efficient known UC commitment scheme so it can work with a CRS of size independent of the number of players, without loss of efficiency....

  2. On reciprocal Baecklund transformations of inverse scattering schemes

    International Nuclear Information System (INIS)

    Rogers, C.; Wong, P.

    1984-01-01

    The notion of reciprocally related inverse scattering schemes is introduced and is shown to be a key component in the link between the AKNS and WKI schemes. Reciprocal auto-Baecklund transformations are represented both for a generalised Harry-Dym equation and an equation descriptive of nonlinear oscillation of elastic beams. Further, the N-loop soliton solution of the KIW equation is generated in a convenient parametric form via reciprocal Baecklund transformations. Finally, an important reduction to canonical spectral form is shown to be a reciprocal transformation. (Auth.)

  3. Electrical Injection Schemes for Nanolasers

    DEFF Research Database (Denmark)

    Lupi, Alexandra; Chung, Il-Sug; Yvind, Kresten

    2014-01-01

    Three electrical injection schemes based on recently demonstrated electrically pumped photonic crystal nanolasers have been numerically investigated: 1) a vertical p-i-n junction through a post structure; 2) a lateral p-i-n junction with a homostructure; and 3) a lateral p-i-n junction....... For this analysis, the properties of different schemes, i.e., electrical resistance, threshold voltage, threshold current, and internal efficiency as energy requirements for optical interconnects are compared and the physics behind the differences is discussed....

  4. Signal multiplexing scheme for LINAC

    International Nuclear Information System (INIS)

    Sujo, C.I.; Mohan, Shyam; Joshi, Gopal; Singh, S.K.; Karande, Jitendra

    2004-01-01

    For the proper operation of the LINAC some signals, RF (radio frequency) as well as LF (low frequency) have to be available at the Master Control Station (MCS). These signals are needed to control, calibrate and characterize the RF fields in the resonators. This can be achieved by proper multiplexing of various signals locally and then routing the selected signals to the MCS. A multiplexing scheme has been designed and implemented, which will allow the signals from the selected cavity to the MCS. High isolation between channels and low insertion loss for a given signal are important issues while selecting the multiplexing scheme. (author)

  5. Capacity-achieving CPM schemes

    OpenAIRE

    Perotti, Alberto; Tarable, Alberto; Benedetto, Sergio; Montorsi, Guido

    2008-01-01

    The pragmatic approach to coded continuous-phase modulation (CPM) is proposed as a capacity-achieving low-complexity alternative to the serially-concatenated CPM (SC-CPM) coding scheme. In this paper, we first perform a selection of the best spectrally-efficient CPM modulations to be embedded into SC-CPM schemes. Then, we consider the pragmatic capacity (a.k.a. BICM capacity) of CPM modulations and optimize it through a careful design of the mapping between input bits and CPM waveforms. The s...

  6. Cryptanalysis of a computer cryptography scheme based on a filter bank

    International Nuclear Information System (INIS)

    Arroyo, David; Li Chengqing; Li Shujun; Alvarez, Gonzalo

    2009-01-01

    This paper analyzes the security of a recently-proposed signal encryption scheme based on a filter bank. A very critical weakness of this new signal encryption procedure is exploited in order to successfully recover the associated secret key.

  7. Entangled quantum key distribution with a biased basis choice

    International Nuclear Information System (INIS)

    Erven, Chris; Ma Xiongfeng; Laflamme, Raymond; Weihs, Gregor

    2009-01-01

    We investigate a quantum key distribution (QKD) scheme that utilizes a biased basis choice in order to increase the efficiency of the scheme. The optimal bias between the two measurement bases, a more refined error analysis and finite key size effects are all studied in order to assure the security of the final key generated with the system. We then implement the scheme in a local entangled QKD system that uses polarization entangled photon pairs to securely distribute the key. A 50/50 non-polarizing beamsplitter (BS) with different optical attenuators is used to simulate a variable BS in order to allow us to study the operation of the system for different biases. Over 6 h of continuous operation with a total bias of 0.9837/0.0163 (Z/X), we were able to generate 0.4567 secure key bits per raw key bit as compared to 0.2550 secure key bits per raw key bit for the unbiased case. This represents an increase in the efficiency of the key generation rate by 79%.

  8. An Implicit Scheme of Lattice Boltzmann Method for Sine-Gordon Equation

    International Nuclear Information System (INIS)

    Hui-Lin, Lai; Chang-Feng, Ma

    2008-01-01

    We establish an implicit scheme of lattice Boltzmann method for simulating the sine-Gordon equation, which can be transformed into the explicit one, so the computation of the scheme is simple. Moreover, the parameter θ of the implicit scheme is independent of the relaxation time, which makes the model more flexible. The numerical results show that this method is very effective. (fundamental areas of phenomenology (including applications))

  9. Report on the fiscal 1996 result of the research on the promotion scheme toward establishment of an international cooperation system for development of welfare equipment; 1996 nendo chosa hokokusho fukushi yogu kaihatsunado no kokusai kyoryoku taisei kakuritsu ni mukete no suishin hosaku no kento

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In order to support the progress and international activity of a Japanese welfare industry, research was made on a concrete approach to establishment of a Japanese international cooperation system on the basis of the activity trend of welfare organizations and groups in North European countries and Japan. Introduction of standards and a mark system for welfare equipment is under investigation in North European countries, and movement for unified standards is also becoming active among these countries. TIDE project called socioeconomic integrated engineering already exists for handicapped and aged persons in Europe, while a rehabilitation act was enforced in the U.S.A. in 1973. Japan participated in ISO and IEC for promotion of a welfare equipment industry. Rehabilitation Engineering Society of Japan (RESJA) for equipment development and technical support, and Japan Wellness and Welfare Industry Association (JWA) for promotion of the related industries were also established. In Europe, North America and Australia, rehabilitation engineering associations are already in action. 8 figs., 17 tabs.

  10. Lightweight SIP/SDP compression scheme (LSSCS)

    Science.gov (United States)

    Wu, Jian J.; Demetrescu, Cristian

    2001-10-01

    In UMTS new IP based services with tight delay constraints will be deployed over the W-CDMA air interface such as IP multimedia and interactive services. To integrate the wireline and wireless IP services, 3GPP standard forum adopted the Session Initiation Protocol (SIP) as the call control protocol for the UMTS Release 5, which will implement next generation, all IP networks for real-time QoS services. In the current form the SIP protocol is not suitable for wireless transmission due to its large message size which will need either a big radio pipe for transmission or it will take far much longer to transmit than the current GSM Call Control (CC) message sequence. In this paper we present a novel compression algorithm called Lightweight SIP/SDP Compression Scheme (LSSCS), which acts at the SIP application layer and therefore removes the information redundancy before it is sent to the network and transport layer. A binary octet-aligned header is added to the compressed SIP/SDP message before sending it to the network layer. The receiver uses this binary header as well as the pre-cached information to regenerate the original SIP/SDP message. The key features of the LSSCS compression scheme are presented in this paper along with implementation examples. It is shown that this compression algorithm makes SIP transmission efficient over the radio interface without losing the SIP generality and flexibility.

  11. Special Semaphore Scheme for UHF Spacecraft Communications

    Science.gov (United States)

    Butman, Stanley; Satorius, Edgar; Ilott, Peter

    2006-01-01

    A semaphore scheme has been devised to satisfy a requirement to enable ultrahigh- frequency (UHF) radio communication between a spacecraft descending from orbit to a landing on Mars and a spacecraft, in orbit about Mars, that relays communications between Earth and the lander spacecraft. There are also two subsidiary requirements: (1) to use UHF transceivers, built and qualified for operation aboard the spacecraft that operate with residual-carrier binary phase-shift-keying (BPSK) modulation at a selectable data rate of 8, 32, 128, or 256 kb/s; and (2) to enable low-rate signaling even when received signals become so weak as to prevent communication at the minimum BPSK rate of 8 kHz. The scheme involves exploitation of Manchester encoding, which is used in conjunction with residual-carrier modulation to aid the carrier-tracking loop. By choosing various sequences of 1s, 0s, or 1s alternating with 0s to be fed to the residual-carrier modulator, one would cause the modulator to generate sidebands at a fundamental frequency of 4 or 8 kHz and harmonics thereof. These sidebands would constitute the desired semaphores. In reception, the semaphores would be detected by a software demodulator.

  12. Nickel exposure from keys: a Brazilian issue.

    Science.gov (United States)

    Suzuki, Nathalie Mie; Duarte, Ida Alzira Gomes; Hafner, Mariana de Figueiredo Silva; Lazzarini, Rosana

    2017-01-01

    Keys are a significant source of exposure to metal allergens and can be a relevant problem for nickel-allergic individuals. This study aimed to perform nickel and cobalt spot testing among the 5 most common Brazilian brands of keys. Among the tested keys, 100% showed positive result to nickel spot test, 83,3% presented strong positive reaction. 50% exhibited cobalt release as well. Nickel release from keys is very common in our country and may cause a negative impact on sensitized individual's quality of life. Study's results highlight the importance of establishing directives to regulate nickel release in Brazil.

  13. Establishing software quality assurance

    International Nuclear Information System (INIS)

    Malsbury, J.

    1983-01-01

    This paper is concerned with four questions about establishing software QA: What is software QA. Why have software QA. What is the role of software QA. What is necessary to ensure the success of software QA

  14. Blood Establishment Registration Database

    Data.gov (United States)

    U.S. Department of Health & Human Services — This application provides information for active, inactive, and pre-registered firms. Query options are by FEI, Applicant Name, Establishment Name, Other Names,...

  15. Key improvements to XTR

    NARCIS (Netherlands)

    Lenstra, A.K.; Verheul, E.R.; Okamoto, T.

    2000-01-01

    This paper describes improved methods for XTR key representation and parameter generation (cf. [4]). If the field characteristic is properly chosen, the size of the XTR public key for signature applications can be reduced by a factor of three at the cost of a small one time computation for the

  16. Establishment of prairies

    International Nuclear Information System (INIS)

    Lotero Cadavid, J.

    2001-01-01

    Are analyzed the establishment of prairies, such as the selection of the species, the factors of the environment, the impact in the establishment and forage production and its relation to the soil, the precipitation, the temperature, the light and the biotic factors. It is indicated that the selection of the species to settle down, is directly related with the climate and the soil and they group to be tolerant to drought, tolerant to flood soils, tolerant to humid soils, tolerant to soils very acids, moderately acids and saline. It is noticed that a bad establishment of the grasses can be due to the bad quality of the seed, a temperature and unfavorable humidity can cause low germination; equally seeds planted very deeply in heavy soils with excess of humidity. Considerations are made about the establishment and growth of the prairies in connection with the germination, cultures, sowing density and sowing on time, as well as for the soil preparation, the sowing in terrestrial mechanic and non mechanic and the use of cultivations forms of low cost and fertilization systems; equally the establishment of leguminous in mixture with gramineous, the renovation of prairies and the establishment of pastures

  17. On 165Ho level scheme

    International Nuclear Information System (INIS)

    Ardisson, Claire; Ardisson, Gerard.

    1976-01-01

    A 165 Ho level scheme was constructed which led to the interpretation of sixty γ rays belonging to the decay of 165 Dy. A new 702.9keV level was identified to be the 5/2 - member of the 1/2 ) 7541{ Nilsson orbit. )] [fr

  18. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min; Ma, Guancong; Wu, Ying; Yang, Zhiyu; Sheng, Ping

    2014-01-01

    the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost

  19. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min

    2014-02-26

    We present a homogenization scheme for acoustic metamaterials that is based on reproducing the lowest orders of scattering amplitudes from a finite volume of metamaterials. This approach is noted to differ significantly from that of coherent potential approximation, which is based on adjusting the effective-medium parameters to minimize scatterings in the long-wavelength limit. With the aid of metamaterials’ eigenstates, the effective parameters, such as mass density and elastic modulus can be obtained by matching the surface responses of a metamaterial\\'s structural unit cell with a piece of homogenized material. From the Green\\'s theorem applied to the exterior domain problem, matching the surface responses is noted to be the same as reproducing the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost exactly with numerical simulations and experiments and the scheme\\'s validity is constrained by the number of dominant surface multipoles instead of the usual long-wavelength assumption. In particular, the validity extends to the full band in one dimension and to regimes near the boundaries of the Brillouin zone in two dimensions.

  20. New practicable Siberian Snake schemes

    International Nuclear Information System (INIS)

    Steffen, K.

    1983-07-01

    Siberian Snake schemes can be inserted in ring accelerators for making the spin tune almost independent of energy. Two such schemes are here suggested which lend particularly well to practical application over a wide energy range. Being composed of horizontal and vertical bending magnets, the proposed snakes are designed to have a small maximum beam excursion in one plane. By applying in this plane a bending correction that varies with energy, they can be operated at fixed geometry in the other plane where most of the bending occurs, thus avoiding complicated magnet motion or excessively large magnet apertures that would otherwise be needed for large energy variations. The first of the proposed schemes employs a pair of standard-type Siberian Snakes, i.e. of the usual 1st and 2nd kind which rotate the spin about the longitudinal and the transverse horizontal axis, respectively. The second scheme employs a pair of novel-type snakes which rotate the spin about either one of the horizontal axes that are at 45 0 to the beam direction. In obvious reference to these axes, they are called left-pointed and right-pointed snakes. (orig.)

  1. Nonlinear Secret Image Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Sang-Ho Shin

    2014-01-01

    efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB and 1.74tlog2⁡m bit-per-pixel (bpp, respectively.

  2. Randomness determines practical security of BB84 quantum key distribution

    Science.gov (United States)

    Li, Hong-Wei; Yin, Zhen-Qiang; Wang, Shuang; Qian, Yong-Jun; Chen, Wei; Guo, Guang-Can; Han, Zheng-Fu

    2015-11-01

    Unconditional security of the BB84 quantum key distribution protocol has been proved by exploiting the fundamental laws of quantum mechanics, but the practical quantum key distribution system maybe hacked by considering the imperfect state preparation and measurement respectively. Until now, different attacking schemes have been proposed by utilizing imperfect devices, but the general security analysis model against all of the practical attacking schemes has not been proposed. Here, we demonstrate that the general practical attacking schemes can be divided into the Trojan horse attack, strong randomness attack and weak randomness attack respectively. We prove security of BB84 protocol under randomness attacking models, and these results can be applied to guarantee the security of the practical quantum key distribution system.

  3. Using farmer knowledge to combat low productive spots in rice fields of a Sahelian irrigation scheme

    NARCIS (Netherlands)

    Asten, van P.J.A.; Barro, S.E.; Wopereis, M.C.S.; Defoer, T.

    2004-01-01

    In the oldest sections of Burkina Faso's largest irrigation scheme in the Sourou Valley (13degrees 10'N, 03degrees 30'W) rice (Oryza sativa L.) yields dropped from about 5 to 6 t ha(-1) in the early 1990s, shortly after establishment of the scheme, to 2 to 4 t ha(-1) from 1995 onwards. Farmers

  4. Quality Assurance in Engineering Education: Comparison of Accreditation Schemes and ISO 9001.

    Science.gov (United States)

    Karapetrovic, Stanislav; Rajamani, Divakar; Willborn, Walter

    1998-01-01

    Outlines quality assurance schemes for distance-education technologies that are based on the ISO 9000 family of international quality-assurance standards. Argues that engineering faculties can establish such systems on the basis of and integrated with accreditation schemes. Contains 34 references. (DDR)

  5. The Spanish external quality assessment scheme for mercury in urine.

    Science.gov (United States)

    Quintana, M J; Mazarrasa, O

    1996-01-01

    In 1986 the Instituto Nacional de Seguridad e Higiene en el Trabajo (INSHT), established the "Programa interlaboratorios de control de calidad de mercurio en orina (PICC-HgU)". The operation of this scheme is explained, criteria for evaluation of laboratory performance are defined and some results obtained are reviewed. Since the scheme started, an improvement in the overall performance of laboratories has been observed. The differences in the analytical methods used by laboratories do not seem to have a clear influence on the results.

  6. HEALTH INSURANCE RULES OF THE CERN HEALTH INSURANCE SCHEME

    CERN Multimedia

    Division HR

    2000-01-01

    A new document which groups together the general principles, the contributions, benefits, reimbursement procedures and other information making up the Rules of the CERN Health Insurance Scheme has been established. It was approved by the Director-General on 7th July 2000 and is being distributed to all contributing members of the Scheme. It has been dispatched by internal mail to members of the personnel and by postal mail to pensioners. These Rules will enter into force on 1st September 2000. Please make sure that you have received your copy. Should this not be the case, an additional copy may be obtained by telephoning 78003

  7. Health Insurance Rules of the CERN Health Insurance scheme

    CERN Multimedia

    Division HR

    2000-01-01

    A new document which groups together the general principles, the contributions, benefits, reimbursement procedures and other information making up the Rules of the CERN Health Insurance Scheme has been established. It was approved by the Director-General on 7th July 2000 and is being distributed to all contributing members of the Scheme. It has been dispatched by internal mail to members of the personnel and by postal mail to pensioners. These Rules will enter into force on 1st September 2000. Please make sure that you have received your copy. Should this not be the case, an additional copy may be obtained by telephoning 78003.

  8. Device-independent secret-key-rate analysis for quantum repeaters

    Science.gov (United States)

    Holz, Timo; Kampermann, Hermann; Bruß, Dagmar

    2018-01-01

    The device-independent approach to quantum key distribution (QKD) aims to establish a secret key between two or more parties with untrusted devices, potentially under full control of a quantum adversary. The performance of a QKD protocol can be quantified by the secret key rate, which can be lower bounded via the violation of an appropriate Bell inequality in a setup with untrusted devices. We study secret key rates in the device-independent scenario for different quantum repeater setups and compare them to their device-dependent analogon. The quantum repeater setups under consideration are the original protocol by Briegel et al. [Phys. Rev. Lett. 81, 5932 (1998), 10.1103/PhysRevLett.81.5932] and the hybrid quantum repeater protocol by van Loock et al. [Phys. Rev. Lett. 96, 240501 (2006), 10.1103/PhysRevLett.96.240501]. For a given repeater scheme and a given QKD protocol, the secret key rate depends on a variety of parameters, such as the gate quality or the detector efficiency. We systematically analyze the impact of these parameters and suggest optimized strategies.

  9. Continuous variable quantum key distribution with modulated entangled states

    DEFF Research Database (Denmark)

    Madsen, Lars S; Usenko, Vladyslav C.; Lassen, Mikael

    2012-01-01

    Quantum key distribution enables two remote parties to grow a shared key, which they can use for unconditionally secure communication over a certain distance. The maximal distance depends on the loss and the excess noise of the connecting quantum channel. Several quantum key distribution schemes...... based on coherent states and continuous variable measurements are resilient to high loss in the channel, but are strongly affected by small amounts of channel excess noise. Here we propose and experimentally address a continuous variable quantum key distribution protocol that uses modulated fragile...... entangled states of light to greatly enhance the robustness to channel noise. We experimentally demonstrate that the resulting quantum key distribution protocol can tolerate more noise than the benchmark set by the ideal continuous variable coherent state protocol. Our scheme represents a very promising...

  10. Robust and Scalable DTLS Session Establishment

    OpenAIRE

    Tiloca, Marco; Gehrmann, Christian; Seitz, Ludwig

    2016-01-01

    The Datagram Transport Layer Security (DTLS) protocol is highly vulnerable to a form of denial-of-service attack (DoS), aimed at establishing a high number of invalid, half-open, secure sessions. Moreover, even when the efficient pre-shared key provisioning mode is considered, the key storage on the server side scales poorly with the number of clients. SICS Swedish ICT has designed a security architecture that efficiently addresses both issues without breaking the current standard.

  11. A chaotic cryptography scheme for generating short ciphertext

    International Nuclear Information System (INIS)

    Wong, Kwok-Wo; Ho, Sun-Wah; Yung, Ching-Ki

    2003-01-01

    Recently, we have proposed a chaotic cryptographic scheme based on iterating the logistic map and updating the look-up table dynamically. The encryption and decryption processes become faster as the number of iterations required is reduced. However, the length of the ciphertext is still at least twice that of the original message. This may result in huge ciphertext files and hence long transmission time when encrypting large multimedia files. In this Letter, we modify the chaotic cryptographic scheme proposed previously so as to reduce the length of the ciphertext to the level slightly longer than that of the original message. Moreover, a session key is introduced in the cryptographic scheme so that the ciphertext length for a given message is not fixed

  12. A Novel Quantum Image Steganography Scheme Based on LSB

    Science.gov (United States)

    Zhou, Ri-Gui; Luo, Jia; Liu, XingAo; Zhu, Changming; Wei, Lai; Zhang, Xiafen

    2018-06-01

    Based on the NEQR representation of quantum images and least significant bit (LSB) scheme, a novel quantum image steganography scheme is proposed. The sizes of the cover image and the original information image are assumed to be 4 n × 4 n and n × n, respectively. Firstly, the bit-plane scrambling method is used to scramble the original information image. Then the scrambled information image is expanded to the same size of the cover image by using the key only known to the operator. The expanded image is scrambled to be a meaningless image with the Arnold scrambling. The embedding procedure and extracting procedure are carried out by K 1 and K 2 which are under control of the operator. For validation of the presented scheme, the peak-signal-to-noise ratio (PSNR), the capacity, the security of the images and the circuit complexity are analyzed.

  13. Enabling an Integrated Rate-temporal Learning Scheme on Memristor

    Science.gov (United States)

    He, Wei; Huang, Kejie; Ning, Ning; Ramanathan, Kiruthika; Li, Guoqi; Jiang, Yu; Sze, Jiayin; Shi, Luping; Zhao, Rong; Pei, Jing

    2014-04-01

    Learning scheme is the key to the utilization of spike-based computation and the emulation of neural/synaptic behaviors toward realization of cognition. The biological observations reveal an integrated spike time- and spike rate-dependent plasticity as a function of presynaptic firing frequency. However, this integrated rate-temporal learning scheme has not been realized on any nano devices. In this paper, such scheme is successfully demonstrated on a memristor. Great robustness against the spiking rate fluctuation is achieved by waveform engineering with the aid of good analog properties exhibited by the iron oxide-based memristor. The spike-time-dependence plasticity (STDP) occurs at moderate presynaptic firing frequencies and spike-rate-dependence plasticity (SRDP) dominates other regions. This demonstration provides a novel approach in neural coding implementation, which facilitates the development of bio-inspired computing systems.

  14. Cryptanalysis on a parallel keyed hash function based on chaotic maps

    International Nuclear Information System (INIS)

    Guo Wei; Wang Xiaoming; He Dake; Cao Yang

    2009-01-01

    This Letter analyzes the security of a novel parallel keyed hash function based on chaotic maps, proposed by Xiao et al. to improve the efficiency in parallel computing environment. We show how to devise forgery attacks on Xiao's scheme with differential cryptanalysis and give the experiment results of two kinds of forgery attacks firstly. Furthermore, we discuss the problem of weak keys in the scheme and demonstrate how to utilize weak keys to construct collision.

  15. Factors affecting sustainability of rural water schemes in Swaziland

    Science.gov (United States)

    Peter, Graciana; Nkambule, Sizwe E.

    The Millennium Development Goal (MDG) target to reduce the proportion of people without sustainable access to safe drinking water by the year 2015 has been met as of 2010, but huge disparities exist. Some regions, particularly Sub-Saharan Africa are lagging behind it is also in this region where up to 30% of the rural schemes are not functional at any given time. There is need for more studies on factors affecting sustainability and necessary measures which when implemented will improve the sustainability of rural water schemes. The main objective of this study was to assess the main factors affecting the sustainability of rural water schemes in Swaziland using a Multi-Criteria Analysis Approach. The main factors considered were: financial, social, technical, environmental and institutional. The study was done in Lubombo region. Fifteen functional water schemes in 11 communities were studied. Data was collected using questionnaires, checklist and focused group discussion guide. A total of 174 heads of households were interviewed. Statistical Package for Social Sciences (SPSS) was used to analyse the data and to calculate sustainability scores for water schemes. SPSS was also used to classify sustainability scores according to sustainability categories: sustainable, partially sustainable and non-sustainable. The averages of the ratings for the different sub-factors studied and the results on the sustainability scores for the sustainable, partially sustainable and non-sustainable schemes were then computed and compared to establish the main factors influencing sustainability of the water schemes. The results indicated technical and social factors as most critical while financial and institutional, although important, played a lesser role. Factors which contributed to the sustainability of water schemes were: functionality; design flow; water fetching time; ability to meet additional demand; use by population; equity; participation in decision making on operation and

  16. On a Stable and Consistent Finite Difference Scheme for a Time ...

    African Journals Online (AJOL)

    NJABS

    established time independent Schrodinger Wave Equation (SWE). To develop the stability criterion .... the rate at which signals in the numerical scheme travel will be faster than their real world counterparts and this unrealistic expectation leads ...

  17. Harmonisation between National and International Tradeable Permit Schemes. CATEP Synthesis Paper

    International Nuclear Information System (INIS)

    Haites, E.

    2003-01-01

    It is technically possible to link national emissions trading schemes with widely divergent designs. Where design differences create potential problems, technical solutions are available. The greater the similarity of their designs, the easier schemes are to link. During the 2005 - 2007 period the EU Directive, if it is adopted, will lead to the establishment of at least 25 national emissions trading schemes. The Directive specifies many of the design features of these schemes, but leaves the allocation of allowances, rules for banking allowances into the commitment period, use of the opt-out provision, and a few other design features to Member States. The resulting differences among Member State schemes are unlikely to undermine the links between the schemes established by the Directive. The Community may enter into agreements with non-members for mutual recognition of allowances between their emissions trading schemes, but few, if any, links of this type are expected prior to 2008 for practical reasons. Beginning in 2008, Article 17 of the Kyoto Protocol establishes an international emissions trading scheme that can link the national trading schemes of Annex I Parties. It imposes no requirements for harmonisation on the national emissions trading schemes linked. Some design differences could create technical problems, although solutions are available and at least one of the governments involved has an incentive to solve the problem. Adverse competitiveness impacts due to differences in the distribution of allowances across national schemes may need to be addressed through institutions such as the WTO. Most of the national trading schemes will also be subject to the EU Directive and be subject to greater harmonisation after 2008. The result is likely to be a progressive expansion and integration of greenhouse gas allowance markets over the next decade

  18. A keyword searchable attribute-based encryption scheme with attribute update for cloud storage.

    Science.gov (United States)

    Wang, Shangping; Ye, Jian; Zhang, Yaling

    2018-01-01

    Ciphertext-policy attribute-based encryption (CP-ABE) scheme is a new type of data encryption primitive, which is very suitable for data cloud storage for its fine-grained access control. Keyword-based searchable encryption scheme enables users to quickly find interesting data stored in the cloud server without revealing any information of the searched keywords. In this work, we provide a keyword searchable attribute-based encryption scheme with attribute update for cloud storage, which is a combination of attribute-based encryption scheme and keyword searchable encryption scheme. The new scheme supports the user's attribute update, especially in our new scheme when a user's attribute need to be updated, only the user's secret key related with the attribute need to be updated, while other user's secret key and the ciphertexts related with this attribute need not to be updated with the help of the cloud server. In addition, we outsource the operation with high computation cost to cloud server to reduce the user's computational burden. Moreover, our scheme is proven to be semantic security against chosen ciphertext-policy and chosen plaintext attack in the general bilinear group model. And our scheme is also proven to be semantic security against chosen keyword attack under bilinear Diffie-Hellman (BDH) assumption.

  19. Key Facts about Tularemia

    Science.gov (United States)

    ... Submit What's this? Submit Button Key Facts About Tularemia Recommend on Facebook Tweet Share Compartir This fact ... and Prevention (CDC) Tularemia Web site . What is Tularemia? Tularemia is a potentially serious illness that occurs ...

  20. Key technologies book

    International Nuclear Information System (INIS)

    1997-01-01

    In this book can be found all the useful information on the French industry key technologies of the years 2000-2005. 136 technologies at the junction of the science advances and of the markets expectations are divided into 9 sectors. Among them, only 4 are interesting here: the environment, the transports, the materials and the energy. In 1995, the secretary's office of State for industry has published a first synthesis book on these key technologies. This 1997 new key technologies book extends and completes the initial study. For each key technology, an encyclopedic sheet is given. Each sheet combines thus some exact and practical information on: advance state of the technology, market characteristics, development forecasts, occupation and involved sectors, technology acquisition cost, research programs but also contacts of the main concerned efficiency poles. (O.M.)

  1. The Key Lake project

    International Nuclear Information System (INIS)

    Glattes, G.

    1985-01-01

    Aspects of project financing for the share of the Canadian subsidiary of Uranerzbergbau-GmbH, Bonn, in the uranium mining and milling facility at Key Lake, Saskatchewan, by a Canadian bank syndicate. (orig.) [de

  2. A Price-Based Demand Response Scheme for Discrete Manufacturing in Smart Grids

    Directory of Open Access Journals (Sweden)

    Zhe Luo

    2016-08-01

    Full Text Available Demand response (DR is a key technique in smart grid (SG technologies for reducing energy costs and maintaining the stability of electrical grids. Since manufacturing is one of the major consumers of electrical energy, implementing DR in factory energy management systems (FEMSs provides an effective way to manage energy in manufacturing processes. Although previous studies have investigated DR applications in process manufacturing, they were not conducted for discrete manufacturing. In this study, the state-task network (STN model is implemented to represent a discrete manufacturing system. On this basis, a DR scheme with a specific DR algorithm is applied to a typical discrete manufacturing—automobile manufacturing—and operational scenarios are established for the stamping process of the automobile production line. The DR scheme determines the optimal operating points for the stamping process using mixed integer linear programming (MILP. The results show that parts of the electricity demand can be shifted from peak to off-peak periods, reducing a significant overall energy costs without degrading production processes.

  3. Incentive schemes in development of socio-economic systems

    Science.gov (United States)

    Grachev, V. V.; Ivushkin, K. A.; Myshlyaev, L. P.

    2018-05-01

    The paper is devoted to the study of incentive schemes when developing socio-economic systems. The article analyzes the existing incentive schemes. It is established that the traditional incentive mechanisms do not fully take into account the specifics of the creation of each socio-economic system and, as a rule, are difficult to implement. The incentive schemes based on the full-scale simulation approach, which allow the most complete information from the existing projects of creation of socio-economic systems to be extracted, are proposed. The statement of the problem is given, the method and algorithm of the full-scale simulation study of the efficiency of incentive functions is developed. The results of the study are presented. It is shown that the use of quadratic and piecewise linear functions of incentive allows the time and costs for creating social and economic systems to be reduced by 10%-15%.

  4. An Efficient and Practical Smart Card Based Anonymity Preserving User Authentication Scheme for TMIS using Elliptic Curve Cryptography.

    Science.gov (United States)

    Amin, Ruhul; Islam, S K Hafizul; Biswas, G P; Khan, Muhammad Khurram; Kumar, Neeraj

    2015-11-01

    In the last few years, numerous remote user authentication and session key agreement schemes have been put forwarded for Telecare Medical Information System, where the patient and medical server exchange medical information using Internet. We have found that most of the schemes are not usable for practical applications due to known security weaknesses. It is also worth to note that unrestricted number of patients login to the single medical server across the globe. Therefore, the computation and maintenance overhead would be high and the server may fail to provide services. In this article, we have designed a medical system architecture and a standard mutual authentication scheme for single medical server, where the patient can securely exchange medical data with the doctor(s) via trusted central medical server over any insecure network. We then explored the security of the scheme with its resilience to attacks. Moreover, we formally validated the proposed scheme through the simulation using Automated Validation of Internet Security Schemes and Applications software whose outcomes confirm that the scheme is protected against active and passive attacks. The performance comparison demonstrated that the proposed scheme has lower communication cost than the existing schemes in literature. In addition, the computation cost of the proposed scheme is nearly equal to the exiting schemes. The proposed scheme not only efficient in terms of different security attacks, but it also provides an efficient login, mutual authentication, session key agreement and verification and password update phases along with password recovery.

  5. Support Schemes and Ownership Structures

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Schröder, Sascha Thorsten; Costa, Ana

    , Denmark, France and Portugal. Another crucial aspect for the diffusion of the mCHP technology is possible ownership structures. These may range from full consumer ownership to ownership by utilities and energy service companies, which is discussed in Section 6. Finally, a conclusion (Section 7) wraps up......In recent years, fuel cell based micro‐combined heat and power has received increasing attention due to its potential contribution to energy savings, efficiency gains, customer proximity and flexibility in operation and capacity size. The FC4Home project assesses technical and economic aspects...... of support scheme simultaneously affects risk and technological development, which is the focus of Section 4. Subsequent to this conceptual overview, Section 5 takes a glance at the national application of support schemes for mCHP in practice, notably in the three country cases of the FC4Home project...

  6. [PICS: pharmaceutical inspection cooperation scheme].

    Science.gov (United States)

    Morénas, J

    2009-01-01

    The pharmaceutical inspection cooperation scheme (PICS) is a structure containing 34 participating authorities located worldwide (October 2008). It has been created in 1995 on the basis of the pharmaceutical inspection convention (PIC) settled by the European free trade association (EFTA) in1970. This scheme has different goals as to be an international recognised body in the field of good manufacturing practices (GMP), for training inspectors (by the way of an annual seminar and experts circles related notably to active pharmaceutical ingredients [API], quality risk management, computerized systems, useful for the writing of inspection's aide-memoires). PICS is also leading to high standards for GMP inspectorates (through regular crossed audits) and being a room for exchanges on technical matters between inspectors but also between inspectors and pharmaceutical industry.

  7. Project financing renewable energy schemes

    International Nuclear Information System (INIS)

    Brandler, A.

    1993-01-01

    The viability of many Renewable Energy projects is critically dependent upon the ability of these projects to secure the necessary financing on acceptable terms. The principal objective of the study was to provide an overview to project developers of project financing techniques and the conditions under which project finance for Renewable Energy schemes could be raised, focussing on the potential sources of finance, the typical project financing structures that could be utilised for Renewable Energy schemes and the risk/return and security requirements of lenders, investors and other potential sources of financing. A second objective is to describe the appropriate strategy and tactics for developers to adopt in approaching the financing markets for such projects. (author)

  8. Network Regulation and Support Schemes

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Schröder, Sascha Thorsten; Jacobsen, Henrik

    2009-01-01

    -in tariffs to market-based quota systems, and network regulation approaches, comprising rate-of-return and incentive regulation. National regulation and the vertical structure of the electricity sector shape the incentives of market agents, notably of distributed generators and network operators......At present, there exists no explicit European policy framework on distributed generation. Various Directives encompass distributed generation; inherently, their implementation is to the discretion of the Member States. The latter have adopted different kinds of support schemes, ranging from feed....... This article seeks to investigate the interactions between the policy dimensions of support schemes and network regulation and how they affect the deployment of distributed generation. Firstly, a conceptual analysis examines how the incentives of the different market agents are affected. In particular...

  9. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben

    2016-01-01

    We consider distance labeling schemes for trees: given a tree with n nodes, label the nodes with binary strings such that, given the labels of any two nodes, one can determine, by looking only at the labels, the distance in the tree between the two nodes. A lower bound by Gavoille et al. [Gavoille...... variants such as, for example, small distances in trees [Alstrup et al., SODA, 2003]. We improve the known upper and lower bounds of exact distance labeling by showing that 1/4 log2(n) bits are needed and that 1/2 log2(n) bits are sufficient. We also give (1 + ε)-stretch labeling schemes using Theta...

  10. Small-scale classification schemes

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2004-01-01

    Small-scale classification schemes are used extensively in the coordination of cooperative work. This study investigates the creation and use of a classification scheme for handling the system requirements during the redevelopment of a nation-wide information system. This requirements...... classification inherited a lot of its structure from the existing system and rendered requirements that transcended the framework laid out by the existing system almost invisible. As a result, the requirements classification became a defining element of the requirements-engineering process, though its main...... effects remained largely implicit. The requirements classification contributed to constraining the requirements-engineering process by supporting the software engineers in maintaining some level of control over the process. This way, the requirements classification provided the software engineers...

  11. Risk:reward sharing contracts in the oil industry: the effects of bonus:penalty schemes

    International Nuclear Information System (INIS)

    Kemp, A.G.; Stephen, L.

    1999-01-01

    Partnering and alliancing among oil companies and their contractors have become common in the oil industry in recent years. The risk:reward mechanisms established very often incorporate bonus/penalty schemes in relation to agreed base values. This paper examines the efficiency requirements of such schemes. The effects of project cost and completion risks on the risk: reward positions of field investors and contractors with and without bonus/penalty schemes are examined with the aid of Monte Carlo simulation analysis. The schemes increase the total risk for contractors and have consequence for their cost of capital and optimal risk-bearing arrangements within the industry. (author)

  12. Establishing a University Foundation.

    Science.gov (United States)

    Lemish, Donald L.

    A handbook on how to establish a university foundation is presented. It presupposes that a foundation will be used as the umbrella organization for receiving all private gifts, restricted and unrestricted, for the benefit of a public college or university; and hence it chiefly addresses readers from public colleges and universities. Information is…

  13. AN ADVANCED LEAKAGE SCHEME FOR NEUTRINO TREATMENT IN ASTROPHYSICAL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 2, D-64289 Darmstadt (Germany); Cabezón, R. M. [Physics Department, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Käppeli, R., E-mail: albino.perego@physik.tu-darmstadt.de [Seminar for Applied Mathematics, ETH Zürich, Rämistrasse 101, 8092 Zürich (Switzerland)

    2016-04-15

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  14. Identity based Encryption and Biometric Authentication Scheme for Secure Data Access in Cloud Computing

    DEFF Research Database (Denmark)

    Cheng, Hongbing; Rong, Chunming; Tan, Zheng-Hua

    2012-01-01

    Cloud computing will be a main information infrastructure in the future; it consists of many large datacenters which are usually geographically distributed and heterogeneous. How to design a secure data access for cloud computing platform is a big challenge. In this paper, we propose a secure data...... access scheme based on identity-based encryption and biometric authentication for cloud computing. Firstly, we describe the security concern of cloud computing and then propose an integrated data access scheme for cloud computing, the procedure of the proposed scheme include parameter setup, key...... distribution, feature template creation, cloud data processing and secure data access control. Finally, we compare the proposed scheme with other schemes through comprehensive analysis and simulation. The results show that the proposed data access scheme is feasible and secure for cloud computing....

  15. BVS: A Lightweight Forward and Backward Secure Scheme for PMU Communications in Smart Grid

    Directory of Open Access Journals (Sweden)

    Wei Ren

    2011-01-01

    Full Text Available In smart grid, phaser measurement units (PMUs can upload readings to utility centers via supervisory control and data acquisition (SCADA or energy management system (EMS to enable intelligent controlling and scheduling. It is critical to maintain the secrecy of readings so as to protect customers' privacy, together with integrity and source authentication for the reliability and stability of power scheduling. In particular, appealing security scheme needs to perform well in PMUs that usually have computational resource constraints, thus designed security protocols have to remain lightweight in terms of computation and storage. In this paper, we propose a family of schemes to solve this problem. They are public key based scheme (PKS, password based scheme (PWS and billed value-based scheme (BVS. BVS can achieve forward and backward security and only relies on hash functions. Security analysis justifies that the proposed schemes, especially BVS, can attain the security goals with low computation and storage cost.

  16. A MODIFIED CUMULUS PARAMETERIZATION SCHEME AND ITS APPLICATION IN THE SIMULATIONS OF THE HEAVY PRECIPITATION CASES

    Institute of Scientific and Technical Information of China (English)

    PING Fan; TANG Xi-ba; YIN Lei

    2016-01-01

    According to the characteristics of organized cumulus convective precipitation in China,a cumulus parameterization scheme suitable for describing the organized convective precipitation in East Asia is presented and modified.The Kain-Fristch scheme is chosen as the scheme to be modified based on analyses and comparisons of simulated precipitation in East Asia by several commonly-used mesoscale parameterization schemes.A key dynamic parameter to dynamically control the cumulus parameterization is then proposed to improve the Kain-Fristch scheme.Numerical simulations of a typhoon case and a Mei-yu front rainfall case are carried out with the improved scheme,and the results show that the improved version performs better than the original in simulating the track and intensity of the typhoons,as well as the distribution of Mei-yu front precipitation.

  17. Cambridge community Optometry Glaucoma Scheme.

    Science.gov (United States)

    Keenan, Jonathan; Shahid, Humma; Bourne, Rupert R; White, Andrew J; Martin, Keith R

    2015-04-01

    With a higher life expectancy, there is an increased demand for hospital glaucoma services in the United Kingdom. The Cambridge community Optometry Glaucoma Scheme (COGS) was initiated in 2010, where new referrals for suspected glaucoma are evaluated by community optometrists with a special interest in glaucoma, with virtual electronic review and validation by a consultant ophthalmologist with special interest in glaucoma. 1733 patients were evaluated by this scheme between 2010 and 2013. Clinical assessment is performed by the optometrist at a remote site. Goldmann applanation tonometry, pachymetry, monoscopic colour optic disc photographs and automated Humphrey visual field testing are performed. A clinical decision is made as to whether a patient has glaucoma or is a suspect, and referred on or discharged as a false positive referral. The clinical findings, optic disc photographs and visual field test results are transmitted electronically for virtual review by a consultant ophthalmologist. The number of false positive referrals from initial referral into the scheme. Of the patients, 46.6% were discharged at assessment and a further 5.7% were discharged following virtual review. Of the patients initially discharged, 2.8% were recalled following virtual review. Following assessment at the hospital, a further 10.5% were discharged after a single visit. The COGS community-based glaucoma screening programme is a safe and effective way of evaluating glaucoma referrals in the community and reducing false-positive referrals for glaucoma into the hospital system. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

  18. New schemes for particle accelerators

    International Nuclear Information System (INIS)

    Nishida, Y.

    1985-01-01

    In the present paper, the authors propose new schemes for realizing the v/sub p/xB accelerator, by using no plasma system for producing the strong longitudinal waves. The first method is to use a grating for obtaining extended interaction of an electron beam moving along the grating surface with light beam incident also along the surface. Here, the light beam propagates obliquely to the grating grooves for producing strong electric field, and the electron beam propagates in parallel to the light beam. The static magnetic field is applied perpendicularly to the grating surface. In the present system, the beam interacts synchronously with the p-polarized wave which has the electric field be parallel to the grating surface. Another conventional scheme is to use a delay circuit. Here, the light beam propagates obliquely between a pair of array of conductor fins or slots. The phase velocity of the spatial harmonics in the y-direction (right angle to the array of slots) is slower than the speed of light. With the aid of powerful laser light or microwave source, it should be possible to miniaturise linacs by using the v/sub p/xB effect and schemes proposed here

  19. Establishing an ethanol production business

    International Nuclear Information System (INIS)

    1993-01-01

    Many Saskatchewan communities are interested in the potential benefits of establishing an ethanol production facility. A guide is presented to outline areas that communities should consider when contemplating the development of an ethanol production facility. Political issues affecting the ethanol industry are discussed including environmental impacts, United States legislation, Canadian legislation, and government incentives. Key success factors in starting a business, project management, marketing, financing, production, physical requirements, and licensing and regulation are considered. Factors which must be taken into consideration by the project manager and team include markets for ethanol and co-products, competent business management staff, equity partners for financing, production and co-product utilization technologies, integration with another facility such as a feedlot or gluten plant, use of outside consultants, and feedstock, water, energy, labour, environmental and site size requirements. 2 figs., 2 tabs

  20. Secure Trust Based Key Management Routing Framework for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Jugminder Kaur

    2016-01-01

    Full Text Available Security is always a major concern in wireless sensor networks (WSNs. Several trust based routing protocols are designed that play an important role in enhancing the performance of a wireless network. However they still have some disadvantages like limited energy resources, susceptibility to physical capture, and little protection against various attacks due to insecure wireless communication channels. This paper presents a secure trust based key management (STKF routing framework that establishes a secure trustworthy route depending upon the present and past node to node interactions. This route is then updated by isolating the malicious or compromised nodes from the route, if any, and a dedicated link is created between every pair of nodes in the selected route with the help of “q” composite random key predistribution scheme (RKPS to ensure data delivery from source to destination. The performance of trust aware secure routing framework (TSRF is compared with the proposed routing scheme. The results indicate that STKF provides an effective mechanism for finding out a secure route with better trustworthiness than TSRF which avoids the data dropping, thereby increasing the data delivery ratio. Also the distance required to reach the destination in the proposed protocol is less hence effectively utilizing the resources.

  1. A Memory Efficient Network Encryption Scheme

    Science.gov (United States)

    El-Fotouh, Mohamed Abo; Diepold, Klaus

    In this paper, we studied the two widely used encryption schemes in network applications. Shortcomings have been found in both schemes, as these schemes consume either more memory to gain high throughput or low memory with low throughput. The need has aroused for a scheme that has low memory requirements and in the same time possesses high speed, as the number of the internet users increases each day. We used the SSM model [1], to construct an encryption scheme based on the AES. The proposed scheme possesses high throughput together with low memory requirements.

  2. An Arbitrated Quantum Signature Scheme without Entanglement*

    International Nuclear Information System (INIS)

    Li Hui-Ran; Luo Ming-Xing; Peng Dai-Yuan; Wang Xiao-Jun

    2017-01-01

    Several quantum signature schemes are recently proposed to realize secure signatures of quantum or classical messages. Arbitrated quantum signature as one nontrivial scheme has attracted great interests because of its usefulness and efficiency. Unfortunately, previous schemes cannot against Trojan horse attack and DoS attack and lack of the unforgeability and the non-repudiation. In this paper, we propose an improved arbitrated quantum signature to address these secure issues with the honesty arbitrator. Our scheme takes use of qubit states not entanglements. More importantly, the qubit scheme can achieve the unforgeability and the non-repudiation. Our scheme is also secure for other known quantum attacks . (paper)

  3. A scheme of hidden-structure attribute-based encryption with multiple authorities

    Science.gov (United States)

    Ling, J.; Weng, A. X.

    2018-05-01

    In the most of the CP-ABE schemes with hidden access structure, both all the user attributes and the key generation are managed by only one authority. The key generation efficiency will decrease as the number of user increases, and the data will encounter security issues as the only authority is attacked. We proposed a scheme of hidden-structure attribute-based encryption with multiple authorities, which introduces multiple semi-trusted attribute authorities, avoiding the threat even though one or more authorities are attacked. We also realized user revocation by managing a revocation list. Based on DBDH assumption, we proved that our scheme is of IND-CMA security. The analysis shows that our scheme improves the key generation efficiency.

  4. Multiple image encryption scheme based on pixel exchange operation and vector decomposition

    Science.gov (United States)

    Xiong, Y.; Quan, C.; Tay, C. J.

    2018-02-01

    We propose a new multiple image encryption scheme based on a pixel exchange operation and a basic vector decomposition in Fourier domain. In this algorithm, original images are imported via a pixel exchange operator, from which scrambled images and pixel position matrices are obtained. Scrambled images encrypted into phase information are imported using the proposed algorithm and phase keys are obtained from the difference between scrambled images and synthesized vectors in a charge-coupled device (CCD) plane. The final synthesized vector is used as an input in a random phase encoding (DRPE) scheme. In the proposed encryption scheme, pixel position matrices and phase keys serve as additional private keys to enhance the security of the cryptosystem which is based on a 4-f system. Numerical simulations are presented to demonstrate the feasibility and robustness of the proposed encryption scheme.

  5. Small private key MQPKS on an embedded microprocessor.

    Science.gov (United States)

    Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

    2014-03-19

    Multivariate quadratic (MQ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key MQ scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing MQ on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key MQ scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES) accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012.

  6. Small Private Key MQPKS on an Embedded Microprocessor

    Directory of Open Access Journals (Sweden)

    Hwajeong Seo

    2014-03-01

    Full Text Available Multivariate quadratic (MQ cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011, a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key MQ scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing MQ on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key MQ scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012.

  7. Small Private Key PKS on an Embedded Microprocessor

    Science.gov (United States)

    Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

    2014-01-01

    Multivariate quadratic ( ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES) accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012. PMID:24651722

  8. PUBLIC KEY INFRASTRUCTURE (PKI)

    Data.gov (United States)

    Federal Laboratory Consortium — Common Access Card (CAC)Enterprise Testing Overview:Established in 2003Performs test and evaluations of the DOD PKI CAC issuance systems from an enterprise level all...

  9. Multipartite secret key distillation and bound entanglement

    International Nuclear Information System (INIS)

    Augusiak, Remigiusz; Horodecki, Pawel

    2009-01-01

    Recently it has been shown that quantum cryptography beyond pure entanglement distillation is possible and a paradigm for the associated protocols has been established. Here we systematically generalize the whole paradigm to the multipartite scenario. We provide constructions of new classes of multipartite bound entangled states, i.e., those with underlying twisted Greenberger-Horne-Zeilinger (GHZ) structure and nonzero distillable cryptographic key. We quantitatively estimate the key from below with the help of the privacy squeezing technique.

  10. Time-and-ID-Based Proxy Reencryption Scheme

    OpenAIRE

    Mtonga, Kambombo; Paul, Anand; Rho, Seungmin

    2014-01-01

    Time- and ID-based proxy reencryption scheme is proposed in this paper in which a type-based proxy reencryption enables the delegator to implement fine-grained policies with one key pair without any additional trust on the proxy. However, in some applications, the time within which the data was sampled or collected is very critical. In such applications, for example, healthcare and criminal investigations, the delegatee may be interested in only some of the messages with some types sampled wi...

  11. How Governance Regimes Shape the Implementation of Water Reuse Schemes

    OpenAIRE

    Frijns, Jos; Smith, Heather M.; Brouwer, Stijn; Garnett, Kenisha; Elelman, Richard; Jeffrey, Paul

    2016-01-01

    The governance dimensions of water reuse scheme development and operation, such as policies and regulatory frameworks, and public involvement and stakeholder collaboration, can serve to both facilitate and constrain wider adoption of water reuse practices. This paper explores the significance and underlying structure of the key governance challenges facing the water reuse sector in Europe. It presents empirical evidence from interviews and focus group sessions conducted at four water reuse sc...

  12. Comparison of two schemes for automatic keyword extraction from MEDLINE for functional gene clustering.

    Science.gov (United States)

    Liu, Ying; Ciliax, Brian J; Borges, Karin; Dasigi, Venu; Ram, Ashwin; Navathe, Shamkant B; Dingledine, Ray

    2004-01-01

    One of the key challenges of microarray studies is to derive biological insights from the unprecedented quatities of data on gene-expression patterns. Clustering genes by functional keyword association can provide direct information about the nature of the functional links among genes within the derived clusters. However, the quality of the keyword lists extracted from biomedical literature for each gene significantly affects the clustering results. We extracted keywords from MEDLINE that describes the most prominent functions of the genes, and used the resulting weights of the keywords as feature vectors for gene clustering. By analyzing the resulting cluster quality, we compared two keyword weighting schemes: normalized z-score and term frequency-inverse document frequency (TFIDF). The best combination of background comparison set, stop list and stemming algorithm was selected based on precision and recall metrics. In a test set of four known gene groups, a hierarchical algorithm correctly assigned 25 of 26 genes to the appropriate clusters based on keywords extracted by the TDFIDF weighting scheme, but only 23 og 26 with the z-score method. To evaluate the effectiveness of the weighting schemes for keyword extraction for gene clusters from microarray profiles, 44 yeast genes that are differentially expressed during the cell cycle were used as a second test set. Using established measures of cluster quality, the results produced from TFIDF-weighted keywords had higher purity, lower entropy, and higher mutual information than those produced from normalized z-score weighted keywords. The optimized algorithms should be useful for sorting genes from microarray lists into functionally discrete clusters.

  13. Impacts of Rotation Schemes on Ground-Dwelling Beneficial Arthropods.

    Science.gov (United States)

    Dunbar, Mike W; Gassmann, Aaron J; O'Neal, Matthew E

    2016-10-01

    Crop rotation alters agroecosystem diversity temporally, and increasing the number of crops in rotation schemes can increase crop yields and reduce reliance on pesticides. We hypothesized that increasing the number of crops in annual rotation schemes would positively affect ground-dwelling beneficial arthropod communities. During 2012 and 2013, pitfall traps were used to measure activity-density and diversity of ground-dwelling communities within three previously established, long-term crop rotation studies located in Wisconsin and Illinois. Rotation schemes sampled included continuous corn, a 2-yr annual rotation of corn and soybean, and a 3-yr annual rotation of corn, soybean, and wheat. Insects captured were identified to family, and non-insect arthropods were identified to class, order, or family, depending upon the taxa. Beneficial arthropods captured included natural enemies, granivores, and detritivores. The beneficial community from continuous corn plots was significantly more diverse compared with the community in the 2-yr rotation, whereas the community in the 3-yr rotation did not differ from either rotation scheme. The activity-density of the total community and any individual taxa did not differ among rotation schemes in either corn or soybean. Crop species within all three rotation schemes were annual crops, and are associated with agricultural practices that make infield habitat subject to anthropogenic disturbances and temporally unstable. Habitat instability and disturbance can limit the effectiveness and retention of beneficial arthropods, including natural enemies, granivores, and detritivores. Increasing non-crop and perennial species within landscapes in conjunction with more diverse rotation schemes may increase the effect of biological control of pests by natural enemies. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Experimental demonstration of subcarrier multiplexed quantum key distribution system.

    Science.gov (United States)

    Mora, José; Ruiz-Alba, Antonio; Amaya, Waldimar; Martínez, Alfonso; García-Muñoz, Víctor; Calvo, David; Capmany, José

    2012-06-01

    We provide, to our knowledge, the first experimental demonstration of the feasibility of sending several parallel keys by exploiting the technique of subcarrier multiplexing (SCM) widely employed in microwave photonics. This approach brings several advantages such as high spectral efficiency compatible with the actual secure key rates, the sharing of the optical fainted pulse by all the quantum multiplexed channels reducing the system complexity, and the possibility of upgrading with wavelength division multiplexing in a two-tier scheme, to increase the number of parallel keys. Two independent quantum SCM channels featuring a sifted key rate of 10 Kb/s/channel over a link with quantum bit error rate <2% is reported.

  15. Security enhanced multi-factor biometric authentication scheme using bio-hash function.

    Directory of Open Access Journals (Sweden)

    Younsung Choi

    Full Text Available With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An's scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user's ID during login. Cao and Ge improved upon Younghwa An's scheme, but various security problems remained. This study demonstrates that Cao and Ge's scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge's scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost.

  16. A privacy preserving secure and efficient authentication scheme for telecare medical information systems.

    Science.gov (United States)

    Mishra, Raghavendra; Barnwal, Amit Kumar

    2015-05-01

    The Telecare medical information system (TMIS) presents effective healthcare delivery services by employing information and communication technologies. The emerging privacy and security are always a matter of great concern in TMIS. Recently, Chen at al. presented a password based authentication schemes to address the privacy and security. Later on, it is proved insecure against various active and passive attacks. To erase the drawbacks of Chen et al.'s anonymous authentication scheme, several password based authentication schemes have been proposed using public key cryptosystem. However, most of them do not present pre-smart card authentication which leads to inefficient login and password change phases. To present an authentication scheme with pre-smart card authentication, we present an improved anonymous smart card based authentication scheme for TMIS. The proposed scheme protects user anonymity and satisfies all the desirable security attributes. Moreover, the proposed scheme presents efficient login and password change phases where incorrect input can be quickly detected and a user can freely change his password without server assistance. Moreover, we demonstrate the validity of the proposed scheme by utilizing the widely-accepted BAN (Burrows, Abadi, and Needham) logic. The proposed scheme is also comparable in terms of computational overheads with relevant schemes.

  17. Security enhanced multi-factor biometric authentication scheme using bio-hash function

    Science.gov (United States)

    Lee, Youngsook; Moon, Jongho

    2017-01-01

    With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An’s scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user’s ID during login. Cao and Ge improved upon Younghwa An’s scheme, but various security problems remained. This study demonstrates that Cao and Ge’s scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge’s scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost. PMID:28459867

  18. Security enhanced multi-factor biometric authentication scheme using bio-hash function.

    Science.gov (United States)

    Choi, Younsung; Lee, Youngsook; Moon, Jongho; Won, Dongho

    2017-01-01

    With the rapid development of personal information and wireless communication technology, user authentication schemes have been crucial to ensure that wireless communications are secure. As such, various authentication schemes with multi-factor authentication have been proposed to improve the security of electronic communications. Multi-factor authentication involves the use of passwords, smart cards, and various biometrics to provide users with the utmost privacy and data protection. Cao and Ge analyzed various authentication schemes and found that Younghwa An's scheme was susceptible to a replay attack where an adversary masquerades as a legal server and a user masquerading attack where user anonymity is not provided, allowing an adversary to execute a password change process by intercepting the user's ID during login. Cao and Ge improved upon Younghwa An's scheme, but various security problems remained. This study demonstrates that Cao and Ge's scheme is susceptible to a biometric recognition error, slow wrong password detection, off-line password attack, user impersonation attack, ID guessing attack, a DoS attack, and that their scheme cannot provide session key agreement. Then, to address all weaknesses identified in Cao and Ge's scheme, this study proposes a security enhanced multi-factor biometric authentication scheme and provides a security analysis and formal analysis using Burrows-Abadi-Needham logic. Finally, the efficiency analysis reveals that the proposed scheme can protect against several possible types of attacks with only a slightly high computational cost.

  19. Mammography image assessment; validity and reliability of current scheme

    International Nuclear Information System (INIS)

    Hill, C.; Robinson, L.

    2015-01-01

    Mammographers currently score their own images according to criteria set out by Regional Quality Assurance. The criteria used are based on the ‘Perfect, Good, Moderate, Inadequate’ (PGMI) marking criteria established by the National Health Service Breast Screening Programme (NHSBSP) in their Quality Assurance Guidelines of 2006 1 . This document discusses the validity and reliability of the current mammography image assessment scheme. Commencing with a critical review of the literature this document sets out to highlight problems with the national approach to the use of marking schemes. The findings suggest that ‘PGMI’ scheme is flawed in terms of reliability and validity and is not universally applied across the UK. There also appear to be differences in schemes used by trainees and qualified mammographers. Initial recommendations are to be made in collaboration with colleagues within the National Health Service Breast Screening Programme (NHSBSP), Higher Education Centres, College of Radiographers and the Royal College of Radiologists in order to identify a mammography image appraisal scheme that is fit for purpose. - Highlights: • Currently no robust evidence based marking tools in use for the assessment of images in mammography. • Is current system valid, reliable and robust? • How can the current image assessment tool be improved? • Should students and qualified mammographers use the same tool? • What marking criteria are available for image assessment?

  20. Securing Body Sensor Networks with Biometric Methods: A New Key Negotiation Method and a Key Sampling Method for Linear Interpolation Encryption

    OpenAIRE

    Zhao, Huawei; Chen, Chi; Hu, Jiankun; Qin, Jing

    2015-01-01

    We present two approaches that exploit biometric data to address security problems in the body sensor networks: a new key negotiation scheme based on the fuzzy extractor technology and an improved linear interpolation encryption method. The first approach designs two attack games to give the formal definition of fuzzy negotiation that forms a new key negotiation scheme based on fuzzy extractor technology. According to the definition, we further define a concrete structure of fuzzy negotiation...

  1. Atomic Weapons Establishment Bill

    International Nuclear Information System (INIS)

    Clark, Alan; Dalyell, Tam; Haynes, Frank

    1990-01-01

    The Bill debated concerns the government's proposal for the future organisations of the atomic weapons establishment in the United Kingdom. The proposals arise from a full review carried out in 1989 and include points raised by the Select Committee on the Trident programme. Studies of productivity, pay and conditions, information systems and long term manufacturing strategy have been started to enable recommendations of the reorganisation of the establishments to be made. The details of the Bill were debated for just over two hours. The debate is reported verbatim. The main issues were over the principle of contractorisation, possible staff redundancies, conditions of employment, safety and security. The proposal that the Bill be read a second time was carried. (UK)

  2. Key World Energy Statistics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    The IEA produced its first handy, pocket-sized summary of key energy data in 1997. This new edition responds to the enormously positive reaction to the book since then. Key World Energy Statistics produced by the IEA contains timely, clearly-presented data on supply, transformation and consumption of all major energy sources. The interested businessman, journalist or student will have at his or her fingertips the annual Canadian production of coal, the electricity consumption in Thailand, the price of diesel oil in Spain and thousands of other useful energy facts. It exists in different formats to suit our readers' requirements.

  3. Decoupling schemes for the SSC Collider

    International Nuclear Information System (INIS)

    Cai, Y.; Bourianoff, G.; Cole, B.; Meinke, R.; Peterson, J.; Pilat, F.; Stampke, S.; Syphers, M.; Talman, R.

    1993-05-01

    A decoupling system is designed for the SSC Collider. This system can accommodate three decoupling schemes by using 44 skew quadrupoles in the different configurations. Several decoupling schemes are studied and compared in this paper

  4. Renormalization scheme-invariant perturbation theory

    International Nuclear Information System (INIS)

    Dhar, A.

    1983-01-01

    A complete solution to the problem of the renormalization scheme dependence of perturbative approximants to physical quantities is presented. An equation is derived which determines any physical quantity implicitly as a function of only scheme independent variables. (orig.)

  5. Wireless Broadband Access and Accounting Schemes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we propose two wireless broadband access and accounting schemes. In both schemes, the accounting system adopts RADIUS protocol, but the access system adopts SSH and SSL protocols respectively.

  6. Public/private key certification authority and key distribution. Draft

    Energy Technology Data Exchange (ETDEWEB)

    Long, J.P.; Christensen, M.J.; Sturtevant, A.P.; Johnston, W.E.

    1995-09-25

    Traditional encryption, which protects messages from prying eyes, has been used for many decades. The present concepts of encryption are built from that heritage. Utilization of modern software-based encryption techniques implies much more than simply converting files to an unreadable form. Ubiquitous use of computers and advances in encryption technology coupled with the use of wide-area networking completely changed the reasons for utilizing encryption technology. The technology demands a new and extensive infrastructure to support these functions. Full understanding of these functions, their utility and value, and the need for an infrastructure, takes extensive exposure to the new paradigm. This paper addresses issues surrounding the establishment and operation of a key management system (i.e., certification authority) that is essential to the successful implementation and wide-spread use of encryption.

  7. Tightly Secure Signatures From Lossy Identification Schemes

    OpenAIRE

    Abdalla , Michel; Fouque , Pierre-Alain; Lyubashevsky , Vadim; Tibouchi , Mehdi

    2015-01-01

    International audience; In this paper, we present three digital signature schemes with tight security reductions in the random oracle model. Our first signature scheme is a particularly efficient version of the short exponent discrete log-based scheme of Girault et al. (J Cryptol 19(4):463–487, 2006). Our scheme has a tight reduction to the decisional short discrete logarithm problem, while still maintaining the non-tight reduction to the computational version of the problem upon which the or...

  8. Rural health prepayment schemes in China: towards a more active role for government.

    Science.gov (United States)

    Bloom, G; Shenglan, T

    1999-04-01

    A large majority of China's rural population were members of health prepayment schemes in the 1970's. Most of these schemes collapsed during the transition to a market economy. Some localities subsequently reestablished schemes. In early 1997 a new government policy identified health prepayment as a major potential source of rural health finance. This paper draws on the experience of existing schemes to explore how government can support implementation of this policy. The decision to support the establishment of health prepayment schemes is part of the government's effort to establish new sources of finance for social services. It believes that individuals are more likely to accept voluntary contributions to a prepayment scheme than tax increases. The voluntary nature of the contributions limits the possibilities for risk-sharing and redistribution between rich and poor. This underlines the need for the government to fund a substantial share of health expenditure out of general revenues, particularly in poor localities. The paper notes that many successful prepayment schemes depend on close supervision by local political leaders. It argues that the national programme will have to translate these measures into a regulatory system which defines the responsibilities of scheme management bodies and local governments. A number of prepayment schemes have collapsed because members did not feel they got value for money. Local health bureaux will have to cooperate with prepayment schemes to ensure that health facilities provide good quality services at a reasonable cost. Users' representatives can also monitor performance. The paper concludes that government needs to clarify the relationship between health prepayment schemes and other actors in rural localities in order to increase the chance that schemes will become a major source rural health finance.

  9. Keyed shear joints

    DEFF Research Database (Denmark)

    Hansen, Klaus

    This report gives a summary of the present information on the behaviour of vertical keyed shear joints in large panel structures. An attemp is made to outline the implications which this information might have on the analysis and design of a complete wall. The publications also gives a short...

  10. Cryptographic Key Management System

    Energy Technology Data Exchange (ETDEWEB)

    No, author

    2014-02-21

    This report summarizes the outcome of U.S. Department of Energy (DOE) contract DE-OE0000543, requesting the design of a Cryptographic Key Management System (CKMS) for the secure management of cryptographic keys for the energy sector infrastructure. Prime contractor Sypris Electronics, in collaboration with Oak Ridge National Laboratories (ORNL), Electric Power Research Institute (EPRI), Valicore Technologies, and Purdue University's Center for Education and Research in Information Assurance and Security (CERIAS) and Smart Meter Integration Laboratory (SMIL), has designed, developed and evaluated the CKMS solution. We provide an overview of the project in Section 3, review the core contributions of all contractors in Section 4, and discuss bene ts to the DOE in Section 5. In Section 6 we describe the technical construction of the CKMS solution, and review its key contributions in Section 6.9. Section 7 describes the evaluation and demonstration of the CKMS solution in different environments. We summarize the key project objectives in Section 8, list publications resulting from the project in Section 9, and conclude with a discussion on commercialization in Section 10 and future work in Section 11.

  11. Turn key contracts

    International Nuclear Information System (INIS)

    Feretic, D.

    1975-01-01

    The aim of this summary is to point out some specific areas which have to be covered in a turn-key contract and which are of primarily interest to the buyer of a nuclear plant. It will be assumed that the buyer is utility company in a developing country and a plant supplier a company in an industrial country. (orig./FW) [de

  12. Key numbers: Energy

    International Nuclear Information System (INIS)

    1994-01-01

    The key numbers of energy give statistical data related to production, consumption, and to foreign trade of each energy in the World and in France. A chapter is dedicated to environment and brings quantitative elements on pollutant emissions connected to energy uses

  13. Key performance indicators

    NARCIS (Netherlands)

    Zwetsloot, G.I.J.M.

    2014-01-01

    This paper addresses how organisations can use OSH performance indicators. This is an important way to mainstream OSH into business management. Key performance indicators (KPIs) should provide objective data on the OSH situation. It is often said that ‘what gets measured gets managed’. Without

  14. Locks and Keys Service

    CERN Multimedia

    Claude Ducastel

    The GS-LS-SEM section is pleased to inform you that as from Monday 30 November 2009, the opening hours of the Locks and Keys service will be the following: 08h30 - 12h30 / 13h30 - 16:30, Mondays to Fridays. GS-SEM-LS 73333

  15. Comparative study of numerical schemes of TVD3, UNO3-ACM and optimized compact scheme

    Science.gov (United States)

    Lee, Duck-Joo; Hwang, Chang-Jeon; Ko, Duck-Kon; Kim, Jae-Wook

    1995-01-01

    Three different schemes are employed to solve the benchmark problem. The first one is a conventional TVD-MUSCL (Monotone Upwind Schemes for Conservation Laws) scheme. The second scheme is a UNO3-ACM (Uniformly Non-Oscillatory Artificial Compression Method) scheme. The third scheme is an optimized compact finite difference scheme modified by us: the 4th order Runge Kutta time stepping, the 4th order pentadiagonal compact spatial discretization with the maximum resolution characteristics. The problems of category 1 are solved by using the second (UNO3-ACM) and third (Optimized Compact) schemes. The problems of category 2 are solved by using the first (TVD3) and second (UNO3-ACM) schemes. The problem of category 5 is solved by using the first (TVD3) scheme. It can be concluded from the present calculations that the Optimized Compact scheme and the UN03-ACM show good resolutions for category 1 and category 2 respectively.

  16. Key-space analysis of double random phase encryption technique

    Science.gov (United States)

    Monaghan, David S.; Gopinathan, Unnikrishnan; Naughton, Thomas J.; Sheridan, John T.

    2007-09-01

    We perform a numerical analysis on the double random phase encryption/decryption technique. The key-space of an encryption technique is the set of possible keys that can be used to encode data using that technique. In the case of a strong encryption scheme, many keys must be tried in any brute-force attack on that technique. Traditionally, designers of optical image encryption systems demonstrate only how a small number of arbitrary keys cannot decrypt a chosen encrypted image in their system. However, this type of demonstration does not discuss the properties of the key-space nor refute the feasibility of an efficient brute-force attack. To clarify these issues we present a key-space analysis of the technique. For a range of problem instances we plot the distribution of decryption errors in the key-space indicating the lack of feasibility of a simple brute-force attack.

  17. Parametric Human Body Reconstruction Based on Sparse Key Points.

    Science.gov (United States)

    Cheng, Ke-Li; Tong, Ruo-Feng; Tang, Min; Qian, Jing-Ye; Sarkis, Michel

    2016-11-01

    We propose an automatic parametric human body reconstruction algorithm which can efficiently construct a model using a single Kinect sensor. A user needs to stand still in front of the sensor for a couple of seconds to measure the range data. The user's body shape and pose will then be automatically constructed in several seconds. Traditional methods optimize dense correspondences between range data and meshes. In contrast, our proposed scheme relies on sparse key points for the reconstruction. It employs regression to find the corresponding key points between the scanned range data and some annotated training data. We design two kinds of feature descriptors as well as corresponding regression stages to make the regression robust and accurate. Our scheme follows with dense refinement where a pre-factorization method is applied to improve the computational efficiency. Compared with other methods, our scheme achieves similar reconstruction accuracy but significantly reduces runtime.

  18. Optimal Sales Schemes for Network Goods

    DEFF Research Database (Denmark)

    Parakhonyak, Alexei; Vikander, Nick

    consumers simultaneously, serve them all sequentially, or employ any intermediate scheme. We show that the optimal sales scheme is purely sequential, where each consumer observes all previous sales before choosing whether to buy himself. A sequential scheme maximizes the amount of information available...

  19. THROUGHPUT ANALYSIS OF EXTENDED ARQ SCHEMES

    African Journals Online (AJOL)

    PUBLICATIONS1

    ABSTRACT. Various Automatic Repeat Request (ARQ) schemes have been used to combat errors that befall in- formation transmitted in digital communication systems. Such schemes include simple ARQ, mixed mode ARQ and Hybrid ARQ (HARQ). In this study we introduce extended ARQ schemes and derive.

  20. Arbitrated quantum signature scheme with message recovery

    International Nuclear Information System (INIS)

    Lee, Hwayean; Hong, Changho; Kim, Hyunsang; Lim, Jongin; Yang, Hyung Jin

    2004-01-01

    Two quantum signature schemes with message recovery relying on the availability of an arbitrator are proposed. One scheme uses a public board and the other does not. However both schemes provide confidentiality of the message and a higher efficiency in transmission

  1. Semantic Keys and Reading

    Directory of Open Access Journals (Sweden)

    Zev bar-Lev

    2016-12-01

    Full Text Available Semantic Keys are elements (word-parts of written language that give an iconic, general representation of the whole word’s meaning. In written Sino-Japanese the “radical” or semantic components play this role. For example, the character meaning ‘woman, female’ is the Semantic Key of the character for Ma ‘Mama’ (alongside the phonetic component Ma, which means ‘horse’ as a separate character. The theory of semantic Keys in both graphic and phonemic aspects is called qTheory or nanosemantics. The most innovative aspect of the present article is the hypothesis that, in languages using alphabetic writing systems, the role of Semantic Key is played by consonants, more specifically the first consonant. Thus, L meaning ‘LIFT’ is the Semantic Key of English Lift, Ladle, Lofty, aLps, eLevator, oLympus; Spanish Leva, Lecantarse, aLto, Lengua; Arabic aLLah, and Hebrew① ªeL-ºaL ‘upto-above’ (the Israeli airline, Polish Lot ‘flight’ (the Polish airline; Hebrew ªeL, ªeLohim ‘God’, and haLLeluyah ‘praise-ye God’ (using Parallels, ‘Lift up God’. Evidence for the universality of the theory is shown by many examples drawn from various languages, including Indo-European Semitic, Chinese and Japanese. The theory reveals hundreds of relationships within and between languages, related and unrelated, that have been “Hiding in Plain Sight”, to mention just one example: the Parallel between Spanish Pan ‘bread’ and Mandarin Fan ‘rice’.

  2. Synchronization in Quantum Key Distribution Systems

    Directory of Open Access Journals (Sweden)

    Anton Pljonkin

    2017-10-01

    Full Text Available In the description of quantum key distribution systems, much attention is paid to the operation of quantum cryptography protocols. The main problem is the insufficient study of the synchronization process of quantum key distribution systems. This paper contains a general description of quantum cryptography principles. A two-line fiber-optic quantum key distribution system with phase coding of photon states in transceiver and coding station synchronization mode was examined. A quantum key distribution system was built on the basis of the scheme with automatic compensation of polarization mode distortions. Single-photon avalanche diodes were used as optical radiation detecting devices. It was estimated how the parameters used in quantum key distribution systems of optical detectors affect the detection of the time frame with attenuated optical pulse in synchronization mode with respect to its probabilistic and time-domain characteristics. A design method was given for the process that detects the time frame that includes an optical pulse during synchronization. This paper describes the main quantum communication channel attack methods by removing a portion of optical emission. This paper describes the developed synchronization algorithm that takes into account the time required to restore the photodetector’s operation state after the photon has been registered during synchronization. The computer simulation results of the developed synchronization algorithm were analyzed. The efficiency of the developed algorithm with respect to synchronization process protection from unauthorized gathering of optical emission is demonstrated herein.

  3. Secular Religious Establishment

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2013-01-01

    Secularism as a political doctrine claims that religion and politics should be separated. The compatibility question is whether secularism can accept some forms of religious establishment in the form of institutional linkages between state and organised religion. I argue that the answer...... to the compatibility question is not obvious and requires a systematic analysis of secularism. Based on a distinction between a general concept and specific conceptions of secularism I offer a general structure for conceptions of secularism that incorporates both a) basic values, e.g. political equality and freedom...

  4. Compatible discrete operator schemes on polyhedral meshes for elliptic and Stokes equations

    International Nuclear Information System (INIS)

    Bonelle, Jerome

    2014-01-01

    This thesis presents a new class of spatial discretization schemes on polyhedral meshes, called Compatible Discrete Operator (CDO) schemes and their application to elliptic and Stokes equations In CDO schemes, preserving the structural properties of the continuous equations is the leading principle to design the discrete operators. De Rham maps define the degrees of freedom according to the physical nature of fields to discretize. CDO schemes operate a clear separation between topological relations (balance equations) and constitutive relations (closure laws). Topological relations are related to discrete differential operators, and constitutive relations to discrete Hodge operators. A feature of CDO schemes is the explicit use of a second mesh, called dual mesh, to build the discrete Hodge operator. Two families of CDO schemes are considered: vertex-based schemes where the potential is located at (primal) mesh vertices, and cell-based schemes where the potential is located at dual mesh vertices (dual vertices being in one-to-one correspondence with primal cells). The CDO schemes related to these two families are presented and their convergence is analyzed. A first analysis hinges on an algebraic definition of the discrete Hodge operator and allows one to identify three key properties: symmetry, stability, and P0-consistency. A second analysis hinges on a definition of the discrete Hodge operator using reconstruction operators, and the requirements on these reconstruction operators are identified. In addition, CDO schemes provide a unified vision on a broad class of schemes proposed in the literature (finite element, finite element, mimetic schemes... ). Finally, the reliability and the efficiency of CDO schemes are assessed on various test cases and several polyhedral meshes. (author)

  5. Quality control scheme for thyroid related hormones measured by radioimmunoassay

    International Nuclear Information System (INIS)

    Kamel, R.S.

    1989-09-01

    A regional quality control scheme for thyroid related hormones measured by radioimmunoassay is being established in the Middle East. The scheme started in January 1985, with eight laboratories which were all from Iraq. At the present nineteen laboratories from Iraq, Jordan, Kuwait, Saudi Arabia and United Arab Emirates (Dubai) are now participating in the scheme. The scheme was supported by the International Atomic Energy Agency. All participants received monthly three freeze dried quality control samples for assay. Results for T3, T4 and TSH received from participants are analysed statistically batch by batch and returned to the participants. Laboratories reporting quite marked bias results were contacted to check the assay performance for that particular batch and to define the weak points. Clinical interpretation for certain well defined samples were reported. A regular case study report is recently introduced to the scheme and will be distributed regularly as one of the guidelines in establishing a trouble shooting programme throughout the scheme. The overall mean between the laboratory performance showed a good result for the T4, moderate but acceptable for T3 and poor for TSH. The statistical analysis of the results based on the concept of a ''target'' value is derived from the believed correct value the ''Median''. The overall mean bias values (ignoring signs) for respectively low, normal and high concentration samples were for T4 18.0 ± 12.5, 11.2 ± 6.4 and 11.2 ± 6.4, for T3 28.8 ± 23.5, 11.2 ± 8.4 and 13.4 ± 9.0 and for TSH 46.3 ± 50.1, 37.2 ± 28.5 and 19.1 ± 12.1. The scheme proved to be effective not only in improving the overall performance but also it helped to develop awareness of the need for internal quality control programmes and gave confidence in the results of the participants. The scheme will continue and will be expanded to involve more laboratories in the region. Refs, fig and tabs

  6. An enhanced biometric-based authentication scheme for telecare medicine information systems using elliptic curve cryptosystem.

    Science.gov (United States)

    Lu, Yanrong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2015-03-01

    The telecare medical information systems (TMISs) enable patients to conveniently enjoy telecare services at home. The protection of patient's privacy is a key issue due to the openness of communication environment. Authentication as a typical approach is adopted to guarantee confidential and authorized interaction between the patient and remote server. In order to achieve the goals, numerous remote authentication schemes based on cryptography have been presented. Recently, Arshad et al. (J Med Syst 38(12): 2014) presented a secure and efficient three-factor authenticated key exchange scheme to remedy the weaknesses of Tan et al.'s scheme (J Med Syst 38(3): 2014). In this paper, we found that once a successful off-line password attack that results in an adversary could impersonate any user of the system in Arshad et al.'s scheme. In order to thwart these security attacks, an enhanced biometric and smart card based remote authentication scheme for TMISs is proposed. In addition, the BAN logic is applied to demonstrate the completeness of the enhanced scheme. Security and performance analyses show that our enhanced scheme satisfies more security properties and less computational cost compared with previously proposed schemes.

  7. Two-way quantum key distribution at telecommunication wavelength

    International Nuclear Information System (INIS)

    Kumar, Rupesh; Lucamarini, Marco; Di Giuseppe, Giovanni; Natali, Riccardo; Mancini, Giorgio; Tombesi, Paolo

    2008-01-01

    We report on a quantum key distribution effected with a two-way deterministic protocol over a standard telecommunication fiber. Despite the common belief of a prohibitive loss rate for such a scheme, our results show its feasibility on distances of few tenths of kilometers

  8. Secure quantum key distribution using squeezed states

    International Nuclear Information System (INIS)

    Gottesman, Daniel; Preskill, John

    2001-01-01

    We prove the security of a quantum key distribution scheme based on transmission of squeezed quantum states of a harmonic oscillator. Our proof employs quantum error-correcting codes that encode a finite-dimensional quantum system in the infinite-dimensional Hilbert space of an oscillator, and protect against errors that shift the canonical variables p and q. If the noise in the quantum channel is weak, squeezing signal states by 2.51 dB (a squeeze factor e r =1.34) is sufficient in principle to ensure the security of a protocol that is suitably enhanced by classical error correction and privacy amplification. Secure key distribution can be achieved over distances comparable to the attenuation length of the quantum channel

  9. REMINDER: Saved Leave Scheme (SLS)

    CERN Multimedia

    2003-01-01

    Transfer of leave to saved leave accounts Under the provisions of the voluntary saved leave scheme (SLS), a maximum total of 10 days'* annual and compensatory leave (excluding saved leave accumulated in accordance with the provisions of Administrative Circular No 22B) can be transferred to the saved leave account at the end of the leave year (30 September). We remind you that unused leave of all those taking part in the saved leave scheme at the closure of the leave year accounts is transferred automatically to the saved leave account on that date. Therefore, staff members have no administrative steps to take. In addition, the transfer, which eliminates the risk of omitting to request leave transfers and rules out calculation errors in transfer requests, will be clearly shown in the list of leave transactions that can be consulted in EDH from October 2003 onwards. Furthermore, this automatic leave transfer optimizes staff members' chances of benefiting from a saved leave bonus provided that they ar...

  10. Quantum Secure Communication Scheme with W State

    International Nuclear Information System (INIS)

    Wang Jian; Zhang Quan; Tang Chaojng

    2007-01-01

    We present a quantum secure communication scheme using three-qubit W state. It is unnecessary for the present scheme to use alternative measurement or Bell basis measurement. Compared with the quantum secure direct communication scheme proposed by Cao et al. [H.J. Cao and H.S. Song, Chin. Phys. Lett. 23 (2006) 290], in our scheme, the detection probability for an eavesdropper's attack increases from 8.3% to 25%. We also show that our scheme is secure for a noise quantum channel.

  11. Labeling schemes for bounded degree graphs

    DEFF Research Database (Denmark)

    Adjiashvili, David; Rotbart, Noy Galil

    2014-01-01

    We investigate adjacency labeling schemes for graphs of bounded degree Δ = O(1). In particular, we present an optimal (up to an additive constant) log n + O(1) adjacency labeling scheme for bounded degree trees. The latter scheme is derived from a labeling scheme for bounded degree outerplanar...... graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 2010], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 2002]. We also provide improved labeling schemes for bounded degree...

  12. Comparison of different incremental analysis update schemes in a realistic assimilation system with Ensemble Kalman Filter

    Science.gov (United States)

    Yan, Y.; Barth, A.; Beckers, J. M.; Brankart, J. M.; Brasseur, P.; Candille, G.

    2017-07-01

    In this paper, three incremental analysis update schemes (IAU 0, IAU 50 and IAU 100) are compared in the same assimilation experiments with a realistic eddy permitting primitive equation model of the North Atlantic Ocean using the Ensemble Kalman Filter. The difference between the three IAU schemes lies on the position of the increment update window. The relevance of each IAU scheme is evaluated through analyses on both thermohaline and dynamical variables. The validation of the assimilation results is performed according to both deterministic and probabilistic metrics against different sources of observations. For deterministic validation, the ensemble mean and the ensemble spread are compared to the observations. For probabilistic validation, the continuous ranked probability score (CRPS) is used to evaluate the ensemble forecast system according to reliability and resolution. The reliability is further decomposed into bias and dispersion by the reduced centred random variable (RCRV) score. The obtained results show that 1) the IAU 50 scheme has the same performance as the IAU 100 scheme 2) the IAU 50/100 schemes outperform the IAU 0 scheme in error covariance propagation for thermohaline variables in relatively stable region, while the IAU 0 scheme outperforms the IAU 50/100 schemes in dynamical variables estimation in dynamically active region 3) in case with sufficient number of observations and good error specification, the impact of IAU schemes is negligible. The differences between the IAU 0 scheme and the IAU 50/100 schemes are mainly due to different model integration time and different instability (density inversion, large vertical velocity, etc.) induced by the increment update. The longer model integration time with the IAU 50/100 schemes, especially the free model integration, on one hand, allows for better re-establishment of the equilibrium model state, on the other hand, smooths the strong gradients in dynamically active region.

  13. Understanding the types of fraud in claims to South African medical schemes.

    Science.gov (United States)

    Legotlo, T G; Mutezo, A

    2018-03-28

    Medical schemes play a significant role in funding private healthcare in South Africa (SA). However, the sector is negatively affected by the high rate of fraudulent claims. To identify the types of fraudulent activities committed in SA medical scheme claims. A cross-sectional qualitative study was conducted, adopting a case study strategy. A sample of 15 employees was purposively selected from a single medical scheme administration company in SA. Semi-structured interviews were conducted to collect data from study participants. A thematic analysis of the data was done using ATLAS.ti software (ATLAS.ti Scientific Software Development, Germany). The study population comprised the 17 companies that administer medical schemes in SA. Data were collected from 15 study participants, who were selected from the medical scheme administrator chosen as a case study. The study found that medical schemes were defrauded in numerous ways. The perpetrators of this type of fraud include healthcare service providers, medical scheme members, employees, brokers and syndicates. Medical schemes are mostly defrauded by the submission of false claims by service providers and syndicates. Fraud committed by medical scheme members encompasses the sharing of medical scheme benefits with non-members (card farming) and non-disclosure of pre-existing conditions at the application stage. The study concluded that perpetrators of fraud have found several ways of defrauding SA medical schemes regarding claims. Understanding and identifying the types of fraud events facing medical schemes is the initial step towards establishing methods to mitigate this risk. Future studies should examine strategies to manage fraudulent medical scheme claims.

  14. Key Concepts in Microbial Oceanography

    Science.gov (United States)

    Bruno, B. C.; Achilles, K.; Walker, G.; Weersing, K.; Team, A

    2008-12-01

    The Center for Microbial Oceanography: Research and Education (C-MORE) is a multi-institution Science and Technology Center, established by the National Science Foundation in 2006. C-MORE's research mission is to facilitate a more comprehensive understanding of the diverse assemblages of microorganisms in the sea, ranging from the genetic basis of marine microbial biogeochemistry including the metabolic regulation and environmental controls of gene expression, to the processes that underpin the fluxes of carbon, related bioelements, and energy in the marine environment. The C-MORE education and outreach program is focused on increasing scientific literacy in microbial oceanography among students, educators, and the general public. A first step toward this goal is defining the key concepts that constitute microbial oceanography. After lengthy discussions with scientists and educators, both within and outside C-MORE, we have arrived at six key concepts: 1) Marine microbes are very small and have been around for a long time; 2) Life on Earth could not exist without microbes; 3) Most marine microbes are beneficial; 4) Microbes are everywhere: they are extremely abundant and diverse; 5) Microbes significantly impact our global climate; and 6) There are new discoveries every day in the field of microbial oceanography. A C-MORE-produced brochure on these six key concepts will be distributed at the meeting. Advanced copies may be requested by email or downloaded from the C-MORE web site(http://cmore.soest.hawaii.edu/downloads/MO_key_concepts_hi-res.pdf). This brochure also includes information on career pathways in microbial oceanography, with the aim of broadening participation in the field. C-MORE is eager to work in partnership to incorporate these key concepts into other science literacy publications, particularly those involving ocean and climate literacy. We thank the following contributors and reviewers: P Chisholm, A Dolberry, and A Thompson (MIT); N Lawrence

  15. Key on demand (KoD) for software-defined optical networks secured by quantum key distribution (QKD).

    Science.gov (United States)

    Cao, Yuan; Zhao, Yongli; Colman-Meixner, Carlos; Yu, Xiaosong; Zhang, Jie

    2017-10-30

    Software-defined optical networking (SDON) will become the next generation optical network architecture. However, the optical layer and control layer of SDON are vulnerable to cyberattacks. While, data encryption is an effective method to minimize the negative effects of cyberattacks, secure key interchange is its major challenge which can be addressed by the quantum key distribution (QKD) technique. Hence, in this paper we discuss the integration of QKD with WDM optical networks to secure the SDON architecture by introducing a novel key on demand (KoD) scheme which is enabled by a novel routing, wavelength and key assignment (RWKA) algorithm. The QKD over SDON with KoD model follows two steps to provide security: i) quantum key pools (QKPs) construction for securing the control channels (CChs) and data channels (DChs); ii) the KoD scheme uses RWKA algorithm to allocate and update secret keys for different security requirements. To test our model, we define a security probability index which measures the security gain in CChs and DChs. Simulation results indicate that the security performance of CChs and DChs can be enhanced by provisioning sufficient secret keys in QKPs and performing key-updating considering potential cyberattacks. Also, KoD is beneficial to achieve a positive balance between security requirements and key resource usage.

  16. Ancel Keys: a tribute

    Directory of Open Access Journals (Sweden)

    VanItallie Theodore B

    2005-02-01

    Full Text Available Abstract Ancel Keys, Ph.D., who died in November, 2004, at the age of 100, was among the first scientists to recognize that human atherosclerosis is not an inevitable consequence of aging, and that a high-fat diet can be a major risk factor for coronary heart disease. During World War II, he and a group of talented co-workers at the University of Minnesota conducted a large-scale study of experimentally-induced human starvation. The data generated by this study – which was immediately recognized to be a classic – continue to be of inestimable value to nutrition scientists. In his later years, Keys spent more time at his home in Naples, Italy, where he had the opportunity to continue his personal study of the beneficial effects on health and longevity of a Mediterranean diet.

  17. Physician Appraisals: Key Challenges

    Directory of Open Access Journals (Sweden)

    Klich Jacek

    2017-06-01

    Full Text Available The main purpose of the article is to identify key criteria being used for physician appraisals and to find how communication skills of physicians are valued in those appraisals. ScienceDirect and EBSCOhost databases were used for this search. The results show that a physician appraisal is underestimated both theoretically and empirically. The particular gap exists with respect to the communication skills of physicians, which are rarely present in medical training syllabi and physician assessments. The article contributes to the theoretical discourse on physician appraisals and points out at the inconsistency between the high status of physicians as a key hospital resource on the one hand and, on the other hand, at inadequate and poorly researched assessment of their performance with a special emphasis on communication skills. The article may inspire health managers to develop and implement up-to-date assessment forms for physicians and good managerial practices in this respect in hospitals and other health care units.

  18. Enhancing the performance of the measurement-device-independent quantum key distribution with heralded pair-coherent sources

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Feng; Zhang, Chun-Hui; Liu, Ai-Ping [Institute of Signal Processing Transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003 (China); Key Lab of Broadband Wireless Communication and Sensor Network Technology, Nanjing University of Posts and Telecommunications, Ministry of Education, Nanjing 210003 (China); Wang, Qin, E-mail: qinw@njupt.edu.cn [Institute of Signal Processing Transmission, Nanjing University of Posts and Telecommunications, Nanjing 210003 (China); Key Lab of Broadband Wireless Communication and Sensor Network Technology, Nanjing University of Posts and Telecommunications, Ministry of Education, Nanjing 210003 (China); Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026 (China)

    2016-04-01

    In this paper, we propose to implement the heralded pair-coherent source into the measurement-device-independent quantum key distribution. By comparing its performance with other existing schemes, we demonstrate that our new scheme can overcome many shortcomings existing in current schemes, and show excellent behavior in the quantum key distribution. Moreover, even when taking the statistical fluctuation into account, we can still obtain quite high key generation rate at very long transmission distance by using our new scheme. - Highlights: • Implement the heralded pair-coherent source into the measurement-device-independent quantum key distribution. • Overcome many shortcomings existing in current schemes and show excellent behavior. • Obtain quite high key generation rate even when taking statistical fluctuation into account.

  19. A General Construction of IND-CCA2 Secure Public Key Encryption

    DEFF Research Database (Denmark)

    Kiltz, Eike; Malone-Lee, John

    2003-01-01

    We propose a general construction for public key encryption schemes that are IND-CCA2 secure in the random oracle model. We show that the scheme proposed in [1, 2] fits our general framework and moreover that our method of analysis leads to a more efficient security reduction....

  20. Establishing Substantial Equivalence: Transcriptomics

    Science.gov (United States)

    Baudo, María Marcela; Powers, Stephen J.; Mitchell, Rowan A. C.; Shewry, Peter R.

    Regulatory authorities in Western Europe require transgenic crops to be substantially equivalent to conventionally bred forms if they are to be approved for commercial production. One way to establish substantial equivalence is to compare the transcript profiles of developing grain and other tissues of transgenic and conventionally bred lines, in order to identify any unintended effects of the transformation process. We present detailed protocols for transcriptomic comparisons of developing wheat grain and leaf material, and illustrate their use by reference to our own studies of lines transformed to express additional gluten protein genes controlled by their own endosperm-specific promoters. The results show that the transgenes present in these lines (which included those encoding marker genes) did not have any significant unpredicted effects on the expression of endogenous genes and that the transgenic plants were therefore substantially equivalent to the corresponding parental lines.