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Sample records for quantum secret sharing

  1. Circular threshold quantum secret sharing

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Guang; Wen Qiao-Yan

    2008-01-01

    This paper proposes a circular threshold quantum secret sharing (TQSS) scheme with polarized single photons.A polarized single photon sequence runs circularly among any t or more of n parties and any t or more of n parties can reconstruct the secret key when they collaborate.It shows that entanglement is not necessary for quantum secret sharing.Moreover,the theoretic efficiency is improved to approach 100% as the single photons carrying the secret key are deterministically forwarded among any t or more of n parties,and each photon can carry one bit of information without quantum storage.This protocol is feasible with current technology.

  2. Quantum secret sharing with minimized quantum communication

    Science.gov (United States)

    Fortescue, Ben; Gour, Gilad

    2013-03-01

    Standard techniques for sharing a quantum secret among multiple players (such that certain subsets of the players can recover the secret while others are denied all knowledge of the secret) require a large amount of quantum communication to distribute the secret, which is likely to be the most costly resource in any practical scheme. Two known methods for reducing this cost are the use of imperfect ``ramp'' secret sharing (in which security is sacrificed for efficiency) and classical encryption (in which certain elements of the players' shares consist of classical information only). We demonstrate how one may combine these methods to reduce the required quantum communication below what has been previously achieved, in some cases to a provable minimum, without any loss of security. The techniques involved are closely-related to the properties of stabilizer codes, and thus have strong potential for being adapted to a wide range of quantum secret sharing schemes.

  3. Multiparty Quantum Secret Sharing of Quantum States with Quantum Registers

    Institute of Scientific and Technical Information of China (English)

    GUO Ying; ZENG Gui-Hua; CHEN Zhi-Gang

    2007-01-01

    A quantum secret sharing scheme is proposed by making use of quantum registers.In the proposed scheme,secret message state is encoded into multipartite entangled states.Several identical multi-particle entanglement states are generated and each particle of the entanglement state is filled in different quantum registers which act as shares of the secret message.Two modes,j.e.the detecting mode and the message mode,are employed so that the eavesdropping can be detected easily and the secret message may be recovered.The seeurity analysis shows that the proposed scheme is secure against eavesdropping of eavesdropper and cheating of participants.

  4. Secret Sharing of a Quantum State.

    Science.gov (United States)

    Lu, He; Zhang, Zhen; Chen, Luo-Kan; Li, Zheng-Da; Liu, Chang; Li, Li; Liu, Nai-Le; Ma, Xiongfeng; Chen, Yu-Ao; Pan, Jian-Wei

    2016-07-15

    Secret sharing of a quantum state, or quantum secret sharing, in which a dealer wants to share a certain amount of quantum information with a few players, has wide applications in quantum information. The critical criterion in a threshold secret sharing scheme is confidentiality: with less than the designated number of players, no information can be recovered. Furthermore, in a quantum scenario, one additional critical criterion exists: the capability of sharing entangled and unknown quantum information. Here, by employing a six-photon entangled state, we demonstrate a quantum threshold scheme, where the shared quantum secrecy can be efficiently reconstructed with a state fidelity as high as 93%. By observing that any one or two parties cannot recover the secrecy, we show that our scheme meets the confidentiality criterion. Meanwhile, we also demonstrate that entangled quantum information can be shared and recovered via our setting, which shows that our implemented scheme is fully quantum. Moreover, our experimental setup can be treated as a decoding circuit of the five-qubit quantum error-correcting code with two erasure errors.

  5. A new scheme for quantum secret sharing

    CERN Document Server

    Bagherinezhad, S; Bagherinezhad, Saber; Karimipour, Vahid

    2002-01-01

    We introduce a protocol for quantum secret sharing based on reusable entangled states. The entangled state between the sender and the receiver acts only as a carrier and no measurement is performed on this shared state. Half of the sequence of bits can be retrieved independently and for the other half the receivers need each other's assistance. We also show that the protocol is completely safe against eavesdropping.

  6. Quantum secret sharing based on quantum error-correcting codes

    Institute of Scientific and Technical Information of China (English)

    Zhang Zu-Rong; Liu Wei-Tao; Li Cheng-Zu

    2011-01-01

    Quantum secret sharing(QSS) is a procedure of sharing classical information or quantum information by using quantum states. This paper presents how to use a [2k - 1,1, k] quantum error-correcting code (QECC) to implement a quantum (k, 2k - 1) threshold scheme. It also takes advantage of classical enhancement of the [2k - 1, l,k] QECC to establish a QSS scheme which can share classical information and quantum information simultaneously. Because information is encoded into QECC, these schemes can prevent intercept-resend attacks and be implemented on some noisy channels.

  7. Quantum Secret Sharing by applying Analytic Geometry

    OpenAIRE

    Liu, Ruilong

    2010-01-01

    In this paper, we investigate a novel $(2,2)$-threshold scheme and then generalize this to a $(n,n)$-threshold scheme for quantum secret sharing (QSS) which makes use of the fundamentals of Analytic Geometry. The dealer aptly selects GHZ states related to the coefficients which determine straight lines on a two-dimension plane. Then by computing each two of the lines intercept or not, we obtain a judging matrix whose rank can be used to determine the secret stored in entangled bits. Based on ...

  8. Multiparty quantum secret sharing of classical and quantum messages

    Institute of Scientific and Technical Information of China (English)

    CHEN Pan; DENG Fuguo; LONG Guilu

    2007-01-01

    A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum information between N agents. The security of our scheme is also confirmed.

  9. Multiparty Quantum Secret Sharing of Quantum States Using Entanglement States

    Institute of Scientific and Technical Information of China (English)

    GUO Ying; HUANG Da-Zu; ZENG Gui-Hua; LEE Moon Ho

    2008-01-01

    A multi-partite-controlled quantum secret sharing scheme using several non-orthogonal entanglement states is presented with unconditional security.In this scheme,the participants share the secret quantum state by exchanging the secret polarization angles of the disordered travel particles.The security of the secret quantum state is also guaranteed by the non-orthogonal multi-partite-controlled entanglement states,the participants'secret polarizations,and the disorder of the travelling particles.Moreover,the present scheme is secure against the particle-number splitting attack and the intercept-and-resend attack.It may be still secure even if the distributed quantum state is embedded in a not-so-weak coherent-state pulse.

  10. Experimental quantum secret sharing and third-man quantum cryptography.

    Science.gov (United States)

    Chen, Yu-Ao; Zhang, An-Ning; Zhao, Zhi; Zhou, Xiao-Qi; Lu, Chao-Yang; Peng, Cheng-Zhi; Yang, Tao; Pan, Jian-Wei

    2005-11-11

    Quantum secret sharing (QSS) and third-man quantum cryptography (TQC) are essential for advanced quantum communication; however, the low intensity and fragility of the multiphoton entanglement source in previous experiments have made their realization an extreme experimental challenge. Here, we develop and exploit an ultrastable high intensity source of four-photon entanglement to report an experimental realization of QSS and TQC. The technology developed in our experiment will be important for future multiparty quantum communication.

  11. Secret key generation via a modified quantum secret sharing protocol

    Science.gov (United States)

    Smith, A. M.; Evans, P. G.; Lawrie, B.; Legré, M.; Lougovski, P.; Ray, W.; Williams, B. P.; Qi, B.; Grice, W. P.

    2015-05-01

    We present and experimentally show a novel protocol for distributing secret information between two and only two parties in a N-party single-qubit Quantum Secret Sharing (QSS) system. We demonstrate this new algorithm with N = 3 active parties over ~6km of telecom. fiber. Our experimental device is based on the Clavis2 Quantum Key Distribution (QKD) system built by ID Quantique but is generalizable to any implementation. We show that any two out of the N parties can build secret keys based on partial information from each other and with collaboration from the remaining N - 2 parties. This algorithm allows for the creation of two-party secret keys were standard QSS does not and significantly reduces the number of resources needed to implement QKD on a highly connected network such as the electrical grid.

  12. Secret Key Generation via a Modified Quantum Secret Sharing Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Smith IV, Amos M [ORNL; Evans, Philip G [ORNL; Lawrie, Benjamin J [ORNL; Legre, Matthieu [ID Quantique, Inc.; Lougovski, Pavel [ORNL; Ray, William R [ORNL; Williams, Brian P [ORNL; Qi, Bing [ORNL; Grice, Warren P [ORNL

    2015-01-01

    We present and experimentally show a novel protocol for distributing secret information between two and only two parties in a N-party single-qubit Quantum Secret Sharing (QSS) system. We demonstrate this new algorithm with N = 3 active parties over 6km of telecom. ber. Our experimental device is based on the Clavis2 Quantum Key Distribution (QKD) system built by ID Quantique but is generalizable to any implementation. We show that any two out of the N parties can build secret keys based on partial information from each other and with collaboration from the remaining N > 2 parties. This algorithm allows for the creation of two-party secret keys were standard QSS does not and signicantly reduces the number of resources needed to implement QKD on a highly connected network such as the electrical grid.

  13. Quantum Secret Sharing with Error Correction

    Institute of Scientific and Technical Information of China (English)

    Aziz Mouzali; Fatiha Merazka; Damian Markham

    2012-01-01

    We investigate in this work a quantum error correction on a five-qubits graph state used for secret sharing through five noisy channels. We describe the procedure for the five, seven and nine qubits codes. It is known that the three codes always allow error recovery if only one among the sent qubits is disturbed in the transmitting channel. However, if two qubits and more are disturbed, then the correction will depend on the used code. We compare in this paper the three codes by computing the average fidelity between the sent secret and that measured by the receivers. We will treat the case where, at most, two qubits are affected in each one of five depolarizing channels.

  14. Multiparty Quantum Secret Sharing Using Quantum Fourier Transform

    Institute of Scientific and Technical Information of China (English)

    HUANG Da-Zu; CHEN Zhi-Gang; GUO Ying

    2009-01-01

    A (n, n )-threshold scheme of multiparty quantum secret sharing of classical or quantum message is proposed based on the discrete quantum Fourier transform.In our proposed scheme, the secret message, which is encoded by using the forward quantum Fourier transform and decoded by using the reverse, is split and shared in such a way that it can be reconstructed among them only if all the participants work in concert.Furthermore, we also discuss how this protocol must be carefully designed for correcting errors and checking eavesdropping or a dishonest participant.Security analysis shows that our scheme is secure.Also, this scheme has an advantage that it is completely compatible with quantum computation and easier to realize in the distributed quantum secure computation.

  15. Continuous-variable quantum secret sharing by optical interferometry

    CERN Document Server

    Tyc, T; Tyc, Tomas; Sanders, Barry C.

    2001-01-01

    We develop the theory of continuous-variable quantum secret sharing and propose its interferometric realization using passive and active optical elements. In the ideal case of infinite squeezing, a fidelity ${\\cal F}$ of unity can be achieved with respect to reconstructing the quantum secret. We quantify the reduction in fidelity for the (2,3) threshold scheme due to finite squeezing and establish the condition for verifying that genuine quantum secret sharing has occurred.

  16. Quantum Secret Sharing Based on Chinese Remainder Theorem

    Institute of Scientific and Technical Information of China (English)

    SHI Rong-Hua; SU Qian; GUO Ying; LEE Moon Ho

    2011-01-01

    A novel quantum secret sharing (QSS) scheme is proposed on the basis of Chinese Remainder Theorem (CRT).In the scheme, the classical messages are mapped to secret sequences according to CRT equations, and distributed to different receivers by different dimensional superdense-coding respectively.CRT's secret sharing function, together with high-dimensional superdense-coding, provide convenience, security, and large capability quantum channel for secret distribution and recovering.Analysis shows the security of the scheme.

  17. Verifiable Quantum ( k, n)-threshold Secret Key Sharing

    Science.gov (United States)

    Yang, Yu-Guang; Teng, Yi-Wei; Chai, Hai-Ping; Wen, Qiao-Yan

    2011-03-01

    Based on Lagrange interpolation formula and the post-verification mechanism, we show how to construct a verifiable quantum ( k, n) threshold secret key sharing scheme. Compared with the previous secret sharing protocols, ours has the merits: (i) it can resist the fraud of the dealer who generates and distributes fake shares among the participants during the secret distribution phase; Most importantly, (ii) It can check the cheating of the dishonest participant who provides a false share during the secret reconstruction phase such that the authorized group cannot recover the correct secret.

  18. Experimental demonstration of graph-state quantum secret sharing

    CERN Document Server

    Bell, B A; Herrera-Martí, D A; Marin, A; Wadsworth, W J; Rarity, J G; Tame, M S

    2014-01-01

    Distributed quantum communication and quantum computing offer many new opportunities for quantum information processing. Here networks based on highly nonlocal quantum resources with complex entanglement structures have been proposed for distributing, sharing and processing quantum information. Graph states in particular have emerged as powerful resources for such tasks using measurement-based techniques. We report an experimental demonstration of graph-state quantum secret sharing, an important primitive for a quantum network. We use an all-optical setup to encode quantum information into photons representing a five-qubit graph state. We are able to reliably encode, distribute and share quantum information between four parties. In our experiment we demonstrate the integration of three distinct secret sharing protocols, which allow for security and protocol parameters not possible with any single protocol alone. Our results show that graph states are a promising approach for sophisticated multi-layered protoc...

  19. Threshold Quantum Secret Sharing of Secure Direct Communication

    Institute of Scientific and Technical Information of China (English)

    LI Bao-Kui; YANG Yu-Guang; WEN Qiao-Yan

    2009-01-01

    We propose a (t, n)-threshold quantum secret sharing protocol of secure direct communication following some ideas of Zhang's protocol [Phys. Lett. A 342 (2005) 60] and Tokunaga et al.'s protocol [Phys. Rev. A 71 (2005) 012314]. The sender distributes the classical secret shares to his or her n agents and each agent owns a secret share in advance. The sender's secure direct communication message can be extracted by an agent subset by collaboration in such a way that at least t or more agents can obtain the secret message with the mutual assistances but any t - 1 or fewer agents cannot. In contrast to the previous multiparty quantum secret sharing protocols in which the sender's secret message can be recovered only if all the agents collaborate, our protocol is more practical and more flexible.

  20. Continuous Variables (2,3) Threshold Quantum Secret Sharing Schemes

    CERN Document Server

    Lance, A M; Bowen, W P; Tyc, T; Sanders, B C; Lam, P K

    2003-01-01

    We present two experimental schemes to perform continuous variable (2,3) threshold quantum secret sharing on the quadratures amplitudes of bright light beams. Both schemes require a pair of entangled light beams. The first scheme utilizes two phase sensitive optical amplifiers, whilst the second uses an electro-optic feedforward loop for the reconstruction of the secret. We examine the efficacy of quantum secret sharing in terms of fidelity, as well as the signal transfer coefficients and the conditional variances of the reconstructed output state. We show that both schemes in the ideal case yield perfect secret reconstruction.

  1. Multi-group dynamic quantum secret sharing with single photons

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongwei [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Ma, Haiqiang, E-mail: hqma@bupt.edu.cn [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wei, Kejin [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Yang, Xiuqing [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2016-07-15

    In this letter, we propose a novel scheme for the realization of single-photon dynamic quantum secret sharing between a boss and three dynamic agent groups. In our system, the boss can not only choose one of these three groups to share the secret with, but also can share two sets of independent keys with two groups without redistribution. Furthermore, the security of communication is enhanced by using a control mode. Compared with previous schemes, our scheme is more flexible and will contribute to a practical application. - Highlights: • A multi-group dynamic quantum secret sharing with single photons scheme is proposed. • Any one of the groups can be chosen to share secret through controlling the polarization of photons. • Two sets of keys can be shared simultaneously without redistribution.

  2. Universal Three-Party Quantum Secret Sharing Against Collective Noise

    Institute of Scientific and Technical Information of China (English)

    YANG Yu-Guang; WANG Yuan; TENG Yi-Wei; WEN Qiao-Yan

    2011-01-01

    we present a robust and universal quantum secret sharing protocol with four-qubit decoherence-free (DF) states against collective noise. The transmission's safety is ensured by the nonorthogonality of the noiseless states traveling on the quantum channel. Although this scheme uses entangled states for encoding, only single-particle product measurements are required.

  3. Scheme for implementing quantum secret sharing via cavity QED

    Institute of Scientific and Technical Information of China (English)

    Chen Zhi-Hua; Lin Xiu-Min

    2005-01-01

    An experimentally feasible scheme for implementing quantum secret sharing via cavity quantum electrodynamics (QED) is proposed. The scheme requires the large detuning of the cavity field from the atomic transition, the cavity is only virtually excited, thus the requirement on the quality factor of the cavity is greatly loosened.

  4. Participant attack on quantum secret sharing based on entanglement swapping

    Institute of Scientific and Technical Information of China (English)

    Song Ting-Ting; Zhang Jie; Gao Fei; Wen Qiao-Yan; Zhu Fu-Chen

    2009-01-01

    The security of quantum secret sharing based on entanglement swapping is revisited and a participant attack is presented.In this attack two dishonest agents together can illegally recover the secret quantum state without the help of any other controller,and it will not be detected by any othcr users.Furthermore,by modifying the distribution process of particles and adding a detection step after each distribution process,we propose an improved protocol which can resist this kind of attack.

  5. Multiparty simultaneous quantum identity authentication with secret sharing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented. All the users can be authenticated by a trusted third party (TTP) simultaneously. In the first protocol,the TTP shares a random key K with all the users using quantum secret sharing. The ith share acts as the authentication key of the ith user. When it is necessary to perform MSQIA,the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users. According to his share,each user performs the corresponding unitary operations on the single photon sequence sequentially. At last,the TTP can judge whether the impersonator exists. The sec-ond protocol is a modified version with a circular structure. The two protocols can be efficiently used for MSQIA in a network. They are feasible with current technol-ogy.

  6. Multiparty simultaneous quantum identity authentication with secret sharing

    Institute of Scientific and Technical Information of China (English)

    YANG YuGuang; WEN QiaoYan; ZHANG Xing

    2008-01-01

    Two multiparty simultaneous quantum identity authentication (MSQIA) protocols based on secret sharing are presented.All the users can be authenticated by a trusted third party (TTP) simultaneously.In the first protocol, the TTP shares a random key K with all the users using quantum secret sharing.The ith share acts as the authentication key of the ith user.When it is necessary to perform MSQIA, the TTP generates a random number R secretly and sends a sequence of single photons encoded with K and R to all the users.According to his share, each user performs the corresponding unitary operations on the single photon sequence sequentially.At last, the TTP can judge whether the impersonator exists.The sec-ond protocol is a modified version with a circular structure.The two protocols can be efficiently used for MSQIA in a network.They are feasible with current technol-ogy.

  7. Quantum Secret Sharing with Two-Particle Entangled States

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-Tao; LIANG Lin-Mei; LI Cheng-Zu; YUAN Jian-Min

    2006-01-01

    We present a new protocol for the quantum secret sharing (QSS) task among multiparties with two-particle entangled states. In our scheme, the secret is split among a number of participating partners and the reconstruction requires collaboration of all the authorized partners. Instead of multiparticle Greenberger-Horne-Zeilinger states,only two-particle entangled states are employed in this scheme. By local operations and individual measurements on either of the two entangled particles, each authorized partner obtains a sequence of secret bits shared with other authorized partners. This protocol can be experimentally realized using only linear optical elements and simple entanglement source. It is scalable in practice.

  8. Efficient sharing of a continuous-variable quantum secret

    CERN Document Server

    Tyc, T; Sanders, B C; Tyc, Tomas; Rowe, David J.; Sanders, Barry C.

    2003-01-01

    We propose an efficient scheme for sharing a continuous variable quantum secret using passive optical interferometry and squeezers: this efficiency is achieved by showing that a maximum of two squeezers is required to replicate the secret state, and we obtain the cheapest configuration in terms of total squeezing cost. Squeezing is a cost for the dealer of the secret as well as for the receivers, and we quantify limitations to the fidelity of the replicated secret state in terms of the squeezing employed by the dealer.

  9. Multi-group dynamic quantum secret sharing with single photons

    Science.gov (United States)

    Liu, Hongwei; Ma, Haiqiang; Wei, Kejin; Yang, Xiuqing; Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu

    2016-07-01

    In this letter, we propose a novel scheme for the realization of single-photon dynamic quantum secret sharing between a boss and three dynamic agent groups. In our system, the boss can not only choose one of these three groups to share the secret with, but also can share two sets of independent keys with two groups without redistribution. Furthermore, the security of communication is enhanced by using a control mode. Compared with previous schemes, our scheme is more flexible and will contribute to a practical application.

  10. Quantum secret sharing using the d-dimensional GHZ state

    Science.gov (United States)

    Bai, Chen-Ming; Li, Zhi-Hui; Xu, Ting-Ting; Li, Yong-Ming

    2017-03-01

    We propose a quantum secret sharing scheme that uses an orthogonal pair of n-qudit GHZ states and local distinguishability. In the proposed protocol, the participants use an X-basis measurement and classical communication to distinguish between the two orthogonal states and reconstruct the original secret. We also present (2, n)-threshold and generalized restricted (2, n)-threshold schemes that enable any two cooperating players from two disjoint groups to always reconstruct the secret. Compared to the existing scheme by Rahaman and Parker (Phys Rev A 91:022330, 2015), the proposed scheme is more general and the access structure contains more authorized sets.

  11. A kind of universal quantum secret sharing protocol

    Science.gov (United States)

    Chen, Xiu-Bo; Dou, Zhao; Xu, Gang; He, Xiao-Yu; Yang, Yi-Xian

    2017-01-01

    Universality is an important feature, but less researched in quantum communication protocols. In this paper, a kind of universal quantum secret sharing protocol is investigated. Firstly, we design a quantum secret sharing protocol based on the Borras-Plastino-Batle (BPB) state. Departing from previous research, our protocol has a salient feature in that participants in our protocol only need projective measurement instead of any unitary operations. It makes our protocol more flexible. Secondly, universality of quantum communication protocols is studied for the first time. More specifically, module division of quantum communication protocols and coupling between different modules are discussed. Our aforementioned protocol is analyzed as an example. On one hand, plenty of quantum states (the BPB-class states and the BPB-like-class states, which are proposed in this paper) could be used as carrier to perform our protocol. On the other hand, our protocol also could be regarded as a quantum private comparison protocol with a little revision. These features are rare for quantum communication protocols, and make our protocol more robust. Thirdly, entanglements of the BPB-class states are calculated in the Appendix.

  12. A kind of universal quantum secret sharing protocol.

    Science.gov (United States)

    Chen, Xiu-Bo; Dou, Zhao; Xu, Gang; He, Xiao-Yu; Yang, Yi-Xian

    2017-01-12

    Universality is an important feature, but less researched in quantum communication protocols. In this paper, a kind of universal quantum secret sharing protocol is investigated. Firstly, we design a quantum secret sharing protocol based on the Borras-Plastino-Batle (BPB) state. Departing from previous research, our protocol has a salient feature in that participants in our protocol only need projective measurement instead of any unitary operations. It makes our protocol more flexible. Secondly, universality of quantum communication protocols is studied for the first time. More specifically, module division of quantum communication protocols and coupling between different modules are discussed. Our aforementioned protocol is analyzed as an example. On one hand, plenty of quantum states (the BPB-class states and the BPB-like-class states, which are proposed in this paper) could be used as carrier to perform our protocol. On the other hand, our protocol also could be regarded as a quantum private comparison protocol with a little revision. These features are rare for quantum communication protocols, and make our protocol more robust. Thirdly, entanglements of the BPB-class states are calculated in the Appendix.

  13. Jones index, secret sharing and total quantum dimension

    Science.gov (United States)

    Fiedler, Leander; Naaijkens, Pieter; Osborne, Tobias J.

    2017-02-01

    We study the total quantum dimension in the thermodynamic limit of topologically ordered systems. In particular, using the anyons (or superselection sectors) of such models, we define a secret sharing scheme, storing information invisible to a malicious party, and argue that the total quantum dimension quantifies how well we can perform this task. We then argue that this can be made mathematically rigorous using the index theory of subfactors, originally due to Jones and later extended by Kosaki and Longo. This theory provides us with a ‘relative entropy’ of two von Neumann algebras and a quantum channel, and we argue how these can be used to quantify how much classical information two parties can hide form an adversary. We also review the total quantum dimension in finite systems, in particular how it relates to topological entanglement entropy. It is known that the latter also has an interpretation in terms of secret sharing schemes, although this is shown by completely different methods from ours. Our work provides a different and independent take on this, which at the same time is completely mathematically rigorous. This complementary point of view might be beneficial, for example, when studying the stability of the total quantum dimension when the system is perturbed.

  14. Eavesdropping in a quantum secret sharing protocol based on Grover algorithm and its solution

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A detailed analysis has showed that the quantum secret sharing protocol based on the Grover algorithm (Phys Rev A, 2003, 68: 022306) is insecure. A dishonest receiver may obtain the full information without being detected. A quantum secret-sharing protocol is presents here, which mends the security loophole of the original secret-sharing protocol, and doubles the information capacity.

  15. An efficient quantum secret sharing protocol with orthogonal product states

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An efficient quantum secret sharing protocol with orthogonal product states in the 33 Hilbert space is presented. The particles in the orthogonal product states form two particle sequences. One sequence is sent to Bob and the other is sent to Charlie after rearranging the particle orders. With the help of Alice, Bob and Charlie make the corresponding local measurement to obtain the information of the or- thogonal product states prepared. This protocol has many distinct features such as great capacity and high efficiency.

  16. An efficient quantum secret sharing protocol with orthogonal product states

    Institute of Scientific and Technical Information of China (English)

    YANG YuGuang; WEN QiaoYan; ZHU FuChen

    2007-01-01

    An efficient quantum secret sharing protocol with orthogonal product states in the 3(×)3 Hilbert space is presented. The particles in the orthogonal product states form two particle sequences. One sequence is sent to Bob and the other is sent to Charlie after rearranging the particle orders. With the help of Alice, Bob and Charlie make the corresponding local measurement to obtain the information of the orthogonal product states prepared. This protocol has many distinct features such as great capacity and high efficiency.

  17. Attack on the Enhanced Multiparty Quantum Secret Sharing

    Institute of Scientific and Technical Information of China (English)

    杨帅; 陈秀波; 杨义先

    2012-01-01

    Recently, Gao et al.'s [Commun. Theor. Phys. 52 (2009) 421] multiparty quantum secret sharing (MQSS) protocol with two-photon three-dimensional Bell states was enhanced by Hwang et al. [Commun. Theor. Phys. 56 (2011) 79]. The improved protocol removes some unnecessary unitary operations, devices, and transmissions by the technique of decoy single photons and careful modification. However, in this paper, we investigate the security of the improved protocol and find it is insecure. The eavesdropper can steal all Alice's secret information. Furthermore, a feasible modification to remedy the security loophole is put forward. Our improved protocol provides a basic method to modify a kind of MQSS protocols which cannot resist the collusion attack.

  18. Authenticated quantum secret sharing with quantum dialogue based on Bell states

    Science.gov (United States)

    Abulkasim, Hussein; Hamad, Safwat; El Bahnasy, Khalid; Rida, Saad Z.

    2016-08-01

    This work proposes a scheme that combines the advantages of a quantum secret sharing procedure and quantum dialogue. The proposed scheme enables the participants to simultaneously make mutual identity authentications, in a simulated scenario where the boss, Alice, shares a secret with her two agents Bob and Charlie. The secret is protected by checking photons to keep untrustworthy agents and outer attacks from getting useful information. Before the two agents cooperate to recover Alice’s secret, they must authenticate their identity using parts of a pre-shared key. In addition, the whole pre-shared key is reused as part of recovering the secret data to avoid any leaks of information. In comparison with previous schemes, the proposed method can efficiently detect eavesdropping and it is free from information leaks. Furthermore, the proposed scheme proved to be secure against man-in-the-middle attacks, impersonation attacks, entangled-and-measure attacks, participant attacks, modification attacks and Trojan-horse attacks.

  19. Multiparty Quantum Secret Sharing of Classical Message using Cavity Quantum Electrodynamic System

    Institute of Scientific and Technical Information of China (English)

    HAN Lian-Fang; LIU Yi-Min; ZHANG Zhan-Jun

    2006-01-01

    @@ An experimental feasible scheme of multiparty secret sharing of classical messages is proposed, based on a cavity quantum electrodynamic system. The secret messages are imposed on atomic Bell states initially in the sender's possession by local unitary operations. By swapping quantum entanglement of atomic Bell states, the secret messages are split into several parts and each part is distributed to a separate party. In this case, any subset of the entire party group can not read out the secret message but the entirety via mutual cooperations. In this scheme, to discriminate atomic Bell states, additional classical fields are employed besides the same highly-detuned single-mode cavities used to prepare atomic Bell states. This scheme is insensitive to the cavity decay and the thermal field, and usual joint Bell-state measurements are unnecessary.

  20. Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding

    Science.gov (United States)

    Lai, Hong; Zhang, Jun; Luo, Ming-Xing; Pan, Lei; Pieprzyk, Josef; Xiao, Fuyuan; Orgun, Mehmet A.

    2016-08-01

    With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.

  1. Unconditional security of entanglement-based continuous-variable quantum secret sharing

    Science.gov (United States)

    Kogias, Ioannis; Xiang, Yu; He, Qiongyi; Adesso, Gerardo

    2017-01-01

    The need for secrecy and security is essential in communication. Secret sharing is a conventional protocol to distribute a secret message to a group of parties, who cannot access it individually but need to cooperate in order to decode it. While several variants of this protocol have been investigated, including realizations using quantum systems, the security of quantum secret sharing schemes still remains unproven almost two decades after their original conception. Here we establish an unconditional security proof for entanglement-based continuous-variable quantum secret sharing schemes, in the limit of asymptotic keys and for an arbitrary number of players. We tackle the problem by resorting to the recently developed one-sided device-independent approach to quantum key distribution. We demonstrate theoretically the feasibility of our scheme, which can be implemented by Gaussian states and homodyne measurements, with no need for ideal single-photon sources or quantum memories. Our results contribute to validating quantum secret sharing as a viable primitive for quantum technologies.

  2. New Protocols and Lower Bound for Quantum Secret Sharing with Graph States

    CERN Document Server

    Javelle, Jérôme; Perdrix, Simon

    2011-01-01

    We introduce a new family of quantum secret sharing protocols with limited quantum resources which extends the protocols proposed by Markham and Sanders and by Broadbent, Chouha, and Tapp. Parametrized by a graph G and a subset of its vertices A, the protocol consists in: (i) encoding the quantum secret into the corresponding graph state by acting on the qubits in A; (ii) use a classical encoding to ensure the existence of a threshold. These new protocols realize ((k,n)) quantum secret sharing i.e., any set of at least k players among n can reconstruct the quantum secret, whereas any set of less than k players has no information about the secret. In the particular case where the secret is encoded on all the qubits, we explore the values of k for which there exists a graph such that the corresponding protocol realizes a ((k,n)) secret sharing. We show that for any threshold k> n-n^{0.68} there exists a graph allowing a ((k,n)) protocol. On the other hand, we prove that for any kn_0.

  3. Two new Controlled not Gate Based Quantum Secret Sharing Protocols without Entanglement Attenuation

    Science.gov (United States)

    Zhu, Zhen-Chao; Hu, Ai-Qun; Fu, An-Min

    2016-05-01

    In this paper, we propose two new controlled not gate based quantum secret sharing protocols. In these two protocols, each photon only travels once, which guarantees the agents located in long distance can be able to derive the dealer's secret without suffering entanglement attenuation problem. The protocols are secure against trojan horse attack, intercept-resend attack, entangle-measure attack and entanglement-swapping attack. The theoretical efficiency for qubits of these two protocols can approach 100 %, except those used for eavesdropping checking, all entangled states can be used for final secret sharing.

  4. Graph State-Based Quantum Secret Sharing with the Chinese Remainder Theorem

    Science.gov (United States)

    Guo, Ying; Luo, Peng; Wang, Yijun

    2016-07-01

    Quantum secret sharing (QSS) is a significant quantum cryptography technology in the literature. Dividing an initial secret into several sub-secrets which are then transferred to other legal participants so that it can be securely recovered in a collaboration fashion. In this paper, we develop a quantum route selection based on the encoded quantum graph state, thus enabling the practical QSS scheme in the small-scale complex quantum network. Legal participants are conveniently designated with the quantum route selection using the entanglement of the encoded graph states. Each participant holds a vertex of the graph state so that legal participants are selected through performing operations on specific vertices. The Chinese remainder theorem (CRT) strengthens the security of the recovering process of the initial secret among the legal participants. The security is ensured by the entanglement of the encoded graph states that are cooperatively prepared and shared by legal users beforehand with the sub-secrets embedded in the CRT over finite fields.

  5. Graph State-Based Quantum Secret Sharing with the Chinese Remainder Theorem

    Science.gov (United States)

    Guo, Ying; Luo, Peng; Wang, Yijun

    2016-11-01

    Quantum secret sharing (QSS) is a significant quantum cryptography technology in the literature. Dividing an initial secret into several sub-secrets which are then transferred to other legal participants so that it can be securely recovered in a collaboration fashion. In this paper, we develop a quantum route selection based on the encoded quantum graph state, thus enabling the practical QSS scheme in the small-scale complex quantum network. Legal participants are conveniently designated with the quantum route selection using the entanglement of the encoded graph states. Each participant holds a vertex of the graph state so that legal participants are selected through performing operations on specific vertices. The Chinese remainder theorem (CRT) strengthens the security of the recovering process of the initial secret among the legal participants. The security is ensured by the entanglement of the encoded graph states that are cooperatively prepared and shared by legal users beforehand with the sub-secrets embedded in the CRT over finite fields.

  6. High-dimension multiparty quantum secret sharing scheme with Einstein-Podolsky-Rosen pairs

    Institute of Scientific and Technical Information of China (English)

    Chen Pan; Deng Fu-Guo; Long Gui-Lu

    2006-01-01

    In this paper a high-dimension multiparty quantum secret sharing scheme is proposed by using Einstein-Podolsky-Rosen pairs and local unitary operators. This scheme has the advantage of not only having higher capacity, but also saving storage space. The security analysis is also given.

  7. Dynamic quantum secret sharing by using d-dimensional GHZ state

    Science.gov (United States)

    Qin, Huawang; Dai, Yuewei

    2017-03-01

    Through generating the d-dimensional GHZ state in the Z-basis and measuring it in the X-basis, a dynamic quantum secret sharing scheme is proposed. In the proposed scheme, multiple participants can be added or deleted in one update period, and the shared secret does not need to be changed. The participants can be added or deleted by themselves, and the dealer does not need to be online. Compared to the existing schemes, the proposed scheme is more efficient and more practical.

  8. High-capacity three-party quantum secret sharing with superdense coding

    Institute of Scientific and Technical Information of China (English)

    Gu Bin; Li Chuan-Qi; Xu Fei; Chen Yu-Lin

    2009-01-01

    This paper presents a scheme for high-capacity three-party quantum secret sharing with quantum superdense coding, following some ideas in the work by Liu et al (2002 Phys. Rev. A 65 022304) and the quantum secret sharing scheme by Deng et al (2008 Phys. Left. A 372 1957). Instead of using two sets of nonorthogonal states, the boss Alice needs only to prepare a sequence of Einstein-Podolsky-Rosen pairs in d-dimension. The two agents Bob and Charlie encode their information with dense coding unitary operations, and security is checked by inserting decoy photons. The scheme has a high capacity and intrinsic efficiency as each pair can carry 21bd bits of information, and almost all the pairs can be used for carrying useful information.

  9. Quantum secret sharing between m-party and n-party with six states

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A quantum secret sharing scheme between an m-party group and an n-party group is proposed using three conjugate bases.A sequence of single photons,each of which is prepared in one of the six states,is used directly to encode classical information in the quantum secret sharing process.In this scheme,each of all m members in group 1 chooses randomly his/her own secret key individually and independently,and directly encodes his/her respective secret information on the states of single photons via unitary operations,then the last one sends 1/n of the resulting qubits to each member of group 2.By measuring their respective qubits,all members in group 2 share the secret information shared by all members in group 1.It renders impossible a Trojan horse attack with a multi-photon signal,a fake-signal attack with EPR pairs,an attack with single photons,and an attack with invisible photons.We give the upper bounds on the average success probabilities for dishonest agent eavesdropping encryption using the fake-signal attack with any two-particle entangled states.

  10. Quantum Secret Sharing Protocol between Multiparty and Multiparty with Single Photons and Unitary Transformations

    Institute of Scientific and Technical Information of China (English)

    YAN Feng-Li; GAO Ting; LI You-Cheng

    2008-01-01

    @@ We propose a scheme of quantum secret sharing between Alice's group and Bob's group with single photons and unitary transformations. In the protocol, one member in Alice's group prepares a sequence of single photons in one of four different states, while other members directly encode their information on the sequence of single photons via unitary operations; after that, the last member sends the sequence of single photons to Bob's group.Then Bob's, except for the last one, do work similarly. Finally the last member in Bob's group measures the qubits. If the security of the quantum channel is guaranteed by some tests, then the qubit states sent by the last member of Alice's group can be used as key bits for secret sharing. It is shown that this scheme is safe.

  11. Cryptanalysis and improvement of a quantum secret sharing scheme based on x-type entangled states

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhen-Chao; Zhang Yu-Qing; Fu An-Min

    2012-01-01

    In the paper [2010 Chin.Phys.B 19 050306],Yang et al.put forward a novel three-party quantum secret sharing protocol of secure direct communication based on x-type entangled states,they claimed that the scheme is secure.However,in this paper,we study the security of the protocol and find that it is insecure.Applying intercept and resend attack,the agent Bob can obtain Alice's secret without the help from the other agent Charlie.In the end,we give our effective modification for its improvement.

  12. Unbreakable distributed storage with quantum key distribution network and password-authenticated secret sharing.

    Science.gov (United States)

    Fujiwara, M; Waseda, A; Nojima, R; Moriai, S; Ogata, W; Sasaki, M

    2016-07-01

    Distributed storage plays an essential role in realizing robust and secure data storage in a network over long periods of time. A distributed storage system consists of a data owner machine, multiple storage servers and channels to link them. In such a system, secret sharing scheme is widely adopted, in which secret data are split into multiple pieces and stored in each server. To reconstruct them, the data owner should gather plural pieces. Shamir's (k, n)-threshold scheme, in which the data are split into n pieces (shares) for storage and at least k pieces of them must be gathered for reconstruction, furnishes information theoretic security, that is, even if attackers could collect shares of less than the threshold k, they cannot get any information about the data, even with unlimited computing power. Behind this scenario, however, assumed is that data transmission and authentication must be perfectly secure, which is not trivial in practice. Here we propose a totally information theoretically secure distributed storage system based on a user-friendly single-password-authenticated secret sharing scheme and secure transmission using quantum key distribution, and demonstrate it in the Tokyo metropolitan area (≤90 km).

  13. Unbreakable distributed storage with quantum key distribution network and password-authenticated secret sharing

    Science.gov (United States)

    Fujiwara, M.; Waseda, A.; Nojima, R.; Moriai, S.; Ogata, W.; Sasaki, M.

    2016-07-01

    Distributed storage plays an essential role in realizing robust and secure data storage in a network over long periods of time. A distributed storage system consists of a data owner machine, multiple storage servers and channels to link them. In such a system, secret sharing scheme is widely adopted, in which secret data are split into multiple pieces and stored in each server. To reconstruct them, the data owner should gather plural pieces. Shamir’s (k, n)-threshold scheme, in which the data are split into n pieces (shares) for storage and at least k pieces of them must be gathered for reconstruction, furnishes information theoretic security, that is, even if attackers could collect shares of less than the threshold k, they cannot get any information about the data, even with unlimited computing power. Behind this scenario, however, assumed is that data transmission and authentication must be perfectly secure, which is not trivial in practice. Here we propose a totally information theoretically secure distributed storage system based on a user-friendly single-password-authenticated secret sharing scheme and secure transmission using quantum key distribution, and demonstrate it in the Tokyo metropolitan area (≤90 km).

  14. Unbreakable distributed storage with quantum key distribution network and password-authenticated secret sharing

    Science.gov (United States)

    Fujiwara, M.; Waseda, A.; Nojima, R.; Moriai, S.; Ogata, W.; Sasaki, M.

    2016-01-01

    Distributed storage plays an essential role in realizing robust and secure data storage in a network over long periods of time. A distributed storage system consists of a data owner machine, multiple storage servers and channels to link them. In such a system, secret sharing scheme is widely adopted, in which secret data are split into multiple pieces and stored in each server. To reconstruct them, the data owner should gather plural pieces. Shamir’s (k, n)-threshold scheme, in which the data are split into n pieces (shares) for storage and at least k pieces of them must be gathered for reconstruction, furnishes information theoretic security, that is, even if attackers could collect shares of less than the threshold k, they cannot get any information about the data, even with unlimited computing power. Behind this scenario, however, assumed is that data transmission and authentication must be perfectly secure, which is not trivial in practice. Here we propose a totally information theoretically secure distributed storage system based on a user-friendly single-password-authenticated secret sharing scheme and secure transmission using quantum key distribution, and demonstrate it in the Tokyo metropolitan area (≤90 km). PMID:27363566

  15. Quantum-secret-sharing scheme based on local distinguishability of orthogonal multiqudit entangled states

    Science.gov (United States)

    Wang, Jingtao; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2017-02-01

    In this study, we propose the concept of judgment space to investigate the quantum-secret-sharing scheme based on local distinguishability (called LOCC-QSS). Because of the proposing of this conception, the property of orthogonal mutiqudit entangled states under restricted local operation and classical communication (LOCC) can be described more clearly. According to these properties, we reveal that, in the previous (k ,n )-threshold LOCC-QSS scheme, there are two required conditions for the selected quantum states to resist the unambiguous attack: (i) their k -level judgment spaces are orthogonal, and (ii) their (k -1 )-level judgment spaces are equal. Practically, if k security, i.e., even if the (k -1 )-level judgment spaces of the selected quantum states are not equal, these states can still be used for defeating the unambiguous attack. With this encoding method, we propose a more secure (k ,n )-threshold LOCC-QSS scheme, and give two specific examples for illustration.

  16. Efficient Multiparty Quantum Secret Sharing with Greenberger-Horne-Zeilinger States

    Institute of Scientific and Technical Information of China (English)

    DENG Fu-Guo; ZHOU Ping; LI Xi-Han; LI Chun-Yan; ZHOU Hong-Yu

    2006-01-01

    @@ An efficient multiparty quantum secret sharing scheme is proposed with Greenberger-Horne-Zeilinger (GHZ)states following some ideas in quantum dense coding. The agents take the single-photon measurements on the photons received for eavesdropping check and exploit the four local unitary operations I, σz, σx and iσy tocode their message. This scheme has the advantage of high capacity as each GHZ state can carry two bits of information. The parties do not need to announce the measuring bases for almost all the photons, which will reduce the classical information exchanged largely. The intrinsic efficiency for qubits and the total efficiency both approach the maximal values.

  17. Improving the security of multiparty quantum secret sharing against Trojan horse attack

    CERN Document Server

    Deng, F G; Deng, Fu-Guo; Zhou, Hong-Yu

    2005-01-01

    Security of the multiparty quantum secret sharing (MQSS) protocol recently proposed by Zhang et al. [Phys. Rev. A \\textbf{71}, 044301 (2005)] is analyzed in the case that the agent who prepares the quantum signal, say Bob wants to eavesdrop the information about the unitary operations done by the other agent, Charlie by using a Trojan horse attack. Bob can replace the single-photon signal with a multi-photon one and Charlie cannot find this cheating as she does not measure the photons before they runs back from the boss Alice, which reveals that this MQSS protocol is not secure. Finally, we present a possible improvement of the MQSS protocol security with two single-photon measurements and four unitary operations.

  18. Fault-Tolerate Three-Party Quantum Secret Sharing over a Collective-Noise Channel

    Institute of Scientific and Technical Information of China (English)

    LI Chun-Yan; LI Yan-Song

    2011-01-01

    We present a fault-tolerate three-party quantum secret sharing (QSS) scheme over a collective-noise channel.Decoherence-free subspaces are used to tolerate two noise modes, a collective-dephasing channel and a collective-rotating channel, respectively. In this scheme, the boss uses two physical qubits to construct a logical qubit which acts as a quantum channel to transmit one bit information to her two agents. The agents can get the information of the private key established by the boss only if they collaborate. The boss Alice encodes information with two unitary operations. Only single-photon measurements are required to rebuilt Alice's information and detect the security by the agents Bob and Charlie, not Bell-state measurements. Moreover, Almost all of the photons are used to distribute information, and its success efficiency approaches 100% in theory.%@@ We present a fault-tolerate three-party quantum secret sharing (QSS) scheme over a collective-noise channel.Decoherence-free subspaces are used to tolerate two noise modes, a collective-dephasing channel and a collective-rotating channel, respectively.In this scheme, the boss uses two physical qubits to construct a logical qubit which acts as a quantum channel to transmit one bit information to her two agents.The agents can get the information of the private key established by the boss only if they collaborate.The boss Alice encodes information with two unitary operations.Only single-photon measurements are required to rebuilt Alice's information and detect the security by the agents Bob and Charlie, not Bell-state measurements.Moreover, Almost all of the photons are used to distribute information, and its success efficiency approaches 100% in theory.

  19. Large-Capacity Three-Party Quantum Digital Secret Sharing Using Three Particular Matrices Coding

    Science.gov (United States)

    Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Tao, Li; Liu, Zhi-Ming; Orgun, Mehmet A.

    2016-11-01

    In this paper, we develop a large-capacity quantum digital secret sharing (QDSS) scheme, combined the Fibonacci- and Lucas-valued orbital angular momentum (OAM) entanglement with the recursive Fibonacci and Lucas matrices. To be exact, Alice prepares pairs of photons in the Fibonacci- and Lucas-valued OAM entangled states, and then allocates them to two participants, say, Bob and Charlie, to establish the secret key. Moreover, the available Fibonacci and Lucas values from the matching entangled states are used as the seed for generating the Fibonacci and Lucas matrices. This is achieved because the entries of the Fibonacci and Lucas matrices are recursive. The secret key can only be obtained jointly by Bob and Charlie, who can further recover the secret. Its security is based on the facts that nonorthogonal states are indistinguishable, and Bob or Charlie detects a Fibonacci number, there is still a twofold uncertainty for Charlie' (Bob') detected value. Supported by the Fundamental Research Funds for the Central Universities under Grant No. XDJK2016C043 and the Doctoral Program of Higher Education under Grant No. SWU115091, the National Natural Science Foundation of China under Grant No. 61303039, the Fundamental Research Funds for the Central Universities under Grant No. XDJK2015C153 and the Doctoral Program of Higher Education under Grant No. SWU114112, and the Financial Support the 1000-Plan of Chongqing by Southwest University under Grant No. SWU116007

  20. Multiparty Quantum Secret Report

    Institute of Scientific and Technical Information of China (English)

    DENG Fu-Guo; LI Xi-Han; LI Chun-Yan; ZHOU Ping; LIANG Yu-Jie; ZHOU Hong-Yu

    2006-01-01

    @@ A multiparty quantum secret report scheme is proposed with quantum encryption. The boss Alice and her M agents first share a sequence of (M + 1)-particle Greenberger-Horne-Zeilinger (GHZ) states that only Alice knows which state each (M + 1)-particle quantum system is in. Each agent exploits a controlled-not (CNot) gate to encrypt the travelling particle by using the particle in the GHZ state as the control qubit. The boss Alice decrypts the travelling particle with a CNot gate after performing a σx operation on her particle in the GHZ state or not.After the GHZ states (the quantum key) are used up, the parties check whether there is a vicious eavesdropper,say Eve, monitoring the quantum line, by picking out some samples from the GHZ states shared and measuring them with two measuring bases. After confirming the security of the quantum key, they use the remaining GHZ states repeatedly for the next round of quantum communication. This scheme has the advantage of high intrinsic efficiency for the qubits and total efficiency.

  1. Cryptanalysis and Improvement of Quantum Secret Sharing Protocol between Multiparty and Multiparty with Single Photons and Unitary Transformations

    Institute of Scientific and Technical Information of China (English)

    LIN Song; WEN Qiao-Yan; LIU Xiao-Fen

    2009-01-01

    In a recent paper[Yan F L et al.Chin.Phys.Lett.25(2008)1187],a quantum secret sharing the protocol between multiparty and multiparty with single photons and unitary transformations was presented.We analyze the security of the protocol and find that a dishonest participant can eavesdrop the key by using a special attack.Finally,we give a description of this strategy and put forward an improved version of this protocol which can stand against this kind of attack.

  2. Almost-perfect secret sharing

    CERN Document Server

    Kaced, Tarik

    2011-01-01

    Splitting a secret s between several participants, we generate (for each value of s) shares for all participants. The goal: authorized groups of participants should be able to reconstruct the secret but forbidden ones get no information about it. In this paper we introduce several notions of non- perfect secret sharing, where some small information leak is permitted. We study its relation to the Kolmogorov complexity version of secret sharing (establishing some connection in both directions) and the effects of changing the secret size (showing that we can decrease the size of the secret and the information leak at the same time).

  3. Information Flow in Secret Sharing Protocols

    CERN Document Server

    Kashefi, Elham; Mhalla, Mehdi; Perdrix, Simon

    2009-01-01

    The entangled graph states have emerged as an elegant and powerful quantum resource, indeed almost all multiparty protocols can be written in terms of graph states including measurement based quantum computation (MBQC), error correction and secret sharing amongst others. In addition they are at the forefront in terms of implementations. As such they represent an excellent opportunity to move towards integrated protocols involving many of these elements. In this paper we look at expressing and extending graph state secret sharing and MBQC in a common framework and graphical language related to flow. We do so with two main contributions. First we express in entirely graphical terms which set of players can access which information in graph state secret sharing protocols. These succinct graphical descriptions of access allow us to take known results from graph theory to make statements on the generalisation of the previous schemes to present new secret sharing protocols. Second, we give a set of necessary condit...

  4. Quantum secret sharing with quantum graph states%基于量子图态的量子秘密共享∗

    Institute of Scientific and Technical Information of China (English)

    梁建武; 程资; 石金晶; 郭迎

    2016-01-01

    Quantum secret sharing is an important way to achieve secure communications, which has critical applications in the field of information security for its physical properties. According to the perspective of the practical applications, improving the confidentiality and integrity of secret sharing schemes is a good method to increase the security and reliability of communications. In this paper, we propose a quantum secret sharing scheme based on generator matrix segmentation and the structural features of quantum graph states. The security of the secure secret sharing scheme is guaranteed by the pattern of transferring information by stabilizers, scalability of the information and new recovery strategy provided by the entanglement of the related graph states. It puts forward an effective solution to the problem of matrix cycle period, where some numbers without the primitive element cannot construct the generation matrix. First of all, the physical properties of quantum bits (qubits), such as uncertainty principle, no-cloning theorem and indistinguishability, not only optimize the classical schemes but also ensure the absolute safety of communication. Secondly, the application of matrix segmentation makes secret information has better scalability. It improves the coding diversity and the difficulty in deciphering. Thirdly, the favorable entanglement properties and mature experiment preparation techniques of graph states provide an approach to the practical applications. The superiority of the yielded graph states is described in graphical fashion with an elegant stabilizer. Fourthly, the shuffling operation can ensure the independence of the message among participants. Therefore, Eve can not obtain any useful information by measuring randomly. Two group-recovery protocols are proposed to show the secret recovering processing through rebuilding sub-secrets among legal cooperative participants. In the scheme design, the dealer extracts the classical secret information

  5. 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.

  6. An Image Secret Sharing Method

    Science.gov (United States)

    2006-07-01

    M. E. Hellman, “On secret sharing systems,” vol. IT-29, no. 1, pp. 35–41, Jan. 1983. [10] K. Kurosawa , K. Okada, K. Sakano, W. Ogata, and S. Tsujii...Ed., Berlin, Germany, 1994, pp. 1–12. [14] W. Ogata and K. Kurosawa , “Some ba- sic properties of general nonperfect secret sharing schemes,” J.UCS

  7. Secret sharing using biometric traits

    Science.gov (United States)

    Kholmatov, Alisher; Yanikoglu, Berrin; Savas, Erkay; Levi, Albert

    2006-04-01

    In biometric based authentication, biometric traits of a person are matched against his/her stored biometric profile and access is granted if there is sufficient match. However, there are other access scenarios, which require participation of multiple previously registered users for a successful authentication or to get an access grant for a certain entity. For instance, there are cryptographic constructs generally known as secret sharing schemes, where a secret is split into shares and distributed amongst participants in such a way that it is reconstructed/revealed only when the necessary number of share holders come together. The revealed secret can then be used for encryption or authentication (if the revealed key is verified against the previously registered value). In this work we propose a method for the biometric based secret sharing. Instead of splitting a secret amongst participants, as is done in cryptography, a single biometric construct is created using the biometric traits of the participants. During authentication, a valid cryptographic key is released out of the construct when the required number of genuine participants present their biometric traits.

  8. Continuous Variable Quantum State Sharing via Quantum Disentanglement

    CERN Document Server

    Lance, A M; Bowen, W P; Sanders, B C; Tyc, T; Ralph, T C; Lam, P K; Lance, Andrew M.; Symul, Thomas; Bowen, Warwick P.; Sanders, Barry C.; Tyc, Tomas; Ralph, Timothy C.; Lam, Ping Koy

    2004-01-01

    Quantum state sharing is a protocol where perfect reconstruction of quantum states is achieved with incomplete or partial information in a multi-partite quantum networks. Quantum state sharing allows for secure communication in a quantum network where partial information is lost or acquired by malicious parties. This protocol utilizes entanglement for the secret state distribution, and a class of "quantum disentangling" protocols for the state reconstruction. We demonstrate a quantum state sharing protocol in which a tripartite entangled state is used to encode and distribute a secret state to three players. Any two of these players can collaborate to reconstruct the secret state, whilst individual players obtain no information. We investigate a number of quantum disentangling processes and experimentally demonstrate quantum state reconstruction using two of these protocols. We experimentally measure a fidelity, averaged over all reconstruction permutations, of F = 0.73. A result achievable only by using quan...

  9. Secret sharing scheme with inherited characteristic

    Institute of Scientific and Technical Information of China (English)

    Ye Zhenjun; Meng Fanzhen

    2006-01-01

    To assure the shareholders can look for their "legal" attorneys to renew the secret, once the secret sharing scheme is initialized, a secret sharing scheme with inherited characteristic is constructed. In this scheme, each shareholder can produce a new share by his algorithm, which is equivalent to the primary one. Together with other shares, the primary secret can be renewed. Since this scheme is constructed not by replacing the primary share with a new share produced by the dealer in his primitive secret sharing scheme, so no matter how much shares the shareholder produces, these shares can not be gathered together to renew the secret in this scheme. Compared with the existing secret sharing schemes, this scheme provides more agility for the shareholders by investing each of them a function but not affect its security.

  10. Cheater identifiable visual secret sharing scheme

    Institute of Scientific and Technical Information of China (English)

    Gan Zhi; Chen Kefei

    2005-01-01

    The visual secret sharing scheme proposed by Naor and Shamir provides a way to encrypt a secret black-white image into shares. A qualified group of participants can recover the secret message without using any cryptographic computation. But the original scheme can easily be corrupted by malicious participant. We propose an extension of VSS(visual secret sharing) to identify cheaters before the secret is recovered. Without the need for any additional information and cryptographic computation, every participant can verify the validity of shares of other participants, thus the security of VSS is enhanced.

  11. Secret Sharing and Proactive Renewal of Shares in Hierarchical Groups

    CERN Document Server

    Naskar, Ruchira; 10.5121/ijcsit.2010.2312

    2010-01-01

    Secret sharing in user hierarchy represents a challenging area for research. Although a lot of work has already been done in this direc- tion, this paper presents a novel approach to share a secret among a hierarchy of users while overcoming the limitations of the already exist- ing mechanisms. Our work is based on traditional (k +1; n)-threshold secret sharing, which is secure as long as an adversary can compromise not more than k secret shares. But in real life it is often feasible for an adversary to obtain more than k shares over a long period of time. So, in our work we also present a way to overcome this vulnerability, while implementing our hierarchical secret sharing scheme. The use of Elliptic Curve Cryptography makes the computations easier and faster in our work.

  12. Linear multi-secret sharing schemes

    Institute of Scientific and Technical Information of China (English)

    XIAO Liangliang; LIU Mulan

    2005-01-01

    In this paper the linear multi-secret sharing schemes are studied by using monotone span programs. A relation between computing monotone Boolean functions by using monotone span programs and realizing multi-access structures by using linear multisecret sharing schemes is shown. Furthermore, the concept of optimal linear multi-secret sharing scheme is presented and the several schemes are proved to be optimal.

  13. DYNAMIC AND VERIFIABLE SECRET SHARING AMONG WEIGHTED PARTICIPANTS

    Institute of Scientific and Technical Information of China (English)

    Yanshuo ZHANG; Zhuojun LIU

    2007-01-01

    A secret sharing scheme permits a secret to be shared among participants in such a way that only qualified subsets of participants can recover the secret. Secret sharing is useful in management of cryptographic keys. Based on identity, we analyze the secret sharing scheme among weighted participants. Then we present a dynamic scheme about secret sharing among weighted participants. At last, we analyze the secret sharing scheme among weighted participants, which can make all weighted participants verifiable and dynamic.

  14. On Secret Sharing with Nonlinear Product Reconstruction

    DEFF Research Database (Denmark)

    Cascudo Pueyo, Ignacio; Cramer, Ronald; Mirandola, Diego

    2015-01-01

    Multiplicative linear secret sharing is a fundamental notion in the area of secure multiparty computation and, since recently, in the area of two-party cryptography as well. In a nutshell, this notion guarantees that the product of two secrets is obtained as a linear function of the vector consis...

  15. On Secret Sharing with Nonlinear Product Reconstruction

    DEFF Research Database (Denmark)

    Cascudo Pueyo, Ignacio; Cramer, Ronald; Mirandola, Diego

    2015-01-01

    Multiplicative linear secret sharing is a fundamental notion in the area of secure multiparty computation and, since recently, in the area of two-party cryptography as well. In a nutshell, this notion guarantees that the product of two secrets is obtained as a linear function of the vector consis...

  16. Meaningful Share Generation for Increased Number of Secrets in Visual Secret-Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Mustafa Ulutas

    2010-01-01

    Full Text Available This paper presents a new scheme for hiding two halftone secret images into two meaningful shares created from halftone cover images. Meaningful shares are more desirable than noise-like (meaningless shares in Visual Secret Sharing because they look natural and do not attract eavesdroppers' attention. Previous works in the field focus on either increasing number of secrets or creating meaningful shares for one secret image. The method outlined in this paper both increases the number of secrets and creates meaningful shares at the same time. While the contrast ratio of shares is equal to that of Extended Visual Cryptography, two secrets are encoded into two shares as opposed to one secret in the Extended Visual Cryptography. Any two natural-looking images can be used as cover unlike the Halftone Visual Cryptography method where one cover should be the negative of the other cover image and can only encode one secret. Effectiveness of the proposed method is verified by an experiment.

  17. Hash function based secret sharing scheme designs

    CERN Document Server

    Chum, Chi Sing

    2011-01-01

    Secret sharing schemes create an effective method to safeguard a secret by dividing it among several participants. By using hash functions and the herding hashes technique, we first set up a (t+1, n) threshold scheme which is perfect and ideal, and then extend it to schemes for any general access structure. The schemes can be further set up as proactive or verifiable if necessary. The setup and recovery of the secret is efficient due to the fast calculation of the hash function. The proposed scheme is flexible because of the use of existing hash functions.

  18. Secret Sharing Schemes and Advanced Encryption Standard

    Science.gov (United States)

    2015-09-01

    Professor Bard xv Mansager, my academic advisor in the Department of Applied Mathematics. Bard was the one who reassured me that the Math Department...are obtained by an eavesdropper, and the eavesdropper decomposes the public shares into the generalized formula yi = (xi+α)k−b0 for secret recovery

  19. Scalable Mechanisms for Rational Secret Sharing

    CERN Document Server

    Dani, Varsha; Saia, Jared

    2012-01-01

    We consider the classical secret sharing problem in the case where all agents are selfish but rational. In recent work, Kol and Naor show that, when there are two players, in the non-simultaneous communication model, i.e. when rushing is possible, there is no Nash equilibrium that ensures both players learn the secret. However, they describe a mechanism for this problem, for any number of players, that is an epsilon-Nash equilibrium, in that no player can gain more than epsilon utility by deviating from it. Unfortunately, the Kol and Naor mechanism, and, to the best of our knowledge, all previous mechanisms for this problem require each agent to send O(n) messages in expectation, where n is the number of agents. This may be problematic for some applications of rational secret sharing such as secure multi-party computation and simulation of a mediator. We address this issue by describing mechanisms for rational secret sharing that are designed for large n. Both of our results hold for n > 2, and are Nash equil...

  20. Visual Secret Sharing Based Digital Image Watermarking

    Directory of Open Access Journals (Sweden)

    B. Surekha

    2012-05-01

    Full Text Available In this paper, a spatial domain image watermarking technique based on Visual Secret Sharing (VSS and unique statistical properties is proposed. A random looking image is generated during watermark hiding process and is secretly registered with an arbitrator for verification during conflicts. Another random looking image is generated during watermark revelation stage and is combined with the existing one, to recover the watermark. This whole process is done without altering the image to be protected and hence the quality of the cover image is high. When compared with similar existing techniques, the proposed technique has three main advantages: Provides greater convenience in carrying and storing the intermediate images called shares; Provides high security; Reduce tradeoff between spatial and frequency domain techniques in terms of robustness

  1. Constructions for Anonymous Secret Sharing Schemes Using Combinatorial Designs

    Institute of Scientific and Technical Information of China (English)

    Ying-pu Deng; Li-feng Guo; Mu-lan Liu

    2007-01-01

    In an anonymous secret sharing scheme the secret can be reconstructed without knowledge of which participants hold which shares. In this paper some constructions of anonymous secret sharing schemes with 2 thresholds by using combinatorial designs are given. Let υ(t, ω, q) denote the minimum size of the set of shares of a perfect anonymous (t, ω) threshold secret sharing scheme with q secrets. In this paper we prove that υ(t, ω, q) = Θ(q) if t and ω are fixed and that the lower bound of the size of the set of shares in [4] is not optimal under certain condition.

  2. Direct Use of Secret Key in Quantum Cryptography

    CERN Document Server

    Yuen, H P

    2006-01-01

    For single-photon quantum key generation between two users, it is shown that for collective attacks the use of a shared secret key extended via a pseudo-random number generator may simultaneously enhance the security and efficiency of the cryptosystem. This effect arises from the intrinsic performance difference between quantum detectors with versus without knowledge of the key, a purely quantum effect and a new principle for key generation. No intrusion level estimation is needed and the method is directly applicable to realistic systems involving multi-photon sources, losses, noises, and finite-sequence statistical fluctuations. It is suggested that such use of a secret key be routinely incorporated in a quantum key generation system. The use of a secret key in quantum direct encryption is also indicated.

  3. ARQ-Based Secret Key Sharing

    CERN Document Server

    Ghany, Mohamed Abdel; Gamal, Hesham El

    2008-01-01

    This paper develops a novel framework for sharing secret keys using existing Automatic Repeat reQuest (ARQ) protocols. Our approach exploits the multi-path nature of the wireless environment to hide the key from passive eavesdroppers. The proposed framework does not assume the availability of any prior channel state information (CSI) and exploits only the one bit ACK/NACK feedback from the legitimate receiver. Compared with earlier approaches, the main innovation lies in the distribution of key bits among multiple ARQ frames. Interestingly, this idea allows for achieving a positive secrecy rate even when the eavesdropper experiences more favorable channel conditions, on average, than the legitimate receiver. In the sequel, we characterize the information theoretic limits of the proposed schemes, develop low complexity explicit implementations, and conclude with numerical results that validate our theoretical claims.

  4. Shared Secrets versus Secrets Kept Private Are Linked to Better Adolescent Adjustment

    Science.gov (United States)

    Frijns, Tom; Finkenauer, Catrin; Keijsers, Loes

    2013-01-01

    It is a household notion that secrecy is bad while sharing is good. But what about shared secrets? The present research adopts a functional analysis of sharing secrets, arguing that it should negate harmful consequences generally associated with secrecy and serves important interpersonal functions in adolescence. A survey study among 790 Dutch…

  5. Information-Theoretic Secure Verifiable Secret Sharing over RSA Modulus

    Institute of Scientific and Technical Information of China (English)

    QIU Gang; WANG Hong; WEI Shimin; XIAO Guozhen

    2006-01-01

    The well-known non-interactive and information-theoretic secure verifiable secret sharing scheme presented by Pedersen is over a large prime. In this paper, we construct a novel non-interactive and information-theoretic verifiable secret sharing over RSA (Rivest,Shamir,Adleman) modulus and give the rigorous security proof. It is shown how to distribute a secret among a group such that any set of k parties get no information about the secret. The presented scheme is generally applied to constructions of secure distributed multiplication and threshold or forward-secure signature protocols.

  6. How to secretly share the treasure map of the captain?

    Science.gov (United States)

    Islam, N.; Puech, W.; Brouzet, R.

    2010-01-01

    In this paper we present a new approach for sharing a secret image between l users exploiting additive homomorphic property of Paillier algorithm. With a traditional approach, when a dealer wants to share an image between l players, the secret image must be sequentially encrypted l + 1 times using l + 1 keys (secret or public keys). When the dealer and the l players want to extract the secret image, they must decrypt sequentially, keeping the same order of the encryption step, by using l + 1 keys (secret or private). With the proposed approach, during the encryption step, each player encrypts his own secret image using the same public key given by the dealer, the dealer encrypts the secret image to be shared with the same key and then the l secret encrypted images plus the encrypted image to be shared are multiplied between them to get a scrambled image. After this step, the dealer can securely use the private key to decrypt this scrambled image to get a new scrambled image which corresponds to the addition of the l + 1 original images because of the additive homomorphic property of Paillier algorithm. When the l players want to extract the secret image, they do not need the dealer and to use keys. Indeed, with our approach, to extract the secret image, the l players need only to subtract their own secret image from the scrambled image. In this paper we illustrate our approach with an example of a captain who wants to share a secret treasure map between l pirates. Experimental results and security analysis show the effectiveness of the proposed scheme.

  7. Leakproof secret sharing protocols with applications to group identification scheme

    Institute of Scientific and Technical Information of China (English)

    TANG ChunMing; GAO ShuHong

    2012-01-01

    In a traditional (t,n)-threshold secret sharing scheme,t or more honest participants can reconstruct the secret K.In the reconstruction process,the individual shares and the secret key K are revealed,hence K is shared once only. In this paper,we firstly give the definition of leakproof secret sharing scheme which is composed of a distribution protocol and a proof protocol,then propose two leakproof secret sharing protocols,a computationally secure protocol and an information-theoretically secure protocol.In our protocols,t or more participants can jointly prove that they hold the secret K by using a multi-prover zero-knowledge argument of knowledge.As a result,the secret K will be shared for as many times as desired.Furthermore,each participant can detect the dealer in the distribution protocol from cheating,and any verifier can prevent non-qualified set of participants in proof protocol from cheating.As an example of the practical impact of our work we use our techniques to construct group identification schemes with zero-knowledge.

  8. Dynamic Vector Space Secret Sharing Based on Certificates

    Institute of Scientific and Technical Information of China (English)

    XU Chunxiang; LI Jiajia; LIU Dongsu

    2006-01-01

    A vector space secret sharing scheme based on certificates is proposed in this paper. The difficulties of solving discrete logarithm assure confidential information's security, and the use of each participant's certificate makes the dealer have no need to transfer secret information to the participants. The proposed scheme is dynamic. It can effectively check cheaters and does not have secure channel requirements.

  9. SSDLP: Sharing Secret Data between Leader and Participant

    Directory of Open Access Journals (Sweden)

    Hazem Al-Najjar

    2014-01-01

    Full Text Available This paper investigates the problem of sharing the secret document containing a secret data between leader and participant(s depending on specific conditions and rules. The participant(s can retrieve part of the secret document but will not be able to retrieve any secret data without the leader. At the same time, the leader may have a little information about the secret document but cannot retrieve the secret data and the secret document without cooperating with participant(s. To evaluate the proposed model and the system efficiency, four tests are suggested, which are concatenation and sharing data test, leader visual test, information entropy analysis, and correlation analysis. Results show that the proposed model is efficient in sharing the data between the leader and participant(s and the model can achieve our concept of the data sharing between leader and participant(s. However, by analyzing the proposed model using numerical tests and visual tests, the results show that the visual tests will not give attackers useful information about the original data, while the numerical tests show that the entropy attacks are not possible and the correlation between the adjacent pixels will not give useful information. Finally, the results show that the proposed model is strong against different types of attacks.

  10. Secret Sharing and Secure Computing from Monotone Formulae

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Kölker, Jonas; Miltersen, Peter Bro

    2012-01-01

    We present a construction of log-depth formulae for various threshold functions based on atomic threshold gates of constant size. From this, we build a new family of linear secret sharing schemes that are multiplicative, scale well as the number of players increases and allows to raise a shared...

  11. Verifiable Rational Secret Sharing Scheme in Mobile Networks

    Directory of Open Access Journals (Sweden)

    En Zhang

    2015-01-01

    Full Text Available With the development of mobile network, lots of people now have access to mobile phones and the mobile networks give users ubiquitous connectivity. However, smart phones and tablets are poor in computational resources such as memory size, processor speed, and disk capacity. So far, all existing rational secret sharing schemes cannot be suitable for mobile networks. In this paper, we propose a verifiable rational secret sharing scheme in mobile networks. The scheme provides a noninteractively verifiable proof for the correctness of participants’ share and handshake protocol is not necessary; there is no need for certificate generation, propagation, and storage in the scheme, which is more suitable for devices with limited size and processing power; in the scheme, every participant uses her encryption on number of each round as the secret share and the dealer does not have to distribute any secret share; every participant cannot gain more by deviating the protocol, so rational participant has an incentive to abide by the protocol; finally, every participant can obtain the secret fairly (means that either everyone receives the secret, or else no one does in mobile networks. The scheme is coalition-resilient and the security of our scheme relies on a computational assumption.

  12. Cropping and noise resilient steganography algorithm using secret image sharing

    Science.gov (United States)

    Juarez-Sandoval, Oswaldo; Fierro-Radilla, Atoany; Espejel-Trujillo, Angelina; Nakano-Miyatake, Mariko; Perez-Meana, Hector

    2015-03-01

    This paper proposes an image steganography scheme, in which a secret image is hidden into a cover image using a secret image sharing (SIS) scheme. Taking advantage of the fault tolerant property of the (k,n)-threshold SIS, where using any k of n shares (k≤n), the secret data can be recovered without any ambiguity, the proposed steganography algorithm becomes resilient to cropping and impulsive noise contamination. Among many SIS schemes proposed until now, Lin and Chan's scheme is selected as SIS, due to its lossless recovery capability of a large amount of secret data. The proposed scheme is evaluated from several points of view, such as imperceptibility of the stegoimage respect to its original cover image, robustness of hidden data to cropping operation and impulsive noise contamination. The evaluation results show a high quality of the extracted secret image from the stegoimage when it suffered more than 20% cropping or high density noise contamination.

  13. (N, N Secret Color Image Sharing Scheme with Dynamic Group

    Directory of Open Access Journals (Sweden)

    Mohamed Fathimal. P

    2015-06-01

    Full Text Available In recent years, secure information sharing has become a top requirement for many applications such as banking and military. Secret Sharing is an effective method to improve security of data. Secret Sharing helps to avoid storing data at a single point through dividing and distributing "shares" of secrets and recovering it later with no loss of original quality. This paper proposes a new Secret Sharing scheme for secure transmission of color images. The key features of this scheme are better visual quality of the recovered image with no pixel expansion, eliminating half toning of color images, eliminating the need for code book to decrypt images since reconstruction is done through XOR ing of all images and non-requirement of regeneration of shares for addition or deletion of users leading to less computational complexity. Besides these advantages, this scheme also helps to renew shares periodically and is highly beneficial in applications where data has to be stored securely in a database.

  14. Special secret sharing scheme with the function of assignment

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A concept of secret sharing scheme with the function of assignment is proposed. It provides great capabilities for many practical applications. In this scheme, the dealer can randomly assign one or more than one participant to get the secret at any time, but these participants can get nothing about the secret before that moment. At the same time, the other participants cannot get any-thing about the secret by stealing the secret value when it is transferred. However, if the dealer is lost, a certain number or more participants of them can reconstruct the secret by cooperating. In order to clear this concept, an illustrating scheme with geometry method and a practical scheme with algebra method is given.

  15. A Homomorphic Method for Sharing Secret Images

    Science.gov (United States)

    Islam, Naveed; Puech, William; Brouzet, Robert

    In this paper, we present a new method for sharing images between two parties exploiting homomorphic property of public key cryptosystem. With our method, we show that it is possible to multiply two encrypted images, to decrypt the resulted image and after to extract and reconstruct one of the two original images if the second original image is available. Indeed, extraction and reconstruction of original image at the receiving end is done with the help of carrier image. Experimental results and security analysis show the effectiveness of the proposed scheme.

  16. Quantum Fingerprints that Keep Secrets

    CERN Document Server

    Gavinsky, Dmitry

    2010-01-01

    We introduce a new type of cryptographic primitive that we call \\e{hiding fingerprinting}. A (quantum) fingerprinting scheme translates a binary string of length $n$ to $d$ (qu)bits, typically $d\\ll n$, such that given any string $y$ and a fingerprint of $x$, one can decide with high accuracy whether $x=y$. Classical fingerprinting schemes cannot hide information very well:\\ a classical fingerprint of $x$ that guarantees error $\\le\\eps$ necessarily reveals \\asOm{\\log(1/\\eps)} bits about $x$. We call a scheme \\e{hiding} if it reveals \\aso{\\log(1/\\eps)} bits; accordingly, no classical scheme is hiding. For any constant $c$, we construct two kinds of hiding fingerprinting schemes, both mapping $x\\in\\01^n$ to \\asO{\\log n} qubits and guaranteeing one-sided error probability at most $1/n^c$. The first kind uses pure states and leaks at most \\asO1 bits, and the second kind uses mixed states and leaks at most $1/n^c$ bits, where the ``leakage'' is bounded via accessible information. The schemes are computationally ef...

  17. Secret Sharing over Fast-Fading MIMO Wiretap Channels

    Directory of Open Access Journals (Sweden)

    Bloch Matthieu

    2009-01-01

    Full Text Available Secret sharing over the fast-fading MIMO wiretap channel is considered. A source and a destination try to share secret information over a fast-fading MIMO channel in the presence of an eavesdropper who also makes channel observations that are different from but correlated to those made by the destination. An interactive, authenticated public channel with unlimited capacity is available to the source and destination for the secret sharing process. This situation is a special case of the "channel model with wiretapper" considered by Ahlswede and Csiszár. An extension of their result to continuous channel alphabets is employed to evaluate the key capacity of the fast-fading MIMO wiretap channel. The effects of spatial dimensionality provided by the use of multiple antennas at the source, destination, and eavesdropper are then investigated.

  18. Security of Linear Secret-Sharing Schemes Against Mass Surveillance

    DEFF Research Database (Denmark)

    Giacomelli, Irene; Olimid, Ruxandra; Ranellucci, Samuel

    2015-01-01

    Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented by a prop......Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented...

  19. Security of Linear Secret-Sharing Schemes Against Mass Surveillance

    DEFF Research Database (Denmark)

    Giacomelli, Irene; Olimid, Ruxandra; Ranellucci, Samuel

    2015-01-01

    Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented by a prop...... there exists an undetectable subversion of it that efficiently allows surveillance. Second, we formalize the security notion that assures that a sharing scheme is secure against ASAs and construct the first sharing scheme that meets this notion....... by a proprietary code that the provider (“big brother”) could manipulate to covertly violate the privacy of the users (by implementing Algorithm-Substitution Attacks or ASAs). First, we formalize the security notion that expresses the goal of big brother and prove that for any linear secret-sharing scheme...

  20. Quantum signal processing-based visual cryptography with unexpanded shares

    Science.gov (United States)

    Das, Surya Sarathi; Sharma, Kaushik Das; Chandra, Jayanta K.; Bera, Jitendra Nath

    2015-09-01

    This paper proposes a visual cryptography scheme (VCS) based on quantum signal processing (QSP). VCS is an image encryption technique that is very simple in formulation and is secure. In (k,n)-VCS, a secret binary image is encoded into n share images and minimum k shares are needed to decrypt the secret image. The efforts to encrypt a grayscale image are few in number and the majority are related to grayscale to binary conversion. Thus, a generalized approach of encryption for all types of images, i.e., binary, gray, and color is needed. Here, a generic VCS is proposed based on QSP where all types of images can be encrypted without pixel expansion along with a smoothing technique to enhance the quality of the decrypted image. The proposed scheme is tested and compared for benchmark images, and the result shows the effectiveness of the scheme.

  1. Optimal Black-Box Secret Sharing over Arbitrary Abelian Groups

    DEFF Research Database (Denmark)

    Cramer, Ronald; Fehr, Serge

    2002-01-01

    . A recent example is secure general multi-party computation over black-box rings. In 1994 Desmedt and Frankel have proposed an elegant approach to the black-box secret sharing problem based in part on polynomial interpolation over cyclotomic number fields. For arbitrary given T t,n with 0

  2. Entanglement Swapping of Generalized Cat States and Secret Sharing

    CERN Document Server

    Karimipour, V; Bahraminasab, A; Karimipour, Vahid; Bagherinezhad, Saber; Bahraminasab, Alireza

    2002-01-01

    We introduce generalized cat states for d-level systems and obtain concise formulas for their entanglement swapping with generalized Bell states. We then use this to provide both a generalization to the d-level case and a transparent proof of validity for an already proposed protocol of secret sharing based on entanglement swapping

  3. Combination of Sharing Matrix and Image Encryption for Lossless $(k,n)$ -Secret Image Sharing.

    Science.gov (United States)

    Bao, Long; Yi, Shuang; Zhou, Yicong

    2017-12-01

    This paper first introduces a (k,n) -sharing matrix S((k, n)) and its generation algorithm. Mathematical analysis is provided to show its potential for secret image sharing. Combining sharing matrix with image encryption, we further propose a lossless (k,n) -secret image sharing scheme (SMIE-SIS). Only with no less than k shares, all the ciphertext information and security key can be reconstructed, which results in a lossless recovery of original information. This can be proved by the correctness and security analysis. Performance evaluation and security analysis demonstrate that the proposed SMIE-SIS with arbitrary settings of k and n has at least five advantages: 1) it is able to fully recover the original image without any distortion; 2) it has much lower pixel expansion than many existing methods; 3) its computation cost is much lower than the polynomial-based secret image sharing methods; 4) it is able to verify and detect a fake share; and 5) even using the same original image with the same initial settings of parameters, every execution of SMIE-SIS is able to generate completely different secret shares that are unpredictable and non-repetitive. This property offers SMIE-SIS a high level of security to withstand many different attacks.

  4. Security of Linear Secret-Sharing Schemes Against Mass Surveillance

    DEFF Research Database (Denmark)

    Giacomelli, Irene; Olimid, Ruxandra; Ranellucci, Samuel

    2015-01-01

    Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented by a prop......Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented...... by a proprietary code that the provider (“big brother”) could manipulate to covertly violate the privacy of the users (by implementing Algorithm-Substitution Attacks or ASAs). First, we formalize the security notion that expresses the goal of big brother and prove that for any linear secret-sharing scheme...... there exists an undetectable subversion of it that efficiently allows surveillance. Second, we formalize the security notion that assures that a sharing scheme is secure against ASAs and construct the first sharing scheme that meets this notion....

  5. A Novel Approach for Verifiable Secret Sharing by using a One Way Hash Function

    CERN Document Server

    Parmar, Keyur

    2012-01-01

    Threshold secret sharing schemes do not prevent any malicious behavior of the dealer or shareholders and so we need verifiable secret sharing, to detect and identify the cheaters, to achieve fair reconstruction of a secret. The problem of verifiable secret sharing is to verify the shares distributed by the dealer. A novel approach for verifiable secret sharing is presented in this paper where both the dealer and shareholders are not assumed to be honest. In this paper, we extend the term verifiable secret sharing to verify the shares, distributed by a dealer as well as shares submitted by shareholders for secret reconstruction, and to verify the reconstructed secret. Our proposed scheme uses a one way hash function and probabilistic homomorphic encryption function to provide verifiability and fair reconstruction of a secret.

  6. An Advanced Threshold Secret Sharing Scheme for Identifying Cheaters

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-cui; ZHANG Jian-zhong

    2003-01-01

    In this paper an advanced threshold secret sharing scheme for identifying cheaters is proposed by using authentication codes. The performance of the scheme is discussed. The results show that in the scheme the valid shareholders can not only identify the impersonation of an adversary, but also detect cheating of some valid shareholders. In particular one honest shareholder is able to detect cheating of other participants forming a collection, and the information rate of the scheme is higher than that of others.

  7. How to Split a Shared Secret into Shared Bits in Constant-Round

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Fitzi, Matthias; Nielsen, Jesper Buus

    We show that if a set of players hold shares of a value $a\\in Z_p$ for some prime $p$ (where the set of shares is written $[a]_p$), it is possible to compute, in constant round and with unconditional security, sharings of the bits of $a$, i.e.~compute sharings $[a_0]_p, \\ldots, [a_{l-1}]_p......$ such that $l = \\lceil \\log_2(p) \\rceil$, $a_0, \\ldots, a_{l-1} \\in \\{0,1\\}$ and $a = \\sum_{i=0}^{l-1} a_i 2^i$. Our protocol is secure against active adversaries and works for any linear secret sharing scheme with a multiplication protocol. This result immediately implies solutions to other long-standing open...... problems, such as constant-round and unconditionally secure protocols for comparing shared numbers and deciding whether a shared number is zero. The complexity of our protocol is $O(l \\log(l))$ invocations of the multiplication protocol for the underlying secret sharing scheme, carried out in $O(1)$....

  8. Information sharing in Quantum Complex Networks

    CERN Document Server

    Cardillo, Alessio; Zueco, David; Gómez-Gardeñes, Jesús

    2013-01-01

    We introduce the use of entanglement entropy as a tool for studying the amount of information shared between the nodes of quantum complex networks. By considering the ground state of a network of coupled quantum harmonic oscillators, we compute the information that each node has on the rest of the system. We show that the nodes storing the largest amount of information are not the ones with the highest connectivity, but those with intermediate connectivity thus breaking down the usual hierarchical picture of classical networks. We show both numerically and analytically that the mutual information characterizes the network topology. As a byproduct, our results point out that the amount of information available for an external node connecting to a quantum network allows to determine the network topology.

  9. On codes, matroids and secure computation from linear secret sharing schemes

    NARCIS (Netherlands)

    Cramer, R.J.F.; Daza, V.; Gracia, J.L.; Jimenez Urroz, J.; Leander, G.; Marti-Farre, J.; Padro, C.

    2008-01-01

    Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes ar

  10. Protection of multicast scalable video by secret sharing: simulation results

    Science.gov (United States)

    Eskicioglu, Ahmet M.; Dexter, Scott; Delp, Edward J., III

    2003-06-01

    Security is an increasingly important attribute for multimedia applications that require prevention of unauthorized access to copyrighted data. Two approaches have been used to protect scalable video content in distribution: Partial encryption and progressive encryption. Partial encryption provides protection for only selected portions of the video. Progressive encryption allows transcoding with simple packet truncation, and eliminates the need to decrypt the video packets at intermediate network nodes with low complexity. Centralized Key Management with Secret Sharing (CKMSS) is a recent approach in which the group manager assigns unique secret shares to the nodes in the hierarchical key distribution tree. It allows the reconstruction of different keys by communicating different activating shares for the same prepositioned information. Once the group key is established, it is used until a member joins/leaves the multicast group or periodic rekeying occurs. In this paper, we will present simulation results regarding the communication and processing requirements of the CKMSS scheme applied to scalable video. In particular, we have measured the rekey message size and the processing time needed by the server for each join/leave request and periodic rekey event.

  11. A Secret Image Sharing Method Using Integer Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Li Ching-Chung

    2007-01-01

    Full Text Available A new image sharing method, based on the reversible integer-to-integer (ITI wavelet transform and Shamir's threshold scheme is presented, that provides highly compact shadows for real-time progressive transmission. This method, working in the wavelet domain, processes the transform coefficients in each subband, divides each of the resulting combination coefficients into shadows, and allows recovery of the complete secret image by using any or more shadows . We take advantages of properties of the wavelet transform multiresolution representation, such as coefficient magnitude decay and excellent energy compaction, to design combination procedures for the transform coefficients and processing sequences in wavelet subbands such that small shadows for real-time progressive transmission are obtained. Experimental results demonstrate that the proposed method yields small shadow images and has the capabilities of real-time progressive transmission and perfect reconstruction of secret images.

  12. A Novel Scheme for Image Authentication and Secret Data Sharing

    Directory of Open Access Journals (Sweden)

    Auqib Hamid Lone

    2016-09-01

    Full Text Available Privacy protection is of extreme importance especially in security sensitive environments. Neither cryptography nor steganography comes up with ultimate solution for privacy preservation in open systems. However, combination of steganography and cryptography can greatly increase the security of communication and is usually considered a good practice for securing security driven communication environments. In this paper we propose a novel scheme for image authentication and secret data sharing based on three level security model viz: Compression, steganography and cryptography. Compression optimizes the resource usage, steganography conceals the existence of message and cryptography is used to achieve confidentiality and authentication.

  13. Quantum information sharing between topologically distinct platforms

    Science.gov (United States)

    Hou, Chang-Yu; Refael, Gil; Shtengel, Kirill

    2016-12-01

    Can topological quantum entanglement between anyons in one topological medium "stray" into a different, topologically distinct medium? In other words, can quantum information encoded nonlocally in the combined state of non-Abelian anyons be shared between two distinct topological media? For one-dimensional topological superconductors with Majorana bound states at the end of system, the quantum information store in those Majorana bound states can be transfered by directly coupling nearby Majorana bound states. However, coupling of two one-dimensional Majorana states will produce a gap, indicating that distinct topological regions of one-dimensional wires unite into a single topological region through the information transfer process. In this paper, we consider a setup with two two-dimensional p -wave superconductors of opposite chirality adjacent to each other. Even two comoving chiral modes at the domain wall between them cannot be gapped through interactions; we demonstrate that information encoded in the fermionic parity of two Majorana zero modes, originally within the same superconducting domain, can be shared between the domains or moved entirely from one domain to another provided that vortices can tunnel between them in a controlled fashion.

  14. Secret Sharing and Secure Computing from Monotone Formulae

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Kölker, Jonas; Miltersen, Peter Bro

    2012-01-01

    We present a construction of log-depth formulae for various threshold functions based on atomic threshold gates of constant size. From this, we build a new family of linear secret sharing schemes that are multiplicative, scale well as the number of players increases and allows to raise a shared...... value to the characteristic of the underlying field without interaction. Some of these schemes are in addition strongly multiplicative. Our formulas can also be used to construct multiparty protocols from protocols for a constant number of parties. In particular we implement black-box multiparty...... computation over non-Abelian groups in a way that is much simpler than previously known and we also show how to get a protocol in this setting that is efficient and actively secure against a constant fraction of corrupted parties, a long standing open problem. Finally, we show a negative result on usage...

  15. Coding Theorems for Cheating-Detectable Secret Sharing Schemes with Two Shares

    CERN Document Server

    Iwamoto, Mitsugu; Yamamoto, Hirosuke

    2010-01-01

    In this paper, we discuss coding theorems on a $(2, 2)$--threshold scheme in the presence of an opponent who impersonates one of the two shareholders in an asymptotic setup. We consider a situation where $n$ secrets $S^n$ from a memoryless source is blockwisely encoded to two shares and the two shares are decoded to $S^n$ with permitting negligible decoding error. We introduce correlation level of the two shares and characterize the minimum attainable rates of the shares and a uniform random number for realizing a $(2, 2)$--threshold scheme that is secure against the impersonation attack by an opponent. It is shown that, if the correlation level between the two shares equals to an $\\ell \\ge 0$, the minimum attainable rates coincide with $H(S)+\\ell$, where $H(S)$ denotes the entropy of the source, and the maximum attainable exponent of the success probability of the impersonation attack equals to $\\ell$. We also give a simple construction of an encoder and a decoder using an ordinary $(2,2)$--threshold scheme ...

  16. Steganography on multiple MP3 files using spread spectrum and Shamir's secret sharing

    Science.gov (United States)

    Yoeseph, N. M.; Purnomo, F. A.; Riasti, B. K.; Safiie, M. A.; Hidayat, T. N.

    2016-11-01

    The purpose of steganography is how to hide data into another media. In order to increase security of data, steganography technique is often combined with cryptography. The weakness of this combination technique is the data was centralized. Therefore, a steganography technique is develop by using combination of spread spectrum and secret sharing technique. In steganography with secret sharing, shares of data is created and hidden in several medium. Medium used to concealed shares were MP3 files. Hiding technique used was Spread Spectrum. Secret sharing scheme used was Shamir's Secret Sharing. The result showed that steganography with spread spectrum combined with Shamir's Secret Share using MP3 files as medium produce a technique that could hid data into several cover. To extract and reconstruct the data hidden in stego object, it is needed the amount of stego object which more or equal to its threshold. Furthermore, stego objects were imperceptible and robust.

  17. A New and Efficient Secret Sharing in Graph-Based Prohibited Structures

    Institute of Scientific and Technical Information of China (English)

    GUOYuanbo; MAJianfeng

    2005-01-01

    The secret sharing realizing the prohibited structure, which specifies the corruptible subsets of participants, can be determined directly by exploitation of the system setting and the attributes of all participants. Recently, Sun et al. had proposed a construction of secret sharing for graph-based prohibited structures where a vertex denotes a participant and an edge a pair of participants who cannot recover the secret. But their scheme is inefficient and costly. In this paper, we present a new and efficient secret sharing realizing graph-based prohibited structures and prove that the scheme satisfies both properties of the secret sharing scheme, i.e. the reconstruction property and the perfect property. The main features of our scheme are that it only needs some modular additions and subtractions in both shares assignment phase and secret recovery phase, which is an advantage in terms of computational complexity, and it can achieve higher information rate than existing ones.

  18. Linear VSS and Distributed Commitments Based on Secret Sharing and Pairwise Checks

    DEFF Research Database (Denmark)

    Fehr, Serge; Maurer, Ueli M.

    2002-01-01

    We present a general treatment of all non-cryptographic (i.e., information-theoretically secure) linear veriable-secret-sharing (VSS) and distributed-commitment (DC) schemes, based on an underlying secret sharing scheme, pairwise checks between players, complaints, and accusations of the dealer. ...

  19. Secret key rates for an encoded quantum repeater

    Science.gov (United States)

    Bratzik, Sylvia; Kampermann, Hermann; Bruß, Dagmar

    2014-03-01

    We investigate secret key rates for the quantum repeater using encoding [L. Jiang et al., Phys. Rev. A 79, 032325 (2009), 10.1103/PhysRevA.79.032325] and compare them to the standard repeater scheme by Briegel, Dür, Cirac, and Zoller. The former scheme has the advantage of a minimal consumption of classical communication. We analyze the trade-off in the secret key rate between the communication time and the required resources. For this purpose we introduce an error model for the repeater using encoding which allows for input Bell states with a fidelity smaller than one, in contrast to the model given by L. Jiang et al. [Phys. Rev. A 79, 032325 (2009), 10.1103/PhysRevA.79.032325]. We show that one can correct additional errors in the encoded connection procedure of this repeater and develop a suitable decoding algorithm. Furthermore, we derive the rate of producing entangled pairs for the quantum repeater using encoding and give the minimal parameter values (gate quality and initial fidelity) for establishing a nonzero secret key. We find that the generic quantum repeater is optimal regarding the secret key rate per memory per second and show that the encoded quantum repeater using the simple three-qubit repetition code can even have an advantage with respect to the resources compared to other recent quantum repeater schemes with encoding.

  20. An Anti-Cutting Watermarking Algorithm Based on Matrix Multiplication Secret Sharing Scheme

    Institute of Scientific and Technical Information of China (English)

    YAO Hui-ming; ZHANG Li-he; SUI Ai-fen

    2004-01-01

    A digital watermarking algorithm based on the matrix multiplication secret sharing scheme is proposed. It partitions the field of the image into n shares, and also partitions the watermark into n shares correspondingly. After the original image is divided, the digital watermark is embedded into the low frequency DCT domain and only needs part shares in the recovering course. Experimental results show that this algorithm has a good effect of hiding, anti-cutting and anti-compressing.

  1. On the new member's subsecret distribution protocol in dynamic group secret-sharing

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; WANG Wei-nong

    2005-01-01

    Secret-sharing is a common method to protect important data, such as the private key of a public-key system. Dynamic Group Secret-sharing (DGS) is a system where all of the members in a group hold a subsecret of the key information and where the number of members in the group is variable. This kind of secret-sharing is broadly used in many special distribution systems, such as Self-secure Ad-hoc Network. Distributing this subsecret to a new member when he enters the group is the common method that ensures all the members participate in the same secret-sharing. However, no' atisfactory subsecret distribution scheme exists at present. This paper proposes a new protocol that tries to satisfy both security and efficiency.

  2. AN EFFICIENT AND SECURE(t,n) THRESHOLD SECRET SHARING SCHEME

    Institute of Scientific and Technical Information of China (English)

    Pang Liaojun; Sun Xi; Wang Yumin

    2006-01-01

    Based on Shamir's threshold secret sharing scheme and the discrete logarithm problem, a new (t,n)threshold secret sharing scheme is proposed in this paper. In this scheme, each participant's secret shadow is selected by the participant himself, and even the secret dealer cannot gain anything about his secret shadow.All the shadows are as short as the shared secret. Each participant can share many secrets with other participants by holding only one shadow. Without extra equations and information designed for verification, each participant is able to check whether another participant provides the true information or not in the recovery phase. Unlike most of the existing schemes, it is unnecessary to maintain a secure channel between each participant and the dealer. Therefore, this scheme is very attractive, especially under the circumstances that there is no secure channel between the dealer and each participant at all. The security of this scheme is based on that of Shamir's threshold scheme and the difficulty in solving the discrete logarithm problem. Analyses show that this scheme is a computationally secure and efficient scheme.

  3. How to Split a Shared Secret into Shared Bits in Constant-Round

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Fitzi, Matthias; Nielsen, Jesper Buus

    We show that if a set of players hold shares of a value $a\\in Z_p$ for some prime $p$ (where the set of shares is written $[a]_p$), it is possible to compute, in constant round and with unconditional security, sharings of the bits of $a$, i.e.~compute sharings $[a_0]_p, \\ldots, [a_{l-1}]_p...

  4. Applying two channels to vector space secret sharing based multi-signature scheme

    Institute of Scientific and Technical Information of China (English)

    XIAO Qing-hua; PING Ling-di; CHEN Xiao-ping; PAN Xue-zeng

    2005-01-01

    Secret sharing and digital signature is an important research area in information security and has wide applications in such fields as safeguarding and legal use of confidential information, secure multiparty computation and electronic commerce. But up to now, study of signature based on general vector space secret sharing is very weak. Aiming at this drawback, the authors did some research on vector space secret sharing against cheaters, and proposed an efficient but secure vector space secret sharing based multi-signature scheme, which is implemented in two channels. In this scheme, the group signature can be easily produced if an authorized subset of participants pool their secret shadows and it is impossible for them to generate a group signature if an unauthorized subset of participants pool their secret shadows. The validity of the group signature can be verified by means of verification equations. A group signature of authorized subset of participants cannot be impersonated by any other set of participants. Moreover, the suspected forgery can be traced, and the malicious participants can be detected in the scheme. None of several possible attacks can successfully break this scheme.

  5. Rational Secret Sharing over an Asynchronous Broadcast Channel with Information Theoretic Security

    CERN Document Server

    Moses, William K; 10.5121/ijnsa.2011.3601

    2011-01-01

    We consider the problem of rational secret sharing introduced by Halpern and Teague [1], where the players involved in secret sharing play only if it is to their advantage. This can be characterized in the form of preferences. Players would prefer to get the secret than to not get it and secondly with lesser preference, they would like as few other players to get the secret as possible. Several positive results have already been published to efficiently solve the problem of rational secret sharing but only a handful of papers have touched upon the use of an asynchronous broadcast channel. [2] used cryptographic primitives, [3] used an interactive dealer, and [4] used an honest minority of players in order to handle an asynchronous broadcast channel. In our paper, we propose an m-out-of-n rational secret sharing scheme which can function over an asynchronous broadcast channel without the use of cryptographic primitives and with a non-interactive dealer. This is possible because our scheme uses a small number, ...

  6. Secret Sharing Schemes with a large number of players from Toric Varieties

    DEFF Research Database (Denmark)

    Hansen, Johan P.

    A general theory for constructing linear secret sharing schemes over a finite field $\\Fq$ from toric varieties is introduced. The number of players can be as large as $(q-1)^r-1$ for $r\\geq 1$. We present general methods for obtaining the reconstruction and privacy thresholds as well as conditions...... for multiplication on the associated secret sharing schemes. In particular we apply the method on certain toric surfaces. The main results are ideal linear secret sharing schemes where the number of players can be as large as $(q-1)^2-1$. We determine bounds for the reconstruction and privacy thresholds...... and conditions for strong multiplication using the cohomology and the intersection theory on toric surfaces....

  7. A potential application in quantum networks—Deterministic quantum operation sharing schemes with Bell states

    Science.gov (United States)

    Zhang, KeJia; Zhang, Long; Song, TingTing; Yang, YingHui

    2016-06-01

    In this paper, we propose certain different design ideas on a novel topic in quantum cryptography — quantum operation sharing (QOS). Following these unique ideas, three QOS schemes, the "HIEC" (The scheme whose messages are hidden in the entanglement correlation), "HIAO" (The scheme whose messages are hidden with the assistant operations) and "HIMB" (The scheme whose messages are hidden in the selected measurement basis), have been presented to share the single-qubit operations determinately on target states in a remote node. These schemes only require Bell states as quantum resources. Therefore, they can be directly applied in quantum networks, since Bell states are considered the basic quantum channels in quantum networks. Furthermore, after analyse on the security and resource consumptions, the task of QOS can be achieved securely and effectively in these schemes.

  8. Quantum synchronization and quantum state sharing in an irregular complex network

    Science.gov (United States)

    Li, Wenlin; Li, Chong; Song, Heshan

    2017-02-01

    We investigate the quantum synchronization phenomenon of the complex network constituted by coupled optomechanical systems and prove that the unknown identical quantum states can be shared or distributed in the quantum network even though the topology is varying. Considering a channel constructed by quantum correlation, we show that quantum synchronization can sustain and maintain high levels in Markovian dissipation for a long time. We also analyze the state-sharing process between two typical complex networks, and the results predict that linked nodes can be directly synchronized, but the whole network will be synchronized only if some specific synchronization conditions are satisfied. Furthermore, we give the synchronization conditions analytically through analyzing network dynamics. This proposal paves the way for studying multi-interaction synchronization and achieving effective quantum information processing in a complex network.

  9. Quantum synchronization and quantum state sharing in an irregular complex network.

    Science.gov (United States)

    Li, Wenlin; Li, Chong; Song, Heshan

    2017-02-01

    We investigate the quantum synchronization phenomenon of the complex network constituted by coupled optomechanical systems and prove that the unknown identical quantum states can be shared or distributed in the quantum network even though the topology is varying. Considering a channel constructed by quantum correlation, we show that quantum synchronization can sustain and maintain high levels in Markovian dissipation for a long time. We also analyze the state-sharing process between two typical complex networks, and the results predict that linked nodes can be directly synchronized, but the whole network will be synchronized only if some specific synchronization conditions are satisfied. Furthermore, we give the synchronization conditions analytically through analyzing network dynamics. This proposal paves the way for studying multi-interaction synchronization and achieving effective quantum information processing in a complex network.

  10. Probabilistic Visual Secret Sharing Schemes for Gray-scale images and Color images

    CERN Document Server

    Wang, Dao-Shun; Li, Xiaobo

    2007-01-01

    Visual secrete sharing (VSS) is an encryption technique that utilizes human visual system in the recovering of the secret image and it does not require any complex calculation. Pixel expansion has been a major issue of VSS schemes. A number of probabilistic VSS schemes with minimum pixel expansion have been proposed for binary secret images. This paper presents a general probabilistic (k, n)-VSS scheme for gray-scale images and another scheme for color images. With our schemes, the pixel expansion can be set to a user-defined value. When this value is 1, there is no pixel expansion at all. The quality of reconstructed secret images, measured by Average Relative Difference, is equivalent to Relative Difference of existing deterministic schemes. Previous probabilistic VSS schemes for black-and-white images with respect to pixel expansion can be viewed as special cases of the schemes proposed here

  11. Rate Regions of Secret Key Sharing in a New Source Model

    CERN Document Server

    Salimi, Somayeh; Aref, Mohammad Reza

    2010-01-01

    A source model for secret key generation between terminals is considered. Two users, namely users 1 and 2, at one side communicate with another user, namely user 3, at the other side via a public channel where three users can observe i.i.d. outputs of correlated sources. Each of users 1 and 2 intends to share a secret key with user 3 where user 1 acts as a wiretapper for user 2 and vice versa. In this model, two situations are considered: communication from users 1 and 2 to user 3 (the forward key strategy) and from user 3 to users 1 and 2 (the backward key strategy). In both situations, the goal is sharing a secret key between user 1 and user 3 while leaking no effective information about that key to user 2, and simultaneously, sharing another secret key between user 2 and user 3 while leaking no effective information about the latter key to user 1. This model is motivated by wireless communications when considering user 3 as a base station and users 1 and 2 as network users. In this paper, for both the forw...

  12. Encryption On Grayscale Image For Digital Image Confidentiality Using Shamir Secret Sharing Scheme

    Science.gov (United States)

    Rodiah; Anggraini, Dyah; Fitrianingsih; Kazhimi, Farizan

    2016-04-01

    The use of high-frequency internet in the process of exchanging information and digital transaction is often accompanied by transmitting digital image in the form of raster images. Secret sharing schemes are multiparty protocols that related to the key establishment which provides protection against any threats of losing cryptography key. The greater the key duplication, the higher the risk of losing the key and vice versa. In this study, Secret Sharing Method was used by employing Shamir Threshold Scheme Algorithm on grayscale digital image with the size of 256×256 pixel obtaining 128×128 pixels of shared image with threshold values (4, 8). The result number of shared images were 8 parts and the recovery process can be carried out by at least using 4 shares of the 8 parts. The result of encryption on grayscale image is capable of producing vague shared image (i.e., no perceptible information), therefore a message in the form of digital image can be kept confidential and secure.

  13. Optimistic fair exchange E-commerce protocol based on secret sharing

    Institute of Scientific and Technical Information of China (English)

    Ma Changshe; Lei Feiyu; Chen Kefei

    2006-01-01

    A key problem of electronic commerce (for short e-commerce) is fair exchange which guarantees that at the end of the transaction, either both parties involved in the transaction receive each other's items or none do. A non-interactive optimistic fair exchange e-commerce protocol model based on the publicly verifiable secret sharing is presented. The main idea of our exchange protocol is to interchange verifiable and recoverable keys of the symmetric encryption for participants' items. So it is especially suitable for exchange of large-size items. Furthermore, our protocol is efficient and simple as it does not need interactive proof system which has been adopted by a large quantity of previously proposed fair exchange protocols. Based on a modified (2,2) secret sharing scheme, a concrete non-interactive fair exchange e-commerce protocol is designed.

  14. SECRET SHARING SCHEMES WITH STRONG MULTIPLICATION AND A LARGE NUMBER OF PLAYERS FROM TORIC VARIETIES

    DEFF Research Database (Denmark)

    Hansen, Johan Peder

    2016-01-01

    This article consider Massey's construction for constructing linear secret sharing schemes from toric varieties over a finite field $\\Fq$ with $q$ elements. The number of players can be as large as $(q-1)^r-1$ for $r\\geq 1$. The schemes have strong multiplication, such schemes can be utilized in ...... schemes where the number of players can be as large as $(q-1)^2-1$, we determine bounds for the reconstruction and privacy thresholds and conditions for strong multiplication using the cohomology and the intersection theory on toric surfaces.......This article consider Massey's construction for constructing linear secret sharing schemes from toric varieties over a finite field $\\Fq$ with $q$ elements. The number of players can be as large as $(q-1)^r-1$ for $r\\geq 1$. The schemes have strong multiplication, such schemes can be utilized...

  15. Penerapan Secret Image Sharing Menggunakan Steganografi dengan Metode Dynamic Embedding dan Authentication-Chaining

    Directory of Open Access Journals (Sweden)

    Arya Widyadhana

    2012-09-01

    Full Text Available Teknik yang banyak digunakan untuk menyebarkan suatu citra rahasia kepada n orang adalah dengan cara membagi citra rahasia ke dalam beberapa bagian yang kemudian diproses menggunakan skema (k, n-Shamir Secret Sharing yang dikemukakan oleh Adi Shamir (1979. Bagian-bagian dari citra rahasia yang sudah diproses tersebut disisipkan ke dalam n citra kamuflase dan menghasilkan n citra stego. Penyisipan dilakukan sedemikian rupa sehingga kualitas visual citra stego semirip mungkin dengan citra kamuflase. Cara untuk memproteksi citra stego dari orang yang tidak berhak adalah dengan cara menyisipkan suatu bit otentikasi yang berfungsi sebagai suatu digital signature dari citra stego. Citra rahasia dapat dirangkai kembali jika terdapat minimal k citra stego asli. Teknik ini dinamakan Secret Image Sharing.

  16. Threshold proxy quantum signature scheme with threshold shared verification

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A threshold proxy quantum signature scheme with threshold shared verification is proposed. An original signer could authorize a group as its proxy signers. Then only t or more of n persons in the proxy group can generate the proxy signature on behalf of the original signer and any t-1 or fewer ones cannot do that. When the proxy signature needs to be verified,any t or more of n persons belonging to the verification group can verify the message and any t-1 or fewer ones cannot verify the validity of the proxy signature.

  17. Ramp Secret Sharing Approach to Authentication and Data Repairing For Document Image

    Directory of Open Access Journals (Sweden)

    Larry Liston

    2014-04-01

    Full Text Available Digital images are widely used to protect confidential and important information. But the problem is to provide the authentication and integrity to these digital images is a very challenging task. Therefore a new efficient authentication method is proposed for document images with verification and data self-repair capability using the Portable Network Graphics (PNG image. Here, an authentication signal is generated for each block of a document image which, combine with the binarized block data, is transformed into several shares using the Ramp secret sharing scheme. These several binarized block data shares are then embedded into an alpha channel plane. During the embedding process, the generated share values are mapped into a range of 238-255 to yield a transparent stego-image with a disguise effect. Alpha channel is combining with the original image and converted into PNG image format. While the process of image authentication, the image block is marked as tampered, if the authentication signal generated from the current block content does not match with share that extracted from the alpha channel plane. Then using reverse Ramp scheme, two shares from unmarked blocks are collected and then data repairing is applied. Some security measures are also proposed for protecting the security of the shares hidden in the alpha channel.

  18. 一种基于密钥矩阵的动态秘密分享方案%A Dynamic Secret Sharing Scheme Based on Key Matrix

    Institute of Scientific and Technical Information of China (English)

    颜浩; 陈克非

    2003-01-01

    In this paper we introduce a dynamic secret sharing scheme. This scheme not only can be used unrestrictedtimes to share and resume different secret without regenerating the information in the users hands,satisfy the (k,n)threshold demand ,but also can realize the asymmetric user right secret sharing and dynamically add and delete the rel-evant users.

  19. Device-dependent and device-independent quantum key distribution without a shared reference frame

    Science.gov (United States)

    Slater, Joshua A.; Branciard, Cyril; Brunner, Nicolas; Tittel, Wolfgang

    2014-04-01

    Standard quantum key distribution (QKD) protocols typically assume that the distant parties share a common reference frame. In practice, however, establishing and maintaining a good alignment between distant observers is rarely a trivial issue, which may significantly restrain the implementation of long-distance quantum communication protocols. Here we propose simple QKD protocols that do not require the parties to share any reference frame, and study their security and feasibility in both the usual device-dependent (DD) case—in which the two parties use well characterized measurement devices—as well as in the device-independent (DI) case—in which the measurement devices can be untrusted, and the security relies on the violation of a Bell inequality. To illustrate the practical relevance of these ideas, we present a proof-of-principle demonstration of our protocols using polarization entangled photons distributed over a coiled 10-km long optical fiber. We consider two situations, in which either the fiber spool's polarization transformation freely drifts, or randomly chosen polarization transformations are applied. The correlations obtained from measurements allow, with high probability, to generate positive asymptotic secret key rates in both the DD and DI scenarios (under the fair-sampling assumption for the latter case).

  20. On the Security of Black-Box Implementation of Visual Secret Sharing Schemes

    Directory of Open Access Journals (Sweden)

    Adrian Atanasiu

    2012-03-01

    Full Text Available Cryptographic software and devices give users the ability to take advantage of the benefits of cryptography more easily. However, this implies that the users must totally trust the manufacturer and the authenticity of the device or software they use. Young and Yung were the first to question the correctness of the manufacturer and considered the advantage that a malicious implementation could offer to a specific attacker. In this paper, we consider a modified version of two visual secret sharing schemes and the advantage that they provide to the attacker in order to reconstruct the secret by himself, while the other participants must fulfill the honest scheme reconstruction conditions. We also analyze the security of the proposed mechanisms and the conditions in which they can be applicable.

  1. Quantum top secret. The solution of the quantum puzzle. Metamorphosis of a picture of world; Quantum top secret. Die Loesung des Quantenraetsels. Metamorphose eines Weltbildes

    Energy Technology Data Exchange (ETDEWEB)

    Wingert, M.

    2008-07-01

    Many physicists believe that because of unexplained causes, which must anyway be concerned with the quantum puzzle and the mysterious consciousness, it would be no more possible to understand the real structure of the reality - this subtle smiling of the nature, which irritates the physicists since 100 years and the disturbed the theoretical physics so much that they threw the towel. Since nature is considered as absurd, strange, and crazy - and quantum theory as very complicated. But in reality the basic experiments are of a touching simplicity, which seems only completely unintelligible in the picture of world of mechanics. For these experiments show that the concept of body of mechanics and the body conceptions of the thinking cannot at all match the structure of nature. If this is objectively taken notice of without doubting on the existence of a reality, the experiments show the real, unveiled face of the nature. Light and matter must then consist of fields, which can themselves divide by non-mechanical way, so with wholeness, comparable only with cell division and branching processes in biology. Either it is completely crazy - or the only logic interpretation, which hitherto only no physicist risked to think. For these experiments disprove the atom and elementary-particle hypothesis, the picture of world of mechanics, and also the quantum-mechanical interpretation - and indeed uniquely. This knowledge could break the Gordian knot, solve the quantum puzzle, and also give away the secret of the thinking spirit.

  2. Algebra for applications cryptography, secret sharing, error-correcting, fingerprinting, compression

    CERN Document Server

    Slinko, Arkadii

    2015-01-01

    This book examines the relationship between mathematics and data in the modern world. Indeed, modern societies are awash with data which must be manipulated in many different ways: encrypted, compressed, shared between users in a prescribed manner, protected from an unauthorised access and transmitted over unreliable channels. All of these operations can be understood only by a person with knowledge of basics in algebra and number theory. This book provides the necessary background in arithmetic, polynomials, groups, fields and elliptic curves that is sufficient to understand such real-life applications as cryptography, secret sharing, error-correcting, fingerprinting and compression of information. It is the first to cover many recent developments in these topics. Based on a lecture course given to third-year undergraduates, it is self-contained with numerous worked examples and exercises provided to test understanding. It can additionally be used for self-study.

  3. The Quantum Affine Origin of the AdS/CFT Secret Symmetry

    CERN Document Server

    de Leeuw, Marius; Torrielli, Alessandro

    2011-01-01

    We find a new quantum affine symmetry of the S-matrix of the one-dimensional Hubbard chain. We show that this symmetry originates from the quantum affine superalgebra U_q(gl(2|2)), and in the rational limit exactly reproduces the secret symmetry of the AdS/CFT worldsheet S-matrix.

  4. Shamir secret sharing scheme with dynamic access structure (SSSDAS). Case study on nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, P.; Thandra, Prasanth Kumar; Rajan, J.; Satyamurthy, S.A.V. [Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam (India). Computer Div.; Aghila, G. [National Institute of Technology, Karaikal (India). Dept. of Computer Science and Engineering

    2015-05-15

    In recent years, due to the sophistication offered by the Internet, strategic organizations like nuclear power plants are linked to the outside world communication through the Internet. The entry of outside world communication into strategic organization (nuclear power plant) increases the hacker's attempts to crack its security and to trace any information which is being sent among the top level officials. Information security system in nuclear power plant is very crucial as even small loophole in the security system will lead to a major disaster. Recent cyber attacks in nuclear power plant provoked information security professionals to look deeply into the information security aspects of strategic organizations (nuclear power plant). In these lines, Shamir secret sharing scheme with dynamic access structure (SSSDAS) is proposed in the paper which provides enhanced security by providing dynamic access structure for each node in different hierarchies. The SSSDAS algorithm can be applied to any strategic organizations with hierarchical structures. In this paper the possible scenarios where SSSDAS algorithm can be applied to nuclear power plant is explained as a case study. The proposed SSSDAS scheme identifies the wrong shares, if any, used for reconstruction of the secret. The SSSDAS scheme also address the three major security parameters namely confidentiality, authentication and integrity.

  5. A Secure and Efficient Scalable Secret Image Sharing Scheme with Flexible Shadow Sizes.

    Science.gov (United States)

    Xie, Dong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2017-01-01

    In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications. Besides, almost all existing SSIS schemes are not applicable under noise circumstances. To address these deficiencies, in this paper we present a novel SSIS scheme based on a brand-new technique, called compressed sensing, which has been widely used in many fields such as image processing, wireless communication and medical imaging. Our scheme has the property of flexibility, which means that the dealer can achieve a compromise between the size of each shadow and the quality of the reconstructed image. In addition, our scheme has many other advantages, including smooth scalability, noise-resilient capability, and high security. The experimental results and the comparison with similar works demonstrate the feasibility and superiority of our scheme.

  6. A Secure and Efficient Scalable Secret Image Sharing Scheme with Flexible Shadow Sizes

    Science.gov (United States)

    Xie, Dong; Li, Lixiang; Peng, Haipeng; Yang, Yixian

    2017-01-01

    In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications. Besides, almost all existing SSIS schemes are not applicable under noise circumstances. To address these deficiencies, in this paper we present a novel SSIS scheme based on a brand-new technique, called compressed sensing, which has been widely used in many fields such as image processing, wireless communication and medical imaging. Our scheme has the property of flexibility, which means that the dealer can achieve a compromise between the size of each shadow and the quality of the reconstructed image. In addition, our scheme has many other advantages, including smooth scalability, noise-resilient capability, and high security. The experimental results and the comparison with similar works demonstrate the feasibility and superiority of our scheme. PMID:28072851

  7. Improvement on the Multihop Shareholder Discovery for ThresholdSecret Sharing in MANETs

    Institute of Scientific and Technical Information of China (English)

    Seleviawati Tarmizi; Prakash Veeraraghavan; Somnath Ghosh

    2011-01-01

    The collaboration of at least a threshold number of secret shareholders in a threshold secret sharing scheme is a strict requirement to ensure its intended functionality.Due to its promising characteristics,such a scheme has been proposed to solve a range of security problems in mobile ad hoc networks.However,discovering a sufficient number of secret shareholders in such dynamic and unpredictable networks is not easy.In this paper,we propose a more efficient shareholder discovery mechanism compared to our previous work.The discovery process is performed in a multihop fashion to adapt to the mobile ad hoc network environment.We introduce batch extension that gradually extends the shareholders' collaboration boundary by more than one hop at a time around the service requestor,to find at least the threshold number of the unknown shareholders.Through the batch extension,reply aggregation is applicable,hence reducing the redundancy use of reply routes,decreasing the required packet transmission,and lessening the service delay,compared to the previously proposed mechanism.Our simulation results show that,with the appropriate batch size,the latest mechanism is more efficient with an insignificant increase of control overhead.

  8. DISTRIBUTED CERTIFICATE AUTHORITY IN CLUSTER-BASED MANET USING MULTI SECRET SHARING SCHEME

    Directory of Open Access Journals (Sweden)

    Mohammed Azza

    2015-11-01

    Full Text Available Providing secure communications in mobile ad hoc networks (MANET is an important and difficult problem, due to a lack of a key management infrastructure. The authentication is an important security service in (MANETs. To provide a node authentication service we use a fully distributed certificate authorities (FDCA based on the threshold cryptography. In this paper we propose an efficient and verifiable multi secret sharing scheme in cluster-based MANET with a low computation system. Our scheme is based on the overdetermined linear system equation in Galois fields GF(2r. We have analyzed our scheme based on security and performance criteria, and compared with existing approaches. The efficiency of our proposed schemes was verified and evaluated by simulation. Simulation results show that this approach is scalable.

  9. Constructing UC Secure and Constant-Round Group Key Exchange Protocols via Secret Sharing

    Directory of Open Access Journals (Sweden)

    Sangjae Moon

    2008-07-01

    Full Text Available Group key exchange (GKE is one of the basic building blocks in securing group communication. A number of solutions to GKE problem have been proposed, but most of them are not scalable and require a number of rounds linear with the number of group members. We present a method of constructing constant-round and identity-based protocol via secret sharing for GKE within universally composability (UC framework. The resultant protocol focuses on round efficiency and three rounds of communication are required. The protocol allows the batch verification of messages signed by all other group participants. Moreover, compared with other identity-based protocols, the key generation center (KGC in our protocol is not always online.

  10. Constructing UC Secure and Constant-Round Group Key Exchange Protocols via Secret Sharing

    Directory of Open Access Journals (Sweden)

    Moon Sangjae

    2008-01-01

    Full Text Available Abstract Group key exchange (GKE is one of the basic building blocks in securing group communication. A number of solutions to GKE problem have been proposed, but most of them are not scalable and require a number of rounds linear with the number of group members. We present a method of constructing constant-round and identity-based protocol via secret sharing for GKE within universally composability (UC framework. The resultant protocol focuses on round efficiency and three rounds of communication are required. The protocol allows the batch verification of messages signed by all other group participants. Moreover, compared with other identity-based protocols, the key generation center (KGC in our protocol is not always online.

  11. A novel lost packets recovery scheme based on visual secret sharing

    Science.gov (United States)

    Lu, Kun; Shan, Hong; Li, Zhi; Niu, Zhao

    2017-08-01

    In this paper, a novel lost packets recovery scheme which encrypts the effective parts of an original packet into two shadow packets based on (2, 2)-threshold XOR-based visual Secret Sharing (VSS) is proposed. The two shadow packets used as watermarks would be embedded into two normal data packets with digital watermarking embedding technology and then sent from one sensor node to another. Each shadow packet would reveal no information of the original packet, which can improve the security of original packet delivery greatly. The two shadow packets which can be extracted from the received two normal data packets delivered from a sensor node can recover the original packet lossless based on XOR-based VSS. The Performance analysis present that the proposed scheme provides essential services as long as possible in the presence of selective forwarding attack. The proposed scheme would not increase the amount of additional traffic, namely, lower energy consumption, which is suitable for Wireless Sensor Network (WSN).

  12. A secure data outsourcing scheme based on Asmuth-Bloom secret sharing

    Science.gov (United States)

    Idris Muhammad, Yusuf; Kaiiali, Mustafa; Habbal, Adib; Wazan, A. S.; Sani Ilyasu, Auwal

    2016-11-01

    Data outsourcing is an emerging paradigm for data management in which a database is provided as a service by third-party service providers. One of the major benefits of offering database as a service is to provide organisations, which are unable to purchase expensive hardware and software to host their databases, with efficient data storage accessible online at a cheap rate. Despite that, several issues of data confidentiality, integrity, availability and efficient indexing of users' queries at the server side have to be addressed in the data outsourcing paradigm. Service providers have to guarantee that their clients' data are secured against internal (insider) and external attacks. This paper briefly analyses the existing indexing schemes in data outsourcing and highlights their advantages and disadvantages. Then, this paper proposes a secure data outsourcing scheme based on Asmuth-Bloom secret sharing which tries to address the issues in data outsourcing such as data confidentiality, availability and order preservation for efficient indexing.

  13. Shared secrets: Web 2.0 and research in Social Sciences

    Directory of Open Access Journals (Sweden)

    Sandra MARTORELL

    2013-12-01

    Full Text Available Web 2.0 represents a revolution in terms of the possibilities it offers for facilitating communication and collaboration between users – something that has become increasingly common in the world of research. A mere few years ago, the information produced by scientists and scholars remained in the hands of a very limited circle of institutions and publishers, as if it were a guarded secret. Today that secret is being shouted from the rooftops and shared with the rest of the scientific community in order to make it more accessible and to allow new advances. A clear example of this can be found in the social sciences, where there is a constant increase in the production of articles and materials that in turn serve for the pursuit of further research, thereby promoting the continuous development of scientific knowledge. This new situation is being fostered by the proliferation of tools and applications that make it possible, but also by a change in mentality towards a philosophy of exchange and open access. In this article, we will examine this phenomenon using a methodological system based on the analysis of platforms for the exchange of scientific knowledge, and especially social networks (both general and specialising in the social sciences, in order to demonstrate their potential in a society that is becoming increasingly aware of the need to overcome physical or institutional boundaries and move forward together.

  14. Quantum Encoder and Decoder for Secret Key Distribution with Check Bits

    Directory of Open Access Journals (Sweden)

    T. Godhavari

    2013-12-01

    Full Text Available The focus of this study is to develop a novel method of encoding the qubits and use as secret key in public key cryptography. In BB 84 protocol, 50% of the random number (generated at source is used as secret key and the remaining bits are used as “check bits”. The check bits are used to detect the presence of eve as well as the nature of quantum channels. In this protocol, random qubits are encoded using different type of polarizations like horizontal, veritical and diagonal. In the proposed quantum encoder, basic quantum gates are used to encode the random secret key along with the check bits. Quantum key distribution, (a cryptographic mechanism relies on the inherent randomness of quantum mechanics and serves as an option to replace techniques made vulnerable by quantum computing. However, it is still subject to clever forms of eavesdropping and poses a significant challenge to implementation. To study the challenges, quantum circuits are first simulated using QCAD.

  15. Secret Key Distillation for Continuous Variable Quantum Key Distribution against Gaussian Classical Eve

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yi-Bo; HAN Zheng-Fu; CHEN Jin-Jian; GU You-Zhen; GUO Guang-Can

    2008-01-01

    The continuous variable quantum key distribution is expected to provide high secret key rate without single photon source and detector, while the lack of the effective key distillation method makes it unpractical under the high loss condition. Here we present a single-bit-reverse-reconciliation protocol against Gaussian classical Eve,which can distill the secret key through practical imperfect error correction with high efficiency. The simulation results show that this protocol can distill secret keys even when the transmission fibre is longer than 150 km,which may make the continuous variable scheme to outvie the single photon one.

  16. Block Access Token Renewal Scheme Based on Secret Sharing in Apache Hadoop

    Directory of Open Access Journals (Sweden)

    Su-Hyun Kim

    2014-07-01

    Full Text Available In a cloud computing environment, user data is encrypted and stored using a large number of distributed servers. Global Internet service companies such as Google and Yahoo have recognized the importance of Internet service platforms and conducted their own research and development to utilize large cluster-based cloud computing platform technologies based on low-cost commercial off-the-shelf nodes. Accordingly, as various data services are now allowed over a distributed computing environment, distributed management of big data has become a major issue. On the other hand, security vulnerability and privacy infringement due to malicious attackers or internal users can occur by means of various usage types of big data. In particular, various security vulnerabilities can occur in the block access token, which is used for the permission control of data blocks in Hadoop. To solve this problem, we have proposed a weight-applied XOR-based efficient distribution storage and recovery scheme in this paper. In particular, various security vulnerabilities can occur in the block access token, which is used for the permission control of data blocks in Hadoop. In this paper, a secret sharing-based block access token management scheme is proposed to overcome such security vulnerabilities.

  17. A Dynamic Key Management Scheme Based on Secret Sharing for Hierarchical Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Enjian Bai

    2013-01-01

    Full Text Available Since wireless sensor networks (WSN for short are often deployed in hostile environments in many applications, security becomes one of the critical issues in WSN. Moreover, due to the limitation of the sensor nodes, traditional key management schemes are not suitable for it. Thereby,a feasible and efficient key management scheme is an important guarantee for WSN to communicate securely. For the moment, many protocols have been proposed and each has its own advantages. However, these protocols cannot provide sufficient security in many cases, such as node capture attack, which makes WSN more vulnerable than traditional wireless networks. Key protection and revocation issues must be considered with special attention in WSN. To address these two issues, we propose a dynamically clustering key management scheme based on secret sharing for WSN. The scheme combined the hierarchical structure of wireless sensor networks with dynamic key management scheme. The analysis results show that the scheme has strong security and resistance of captured attack, as well as low communicational overhead, and it well meets the requirement of scalability.

  18. Novel and effective secret sharing scheme%新型有效的秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    石润华; 黄刘生; 杨威; 仲红

    2012-01-01

    提出了一种新的秘密共享方案.该方案分两层实现:上层,基于Stern-Brocot树把一个大的秘密拆分为t个小整数(子秘密);底层,借鉴一维元胞自动机模型中的进化方法,把上层的t个子秘密作为初始状态,动态生成各参与者的共享.特别地,该方案能够动态扩展参与者,动态调整门限值,动态更新秘密和共享.另外,还具有计算简单,各参与者共享份额短的优点.分析结果表明,该方案安全、有效.%A novel secret sharing scheme was proposed. This scheme consisted of two layer protocols: in the first layer, a larger secret was split into / smaller integers (sub-secrets) based on the Stern-Brocot tree; in the lower layer, (sub-secrets obtained from the first layer were regarded as t initial states in one-dimensional cellular automaton model, and then from the t initial states it could dynamic create all participants' shares according to the simple fixed rule. This scheme could dynamic add new member, adjust the threshold value and renew the secret and the shares. Besides, there were still other advantages that the costs of the computation were very low and the size of the shares was very small. The results of analysis show that it was secure and very efficient.

  19. A Novel Multi-Secret Sharing Approach for Secure Data Warehousing and On-Line Analysis Processing in the Cloud

    OpenAIRE

    Attasena, Varunya; Harbi, Nouria; Darmont, Jérôme

    2015-01-01

    International audience; Cloud computing helps reduce costs, increase business agility and deploy solutions with a high return on investment for many types of applications, including data warehouses and on-line analytical processing. However, storing and transferring sensitive data into the cloud raises legitimate security concerns. In this paper, we propose a new multi-secret sharing approach for deploying data warehouses in the cloud and allowing on-line analysis processing, while enforcing ...

  20. A Novel Multi-Secret Sharing Approach for Secure Data Warehousing and On-Line Analysis Processing in the Cloud

    OpenAIRE

    Attasena, Varunya; Harbi, Nouria; Darmont, Jérôme

    2017-01-01

    Cloud computing helps reduce costs, increase business agility and deploy solutions with a high return on investment for many types of applications, including data warehouses and on-line analytical processing. However, storing and transferring sensitive data into the cloud raises legitimate security concerns. In this paper, we propose a new multi-secret sharing approach for deploying data warehouses in the cloud and allowing on-line analysis processing, while enforcing data privacy, integrity ...

  1. Floodlight quantum key distribution: A practical route to gigabit-per-second secret-key rates

    Science.gov (United States)

    Zhuang, Quntao; Zhang, Zheshen; Dove, Justin; Wong, Franco N. C.; Shapiro, Jeffrey H.

    2016-07-01

    The channel loss incurred in long-distance transmission places a significant burden on quantum key distribution (QKD) systems: they must defeat a passive eavesdropper who detects all the light lost in the quantum channel and does so without disturbing the light that reaches the intended destination. The current QKD implementation with the highest long-distance secret-key rate meets this challenge by transmitting no more than one photon per bit [M. Lucamarini et al., Opt. Express 21, 24550 (2013), 10.1364/OE.21.024550]. As a result, it cannot achieve the Gbps secret-key rate needed for one-time pad encryption of large data files unless an impractically large amount of multiplexing is employed. We introduce floodlight QKD (FL-QKD), which floods the quantum channel with a high number of photons per bit distributed over a much greater number of optical modes. FL-QKD offers security against the optimum frequency-domain collective attack by transmitting less than one photon per mode and using photon-coincidence channel monitoring, and it is completely immune to passive eavesdropping. More importantly, FL-QKD is capable of a 2-Gbps secret-key rate over a 50-km fiber link, without any multiplexing, using available equipment, i.e., no new technology need be developed. FL-QKD achieves this extraordinary secret-key rate by virtue of its unprecedented secret-key efficiency, in bits per channel use, which exceeds those of state-of-the-art systems by two orders of magnitude.

  2. Distillation of secret-key from a class of compound memoryless quantum sources

    Science.gov (United States)

    Boche, H.; Janßen, G.

    2016-08-01

    We consider secret-key distillation from tripartite compound classical-quantum-quantum (cqq) sources with free forward public communication under strong security criterion. We design protocols which are universally reliable and secure in this scenario. These are shown to achieve asymptotically optimal rates as long as a certain regularity condition is fulfilled by the set of its generating density matrices. We derive a multi-letter formula which describes the optimal forward secret-key capacity for all compound cqq sources being regular in this sense. We also determine the forward secret-key distillation capacity for situations where the legitimate sending party has perfect knowledge of his/her marginal state deriving from the source statistics. In this case regularity conditions can be dropped. Our results show that the capacities with and without the mentioned kind of state knowledge are equal as long as the source is generated by a regular set of density matrices. We demonstrate that regularity of cqq sources is not only a technical but also an operational issue. For this reason, we give an example of a source which has zero secret-key distillation capacity without sender knowledge, while achieving positive rates is possible if sender marginal knowledge is provided.

  3. Proactive secret sharing scheme without trusted party%一种无可信中心动态秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    何二庆; 侯整风; 朱晓玲

    2013-01-01

    Some existing secret sharing schemes have not researched the proactive refreshment of new members' secret shares, which greatly reduced the security of the secret sharing system. Against this defect researched, this paper put forward a new proactive secret sharing scheme without trusted part, without exposing the original secret, all members can interact collab-oratively, refresh their secret shares proactively, and add new members. What' s more, new members could also proactively refresh their secret shares with other members at next time period.%现有的无可信中心动态秘密共享方案,尚未对新增成员秘密份额的动态更新问题作相关研究,在很大程度上降低了秘密共享系统的安全性.针对这一缺陷进行研究,提出了一种新的无可信中心动态秘密共享方案,在不暴露原秘密的情况下,成员可以协同交互,动态地更新各自的秘密份额,增加新成员,且新增成员也可以与其他成员协同参加下一轮秘密份额的动态更新.

  4. Quantum broadcast communication

    Institute of Scientific and Technical Information of China (English)

    Wang Jian; Zhang Quan; Tang Chao-Jing

    2007-01-01

    Broadcast encryption allows the sender to securely distribute his/her secret to a dynamically changing group of users over a broadcast channel. In this paper, we just take account of a simple broadcast communication task in quantum scenario, in which the central party broadcasts his secret to multi-receiver via quantum channel. We present three quantum broadcast communication schemes. The first scheme utilizes entanglement swapping and GreenbergerHorne-Zeilinger state to fulfil a task that the central party broadcasts the secret to a group of receivers who share a group key with him. In the second scheme, based on dense coding, the central party broadcasts the secret to multi-receiver,each of which shares an authentication key with him. The third scheme is a quantum broadcast communication scheme with quantum encryption, in which the central party can broadcast the secret to any subset of the legal receivers.

  5. Quantum dense key distribution

    CERN Document Server

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

    2004-01-01

    This paper proposes a new 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 BB84 one. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility.

  6. Secret shared multiple-image encryption based on row scanning compressive ghost imaging and phase retrieval in the Fresnel domain

    Science.gov (United States)

    Li, Xianye; Meng, Xiangfeng; Wang, Yurong; Yang, Xiulun; Yin, Yongkai; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2017-09-01

    A multiple-image encryption method is proposed that is based on row scanning compressive ghost imaging, (t, n) threshold secret sharing, and phase retrieval in the Fresnel domain. In the encryption process, after wavelet transform and Arnold transform of the target image, the ciphertext matrix can be first detected using a bucket detector. Based on a (t, n) threshold secret sharing algorithm, the measurement key used in the row scanning compressive ghost imaging can be decomposed and shared into two pairs of sub-keys, which are then reconstructed using two phase-only mask (POM) keys with fixed pixel values, placed in the input plane and transform plane 2 of the phase retrieval scheme, respectively; and the other POM key in the transform plane 1 can be generated and updated by the iterative encoding of each plaintext image. In each iteration, the target image acts as the input amplitude constraint in the input plane. During decryption, each plaintext image possessing all the correct keys can be successfully decrypted by measurement key regeneration, compression algorithm reconstruction, inverse wavelet transformation, and Fresnel transformation. Theoretical analysis and numerical simulations both verify the feasibility of the proposed method.

  7. Quantum Steganography

    CERN Document Server

    Shaw, Bilal A

    2010-01-01

    Steganography is the process of hiding secret information by embedding it in an "innocent" message. We present protocols for hiding quantum information in a codeword of a quantum error-correcting code passing through a channel. Using either a shared classical secret key or shared entanglement the sender (Alice) disguises her information as errors in the channel. The receiver (Bob) can retrieve the hidden information, but an eavesdropper (Eve) with the power to monitor the channel, but without the secret key, cannot distinguish the message from channel noise. We analyze how difficult it is for Eve to detect the presence of secret messages, and estimate rates of steganographic communication and secret key consumption for certain protocols.

  8. Shared Secrets: Motherhood and Male Homosexuality in Doppelgänger Narratives

    DEFF Research Database (Denmark)

    Sencindiver, Susan Yi

    2011-01-01

    narratives. Enlisting Joseph Conrad’s short story, “The Secret Sharer,” among others, as both a paradigmatic yet self-conscious example, I examine the intersecting hotbed of these two strange bedfellows, motherhood and homosexuality, as well as the significance of gender in the male doppelgänger imaginary....

  9. Neuroticism and Morning Cortisol Secretion: Both Heritable, But No Shared Genetic Influences

    NARCIS (Netherlands)

    Riese, H; Rijsdijk, F.V.; Rosmalen, J.G.M.; Snieder, Harold; Ormel, J.

    2009-01-01

    Neuroticism is widely used as an explanatory concept in etiological research of psychopathology. To clarify what neuroticism actually represents, we investigated the phenotypic and genetic relationship between neuroticism and the morning cortisol secretion. In the current classic twin study, 125 fem

  10. Neuroticism and Morning Cortisol Secretion : Both Heritable, But No Shared Genetic Influences

    NARCIS (Netherlands)

    Riese, Harriette; Rijsdijk, Fruehling V.; Rosmalen, Judith G. M.; Snieder, Harold; Ormel, Johan

    2009-01-01

    Neuroticism is widely used as an explanatory concept in etiological research of psychopathology. To clarify what neuroticism actually represents, we investigated the phenotypic and genetic relationship between neuroticism and the morning cortisol secretion. In the current classic twin study, 125 fem

  11. A Location-aware and Secret-share Based Dynamic Key Management Scheme for Heterogeneous Sensor Networks

    Directory of Open Access Journals (Sweden)

    Chunguang Ma

    2010-04-01

    Full Text Available Recently, Numerous dynamic key management schemes have been proposed for WSN, and it has long-lived networks, more sustained security and survivability, such as SHELL and LCOK. But most of these schemes are greatly depend on some central nodes (gateways, if these nodes were compromised, there will be great threat to the whole networks security and survivability. In this paper, we proposed a Location-aware and secret share based dynamic key management scheme to effectively replace the compromised central node and enhance the security level of the network.

  12. Neuroticism and Morning Cortisol Secretion: Both Heritable, But No Shared Genetic Influences

    OpenAIRE

    Riese, Harriette; Rijsdijk, Fruehling V.; Rosmalen, Judith G. M.; Snieder, Harold; Ormel, Johan

    2009-01-01

    Neuroticism is widely used as an explanatory concept in etiological research of psychopathology. To clarify what neuroticism actually represents, we investigated the phenotypic and genetic relationship between neuroticism and the morning cortisol secretion. In the current classic twin study, 125 female twin pairs (74 monozygotic and 51 dizygotic pairs) participated. For each participant, 4 different neuroticism scores were available to calculate a neuroticism composite score that was used in ...

  13. A Scheme to Share Information via Employing Discrete Algorithm to Quantum States*

    Institute of Scientific and Technical Information of China (English)

    KANG Guo-Dong; FANG Mao-Fa

    2011-01-01

    We propose a protocol for information sharing between two legitimate parties (Bob and Alice) via public-key cryptography. In particular, we specialize the protocol by employing discrete algorithm under mod that maps integers to quantum states via photon rotations. Based on this algorithm, we find that the protocol is secure under various classes of attacks. Specially, owe to the algorithm, the security of the classical privacy contained in the quantum public-key and the corresponding ciphertext is guaranteed. And the protocol is robust against the impersonation attack and the active wiretapping attack by designing particular checking processing, thus the protocol is valid.

  14. General A Scheme to Share Information via Employing Discrete Algorithm to Quantum States

    Science.gov (United States)

    Kang, Guo-Dong; Fang, Mao-Fa

    2011-02-01

    We propose a protocol for information sharing between two legitimate parties (Bob and Alice) via public-key cryptography. In particular, we specialize the protocol by employing discrete algorithm under mod that maps integers to quantum states via photon rotations. Based on this algorithm, we find that the protocol is secure under various classes of attacks. Specially, owe to the algorithm, the security of the classical privacy contained in the quantum public-key and the corresponding ciphertext is guaranteed. And the protocol is robust against the impersonation attack and the active wiretapping attack by designing particular checking processing, thus the protocol is valid.

  15. Type VI secretion and bacteriophage tail tubes share a common assembly pathway

    OpenAIRE

    Yannick R Brunet; Hénin, Jérôme; Celia, Hervé; Cascales, Eric

    2014-01-01

    The Type VI secretion system (T6SS) is a widespread macromolecular structure that delivers protein effectors to both eukaryotic and prokaryotic recipient cells. The current model describes the T6SS as an inverted phage tail composed of a sheath-like structure wrapped around a tube assembled by stacked Hcp hexamers. Although recent progress has been made to understand T6SS sheath assembly and dynamics, there is no evidence that Hcp forms tubes in vivo. Here we show that Hcp interacts with TssB...

  16. Multi-proxy quantum group signature scheme with threshold shared verification

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Guang

    2008-01-01

    A multi-proxy quantum group signature scheme with threshold shared verification is proposed.An original signer may authorize a proxy group as his proxy agent.Then only the cooperation of all the signers in the proxy group can generate the proxy signature on behalf of the original signer.In the scheme,any t or more of n receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the proxy signature.

  17. Robust quantum dialogue based on the entanglement swapping between any two logical Bell states and the shared auxiliary logical Bell state

    Science.gov (United States)

    Ye, Tian-Yu

    2015-04-01

    In this paper, using the quantum entanglement swapping technologies under the collective-dephasing noise and the collective-rotation noise, two robust quantum dialogue protocols are proposed, respectively. The logical Bell states are used as the traveling states to combat the collective noise. The auxiliary logical Bell state is shared privately between two participants through the manner of direct transmission first. After encoded with the receiver's secret messages, it swaps entanglement with its adjacent logical Bell state. In this way, the information leakage problem is avoided. Moreover, Eve's active attacks can be detected with the help of decoy photon technology. For decoding, the Bell state measurements rather than the four-qubit joint measurements are needed.

  18. Secret-Sharing over Multiple-Antenna Channels with Transmit Correlation

    KAUST Repository

    Zorgui, Marwen

    2015-01-07

    We consider secret-key agreement with public discussion over Rayleigh fastfading channels with transmit correlation. The legitimate receiver and the eavesdropper are assumed to have perfect channel knowledge while the transmitter has only knowledge of the transmit correlation matrix. First, We derive the expression of the key capacity under the considered setup. Then, we show that the optimal transmit strategy achieving the key capacity consists in transmitting Gaussian signals along the eingenvectors of the channel covariance matrix. The powers allocated to each channel mode are determined as the solution of a numerical optimization problem that we derive. We also provide a waterfilling interpretation of the optimal power allocation. Finally, we develop a necessary and sufficient condition for beamforming to be optimal, i.e., transmitting along the strongest channel mode only is key capacity-achieving.

  19. 动态安全的多级门限多秘密共享方案%Multi-level threshold multi-secret sharing scheme with proactive security

    Institute of Scientific and Technical Information of China (English)

    邹惠; 王建东

    2009-01-01

    In multi-secret sharing schemes, the secrets can only be shared in the same level threshold. A multi-level threshold multi-secret sharing scheme based on bivariate polynomial and the intractability of the discrete logarithm was proposed. A bivariate polynomial can degenerate to different lower-order bivariate polynomial according to different thresholds. The scheme has the following characteristics: the secrets can be shared in the multiple level threshold; the multiple secrets can be shared in the same level threshold; the scheme is proactive secure, and the shadow of every participant can be renewed periodically.%在已有的多秘密共享方案中,存在只能在同一级门限下共享秘密的限制.基于离散对数问题的难解性,利用二元多项式,给出一种多级门限多秘密共享方案.二元多项式能在不同级门限共享中退化为不同的低阶的二元多项式,实现多级多秘密共享.该方案具有如下特点:在多级门限下共享秘密,在同级门限下可共享任意多个秘密;具有动态安全性,能定时更新成员的子秘密.

  20. A New Loss-Tolerant Image Encryption Scheme Based on Secret Sharing and Two Chaotic Systems

    Directory of Open Access Journals (Sweden)

    Li Li

    2012-04-01

    Full Text Available In this study, we propose an efficient loss-tolerant image encryption scheme that protects both confidentiality and loss-tolerance simultaneously in shadow images. In this scheme, we generate the key sequence based on two chaotic maps and then encrypt the image during the sharing phase based on Shamir’s method. Experimental results show a better performance of the proposed scheme for different images than other methods from human vision. Security analysis confirms a high probability to resist both brute-force and collusion attacks.

  1. Beyond quantum probability: another formalism shared by quantum physics and psychology.

    Science.gov (United States)

    Dzhafarov, Ehtibar N; Kujala, Janne V

    2013-06-01

    There is another meeting place for quantum physics and psychology, both within and outside of cognitive modeling. In physics it is known as the issue of classical (probabilistic) determinism, and in psychology it is known as the issue of selective influences. The formalisms independently developed in the two areas for dealing with these issues turn out to be identical, opening ways for mutually beneficial interactions.

  2. Type VI secretion and bacteriophage tail tubes share a common assembly pathway.

    Science.gov (United States)

    Brunet, Yannick R; Hénin, Jérôme; Celia, Hervé; Cascales, Eric

    2014-03-01

    The Type VI secretion system (T6SS) is a widespread macromolecular structure that delivers protein effectors to both eukaryotic and prokaryotic recipient cells. The current model describes the T6SS as an inverted phage tail composed of a sheath-like structure wrapped around a tube assembled by stacked Hcp hexamers. Although recent progress has been made to understand T6SS sheath assembly and dynamics, there is no evidence that Hcp forms tubes in vivo. Here we show that Hcp interacts with TssB, a component of the T6SS sheath. Using a cysteine substitution approach, we demonstrate that Hcp hexamers assemble tubes in an ordered manner with a head-to-tail stacking that are used as a scaffold for polymerization of the TssB/C sheath-like structure. Finally, we show that VgrG but not TssB/C controls the proper assembly of the Hcp tubular structure. These results highlight the conservation in the assembly mechanisms between the T6SS and the bacteriophage tail tube/sheath.

  3. 基于LUC密码体制的动态多秘密共享方案%Dynamic Multi-secret Sharing Scheme Based on LUC Cryptosystem

    Institute of Scientific and Technical Information of China (English)

    张伟; 杜伟章

    2015-01-01

    On the basis of the existing secret sharing schemes based on LUC cryptosystem,this paper proposes a new dynamic multi-secret sharing scheme. The scheme does not need to build secure channel between secret dealer and members,and the members and secrets can be dynamically added and deleted. In the phase of secret recovery,cooperative members only need to submit shadow shares for designated combiner,and the verifier can verify the validity of shadow shares publicly. Thus the system does not need renew secret shares in sharing multiple secrets and multi-group multi-secret. The security of the scheme is proved in the random oracle model, under assumption of the discrete logarithm problem,the result shows that this scheme is semantic security, and in the aspect of calculation, security, the overall performance is superior to the traditional secret sharing scheme.%在现有基于LUC密码体制的秘密共享方案基础上,提出一种新的动态多秘密共享方案。该方案无需在秘密分发者与成员之间建立安全信道,就能对成员和秘密进行动态添加或删除。在秘密重构过程中,合作成员只需向指定生成者提交影子份额,且验证者可对影子份额进行公开验证,从而使得系统无需更新成员的秘密份额即可实现一次性共享多个秘密和多组秘密。通过随机预言机模型对该方案进行验证,结果表明,在离散对数问题的假设下该方案是语义安全的,并且在计算量、安全性、总体性能方面均优于传统秘密共享方案。

  4. Self-coherent phase reference sharing for continuous-variable quantum key distribution

    Science.gov (United States)

    Marie, Adrien; Alléaume, Romain

    2017-01-01

    We develop a comprehensive framework to model and optimize the performance of continuous-variable quantum key distribution (CV-QKD) with a local local oscillator (LLO), when phase reference sharing and QKD are jointly implemented. We first analyze the limitations of the only existing approach, called LLO-sequential, and show that it requires high modulation dynamics and can only tolerate small phase noise. Our main contribution is to introduce two designs to perform LLO CV-QKD, respectively called LLO-delayline and LLO-displacement, and to study their performance. Both designs rely on a self-coherent approach, in which phase reference information and quantum information are coherently obtained from a single optical wavefront. We show that these designs can lift some limitations of the existing LLO-sequential approach. The LLO-delayline design can in particular tolerate much stronger phase noise and thus appears to be an appealing alternative to LLO-sequential in terms of network integrability. We also investigate, with the LLO-displacement design, how phase reference information and quantum information can be multiplexed within a single optical pulse. By studying the trade-off between phase reference recovery and phase noise induced by displacement, we, however, demonstrate that this design can only tolerate low phase noise. On the other hand, the LLO-displacement design has the advantage of minimal hardware requirements and provides a simple approach to multiplex classical and quantum communications, opening a practical path towards the development of ubiquitous coherent classical-quantum communications systems compatible with next-generation network requirements.

  5. BIVARIATE POLYNOMIAL BASED SECRET SHARING TECHNOLOGY STUDY%基于二元多项式的秘密分享技术研究

    Institute of Scientific and Technical Information of China (English)

    唐聃; 舒红平

    2012-01-01

    At present most secret sharing schemes follow the realization idea of classic Shamir scheme, namely the unary polynomial based (k, n) threshold scheme. Such schemes inherit many advantages of Shamir scheme, such as simple thought, easy implementation, harmony of perfection and idealness and so on. However, still there is a defect in these schemes that their access structure is not rich enough, so that the popularization of secret sharing technology in practical applications is seriously limited. In view of this situation, the paper proposes a bivariate polynomial based secret sharing scheme. Besides possessing the various advantages of Shamir scheme, the access structure of the new scheme is greatly enriched. In addition, the new scheme can easily be introduced to image secret sharing, audio secret sharing as well as other fields.%当前大多数秘密分享方案的设计沿用了经典Shamir方案的实现思路,即基于一元多项式的(k,n)门限方案.此类方案继承了Shamir方案的诸多优点,如思路简洁便于实现、兼有完备性(Perfect)和理想性(Ideal)等.然而,这一类方案也有着准入结构不够丰富的缺陷,极大地限制了秘密分享技术在实际应用中的推广.针对这一情况,提出一种基于二元多项式的秘密分享方案,该方案兼有Shamir方案的诸多优点,而准入结构又得到了极大的丰富.此外,新方案很容易推广到图像秘密分享、音频秘密分享等领域.

  6. Quantum identification system

    OpenAIRE

    Dusek, Miloslav; Haderka, Ondrej; Hendrych, Martin; Myska, Robert

    1998-01-01

    A secure quantum identification system combining a classical identification procedure and quantum key distribution is proposed. Each identification sequence is always used just once and new sequences are ``refuelled'' from a shared provably secret key transferred through the quantum channel. Two identification protocols are devised. The first protocol can be applied when legitimate users have an unjammable public channel at their disposal. The deception probability is derived for the case of ...

  7. Threshold quantum secure direct communication without entanglement

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir’s secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

  8. Rational Secret Sharing Scheme Based on Reputation Mechanism%基于信誉机制的理性秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    刘海; 彭长根; 吕桢; 刘荣飞

    2012-01-01

    理性秘密共享是博弈论与传统秘密共享相结合产生的新的研究方向.在理性秘密共享中,参与者从利益最大化的角度选择行为,在秘密重构阶段易出现“空威胁”和最后一轮不合作的问题.本文基于博弈论分析完全理性参与者在信誉机制下的行为偏好,采用激励相容原理,设计信誉惩罚机制,构建一个理性秘密共享方案.该方案通过信誉惩罚机制有效的约束完全理性参与者的行为,避免出现“空威胁”.并由信誉最高的参与者充当“可信中心”进行秘密重构,有效的解决在秘密重构阶段最后一轮各个参与者相互不合作的问题,防止参与者相互合谋的行为.%Rational secret sharing is a new hot topic, which is generated at the intersection of game theory and traditional secret sharing. The players choose actions by maximizing their payoff in the rational secret sharing. It is easy to cause the "empty threat" and non-cooperation in the last round of the secret reconstruction phase. This paper proposed a rational secret sharing scheme based on analyzing the preference of rational players in the reputation system using game theory, and designing the reputation punishment mechanism with the incentive compatibility. It effectively restricts the behavior of the completely rational players by reputation punishment mechanism, and avoids the "empty threat". Meanwhile, the secret was reconstructed by the highest reputation player that serves as " trusted center". The proposed scheme effectively solves the problem of non-cooperation and collusion of each player in the secret reconstruction phase.

  9. The (2,2)Bayesian Rational Secret Sharing Sche me%(2,2)贝叶斯理性秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    刘海; 彭长根; 田有亮; 吕桢; 刘荣飞

    2014-01-01

    在理性秘密共享协议中,自利性目标可能会驱使理性参与者偏离协议,从而影响协议的公平性。在(t, n)门限理性秘密共享方案中,其特殊情形(2,2)理性秘密共享方案的公平性较难实现。在同时考虑理性参与者的眼前利益和长远利益的基础上,基于不完全信息动态博弈模型,通过分析理性参与者在(2,2)秘密重构阶段可能采取的策略和信念系统,引入理性参与者的期望收益,研究了(2,2)理性秘密共享重构阶段的完美贝叶斯均衡问题。进一步结合机制设计理论中的VCG(Vickrey-Clarke-Groves)机制,设计激励相容的交互记录机制来约束理性参与者的行为,在不需要秘密分发者保持在线的情形下,提出一个适用于异步通信的公平的(2,2)理性秘密共享方案。%The rational secret sharing is an intersection direction between the traditional secret sharing and game theory .In the rational secret sharing scheme,the selfishness maybe impels rational players to deviate from the protocols so as to influence the fairness of scheme .In the existing threshold rational secret sharing schemes,the fairness of (2,2)rational secret sharing scheme, which is a special case,is hard to be realized,especially implementing on the asynchronous communication channel .To achieve fair-ness of (2,2)rational secret sharing over the asynchronous communication channel,this paper firstly analyzes rational players’utili-ty by simultaneously discussing their short-term interest and long-term interest .Then through illustrating rational players’available actions and belief systems,and computing their expected utilities with the dynamic games of incomplete information,the perfect Bayesian equilibrium for reconstruction phase of (2,2)rational secret sharing is studied.Furthermore,combining with the VCG (Vickrey-Clarke-Groves)mechanism of design theory,the incentive compatibility

  10. RESEARCH ON SECRET SHARING OF IMAGE BASED ON CODING THEORY%基于编码理论的图像秘密分享技术研究

    Institute of Scientific and Technical Information of China (English)

    唐聃; 王晓京

    2013-01-01

    图像的秘密分享是信息安全技术领域具有独特吸引力的研究问题。经过近20年的发展,图像秘密分享已经发展成为一个相对独立的技术领域,但却远没有达到完善的程度。当前大多数图像秘密分享方案均采用了Shamir方案的拉格朗日插值法作为分享方案的核心思想,但是这对于数据量巨大的图像而言无疑会大大降低计算的效率和系统的实用性。基于编码和秘密分享的内在联系,提出一种基于编码技术的图像秘密分享方案。除了具备大多数基于拉格朗日插值法图像秘密分享方案的优点外,新方案算法复杂度显著降低且具有思路简单、容易实现和便于扩展到视频音频领域等特点,有着更加明显的实用价值;此外,基于编码的图像秘密分享系统的实现也从一个侧面证实了编码与秘密分享在本质上的联系。%Secret sharing of image is a research subject with unique attraction in information security technology filed .After developing almost 20 years, secret sharing of image has become a relatively independent technical domain , but far from perfect level .Most of the current secret sharing scheme for image uses Lagrange interpolation of Shamir ’ s scheme as their core idea; however for images with huge amount of data, this will greatly reduce the computational efficiency and system availability .According to internal relationship between the coding theory and the secret sharing technology , in the paper we propose a coding theory-based secret scheme of image .In addition to having the advantages which most secret sharing schemes for image based on Lagrange interpolation have , the new method reduces the computational complexity remarkably and has the features such as simple idea , easy to implement , convenient in extending to the field of video and audio , etc., therefore has more apparent practical value .Besides, the realisation of the coding

  11. Multi-Party Quantum Steganography

    Science.gov (United States)

    Mihara, Takashi

    2017-02-01

    Steganography has been proposed as a data hiding technique. As a derivation, quantum steganography based on quantum physics has also been proposed. In this paper, we extend the results in presented (Mihara, Phys. Lett. 379, 952 2015) and propose a multi-party quantum steganography technique that combines quantum error-correcting codes with entanglement. The proposed protocol shares an entangled state among n +1 parties and sends n secret messages, corresponding to the n parties, to the other party. With no knowledge of the other secret messages, the n parties can construct a stego message by cooperating with each other. Finally, we propose a protocol for sending qubits using the same technique.

  12. Proactive Secret Sharing Scheme Based on ECC%一种基于ECC的动态秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    范畅; 茹鹏

    2012-01-01

    Secret keepers have to face some tasks of key generation, distribution and verification in many of secret sharing schemes with trusted center. Members have difficulty in determining if the recovered secret is valid when the dealer cheats. Furthermore, those schemes are hard to achieve real proactive property. For the purpose of solving the problems, we proposed a distributed proactive secret sharing scheme based on elliptic curve cryptosystems without the trusted center. Anyone can check sub - shares provided by any members. The proactive property can be well implemented in solving secret updating and sub - shares reusing based on secure multi - party computation simulation method. Finally, the security and efficiency were analyzed in the paper. Experiments prove that; this scheme is of higher theoretical innovation and practical engineering value in terms of safety improvement, efficiency and feasible.%许多秘密共享方案需要一个可信方参与,并完成掌管秘密及子密钥的产生、分发和验证工作,一旦可信方出现欺诈或故障,成员很难判断恢复秘密的真伪,既没有解决秘密更新和子密钥复用问题,更不具有秘密的动态更新和生命期特性.为此提出了基于椭圆曲线密码体制的秘密共享方案,具有分布式和动态特性,不需要第三可信方参与,并解决了秘密更新和子密钥复用问题;利用安全多方计算的仿真方法实现;经实验证明:动态方案在安全性方面有所提高,在效率方面可行,具有较高的理论创新和实践工程价值.

  13. Probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel and its application in quantum state sharing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper presents a scheme for probabilistic teleportation of an arbitrary GHZ-class state with a pure entangled two-particle quantum channel. The sender Alice first teleports the coefficients of the unknown state to the receiver Bob, and then Bob reconstructs the state with an auxiliary particle and some unitary operations if the teleportation succeeds. This scheme has the advantage of transmitting much less particles for teleporting an arbitrary GHZ-class state than others. Moreover, it discusses the application of this scheme in quantum state sharing.

  14. Sharing Graphs

    CERN Document Server

    Sahasranand, K R

    2010-01-01

    Almost all known secret sharing schemes work on numbers. Such methods will have difficulty in sharing graphs since the number of graphs increases exponentially with the number of nodes. We propose a secret sharing scheme for graphs where we use graph intersection for reconstructing the secret which is hidden as a sub graph in the shares. Our method does not rely on heavy computational operations such as modular arithmetic or polynomial interpolation but makes use of very basic operations like assignment and checking for equality, and graph intersection can also be performed visually. In certain cases, the secret could be reconstructed using just pencil and paper by authorised parties but cannot be broken by an adversary even with unbounded computational power. The method achieves perfect secrecy for (2, n) scheme and requires far fewer operations compared to Shamir's algorithm. The proposed method could be used to share objects such as matrices, sets, plain text and even a heterogeneous collection of these. S...

  15. Quantum Flows for Secret Key Distribution in the Presence of the Photon Number Splitting Attack

    Directory of Open Access Journals (Sweden)

    Luis A. Lizama-Pérez

    2014-06-01

    Full Text Available Physical implementations of quantum key distribution (QKD protocols, like the Bennett-Brassard (BB84, are forced to use attenuated coherent quantum states, because the sources of single photon states are not functional yet for QKD applications. However, when using attenuated coherent states, the relatively high rate of multi-photonic pulses introduces vulnerabilities that can be exploited by the photon number splitting (PNS attack to brake the quantum key. Some QKD protocols have been developed to be resistant to the PNS attack, like the decoy method, but those define a single photonic gain in the quantum channel. To overcome this limitation, we have developed a new QKD protocol, called ack-QKD, which is resistant to the PNS attack. Even more, it uses attenuated quantum states, but defines two interleaved photonic quantum flows to detect the eavesdropper activity by means of the quantum photonic error gain (QPEG or the quantum bit error rate (QBER. The physical implementation of the ack-QKD is similar to the well-known BB84 protocol.

  16. Secure quantum signatures using insecure quantum channels

    Science.gov (United States)

    Amiri, Ryan; Wallden, Petros; Kent, Adrian; Andersson, Erika

    2016-03-01

    Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages. The security of currently used classical schemes relies on computational assumptions. We present a quantum signature scheme that does not require trusted quantum channels. We prove that it is unconditionally secure against the most general coherent attacks, and show that it requires the transmission of significantly fewer quantum states than previous schemes. We also show that the quantum channel noise threshold for our scheme is less strict than for distilling a secure key using quantum key distribution. This shows that "direct" quantum signature schemes can be preferable to signature schemes relying on secret shared keys generated using quantum key distribution.

  17. Dynamic Quantum Allocation and Swap-Time Variability in Time-Sharing Operating Systems.

    Science.gov (United States)

    Bhat, U. Narayan; Nance, Richard E.

    The effects of dynamic quantum allocation and swap-time variability on central processing unit (CPU) behavior are investigated using a model that allows both quantum length and swap-time to be state-dependent random variables. Effective CPU utilization is defined to be the proportion of a CPU busy period that is devoted to program processing, i.e.…

  18. Discovering and Sharing of Secret Architectures: the Hidden Tomb of the Pharaoh of El-Khasneh Jordan

    Science.gov (United States)

    Malinverni, E. S.; Pierdicca, R.

    2017-02-01

    The documentation of the archaeological heritage through 3D models to know ancient findings, has become a common practice within the international panorama. Using minimal hardware, as well as its ease of use in almost every environmental condition, make 3D sampling solutions based on Multiple View Stereo (MVS) matching and Structure from Motion techniques ideal for on-site documentation of excavations or emergencies. Moreover, the availability of inexpensive platforms for web-based visualization represents great benefit in the field of archaeology, where generally the low budged and the limitation of more complex instruments are a must. The case study presented in these pages, experienced in Petra, Jordan, moves towards this direction. In the close proximity of the El- Khasneh façade, is situated an excavation where two entrance, well preserved, give access to the Tomb of Pharaoh. The documentation described in these pages has the twofold objective of providing the research community with a priceless dataset, acquired for one of the most important heritage of the world that is partially still unknown and to share on line these computations. This work confirms how cultural heritage documentation and dissemination of architectural rests, that are important for tourism and their interactive visualization, can strongly benefit from the creation of 3D models and their sharing on the web. This particular archaeological setting is an interesting base for investigation, given the complexity of the structure and its precarious condition.

  19. Experimental quantum multiparty communication protocols

    Science.gov (United States)

    Smania, Massimiliano; Elhassan, Ashraf M.; Tavakoli, Armin; Bourennane, Mohamed

    2016-06-01

    Quantum information science breaks limitations of conventional information transfer, cryptography and computation by using quantum superpositions or entanglement as resources for information processing. Here we report on the experimental realisation of three-party quantum communication protocols using single three-level quantum system (qutrit) communication: secret-sharing, detectable Byzantine agreement and communication complexity reduction for a three-valued function. We have implemented these three schemes using the same optical fibre interferometric setup. Our realisation is easily scalable without compromising on detection efficiency or generating extremely complex many-particle entangled states.

  20. Classical Knowledge for Quantum Security

    CERN Document Server

    D'Hondt, Ellie

    2008-01-01

    We propose a decision procedure for analysing security of quantum cryptographic protocols, combining a classical algebraic rewrite system for knowledge with an operational semantics for quantum distributed computing. As a test case, we use our procedure to reason about security properties of a recently developed quantum secret sharing protocol that uses graph states. We analyze three different scenarios based on the safety assumptions of the classical and quantum channels and discover the path of an attack in the presence of an adversary. The epistemic analysis that leads to this and similar types of attacks is purely based on our classical notion of knowledge.

  1. Quantum Steganography for Multi-party Covert Communication

    Science.gov (United States)

    Liu, Lin; Tang, Guang-Ming; Sun, Yi-Feng; Yan, Shu-Fan

    2016-01-01

    A novel multi-party quantum steganography protocol based on quantum secret sharing is proposed in this paper. Hidden channels are built in HBB and improved HBB quantum secret sharing protocols for secret messages transmitting, via the entanglement swapping of GHZ states and Bell measurement. Compared with the original protocol, there are only a few different GHZ sates transmitted in the proposed protocol, making the hidden channel with good imperceptibility. Moreover, the secret messages keep secure even when the hidden channel is under the attack from the dishonest participators, for the sub-secretmessages distributed randomly to different participators. With good imperceptibility and security, the capacity of proposed protocol is higher than previous multi-party quantum steganography protocol.

  2. On a simple attack, limiting the range transmission of secret keys in a system of quantum cryptography based on coding in a sub-carrier frequency

    Science.gov (United States)

    Klimov, A. N.; Kulik, S. P.; Molotkov, S. N.; Potapova, T. A.

    2017-03-01

    In the paper by Gleim et al (2016 Opt. Express 24 2619), it was declared that the system of quantum cryptography, exploiting quantum key distribution (QKD) protocol BB84 with the additional reference state and encoding in a sub-carrier, is able to distribute secret keys at a distance of 210 km. The following shows that a simple attack realized with a beam splitter results in a loss of privacy of the keys over substantially smaller distances. It turns out that the actual length of the secret key transmission for the QKD system encoding in the sub-carrier frequency is ten times less than that declared in Gleim et al (2016 Opt. Express 24 2619). Therefore it is impossible to safely use the keys when distributed at a larger length of the communication channel than shown below. The maximum communication distance does not exceed 22 km, even in the most optimistic scenario.

  3. Teleportation of Quantum States through Mixed Entangled Pairs

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2006-01-01

    @@ We describe a protocol for quantum state teleportation via mixed entangled pairs. With the help of an ancilla,near-perfect teleportation might be achieved. For pure entangled pairs, perfect teleportation might be achieved with a certain probability without using an ancilla. The protocol is generalized to teleportation of multiparticle states and quantum secret sharing.

  4. Anonymous-key quantum cryptography and unconditionally secure quantum bit commitment

    CERN Document Server

    Yuen, H P

    2000-01-01

    A new cryptographic tool, anonymous quantum key technique, is introduced that leads to unconditionally secure key distribution and encryption schemes that can be readily implemented experimentally in a realistic environment. If quantum memory is available, the technique would have many features of public-key cryptography; an identification protocol that does not require a shared secret key is provided as an illustration. The possibility is also indicated for obtaining unconditionally secure quantum bit commitment protocols with this technique.

  5. Simple Post Quantum Scheme for Higher Key Rate Multiparty Quantum Key Distribution

    Directory of Open Access Journals (Sweden)

    Abudhahir Buhari

    2012-10-01

    Full Text Available We propose a multi-party quantum key distribution protocol which enables all the receivers can converttheir respective private shared key into common secret key without use of entanglement. The maincomponent of our protocol is a simple post quantum scheme for achieving the higher secret key rate.Efficiency of the extracted key rate is almost 100%. We assume that sender established the pre-sharedprivate secret keys and a common secret number with the receivers. Our proposed scheme sends n stringsof number to n receivers in the public channel to convert their respective shared secret key into commonsecret key in the presence of Eve. We also analyze the complexity of attack by the adversary to guess thesecret key

  6. Faithful quantum entanglement sharing based on linear optics with additional qubits

    Institute of Scientific and Technical Information of China (English)

    Li Xi-Han; Duan Xiao-Jiao; Sheng Yu-Bo; Zhou Hong-Yu; Deng Fu-Guo

    2009-01-01

    This paper presents a scheme for faithfully distributing a pure entanglement between two parties over an arbitrary collective-noise channel with linear optics. The transmission is assisted by an additional qubit against collective noise.The receiver can take advantage of the time discrimination and the measurement results of the assistant qubit to reconstruct a pure entanglement with the sender. Although the scheme succeeds probabilistically,the resource used to get a pure entanglement state is finite,and so is easier to establish entanglement in practice than quantum entanglement purification.

  7. Sharing "Sex Secrets" on Facebook: A Content Analysis of Youth Peer Communication and Advice Exchange on Social Media about Sexual Health and Intimate Relations.

    Science.gov (United States)

    Yeo, Tien Ee Dominic; Chu, Tsz Hang

    2017-09-01

    Social media present opportunities and challenges for sexual health communication among young people. This study is one of the first to examine the actual use of Facebook for peer communication of sexual health and intimate relations. Content analysis of 2186 anonymous posts in a "sex secrets" Facebook page unofficially affiliated with a Hong Kong University shows gender balance among posters, inclusiveness of sexual minorities, and frequent sharing of personal experiences in storytelling or advice seeking. The findings illuminate young people's health concerns regarding condom use, avoiding pain, birth control, sexually transmitted infections, and body appearance. Relational concerns found entailed sexual practices, expectations, and needs-predominantly within dating relationships and include not wanting to have sex. Supportive communication among users was prevalent. A majority of posts involved advice solicitation in the form of request for opinion or information (30.38%), request for advice (13.68%), situation comparison (5.40%), or problem disclosure (9.97%). Comments to the advice-seeking posts were mostly supportive (69.49%); nonsupportive responses (unsolicited messages and gratuitous humor) were concentrated with ambiguous advice solicitations. These findings hold implications for understanding self-disclosure of intimate concerns within social networks, and attuning sexual health intervention on social media to young people's actual needs and advice preferences.

  8. Carcinogenic activity of PbS quantum dots screened using exosomal biomarkers secreted from HEK293 cells.

    Science.gov (United States)

    Kim, Jung-Hee; Kim, Hye-Rim; Lee, Bo-Ram; Choi, Eun-Sook; In, Su-Il; Kim, Eunjoo

    2015-01-01

    Lead sulfide (PbS) quantum dots (QDs) have been applied in the biomedical area because they offer an excellent platform for theragnostic applications. In order to comprehensively evaluate the biocompatibility of PbS QDs in human cells, we analyzed the exosomes secreted from cells because exosomes are released during cellular stress to convey signals to other cells and serve as a reservoir of enriched biomarkers. PbS QDs were synthesized and coated with 3-mercaptopropionic acid (MPA) to allow the particles to disperse in water. Exosomes were isolated from HEK293 cells treated with PbS-MPA at concentrations of 0 µg/mL, 5 µg/mL, and 50 µg/mL, and the exosomal expression levels of miRNAs and proteins were analyzed. As a result, five miRNAs and two proteins were proposed as specific exosomal biomarkers for the exposure of HEK293 cells to PbS-MPA. Based on the pathway analysis, the molecular signature of the exosomes suggested that PbS-MPA QDs had carcinogenic activity. The comet assay and expression of molecular markers, such as p53, interleukin (IL)-8, and C-X-C motif chemokine 5, indicated that DNA damage occurred in HEK293 cells following PbS-MPA exposure, which supported the carcinogenic activity of the particles. In addition, there was obvious intensification of miRNA expression signals in the exosomes compared with that of the parent cells, which suggested that exosomal biomarkers could be detected more sensitively than those of whole cellular extracts.

  9. Probabilistic authenticated quantum dialogue

    Science.gov (United States)

    Hwang, Tzonelih; Luo, Yi-Ping

    2015-12-01

    This work proposes a probabilistic authenticated quantum dialogue (PAQD) based on Bell states with the following notable features. (1) In our proposed scheme, the dialogue is encoded in a probabilistic way, i.e., the same messages can be encoded into different quantum states, whereas in the state-of-the-art authenticated quantum dialogue (AQD), the dialogue is encoded in a deterministic way; (2) the pre-shared secret key between two communicants can be reused without any security loophole; (3) each dialogue in the proposed PAQD can be exchanged within only one-step quantum communication and one-step classical communication. However, in the state-of-the-art AQD protocols, both communicants have to run a QKD protocol for each dialogue and each dialogue requires multiple quantum as well as classical communicational steps; (4) nevertheless, the proposed scheme can resist the man-in-the-middle attack, the modification attack, and even other well-known attacks.

  10. 基于 Shamir 秘密共享的云端多副本审计%Multiple-replica auditing in clouds using Shamir secret sharing

    Institute of Scientific and Technical Information of China (English)

    田晖; 陈羽翔; 黄永峰

    2016-01-01

    For auditing the integrity of multiple-replica in clouds,a public auditing scheme based on Shamir secret sharing was presented.The scheme can generate diverse data tags for different replicas of a given file using Shamir-secret-sharing algorithm,which is helpful for avoiding possible attacks from cloud service provider (CSP)and locating errors while the CSP does not exactly store all required replicas.Further,the scheme support batch auditing for multiple-replicas using Boneh-Lynn-Shacham (BLS)signature and bilinear maps,which can cut down times of interactions between the CSP and the auditor,and reduce communication costs.Moreover,random masks were introduced in user′s data preprocessing and auditing process to avert conspiracy attack of the CSP and prevent privacy leakage. The security of the presented scheme was proved in theory,and the auditing performance was experi-mentally compared with that of the previous work.The experimental results demonstrate that the pro-posed scheme can effectively achieve secure auditing for multiple-replica in clouds,and outperforms the existing methods on both time and space costs.%针对云端多副本审计问题,提出了一种基于 Shamir 秘密共享的审计方案。该方案利用 Shamir 秘密共享算法为同一数据文件的所有副本生成不同的数据标签,以防范云服务提供商的多种攻击,且根据该算法特性生成的聚合标签能有助于实现云服务提供商未完全持有全部副本数据时的出错定位;利用 BLS (Boneh-Lynn-Shacham)签名和双线性映射技术实现了多副本的批量审计,避免了云服务提供商与审计者之间的多次交互,从而降低了审计过程中的通信开销;通过在用户数据预处理阶段引入随机掩码实现了对合谋攻击的防范,并在审计过程中应用随机掩码避免了用户隐私的泄漏。对提出方案的安全性进行了理论证明,并与已有方法在性能方面进行了比较和实

  11. A New Rational Secret Sharing Based on Reputation Mechanism%一个新的基于信誉机制的理性秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    徐志聘; 彭长根; 张豹

    2012-01-01

    针对秘密共享中理性参与者的效用函数难以刻画的问题,考虑参与者的信誉值构建了面向秘密共享的信誉机制;通过考虑理性参与者的长远利益和眼前利益,设计了更为合理的效用假设和效用函数,并以此为基础构建了一个新的基于信誉机制的理性秘密共享方案;最后通过博弈分析表明,在理性秘密共享重构阶段,合作是一个严格的占优策略,我们的方案可以有效地促进理性参与者进行合作,产生一个严格的纳什均衡.%In order to solve the problem that the secret sharing rational participants'utility function was difficult to describe, considered the participants'reputation value, a reputation mechanism for secret sharing was presented. Firstly. By considering the long-term interests and immediate interests of rational participants, a more reasonable utility assumption and utility function were designed, and then a new rational secret sharing scheme was constructed based on the reputation mechanism. Finally, the game analysis shows that the cooperation is a strictly dominant strategy in the rational secret sharing reconstruction phase, and the rational participants can be effective to promote cooperation in the proposed scheme, then a strict Nash equilibrium is produced.

  12. Quantum secure direct communication with Greenberger-Horne-Zeilinger-type state (GHZ state) over noisy channels

    Institute of Scientific and Technical Information of China (English)

    Zhang Xiao-Long; Zhang Yue-Xia; Wei Hua

    2009-01-01

    We propose a quantum error-rejection scheme for direct communication with three-qubit quantum codes based on the direct communication of secret messages without any secret key shared in advance. Given the symmetric and independent errors of the transmitted qubits, our scheme can tolerate a bit of error rate up to 33.1%, thus the protocol is deterministically secure against any eavesdropping attack even in a noisy channel.

  13. Quantum secure direct communication and deterministic secure quantum communication

    Institute of Scientific and Technical Information of China (English)

    LONG Gui-lu; DENG Fu-guo; WANG Chuan; LI Xi-han; WEN Kai; WANG Wan-ying

    2007-01-01

    In this review article,we review the recent development of quantum secure direct communication(QSDC)and deterministic secure quantum communication(DSQC) which both are used to transmit secret message,including the criteria for QSDC,some interesting QSDC protocols,the DSQC protocols and QSDC network,etc.The difference between these two branches of quantum Communication is that DSOC requires the two parties exchange at least one bit of classical information for reading out the message in each qubit,and QSDC does not.They are attractivebecause they are deterministic,in particular,the QSDC protocol is fully quantum mechanical.With sophisticated quantum technology in the future,the QSDC may become more and more popular.For ensuring the safety of QSDC with single photons and quantum information sharing of single qubit in a noisy channel,a quantum privacy amplification protocol has been proposed.It involves very simple CHC operations and reduces the information leakage to a negligible small level.Moreover,with the one-party quantum error correction,a relation has been established between classical linear codes and quantum one-party codes,hence it is convenient to transfer many good classical error correction codes to the quantum world.The one-party quantum error correction codes are especially designed for quantum dense coding and related QSDC protocols based on dense coding.

  14. Autocompensating Quantum Cryptography

    CERN Document Server

    Bethune, D S; Bethune, Donald S.; Risk, William P.

    2002-01-01

    Quantum cryptographic key distribution (QKD) uses extremely faint light pulses to carry quantum information between two parties (Alice and Bob), allowing them to generate a shared, secret cryptographic key. Autocompensating QKD systems automatically and passively compensate for uncontrolled time dependent variations of the optical fiber properties by coding the information as a differential phase between orthogonally-polarized components of a light pulse sent on a round trip through the fiber, reflected at mid-course using a Faraday mirror. We have built a prototype system based on standard telecom technology that achieves a privacy-amplified bit generation rate of ~1000 bits/s over a 10-km optical fiber link. Quantum cryptography is an example of an application that, by using quantum states of individual particles to represent information, accomplishes a practical task that is impossible using classical means.

  15. Hiding Quantum Information in the Perfect Code

    CERN Document Server

    Shaw, Bilal A

    2010-01-01

    We present and analyze a protocol for quantum steganography where the sender (Alice) encodes her steganographic information into the error syndromes of the perfect (five-qubit) quantum error-correcting code, and sends it to the receiver (Bob) over a depolarizing channel. Alice and Bob share a classical secret key, and hide quantum information in such a way that to an eavesdropper (Eve) without access to the secret key, the quantum message looks like an innocent codeword with a typical sequence of quantum errors. We calculate the average rate of key consumption, and show how the protocol improves in performance as information is spread over multiple codeword blocks. Alice and Bob utilize different encodings to optimize the average number of steganographic bits that they can send to each other while matching the error statistics of the depolarizing channel.

  16. Fault-tolerant Remote Quantum Entanglement Establishment for Secure Quantum Communications

    Science.gov (United States)

    Tsai, Chia-Wei; Lin, Jason

    2016-07-01

    This work presents a strategy for constructing long-distance quantum communications among a number of remote users through collective-noise channel. With the assistance of semi-honest quantum certificate authorities (QCAs), the remote users can share a secret key through fault-tolerant entanglement swapping. The proposed protocol is feasible for large-scale distributed quantum networks with numerous users. Each pair of communicating parties only needs to establish the quantum channels and the classical authenticated channels with his/her local QCA. Thus, it enables any user to communicate freely without point-to-point pre-establishing any communication channels, which is efficient and feasible for practical environments.

  17. Quantum secure direct communication with quantum encryption based on pure entangled states

    Institute of Scientific and Technical Information of China (English)

    Li Xi-Han; Li Chun-Yan; Deng Fu-Guo; Zhou Ping; Liang Yu-Jie; Zhou Hong-Yu

    2007-01-01

    This paper presents a scheme for quantum secure direct communication with quantum encryption. The two authorized users use repeatedly a sequence of the pure entangled pairs (quantum key) shared for encrypting and decrypting the secret message carried by the travelling photons directly. For checking eavesdropping, the two parties perform the single-photon measurements on some decoy particles before each round. This scheme has the advantage that the pure entangled quantum signal source is feasible at present and any eavesdropper cannot steal the message.

  18. Controlled quantum teleportation and secure direct communication

    Institute of Scientific and Technical Information of China (English)

    Gao Ting; Yan Feng-Li; Wang Zhi-Xi

    2005-01-01

    We present a controlled quantum teleportation protocol. In the protocol, quantum information of an unknown state of a 2-level particle is faithfully transmitted from a sender Alice to a remote receiver Bob via an initially shared triplet of entangled particles under the control of the supervisor Charlie. The distributed entangled particles shared by Alice, Bob and Charlie function as a quantum information channel for faithful transmission. We also propose a controlled and secure direct communication scheme by means of this teleportation. After ensuring the security of the quantum channel, Alice encodes the secret message directly on a sequence of particle states and transmits them to Bob supervised by Charlie using this controlled quantum teleportation. Bob can read out the encoded message directly by the measurement on his qubit. In this scheme, the controlled quantum teleportation transmits Alice's message without revealing any information to a potential eavesdropper. Because there is not a transmission of the qubit carrying the secret message between Alice and Bob in the public channel, it is completely secure for controlled and direct secret communication if perfect quantum channel is used. The special feature of this scheme is that the communication between two sides depends on the agreement of a third side to co-operate.

  19. 基于中国剩余定理的可验证理性秘密共享方案%Verifiable rational secret sharing scheme based on Chinese remainder theorem

    Institute of Scientific and Technical Information of China (English)

    张利远; 张恩

    2012-01-01

    To address the problem that participant can not be added or deleted dynamically in rational secret sharing scheme so far, this paper proposed a dynamic rational secret sharing scheme which combined game theory with cryptography. The scheme based on Chinese remainder theorem, can add or delete the participant dynamically in the secret reconstruction phase. And it is verifiable by using the verifiable random function, and the cheat of participants cannot work. The participants did not know whether the current round was a testing round. And the gain of following the protocol was more than the gain of deviating, so rational player had an incentive to abide the protocol. Finally, every player could obtain the secret fairly. In addition, the scheme satisfied resilient equilibrium and could withstand the conspiracy attack.%针对目前理性秘密共享方案不能动态添加和删除参与者的问题,结合博弈论和密码学理论,提出一种动态理性秘密共享方案.方案基于中国剩余定理,在秘密重构过程,可以动态添加和删除参与者,另外方案采用可验证的随机函数,能检验参与者的欺骗行为.参与者不知当前轮是否是测试轮,偏离协议没有遵守协议的收益大,理性的参与者有动机遵守协议,最终每位参与者公平地得到秘密.方案不需要可信者参与,满足弹性均衡,能防止成员间的合谋攻击.

  20. Proactive Threshold RSA Signature Scheme Based on Polynomial Secret Sharing%基于多项式秘密共享的前摄性门限RSA签名方案

    Institute of Scientific and Technical Information of China (English)

    徐甫

    2016-01-01

    现有可证明安全的前摄性门限RSA签名方案均依赖加性秘密共享方法,存在每次签名均需所有成员参与,易暴露合法成员的秘密份额,签名效率低下等问题。该文以Shoup门限签名为基础,提出一种基于多项式秘密共享的前摄性门限RSA签名方案,并对其进行了详细的安全性及实用性分析。结果表明,在静态移动攻击者模型中,该方案是不可伪造的和稳健的,与现有同类方案相比,其通信开销更低,运算效率更高。%All the existing provable secure proactive threshold RSA signature schemes rely on additive secret sharing, in which all players have to cooperate to produce a signature, valid players’ secret shares may be exposed, and the computing efficiency is too low. Based on Shoup’s threshold RSA signature scheme, a proactive threshold RSA signature scheme is proposed by using polynomial secret sharing, and its security and practicability are analyzed. Results show that the proposed scheme is unforgeable and robust under the model of static mobile adversary, and compared with the existing comparable schemes, its communication overhead is lower and computing efficiency is higher.

  1. Increasing the Efficiencies of Random-Choice-Based Quantum Communication Protocols with Delayed Measurement

    Institute of Scientific and Technical Information of China (English)

    DENG Fu-Guo; LONG Gui-Lu; WANG Yan; XIAO Li

    2004-01-01

    @@ The security of quantum communications lies in the capability of the legitimate parties to detect eavesdropping.Here we propose to use delayed measurement to increase the efficiency of protocols of quantum key distribution and quantum secret sharing that uses a random choice of measuring-basis. In addition to a higher efficiency,these measures also bring the benefit of much reduced amount of classical communications.

  2. 可验证多次使用动态门限大秘密共享方案%Verifiable Multi-Use Dynamic Threshold Large Secret Sharing Scheme

    Institute of Scientific and Technical Information of China (English)

    常利伟; 郑世慧; 邢友松; 金磊; 杨义先

    2015-01-01

    For the efficiency and security problems of large secret sharing, a verifiable multi-use dynamic thres hold large secret sharing scheme was put forward. To improve the efficiency, the large secret is di-vided and represented as a matrix over smaller finite field, and the two-variable one-way function is also utilized;to enhance security, the thres hold modification method is slightly expanded and the elliptic curve discrete logarithm problem is employed. By analysis, this new scheme not only is high-efficiency, but also can prevent dishonest participants from cheating. Meanwhile, the secret shadows can always be kept secret and need not to be renewed in the process of reconstruction. Especially, when the mutual trust varies or the number of the participants belonging to an organization fluctuates, the threshold value will be adjusted by at least t credible participants in time.%针对大秘密共享存在效率和安全方面的不足,提出一个可验证多次使用动态门限大秘密共享方案. 为了提高效率,将大秘密分解,且表示为较小有限域上的矩阵,并利用了二元单向函数. 为了增强安全性,推广门限动态调整方法,利用了椭圆曲线群上离散对数. 理论分析结果表明,该方案不仅存储等效率大大提高,还能抵抗不诚信参与者攻击,且重建过程中秘密份额始终保密无须更新. 尤其当参与者信任发生变化或参与者人数变动时,门限值能够被t个可信参与者及时调整.

  3. A Survey on Recent Security Trends using Quantum Cryptography

    Directory of Open Access Journals (Sweden)

    T. Rubya

    2010-12-01

    Full Text Available Cryptography is the science of keeping private information from nauthorized access of ensuring data integrity and authentication, and it is the strongest tool for controlling against much kind of security threats. Role of cryptography appears in many secured area like government agencies, large banks, telecommunications companies and other corporations who handle sensitive or military data. Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. This paper onsists of the main aspects of quantum cryptography and it investigates the information about where and all quantum cryptography takes place.

  4. PEA: Polymorphic Encryption Algorithm based on quantum computation

    OpenAIRE

    Komninos, N.; Mantas, G.

    2011-01-01

    In this paper, a polymorphic encryption algorithm (PEA), based on basic quantum computations, is proposed for the encryption of binary bits. PEA is a symmetric key encryption algorithm that applies different combinations of quantum gates to encrypt binary bits. PEA is also polymorphic since the states of the shared secret key control the different combinations of the ciphertext. It is shown that PEA achieves perfect secrecy and is resilient to eavesdropping and Trojan horse attacks. A securit...

  5. A System-Level Throughput Model for Quantum Key Distribution

    Science.gov (United States)

    2015-09-17

    quantum mechanics to generate and distribute shared secret keying material. QKD systems generate and distribute key by progressing through a number of...communicate a seed to prime random number generation to construct a very large matrix used in the calculation of Privacy Amplification. We assume that... generate a desired number of final key bits. RQ7: What are the implications of altering the amount of Alice’s memory allocated for Quantum Exchange

  6. Entangled state quantum cryptography: eavesdropping on the ekert protocol

    Science.gov (United States)

    Naik; Peterson; White; Berglund; Kwiat

    2000-05-15

    Using polarization-entangled photons from spontaneous parametric down-conversion, we have implemented Ekert's quantum cryptography protocol. The near-perfect correlations of the photons allow the sharing of a secret key between two parties. The presence of an eavesdropper is continually checked by measuring Bell's inequalities. We investigated several possible eavesdropper strategies, including pseudo-quantum-nondemolition measurements. In all cases, the eavesdropper's presence was readily apparent. We discuss a procedure to increase her detectability.

  7. Quantum

    CERN Document Server

    Al-Khalili, Jim

    2003-01-01

    In this lively look at quantum science, a physicist takes you on an entertaining and enlightening journey through the basics of subatomic physics. Along the way, he examines the paradox of quantum mechanics--beautifully mathematical in theory but confoundingly unpredictable in the real world. Marvel at the Dual Slit experiment as a tiny atom passes through two separate openings at the same time. Ponder the peculiar communication of quantum particles, which can remain in touch no matter how far apart. Join the genius jewel thief as he carries out a quantum measurement on a diamond without ever touching the object in question. Baffle yourself with the bizzareness of quantum tunneling, the equivalent of traveling partway up a hill, only to disappear then reappear traveling down the opposite side. With its clean, colorful layout and conversational tone, this text will hook you into the conundrum that is quantum mechanics.

  8. Efficient quantum dialogue using entangled states and entanglement swapping without information leakage

    Science.gov (United States)

    Wang, He; Zhang, Yu Qing; Liu, Xue Feng; Hu, Yu Pu

    2016-06-01

    We propose a novel quantum dialogue protocol by using the generalized Bell states and entanglement swapping. In the protocol, a sequence of ordered two-qutrit entangled states acts as quantum information channel for exchanging secret messages directly and simultaneously. Besides, a secret key string is shared between the communicants to overcome information leakage. Different from those previous information leakage-resistant quantum dialogue protocols, the particles, composed of one of each pair of entangled states, are transmitted only one time in the proposed protocol. Security analysis shows that our protocol can overcome information leakage and resist several well-known attacks. Moreover, the efficiency of our scheme is acceptable.

  9. Theoretical analysis of the effect of charge-sharing on the Detective Quantum Efficiency of single-photon counting segmented silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Marchal, J [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)], E-mail: julien.marchal@diamond.ac.uk

    2010-01-15

    A detector cascaded model is proposed to describe charge-sharing effect in single-photon counting segmented silicon detectors. Linear system theory is applied to this cascaded model in order to derive detector performance parameters such as large-area gain, presampling Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) as a function of energy detection threshold. This theory is used to model one-dimensional detectors (i.e. strip detectors) where X-ray-generated charge can be shared between two sampling elements, but the concepts developed in this article can be generalized to two-dimensional arrays of detecting elements (i.e. pixels detectors). The zero-frequency DQE derived from this model is consistent with expressions reported in the literature using a different method. The ability of this model to simulate the effect of charge sharing on image quality in the spatial frequency domain is demonstrated by applying it to a hypothetical one-dimensional single-photon counting detector illuminated with a typical mammography spectrum.

  10. Efficient arbitrated quantum signature and its proof of security

    Science.gov (United States)

    Li, Qin; Li, Chengqing; Long, Dongyang; Chan, Wai Hong; Wang, Changji

    2013-07-01

    In this paper, an efficient arbitrated quantum signature scheme is proposed by combining quantum cryptographic techniques and some ideas in classical cryptography. In the presented scheme, the signatory and the receiver can share a long-term secret key with the arbitrator by utilizing the key together with a random number. While in previous quantum signature schemes, the key shared between the signatory and the arbitrator or between the receiver and the arbitrator could be used only once, and thus each time when a signatory needs to sign, the signatory and the receiver have to obtain a new key shared with the arbitrator through a quantum key distribution protocol. Detailed theoretical analysis shows that the proposed scheme is efficient and provably secure.

  11. Efficient adaptive verifiable secret sharing with steganography and tamper resistance scheme%高效自适应可验证抗篡改秘密共享方案

    Institute of Scientific and Technical Information of China (English)

    李瑞林; 陈够喜; 武雪芹

    2015-01-01

    Greater distortion of image steganography was caused by applying the simple least significant bit (LSB) to embed se‐cret information directly in the traditional technology .Therefore ,an efficient verifiable secret sharing method was proposed .A bit sequence was taken as the input of secret sharing which was generated using differential Huffman lossless compression of se‐cret image .The polynomial interpolation and certified value formula were improved .As a result ,the quality of the stego image and the verifiability were enhanced using the technology .Theoretical analysis and experimental results show that high quality of stego image with efficient verifiability and security can be obtained through the scheme .%在传统方案中,直接采用简单最低有效位(LSB)嵌入秘密信息,导致隐写图像失真度较高,为此提出一种高效的可验证秘密共享方案。引入差分哈夫曼无损压缩思想,将产生的比特序列作为秘密共享的输入;通过改进插值多项式和认证值计算公式,增强隐写图像的质量并提高其可验证性。理论分析与实验结果表明,应用该方案可得到高质量的隐写图像,其具有高效可验证性和安全性。

  12. Quantum cryptography over underground optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; Luther, G.G.; Morgan, G.L.; Peterson, C.G.; Simmons, C.

    1996-05-01

    Quantum cryptography is an emerging technology in which two parties may simultaneously generated shared, secret cryptographic key material using the transmission of quantum states of light whose security is based on the inviolability of the laws of quantum mechanics. An adversary can neither successfully tap the key transmissions, nor evade detection, owing to Heisenberg`s uncertainty principle. In this paper the authors describe the theory of quantum cryptography, and the most recent results from their experimental system with which they are generating key material over 14-km of underground optical fiber. These results show that optical-fiber based quantum cryptography could allow secure, real-time key generation over ``open`` multi-km node-to-node optical fiber communications links between secure ``islands.``

  13. Counterfactual quantum cryptography.

    Science.gov (United States)

    Noh, Tae-Gon

    2009-12-01

    Quantum cryptography allows one to distribute a secret key between two remote parties using the fundamental principles of quantum mechanics. The well-known established paradigm for the quantum key distribution relies on the actual transmission of signal particle through a quantum channel. In this Letter, we show that the task of a secret key distribution can be accomplished even though a particle carrying secret information is not in fact transmitted through the quantum channel. The proposed protocols can be implemented with current technologies and provide practical security advantages by eliminating the possibility that an eavesdropper can directly access the entire quantum system of each signal particle.

  14. Capacities of quantum amplifier channels

    Science.gov (United States)

    Qi, Haoyu; Wilde, Mark M.

    2017-01-01

    Quantum amplifier channels are at the core of several physical processes. Not only do they model the optical process of spontaneous parametric down-conversion, but the transformation corresponding to an amplifier channel also describes the physics of the dynamical Casimir effect in superconducting circuits, the Unruh effect, and Hawking radiation. Here we study the communication capabilities of quantum amplifier channels. Invoking a recently established minimum output-entropy theorem for single-mode phase-insensitive Gaussian channels, we determine capacities of quantum-limited amplifier channels in three different scenarios. First, we establish the capacities of quantum-limited amplifier channels for one of the most general communication tasks, characterized by the trade-off between classical communication, quantum communication, and entanglement generation or consumption. Second, we establish capacities of quantum-limited amplifier channels for the trade-off between public classical communication, private classical communication, and secret key generation. Third, we determine the capacity region for a broadcast channel induced by the quantum-limited amplifier channel, and we also show that a fully quantum strategy outperforms those achieved by classical coherent-detection strategies. In all three scenarios, we find that the capacities significantly outperform communication rates achieved with a naive time-sharing strategy.

  15. Topics in quantum cryptography, quantum error correction, and channel simulation

    Science.gov (United States)

    Luo, Zhicheng

    In this thesis, we mainly investigate four different topics: efficiently implementable codes for quantum key expansion [51], quantum error-correcting codes based on privacy amplification [48], private classical capacity of quantum channels [44], and classical channel simulation with quantum side information [49, 50]. For the first topic, we propose an efficiently implementable quantum key expansion protocol, capable of increasing the size of a pre-shared secret key by a constant factor. Previously, the Shor-Preskill proof [64] of the security of the Bennett-Brassard 1984 (BB84) [6] quantum key distribution protocol relied on the theoretical existence of good classical error-correcting codes with the "dual-containing" property. But the explicit and efficiently decodable construction of such codes is unknown. We show that we can lift the dual-containing constraint by employing the non-dual-containing codes with excellent performance and efficient decoding algorithms. For the second topic, we propose a construction of Calderbank-Shor-Steane (CSS) [19, 68] quantum error-correcting codes, which are originally based on pairs of mutually dual-containing classical codes, by combining a classical code with a two-universal hash function. We show, using the results of Renner and Koenig [57], that the communication rates of such codes approach the hashing bound on tensor powers of Pauli channels in the limit of large block-length. For the third topic, we prove a regularized formula for the secret key assisted capacity region of a quantum channel for transmitting private classical information. This result parallels the work of Devetak on entanglement assisted quantum communication capacity. This formula provides a new family protocol, the private father protocol, under the resource inequality framework that includes the private classical communication without the assisted secret keys as a child protocol. For the fourth topic, we study and solve the problem of classical channel

  16. Deterministic secure quantum communication using a single d-level system.

    Science.gov (United States)

    Jiang, Dong; Chen, Yuanyuan; Gu, Xuemei; Xie, Ling; Chen, Lijun

    2017-03-22

    Deterministic secure quantum communication (DSQC) can transmit secret messages between two parties without first generating a shared secret key. Compared with quantum key distribution (QKD), DSQC avoids the waste of qubits arising from basis reconciliation and thus reaches higher efficiency. In this paper, based on data block transmission and order rearrangement technologies, we propose a DSQC protocol. It utilizes a set of single d-level systems as message carriers, which are used to directly encode the secret message in one communication process. Theoretical analysis shows that these employed technologies guarantee the security, and the use of a higher dimensional quantum system makes our protocol achieve higher security and efficiency. Since only quantum memory is required for implementation, our protocol is feasible with current technologies. Furthermore, Trojan horse attack (THA) is taken into account in our protocol. We give a THA model and show that THA significantly increases the multi-photon rate and can thus be detected.

  17. Deterministic secure quantum communication using a single d-level system

    Science.gov (United States)

    Jiang, Dong; Chen, Yuanyuan; Gu, Xuemei; Xie, Ling; Chen, Lijun

    2017-01-01

    Deterministic secure quantum communication (DSQC) can transmit secret messages between two parties without first generating a shared secret key. Compared with quantum key distribution (QKD), DSQC avoids the waste of qubits arising from basis reconciliation and thus reaches higher efficiency. In this paper, based on data block transmission and order rearrangement technologies, we propose a DSQC protocol. It utilizes a set of single d-level systems as message carriers, which are used to directly encode the secret message in one communication process. Theoretical analysis shows that these employed technologies guarantee the security, and the use of a higher dimensional quantum system makes our protocol achieve higher security and efficiency. Since only quantum memory is required for implementation, our protocol is feasible with current technologies. Furthermore, Trojan horse attack (THA) is taken into account in our protocol. We give a THA model and show that THA significantly increases the multi-photon rate and can thus be detected. PMID:28327557

  18. Secure communications using quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G. [and others

    1997-08-01

    The secure distribution of the secret random bit sequences known as {open_quotes}key{close_quotes} material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is an emerging technology for secure key distribution with single-photon transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal single-photon states to generate shared key material over multi-kilometer optical fiber paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. In our optical fiber experiment we have performed quantum key distribution over 24-km of underground optical fiber using single-photon interference states, demonstrating that secure, real-time key generation over {open_quotes}open{close_quotes} multi-km node-to-node optical fiber communications links is possible. We have also constructed a quantum key distribution system for free-space, line-of-sight transmission using single-photon polarization states, which is currently undergoing laboratory testing. 7 figs.

  19. Quantum broadcast scheme and multi-output quantum teleportation via four-qubit cluster state

    Science.gov (United States)

    Yu, Yan; Zha, Xin Wei; Li, Wei

    2017-02-01

    In this paper, two theoretical schemes of the arbitrary single-qubit states via four-qubit cluster state are proposed. One is three-party quantum broadcast scheme, which realizes the broadcast among three participants. The other is multi-output quantum teleportation. Both allow two distant receivers to simultaneously and deterministically obtain the arbitrary single-qubit states, respectively. Compared with former schemes of an arbitrary single-qubit state, the proposed schemes realize quantum multi-cast communication efficiently, which enables Bob and Charlie to obtain the states simultaneously in the case of just knowing Alice's measurement results. The proposed schemes play an important role in quantum information, specially in secret sharing and quantum teleportation.

  20. Quantum cryptography

    CERN Document Server

    Hughes, R J; Dyer, P L; Luther, G G; Morgan, G L; Schauer, M M; Hughes, Richard J; Dyer, P; Luther, G G; Morgan, G L; Schauer, M

    1995-01-01

    Quantum cryptography is a new method for secret communications offering the ultimate security assurance of the inviolability of a Law of Nature. In this paper we shall describe the theory of quantum cryptography, its potential relevance and the development of a prototype system at Los Alamos, which utilises the phenomenon of single-photon interference to perform quantum cryptography over an optical fiber communications link.

  1. REVIEW OF DIGITAL IMAGE SHARING BY DIVERSE IMAGE MEDIA

    Directory of Open Access Journals (Sweden)

    Mayuri Sonkusare

    2015-10-01

    Full Text Available A natural-image-based VSS scheme (NVSS scheme that shares secret images. A natural-imagebasedsecret image sharing scheme (NSISS that can share a color secret image over n - 1 arbitrary naturalimages and one noise-like share image. Instead of altering the contents of the natural images, the encryptionprocess extracts feature images from each natural image. In order to protect the secret image from transmissionphase. (n, n - NVSS scheme shared secret image over n-1 natural share. The natural shares will be digital imageand printed image. By extracting the features of natural shares we can prepare noise-like share. After thatencryption carried out with noise-like share and secret image. Propose possible ways to hide the noise like shareto reduce the transmission risk problem for the share. In this paper Initially Feature Extraction process has beenperformed for Natural Shares. Here Digital image and Printed image have been used as Natural Shares. Withthat extracted features secret image will be encrypted by (n, n - NVSS scheme where process carried by (n-1natural shares. This Encrypted result will be hided using Share-Hiding Algorithm where generated the QR code.In the Recovering of the secret image will be done by Share Extraction Algorithm and also decryptionalgorithm. Finally the secret image with all pixels has been obtained. This proposed possible ways to hide thenoise like share to reduce the transmission risk problem for the share.

  2. Secrets Law

    Directory of Open Access Journals (Sweden)

    Luz Helena Guamanzara Torres

    2013-01-01

    Full Text Available This paper provides a review of the book The Law of Secrets, of the author Juan Carlos Martínez-Villalba Riofrío studying the secrets and how law does protect. To this end, the author has analyzed the general theory of secrecy, secrets and methodology, its overall rating, essential elements and their different legal dimensions, the secret as a subjective right. It also establishes that professional secrecy is protected by constitutional principles such as the right to privacy.

  3. Quantum Secure Dialogue with Quantum Encryption

    Science.gov (United States)

    Ye, Tian-Yu

    2014-09-01

    How to solve the information leakage problem has become the research focus of quantum dialogue. In this paper, in order to overcome the information leakage problem in quantum dialogue, a novel approach for sharing the initial quantum state privately between communicators, i.e., quantum encryption sharing, is proposed by utilizing the idea of quantum encryption. The proposed protocol uses EPR pairs as the private quantum key to encrypt and decrypt the traveling photons, which can be repeatedly used after rotation. Due to quantum encryption sharing, the public announcement on the state of the initial quantum state is omitted, thus the information leakage problem is overcome. The information-theoretical efficiency of the proposed protocol is nearly 100%, much higher than previous information leakage resistant quantum dialogue protocols. Moreover, the proposed protocol only needs single-photon measurements and nearly uses single photons as quantum resource so that it is convenient to implement in practice.

  4. Secrets Shared: A Conversation with Francisco Jimemez.

    Science.gov (United States)

    Barrera, Rosalinda B.

    2003-01-01

    Presents an interview with Francisco Jimenez. Notes that he recently received the Tomas Rivera Mexican American Book Award for his authorship of "Breaking Through." Discusses his works and new ideas for future writing. (SG)

  5. Erratum: Generalized quantum state sharing of the arbitrary two particles state [Sci China Phys Mech Astron, 2010, 53(11): 2064

    Institute of Scientific and Technical Information of China (English)

    WANG Chuan

    2011-01-01

    Eqs.(3)-(6)should read[1]:|φ+m>=M(|00>=+1/m*|11>),(1)|φ-m>=M(1/m|00>-|11>),(2)|φ-m>=M(|01>=+1/m*|10>),(3)|φ-m>=M(1/m|01>-|10>),(4)whereM=|m|/√1+|m|2.Provided that one can prove eq.(8)which describes the state of the composite system,it should read |∧>sub=C1(α|0000>+nβ/m|0101>+nγ/m|1010>+n2δ/m2|1111>)b1b2c1c2,(5)whereC1=1/√|α|2+|nβ/m|2+|nγ/m|2+|n2δ/m2|2is the normalized factor.Here we give the fidelity of a pure state and the density matrix of the state described by eq.(11)should read:F=||α|2+|β|2n/m+|γ|2n/m+|δ|2n2/m2| /|α|2+|βn/m|2+|γn/m|2+|δn2/m2|2.If the quantum channels are composed of generalized Bell states,the state sharing process can be realized by generalized GHZ state measurement.

  6. Telling stories: keeping secrets.

    Science.gov (United States)

    Jensen, Joan M

    2009-01-01

    This article addresses the reticence of some farm women to share their experiences with historians and how that desire to keep secrets collides with the desire by scholars to tell the stories of these women. It argues that scholars must continue to struggle with the issue of which stories to tell publicly and which to keep private. The author discusses her own experience telling stories about rural women in the 1970s and the need to give voice to the heritage of rural women, especially of groups that have feared revealing their experiences. She offers examples of historians of rural women who have successfully worked with formerly silenced populations and urges historians to continue to tell stories about these lives, to reevaluate what has been already learned, to ask new questions, and to discuss which secrets need to be shared.

  7. Cryptanalysis of a multiparty quantum key agreement protocol based on commutative encryption

    Science.gov (United States)

    Mohajer, Razieh; Eslami, Ziba

    2017-08-01

    Recently, Sun et al. (Quantum Inf Process 15(5):2101-2111, 2016) proposed an efficient multiparty quantum key agreement protocol based on commutative encryption. The aim of this protocol is to negotiate a secret shared key among multiple parties with high qubit efficiency as well as security against inside and outside attackers. The shared key is the exclusive-OR of all participants' secret keys. This is achieved by applying the rotation operation on encrypted photons. For retrieving the final secret key, only measurement on single states is needed. Sun et al. claimed that assuming no mutual trust between participants, the scheme is secure against participant's attack. In this paper, we show that this is not true. In particular, we demonstrate how a malicious participant in Sun et al.'s protocol can introduce "a" final fake key to target parties of his choice. We further propose an improvement to guard against this attack.

  8. Practical secure quantum communications

    Science.gov (United States)

    Diamanti, Eleni

    2015-05-01

    We review recent advances in the field of quantum cryptography, focusing in particular on practical implementations of two central protocols for quantum network applications, namely key distribution and coin flipping. The former allows two parties to share secret messages with information-theoretic security, even in the presence of a malicious eavesdropper in the communication channel, which is impossible with classical resources alone. The latter enables two distrustful parties to agree on a random bit, again with information-theoretic security, and with a cheating probability lower than the one that can be reached in a classical scenario. Our implementations rely on continuous-variable technology for quantum key distribution and on a plug and play discrete-variable system for coin flipping, and necessitate a rigorous security analysis adapted to the experimental schemes and their imperfections. In both cases, we demonstrate the protocols with provable security over record long distances in optical fibers and assess the performance of our systems as well as their limitations. The reported advances offer a powerful toolbox for practical applications of secure communications within future quantum networks.

  9. 基于共享秘密的伪随机散列函数RFID双向认证协议%RFID Mutual Authentication Protocol on Pseudo-random Hash Function with Shared Secrets

    Institute of Scientific and Technical Information of China (English)

    石乐义; 贾聪; 宫剑; 刘昕; 陈鸿龙

    2016-01-01

    针对资源受限的 RFID 标签,结合伪随机数和共享秘密机制,该文提出一种基于散列函数的轻量级双向认证协议,实现了后端数据库、阅读器和标签之间的双向认证。详细分析了双向认证协议的抗攻击性能和效率性能,并基于BAN逻辑分析方法对协议模型进行了形式化证明。理论分析表明,该文提出的认证协议能够实现预期安全目标,抗攻击性能好,认证执行效率高且标签开销小,适用于大数量的RFID应用。%Concerning the resource-limited RFID tags, this paper presents a lightweight mutual authentication scheme based on Hash function, combining with the pseudo-random number and shared secret mechanisms, and implements the mutual authentication among the end database, reader and the tags. The anti-attack performance and the overhead of the scheme are analyzed in detail. Afterwards, the protocol security model is formalized using BAN logical analysis method. Theoretical analysis shows that the proposed authentication scheme could achieve the desired security goals, has good anti-attack performance and high efficiency. It can be applied to big population RFID since its low overhead for RFID tags.

  10. Quantum Cryptography for Secure Communications to Low-Earth Orbit Satellites

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G.; Lamoreaux, S.K.; Morgan, G.L.; Peterson, C.G.; Twyeffort, E.; Simmons, C.M.; Nordholt, J.E.

    1999-06-03

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics. An adversary can neither successfully tap the quantum transmissions, nor evade detection. Key material is built up using the transmission of a single-photon per bit. We have developed an experimental quantum cryptography system based on the transmission of non-orthogonal single-photon polarization states to generate shared key material over line-of-sight optical links. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on in orbit.

  11. Fault tolerant quantum secure direct communication with quantum encryption against collective noise

    Science.gov (United States)

    Huang, Wei; Wen, Qiao-Yan; Jia, Heng-Yue; Qin, Su-Juan; Gao, Fei

    2012-10-01

    We present two novel quantum secure direct communication (QSDC) protocols over different collective-noise channels. Different from the previous QSDC schemes over collective-noise channels, which are all source-encrypting protocols, our two protocols are based on channel-encryption. In both schemes, two authorized users first share a sequence of EPR pairs as their reusable quantum key. Then they use their quantum key to encrypt and decrypt the secret message carried by the decoherence-free states over the collective-noise channel. In theory, the intrinsic efficiencies of both protocols are high since there is no need to consume any entangled states including both the quantum key and the information carriers except the ones used for eavesdropping checks. For checking eavesdropping, the two parties only need to perform two-particle measurements on the decoy states during each round. Finally, we make a security analysis of our two protocols and demonstrate that they are secure.

  12. Quantum Secure Direct Communication with Five-Qubit Entangled State

    Institute of Scientific and Technical Information of China (English)

    LIN Song; GAO Fei; LIU Xiao-Fen

    2011-01-01

    Recently, a genuine five-qubit entangled state has been achieved by Brown et al.[J. Phys. A 38(2005)1119]. Later it was indicated that this state can be used for quantum teleportation and quantum state sharing. Here we build a quantum secure direct communication protocol with this state, and prove that it is secure in ideal conditions.In the protocol, the sender performs unitary transformations to encode a secret message on his/her particles and sends them to the receiver. The receiver then performs projective determinate measurement to decode the secret message directly.Fhrthermore, this protocol utilizes superdense coding to achieve a high intrinsic efficiency and source capacity.

  13. Quantum steganography using prior entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Mihara, Takashi, E-mail: mihara@toyo.jp

    2015-06-05

    Steganography is the hiding of secret information within innocent-looking information (e.g., text, audio, image, video, etc.). A quantum version of steganography is a method based on quantum physics. In this paper, we propose quantum steganography by combining quantum error-correcting codes with prior entanglement. In many steganographic techniques, embedding secret messages in error-correcting codes may cause damage to them if the embedded part is corrupted. However, our proposed steganography can separately create secret messages and the content of cover messages. The intrinsic form of the cover message does not have to be modified for embedding secret messages. - Highlights: • Our steganography combines quantum error-correcting codes with prior entanglement. • Our steganography can separately create secret messages and the content of cover messages. • Errors in cover messages do not have affect the recovery of secret messages. • We embed a secret message in the Steane code as an example of our steganography.

  14. Percolation of secret in a network

    CERN Document Server

    Leverrier, Anthony

    2011-01-01

    In this work, we explore the analogy between entanglement and secret classical correlations in the context of large networks, more precisely the question of percolation of secret correlations in a network. It is known that entanglement percolation in quantum networks can display a highly nontrivial behavior depending on the topology of the network and on the presence of entanglement between the nodes. Here we show that this behavior, thought to be of a genuine quantum nature, also occurs in a classical context.

  15. Efficient quantum walk on a quantum processor

    OpenAIRE

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiao-Qi; O'Brien, Jeremy; Wang, Jingbo; Matthews, Jonathan

    2016-01-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise quantum walks have shown much potential as a frame- work for developing new quantum algorithms. In this paper, we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs ef...

  16. Multiuser-based Gray-level Watermarking Sharing System

    Directory of Open Access Journals (Sweden)

    Bin Luo

    2009-12-01

    Full Text Available A novel watermarking sharing system having the ability of sharing gray-level secret images with multi-user is proposed. Multiple-based number system is used to split the secret into n meaningless shares, each share is embedded into respective cover image with controlled distortion and to be assigned to each user afterwards. The architecture of the proposed watermarking system is an open issue, which means the system is easy to be implemented according to the purposes and concerns of the users. The main feature of the proposed system is sharing a secret of gray-level image among multi-users; another application of such system is ownership verification. To reveal the secret, the necessary amount of shares has to be presented. That is, the secret can be recovered even if some shares were lost. Simulation results show that the recovered secret has robustness against a wide range of imaging processing operations.

  17. 基于秘密共享的具有签名功能的电子取证方案*%Forensic Investigation Based on Secret Sharing and Digital Signature

    Institute of Scientific and Technical Information of China (English)

    李想; 范玉妹

    2013-01-01

    调查取证与隐私保护存在冲突,如何实现既能取得与法律客观性保持一致的电子证据又能保护或避免披露无关用户的数据隐私变得日趋重要。针对这一问题,Hou et al提出了一类基于加密算法的电子取证方案,将取证关键词与被调查数据进行加密,再将两者的密文进行搜索匹配,最后解密匹配到的数据密文进行取证调查。由于复杂的加解密过程,该类方案计算复杂度高、处理时间长、取证效率低。为了提高取证效率,该文提出了一种基于秘密共享技术的取证方案。所提方案在提高取证效率的同时利用数字签名技术验证了所收集数据的真实性与完整性,有效地保障了电子证据的法律效力。%Forensic investigation conflicts with privacy protection. It is important how to collect the evidence admitted in a court while preserving the privacy of irrelevant users. To tackle this problem, Hou et al presented several encryption-based schemes. The main shortcoming of these schemes consists in that both the encryption and decryption procedures are time consuming, espe?cially on huge volume of data. This leads to low efficiency during forensic investigation. In this paper, we propose a secret shar?ing based solution to improve the investigation efficiency. Further, we utilize digital signature to verify data integrity and data au?thenticity so as to ensure that the collected data can be admitted as evidence in a court.

  18. Quantum Key Distribution

    Science.gov (United States)

    Seshu, Ch.

    Quantum Key Distribution (QKD) uses Quantum Mechanics to guarantee secure communication. It enables two parties to produce a shared random bit string known only to them, which can be used as a key to encrypt and decrypt messages.

  19. FREE-SPACE QUANTUM CRYPTOGRAPHY IN DAYLIGHT

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; Buttler, W.T. [and others

    2000-01-01

    Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on orbit. We present a feasibility analysis of surface-to-satellite quantum key generation.

  20. Shared lives, shared energy

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, P.; Goss, K.

    1982-07-01

    A social experiment in Denmark is described in which 25 families combine private ownership (each family owns its own home) and collectivism (each family owns 1/25 of the grounds, large common house and other facilities). The superinsulated individual homes are small (< 1000 ft/sup 2/) but the common house (7800 ft/sup 2/) provides dining and meeting facilities for all 25 families as well as a central heating plant. Heat may be supplied from solar, wind and/or oil-fired boiler. Adequate hot water storage is provided using solar collectors and a 55 kW Vesta wind generator (surplus power is sold). All south facing roof surfaces are fitted with solar collectors (4455 ft/sup 2/ total). A total of 70% of the energy used is produced on site (solar and wind). The manner of living and sharing (child care, automobiles, cooking, etc.) is described as well as typical floor plans for the units. Other collective housing in Denmark is described and it is postulated that overdrevet may serve as a model. (MJJ)

  1. Secret Symmetries in AdS/CFT

    CERN Document Server

    de Leeuw, Marius; Moriyama, Sanefumi; Regelskis, Vidas; Torrielli, Alessandro

    2012-01-01

    We discuss special quantum group (secret) symmetries of the integrable system associated to the AdS/CFT correspondence. These symmetries have by now been observed in a variety of forms, including the spectral problem, the boundary scattering problem, n-point amplitudes, the pure-spinor formulation and quantum affine deformations.

  2. Gaussian private quantum channel with squeezed coherent states

    Science.gov (United States)

    Jeong, Kabgyun; Kim, Jaewan; Lee, Su-Yong

    2015-01-01

    While the objective of conventional quantum key distribution (QKD) is to secretly generate and share the classical bits concealed in the form of maximally mixed quantum states, that of private quantum channel (PQC) is to secretly transmit individual quantum states concealed in the form of maximally mixed states using shared one-time pad and it is called Gaussian private quantum channel (GPQC) when the scheme is in the regime of continuous variables. We propose a GPQC enhanced with squeezed coherent states (GPQCwSC), which is a generalization of GPQC with coherent states only (GPQCo) [Phys. Rev. A 72, 042313 (2005)]. We show that GPQCwSC beats the GPQCo for the upper bound on accessible information. As a subsidiary example, it is shown that the squeezed states take an advantage over the coherent states against a beam splitting attack in a continuous variable QKD. It is also shown that a squeezing operation can be approximated as a superposition of two different displacement operations in the small squeezing regime. PMID:26364893

  3. Atmospheric Quantum Key Distribution in Daylight

    Science.gov (United States)

    Buttler, William; Hughes, Richard; Morgan, George; Nordholt, Jane; Peterson, Charles

    2001-05-01

    In quantum key distribution (QKD) single-photon transmissions generate the shared, secret random number sequences, known as cryptographic keys, that are used to encrypt and decrypt secret communications. Because the security of QKD is based on principles of quantum physics an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed an experimental QKD system that uses the four-state “BB84” protocol with non-orthogonal photon polarization states and lowest-order adaptive optics to generate shared key material over multi-kilometer atmospheric, line-of-sight paths. We will present results of a daylight demonstration of this system. Key material is built up using the transmission of a photon-pulse per bit of an initial secret random sequence. We will describe the design and operation of the system, present an analysis of the system's security, efficiency and error rate, and describe the prospects for longer-distance applications of free-space QKD.

  4. Sharing Economy

    DEFF Research Database (Denmark)

    Marton, Attila; Constantiou, Ioanna; Thoma, Antonela

    De spite the hype the notion of the sharing economy is surrounded by, our understanding of sharing is surprisingly undertheorized. In this paper, we make a first step towards rem edying this state of affairs by analy sing sharing as a s ocial practice. Based on a multi ple - case study, we analyse...... the institutional assemblage of sharing on online platforms to counter the prevalent assumpti o n i n the literature that sharing derives primarily from the shareability of goods and resources. Sharing, we contend, is a fundament al human practice that, in our case study, takes the particular form of coord inated...

  5. Improving Continuous-Variable Measurement-Device-Independent Multipartite Quantum Communication with Optical Amplifiers*

    Science.gov (United States)

    Guo, Ying; Zhao, Wei; Li, Fei; Huang, Duan; Liao, Qin; Xie, Cai-Lang

    2017-08-01

    The developing tendency of continuous-variable (CV) measurement-device-independent (MDI) quantum cryptography is to cope with the practical issue of implementing scalable quantum networks. Up to now, most theoretical and experimental researches on CV-MDI QKD are focused on two-party protocols. However, we suggest a CV-MDI multipartite quantum secret sharing (QSS) protocol use the EPR states coupled with optical amplifiers. More remarkable, QSS is the real application in multipartite CV-MDI QKD, in other words, is the concrete implementation method of multipartite CV-MDI QKD. It can implement a practical quantum network scheme, under which the legal participants create the secret correlations by using EPR states connecting to an untrusted relay via insecure links and applying the multi-entangled Greenberger-Horne-Zeilinger (GHZ) state analysis at relay station. Even if there is a possibility that the relay may be completely tampered, the legal participants are still able to extract a secret key from network communication. The numerical simulation indicates that the quantum network communication can be achieved in an asymmetric scenario, fulfilling the demands of a practical quantum network. Additionally, we illustrate that the use of optical amplifiers can compensate the partial inherent imperfections of detectors and increase the transmission distance of the CV-MDI quantum system.

  6. Theoretically extensible quantum digital signature with starlike cluster states

    Science.gov (United States)

    Yang, Yu-Guang; Liu, Zhi-Chao; Li, Jian; Chen, Xiu-Bo; Zuo, Hui-Juan; Zhou, Yi-Hua; Shi, Wei-Min

    2017-01-01

    Chen et al. (Phys Rev A 73:012303, 2006) constructed this "starlike cluster" state, which involves one qubit located at the center and n neighboring two-qubit arms. This genuine entangled state has been used for the construction of 2D and 3D cluster states, topological one-way computation, and dynamical quantum secret sharing. In this paper, we investigate the usefulness of this starlike cluster state and propose a theoretically extensible quantum digital signature scheme. The proposed scheme can be theoretically generalized to more than three participants. Moreover, it retains the merits of no requirements such as authenticated quantum channels and long-term quantum memory. We also give a security proof for the proposed scheme against repudiation and forgery.

  7. Quantum Steganography via Greenberger-Horne-Zeilinger GHZ_4 State

    Institute of Scientific and Technical Information of China (English)

    A.El Allati; M.B.Ould Medeni; Y.Hassouni

    2012-01-01

    A quantum steganography communication scheme via Greenberger-Horne-Zeilinger GHZ 4 state is constructed to investigate the possibility of remotely transferred hidden information.Moreover,the multipartite entangled states are become a hectic topic due to its important applications and deep effects on aspects of quantum information.Then,the scheme consists of sharing the correlation of four particle GHZ4 states between the legitimate users.After insuring the security of the quantum channel,they begin to hide the secret information in the cover of message.Comparing the scheme with the previous quantum steganographies,capacity and imperceptibility of hidden message are good.The security of the present scheme against many attacks is also discussed.

  8. An efficient quantum secure direct communication scheme with authentication

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Guang; Wen Qiao-Yan; Zhu Fu-Chen

    2007-01-01

    In this paper an efficient quantum secure direct communication (QSDC) scheme with authentication is presented,which is based on quantum entanglement and polarized single photons. The present protocol uses Einstein-PodolskyRosen (EPR) pairs and polarized single photons in batches. A particle of the EPR pairs is retained in the sender's QSDC protocol. According to the shared information beforehand, these two kinds of quantum states are mixed and then transmitted via a quantum channel. The EPR pairs are used to transmit secret messages and the polarized single photons used for authentication and eavesdropping check. Consequently, because of the dual contributions of the polarized single photons, no classical information is needed. The intrinsic efficiency and total efficiency are both 1 in this scheme as almost all of the instances are useful and each EPR pair can be used to carry two bits of information.

  9. Sharing Economy

    DEFF Research Database (Denmark)

    Marton, Attila; Constantiou, Ioanna; Thoma, Antonela

    De spite the hype the notion of the sharing economy is surrounded by, our understanding of sharing is surprisingly undertheorized. In this paper, we make a first step towards rem edying this state of affairs by analy sing sharing as a s ocial practice. Based on a multi ple - case study, we analyse...

  10. IMPACT OF ERROR FILTERS ON SHARES IN HALFTONE VISUAL CRYPTOGRAPHY

    OpenAIRE

    Sunil Agrawal; Anshul Sharma

    2012-01-01

    Visual cryptography encodes a secret binary image (SI) into shares of random binary patterns. If the shares are xeroxed onto transparencies, the secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset. The binary patterns of the shares, however, have no visual meaning and hinder the objectives of visual cryptography. Halftone visual cryptography encodes a s...

  11. A secure quantum key distribution scheme based on variable quantum encoding algorithms

    Institute of Scientific and Technical Information of China (English)

    Zhiwen Zhao; Yi Luo; Zhangji Zhao; Haiming Long

    2011-01-01

    The security of the quantum secret key plays a critical role in quantum communications. Thus far, one problem that still exists in existing protocols is the leakage of the length of the secret key. In this letter, based on variable quantum encoding algorithms, we propose a secure quantum key distribution scheme, which can overcome the security problem involving the leakage of the secret key. Security analysis shows that the proposed scheme is both secure and effective.%@@ The security of the quantum secret key plays a critical role in quantum communications.Thus far, one problem that still exists in existing protocols is the leakage of the length of the secret key.In this letter,based on variable quantum encoding algorithms, we propose a secure quantum key distribution scheme,which can overcome the security problem involving the leakage of the secret key.Security analysis shows that the proposed scheme is both secure and effective.

  12. Sharing City

    DEFF Research Database (Denmark)

    This magazine offers an insight into the growing commercial innovation, civic movements, and political narratives surrounding sharing economy services, solutions and organisational types. It presents a cross-section of the manifold sharing economy services and solutions that can be found in Denmark....... Solutions of sharing that seeks to improve our cities and local communities in both urban and rural environments. 24 sharing economy organisations and businesses addressing urban and rural issues are being portrayed and seven Danish municipalities that have explored the potentials of sharing economy....... Moreover, 15 thought leading experts - professionals and academic - have been invited to give their perspective on sharing economy for cities. This magazine touches upon aspects of the sharing economy as mobility, communities, sustainability, business development, mobility, and urban-rural relation....

  13. Quantum information causality

    OpenAIRE

    Pitalúa-García, Damián

    2012-01-01

    How much information can a transmitted physical system fundamentally communicate? We introduce the principle of quantum information causality, which states the maximum amount of quantum information that a quantum system can communicate as a function of its dimension, independently of any previously shared quantum physical resources. We present a new quantum information task, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combin...

  14. Design and Implementation of Hierarchical Visual Cryptography with Expansionless Shares

    Directory of Open Access Journals (Sweden)

    Pallavi Vijay Chavan

    2014-04-01

    Full Text Available Visual cryptography is the art of encrypting visual information such as handwritten text, images etc. The encryption takes place in such a way that no mathematical computations are required in order to decrypt the secret. The original information to be encrypted is called as secret. After encryption, ciphers are generated and referred as shares. The part of secret in scrambled form is known as share. Fundamental idea behind visual cryptography is to share the secret among group of nparticipants. In order to share the secret, it is divided inton number of pieces called shares. These shares are distributed among the participants. To reveal the original secret, each participant provides his own share. Complete knowledge of n-1 shares is unable to decrypt the secret. Many visual cryptographic schemes exist. The basic scheme is 2 out of 2 visual cryptography in which the secret is partitioned into exactly two parts. To reveal the secret these two shares must participate. Following figure indicates simple example of 2 out of 2 visual cryptography scheme.

  15. 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.

  16. Quantum key management

    Science.gov (United States)

    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. Quantum protocols within Spekkens' toy model

    Science.gov (United States)

    Disilvestro, Leonardo; Markham, Damian

    2017-05-01

    Quantum mechanics is known to provide significant improvements in information processing tasks when compared to classical models. These advantages range from computational speedups to security improvements. A key question is where these advantages come from. The toy model developed by Spekkens [R. W. Spekkens, Phys. Rev. A 75, 032110 (2007), 10.1103/PhysRevA.75.032110] mimics many of the features of quantum mechanics, such as entanglement and no cloning, regarded as being important in this regard, despite being a local hidden variable theory. In this work, we study several protocols within Spekkens' toy model where we see it can also mimic the advantages and limitations shown in the quantum case. We first provide explicit proofs for the impossibility of toy bit commitment and the existence of a toy error correction protocol and consequent k -threshold secret sharing. Then, defining a toy computational model based on the quantum one-way computer, we prove the existence of blind and verified protocols. Importantly, these two last quantum protocols are known to achieve a better-than-classical security. Our results suggest that such quantum improvements need not arise from any Bell-type nonlocality or contextuality, but rather as a consequence of steering correlations.

  18. Efficient quantum walk on a quantum processor

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.

    2016-05-01

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  19. Efficient quantum walk on a quantum processor.

    Science.gov (United States)

    Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L; Wang, Jingbo B; Matthews, Jonathan C F

    2016-05-05

    The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor.

  20. Google Secrets

    CERN Document Server

    Davis, Yvette

    2011-01-01

    Become a Google guru with these effective tips, tricks, and techniques Sure, you use Google. But do you really use Google-and everything it has to offer-in the most effective way possible? Wish you could just sit down with a Google expert who would show you how to take your Google savviness to the next level? With Google Secrets, you can! Tech expert Jerri Ledford reveals the ins, outs, and little-known facts about Google to show you how to sharpen your skills so you can get more done, more efficiently. You may already be familiar with Google's most popular applications, but this indispensable

  1. Sharing code

    OpenAIRE

    Kubilius, Jonas

    2014-01-01

    Sharing code is becoming increasingly important in the wake of Open Science. In this review I describe and compare two popular code-sharing utilities, GitHub and Open Science Framework (OSF). GitHub is a mature, industry-standard tool but lacks focus towards researchers. In comparison, OSF offers a one-stop solution for researchers but a lot of functionality is still under development. I conclude by listing alternative lesser-known tools for code and materials sharing.

  2. Two-party quantum key agreement based on four-particle GHZ states

    Science.gov (United States)

    He, Ye-Feng; Ma, Wen-Ping

    2016-04-01

    Based on four-particle GHZ states, the double CNOT operation and the delayed measurement technique, a two-party quantum key agreement (QKA) protocols is proposed. The double CNOT operation makes each four-particle GHZ state collapse into two independent quantum states without any entanglement. Furthermore, one party can directly know the two quantum states and the other party can be aware of the two quantum states by using the corresponding measurement. According to the initial states of the two quantum states, two parties can extract the secret keys of each other by using the publicly announced value or by performing the delayed measurement, respectively. Then the protocol achieves the fair establishment of a shared key. The security analysis shows that the new protocol can resist against participant attacks, the Trojan horse attacks and other outsider attacks. Furthermore, the new protocol also has no information leakage problem and has high qubit efficiency.

  3. Quantum cryptography for secure free-space communications

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; Buttler, W.T.; Kwiat, P.G.; Lamoreaux, S.K.; Luther, G.G.; Morgan, G.L.; Nordholt, J.E.; Peterson, C.G.

    1999-03-01

    The secure distribution of the secret random bit sequences known as key material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is a new technique for secure key distribution with single-photon transmissions: Heisenberg`s uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). The authors have developed experimental quantum cryptography systems based on the transmission of non-orthogonal photon polarization states to generate shared key material over line-of-sight optical links. Key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. The authors have developed and tested a free-space quantum key distribution (QKD) system over an outdoor optical path of {approximately}1 km at Los Alamos National Laboratory under nighttime conditions. Results show that free-space QKD can provide secure real-time key distribution between parties who have a need to communicate secretly. Finally, they examine the feasibility of surface to satellite QKD.

  4. A novel protocol for multiparty quantum key management

    Science.gov (United States)

    Xu, Gang; Chen, Xiu-Bo; Dou, Zhao; Yang, Yi-Xian; Li, Zongpeng

    2015-08-01

    Key management plays a fundamental role in the field of cryptography. In this paper, we propose a novel multiparty quantum key management (QKM) protocol. Departing from single-function quantum cryptography protocols, our protocol has a salient feature in that it accomplishes a complete QKM process. In this process, we can simultaneously realize the functions of key generation, key distribution and key backup by executing the protocol once. Meanwhile, for the first time, we propose the idea of multi-function QKM. Firstly, the secret key is randomly generated by managers via the quantum measurements in -level Bell basis. Then, through entanglement swapping, the secret key is successfully distributed to users. Under circumstances of urgent requirement, all managers can cooperate to recover the users' secret key, but neither of them can recover it unilaterally. Furthermore, this protocol is further generalized into the multi-manager and multi-user QKM scenario. It has clear advantages in the burgeoning area of quantum security group communication. In this system, all group members share the same group key, and group key management is the foundation of secure group communication and hence an important subject of study.

  5. Shift visual cryptography scheme of two secret images

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new visual cryptography scheme of two secret images, which is named the shift visual cryptography of two secret images, is given. The compound function family of a general construction model is also introduced. The uniqueness and validity of this model are proved, and the minimum rows and columns for realizing the scheme are obtained. Compared with visual cryptography of one secret image, the shift visual cryptography scheme can share two secret images with the same size of pixels expansion without losing the contrast. It has randomness and various forms, and furthermore, we can also visually recover two secret images even if the two shares are different in form and color.

  6. Practical quantum key distribution over a 48-km optical fiber network

    CERN Document Server

    Hughes, R J; Peterson, C G; Hughes, Richard J.; Morgan, George L.

    1999-01-01

    The secure distribution of the secret random bit sequences known as "key" material, is an essential precursor to their use for the encryption and decryption of confidential communications. Quantum cryptography is a new technique for secure key distribution with single-photon transmissions: Heisenberg's uncertainty principle ensures that an adversary can neither successfully tap the key transmissions, nor evade detection (eavesdropping raises the key error rate above a threshold value). We have developed experimental quantum cryptography systems based on the transmission of non-orthogonal photon states to generate shared key material over multi-kilometer optical fiber paths and over line-of-sight links. In both cases, key material is built up using the transmission of a single-photon per bit of an initial secret random sequence. A quantum-mechanically random subset of this sequence is identified, becoming the key material after a data reconciliation stage with the sender. Here we report the most recent results...

  7. Full-field implementation of a perfect eavesdropper on a quantum cryptography system.

    Science.gov (United States)

    Gerhardt, Ilja; Liu, Qin; Lamas-Linares, Antía; Skaar, Johannes; Kurtsiefer, Christian; Makarov, Vadim

    2011-06-14

    Quantum key distribution (QKD) allows two remote parties to grow a shared secret key. Its security is founded on the principles of quantum mechanics, but in reality it significantly relies on the physical implementation. Technological imperfections of QKD systems have been previously explored, but no attack on an established QKD connection has been realized so far. Here we show the first full-field implementation of a complete attack on a running QKD connection. An installed eavesdropper obtains the entire 'secret' key, while none of the parameters monitored by the legitimate parties indicate a security breach. This confirms that non-idealities in physical implementations of QKD can be fully practically exploitable, and must be given increased scrutiny if quantum cryptography is to become highly secure.

  8. File sharing

    NARCIS (Netherlands)

    van Eijk, N.

    2011-01-01

    ‘File sharing’ has become generally accepted on the Internet. Users share files for downloading music, films, games, software etc. In this note, we have a closer look at the definition of file sharing, the legal and policy-based context as well as enforcement issues. The economic and cultural impact

  9. Shared leadership

    DEFF Research Database (Denmark)

    Ulhøi, John Parm; Müller, Sabine

    2012-01-01

    The aim of this paper is twofold. First, this paper comprehensively will review the conceptual and empirical literature to identify such critical underlying mechanisms which enable shared or collective leadership. Second, this article identifies the antecedents and outcomes of shared leadership...... according to the literature review to develop a re-conceptualised and synthesized framework for managing the organizational issues associated with shared leadership on various organizational levels. The paper rectifies this by identifying the critical factors and mechanisms which enable shared leadership...... and its antecedents and outcomes, and to develop a re-conceptualized and synthesized framework of shared leadership. The paper closes with a brief discussion of avenues for future research and implications for managers....

  10. Shared leadership

    DEFF Research Database (Denmark)

    Ulhøi, John Parm; Müller, Sabine

    2012-01-01

    The aim of this paper is twofold. First, this paper comprehensively will review the conceptual and empirical literature to identify such critical underlying mechanisms which enable shared or collective leadership. Second, this article identifies the antecedents and outcomes of shared leadership...... according to the literature review to develop a re-conceptualised and synthesized framework for managing the organizational issues associated with shared leadership on various organizational levels. The paper rectifies this by identifying the critical factors and mechanisms which enable shared leadership...... and its antecedents and outcomes, and to develop a re-conceptualized and synthesized framework of shared leadership. The paper closes with a brief discussion of avenues for future research and implications for managers....

  11. Quantum dice

    OpenAIRE

    de Bianchi, Massimiliano Sassoli

    2013-01-01

    In a letter to Born, Einstein wrote: "Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the old one. I, at any rate, am convinced that He does not throw dice." In this paper we take seriously Einstein's famous metaphor, and show that we can gain considerable insight into quantum mechanics by doing something as simple as rolling dice. More precisely, we show how...

  12. Shared Attention.

    Science.gov (United States)

    Shteynberg, Garriy

    2015-09-01

    Shared attention is extremely common. In stadiums, public squares, and private living rooms, people attend to the world with others. Humans do so across all sensory modalities-sharing the sights, sounds, tastes, smells, and textures of everyday life with one another. The potential for attending with others has grown considerably with the emergence of mass media technologies, which allow for the sharing of attention in the absence of physical co-presence. In the last several years, studies have begun to outline the conditions under which attending together is consequential for human memory, motivation, judgment, emotion, and behavior. Here, I advance a psychological theory of shared attention, defining its properties as a mental state and outlining its cognitive, affective, and behavioral consequences. I review empirical findings that are uniquely predicted by shared-attention theory and discuss the possibility of integrating shared-attention, social-facilitation, and social-loafing perspectives. Finally, I reflect on what shared-attention theory implies for living in the digital world.

  13. Versatility of continuous-variable asymmetric tripartite entanglement allows Alice and Clare to keep secrets from Bob

    Science.gov (United States)

    Olsen, M. K.; Cavalcanti, E. G.

    2016-07-01

    The fully symmetric Gaussian tripartite entangled pure states will not exhibit two-mode Einstein-Podolsky-Rosen (EPR) steering. This means that any two participants cannot share quantum secrets using the security of one-sided device independent quantum key distribution (1SDI-QKD) without involving the third. They are restricted at most to standard quantum key distribution, which is less secure. Here we demonstrate an asymmetric tripartite system that can exhibit bipartite EPR steering, so that two of the participants can use 1SDI-QKD without involving the other. This is possible because the promiscuity relations of continuous-variable tripartite entanglement are different from those of discrete-variable systems. We analyze these properties for two different systems, showing that the asymmetric system exhibits practical properties not found in the symmetric one.

  14. On family secrets and -K.

    Science.gov (United States)

    Orgad, Yariv

    2014-08-01

    In this paper I present a novel interpretation of family secrets. Leaning on Bion's concept of -K, the constitution of secrecy is interpreted in terms of family dynamics that actively prevent knowledge formation and mental growth. Family secrets are interpreted as a destructive process that attacks the family's truth-generating-space - the shared semiotic space within which meanings are constituted through family relationships. The paper explores the microstructure interpersonal process of -K through the analysis of Mike Leigh's movie, Secrets and Lies. Two scenes in the movie are used to demonstrate how -K is worked out in the form of a specific intersubjective semiotic endeavor that unconsciously blocks the process of meaning-making.

  15. Teleportation-based continuous variable quantum cryptography

    Science.gov (United States)

    Luiz, F. S.; Rigolin, Gustavo

    2017-03-01

    We present a continuous variable (CV) quantum key distribution (QKD) scheme based on the CV quantum teleportation of coherent states that yields a raw secret key made up of discrete variables for both Alice and Bob. This protocol preserves the efficient detection schemes of current CV technology (no single-photon detection techniques) and, at the same time, has efficient error correction and privacy amplification schemes due to the binary modulation of the key. We show that for a certain type of incoherent attack, it is secure for almost any value of the transmittance of the optical line used by Alice to share entangled two-mode squeezed states with Bob (no 3 dB or 50% loss limitation characteristic of beam splitting attacks). The present CVQKD protocol works deterministically (no postselection needed) with efficient direct reconciliation techniques (no reverse reconciliation) in order to generate a secure key and beyond the 50% loss case at the incoherent attack level.

  16. IMPACT OF ERROR FILTERS ON SHARES IN HALFTONE VISUAL CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Sunil Agrawal

    2012-05-01

    Full Text Available Visual cryptography encodes a secret binary image (SI into shares of random binary patterns. If the shares are xeroxed onto transparencies, the secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset. The binary patterns of the shares, however, have no visual meaning and hinder the objectives of visual cryptography. Halftone visual cryptography encodes a secret binary image into n halftone shares (images carrying significant visual information. When secrecy is important factor rather than the quality of recovered image the shares must be of better visual quality. Different filters such as Floyd-Steinberg, Jarvis, Stuki, Burkes, Sierra, and Stevenson’s-Arce are used and their impact on visual quality of shares is seen. The simulation shows that error filters used in error diffusion lays a great impact on the visual quality of the shares.

  17. Knowledge Sharing

    DEFF Research Database (Denmark)

    Holdt Christensen, Peter

    The concept of knowledge management has, indeed, become a buzzword that every single organization is expected to practice and live by. Knowledge management is about managing the organization's knowledge for the common good of the organization -but practicing knowledge management is not as simple...... as that. This article focuses on knowledge sharing as the process seeking to reduce the resources spent on reinventing the wheel.The article introduces the concept of time sensitiveness; i.e. that knowledge is either urgently needed, or not that urgently needed. Furthermore, knowledge sharing...... is considered as either a push or pull system. Four strategies for sharing knowledge - help, post-it, manuals and meeting, and advice are introduced. Each strategy requires different channels for sharing knowledge. An empirical analysis in a production facility highlights how the strategies can be practiced....

  18. A fully efficient secure quantum cryptography protocol

    CERN Document Server

    Xiang Bin Wang

    2001-01-01

    Since Bennett and Brassard suggested their quantum key distribution protocol(BB84 protocol) in 1984, the subject has been extensively studied both theoretically and experimentally. The protocol allows two remote parties Alice and Bob to create and share a secret key using a quantum channel and public authenticated communications. The quantum key created in this way is in principle secure because eavesdroppers have no way to tap the quantum channel without disturb it. In the protocol, two level quantum bits are measured in two basis, $X$ and $Z$ randomly by Bob. So at least half of the measurement results will be discarded because Bob has a half probability taking the measurement in a wrong basis. On the other hand, the security is not the maximum in BB84 protocol. To increase the security, one may straightforwardly increase the number of basis used in the protocol. For example, six state protocol was proposed recently for two level system. However, in this way, it seems to be the case that the higher the secu...

  19. Cosmic secrets

    Science.gov (United States)

    Schommers, W.

    1. The absolute truth. 1.1. Final truth. 1.2. Two important questions. 1.3. Why does the cosmos exist? 1.4. Are the laws of nature independent of the observer's own nature? 1.5. Self0indulgence was dominant. 1.6. Newton's mechanics and its overestimation. 1.7. Scientific realism. 1.8. An important principle: as little outside world as possible. 1.9. Inside world and outside world. 1.10. Principal questions. 1.11. How does science progress? 1.12. Final remarks -- 2. The projection principle. 2.1. The elements of space and time. 2.2. Relationship between matter and space-time. 2.3. Two relevant features. 2.4. Two kinds of "objects". 2.5. Perception processes. 2.6. Inside world and outside world. 2.7. The influence of evolution. 2.8. Information in the picture versus information in basic reality (outside reality). 2.9. Other biological systems. 2.10. How many (geometrical) objects can be in space-time? 2.11. Two types of space-time? 2.12. Summary -- 3. Fictitious realities. 3.1. Conventional quantum theory: critical remarks. 3.2. The projection principle in connection with fictitious realities. 3.3. Distribution of information. 3.4. Basic transformation effects. 3.5. Pictures within projection theory. 3.6. Auxiliary construction. 3.7. Basic laws. 3.8. Extension of conventional quantum theory. 3.9. Only processes are relevant! 3.10. Interactions. 3.11. Distance-independent interactions. 3.12. Arbitrary jumps within (r, t)-space. 3.13.Mach's principle: preliminary remarks. 3.14. Can a lone, elementary object exist in the cosmos? 3.15. The meaning of the potential functions. 3.16. Time. 3.17. Time travel in physics. 3.18. Summary -- 4. Basic reality and levels of reality. 4.1. Hard objects. 4.2. General physical laws. 4.3. States of mind. 4.4. Outside world and basic reality. 4.5. Objective processes. 4.6. Observations. 4.7. No interactions within (r, t)-space. 4.8. The general cannot be deduced from the particular. 4.9. Remarks on the notion "world equation". 4.10. On

  20. Practical Quantum Cryptography for Secure Free-Space Communications

    Energy Technology Data Exchange (ETDEWEB)

    Buttler, W.T.; Hughes, R.J.; Kwiat, P.G.; Lamoreaux, S.K.; Morgan, G.L.; Nordholt, J.E.; Peterson, C.G.

    1999-02-01

    Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on orbit. We present a feasibility analysis of surface-to-satellite quantum key generation.

  1. Quantum information causality.

    Science.gov (United States)

    Pitalúa-García, Damián

    2013-05-24

    How much information can a transmitted physical system fundamentally communicate? We introduce the principle of quantum information causality, which states the maximum amount of quantum information that a quantum system can communicate as a function of its dimension, independently of any previously shared quantum physical resources. We present a new quantum information task, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combines the quantum teleportation and superdense coding protocols with a task that has classical inputs.

  2. The Quantum Steganography Protocol via Quantum Noisy Channels

    Science.gov (United States)

    Wei, Zhan-Hong; Chen, Xiu-Bo; Niu, Xin-Xin; Yang, Yi-Xian

    2015-08-01

    As a promising branch of quantum information hiding, Quantum steganography aims to transmit secret messages covertly in public quantum channels. But due to environment noise and decoherence, quantum states easily decay and change. Therefore, it is very meaningful to make a quantum information hiding protocol apply to quantum noisy channels. In this paper, we make the further research on a quantum steganography protocol for quantum noisy channels. The paper proved that the protocol can apply to transmit secret message covertly in quantum noisy channels, and explicity showed quantum steganography protocol. In the protocol, without publishing the cover data, legal receivers can extract the secret message with a certain probability, which make the protocol have a good secrecy. Moreover, our protocol owns the independent security, and can be used in general quantum communications. The communication, which happen in our protocol, do not need entangled states, so our protocol can be used without the limitation of entanglement resource. More importantly, the protocol apply to quantum noisy channels, and can be used widely in the future quantum communication.

  3. Aggregating quantum repeaters for the quantum internet

    Science.gov (United States)

    Azuma, Koji; Kato, Go

    2017-09-01

    The quantum internet holds promise for accomplishing quantum teleportation and unconditionally secure communication freely between arbitrary clients all over the globe, as well as the simulation of quantum many-body systems. For such a quantum internet protocol, a general fundamental upper bound on the obtainable entanglement or secret key has been derived [K. Azuma, A. Mizutani, and H.-K. Lo, Nat. Commun. 7, 13523 (2016), 10.1038/ncomms13523]. Here we consider its converse problem. In particular, we present a universal protocol constructible from any given quantum network, which is based on running quantum repeater schemes in parallel over the network. For arbitrary lossy optical channel networks, our protocol has no scaling gap with the upper bound, even based on existing quantum repeater schemes. In an asymptotic limit, our protocol works as an optimal entanglement or secret-key distribution over any quantum network composed of practical channels such as erasure channels, dephasing channels, bosonic quantum amplifier channels, and lossy optical channels.

  4. Quantum fingerprinting

    CERN Document Server

    Buhrman, H; Watrous, J; De Wolf, R; Buhrman, Harry; Cleve, Richard; Watrous, John; Wolf, Ronald de

    2001-01-01

    Classical fingerprinting associates with each string a shorter string (its fingerprint), such that, with high probability, any two distinct strings can be distinguished by comparing their fingerprints alone. The fingerprints can be exponentially smaller than the original strings if the parties preparing the fingerprints share a random key, but not if they only have access to uncorrelated random sources. In this paper we show that fingerprints consisting of quantum information can be made exponentially smaller than the original strings without any correlations or entanglement between the parties: we give a scheme where the quantum fingerprints are exponentially shorter than the original strings and we give a test that distinguishes any two unknown quantum fingerprints with high probability. Our scheme implies an exponential quantum/classical gap for the equality problem in the simultaneous message passing model of communication complexity. We optimize several aspects of our scheme.

  5. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  6. A novel quantum deniable authentication protocol without entanglement

    Science.gov (United States)

    Shi, Wei-Min; Zhang, Jian-Biao; Zhou, Yi-Hua; Yang, Yu-Guang

    2015-06-01

    A novel quantum deniable authentication protocol based on single photons is proposed. In this scheme, the message sender and the specified receiver will first agree a new shared secret key by key update phases with the help of a third center, where only they can encrypt and decrypt the message by using the new shared secret key. Hence, this scheme can guarantee that only the specified receiver can identify the true source of a given message and the specified receiver cannot prove the source of the message to a third party by a transcript simulation algorithm. Compared with our previous scheme (Shi et al. in Quantum Inf Process 13:1501-1510, 2014), this scheme has the remarkable advantages of the higher qubit efficiency and consuming fewer quantum resources. Finally, security analysis results show that this scheme satisfies known key security and the basic security requirements of deniable authentication protocol such as completeness and deniability, and can withstand forgery attack, impersonation attack and inter-resend attack.

  7. Two-party quantum key agreement protocol with four-particle entangled states

    Science.gov (United States)

    He, Yefeng; Ma, Wenping

    2016-09-01

    Based on four-particle entangled states and the delayed measurement technique, a two-party quantum key agreement protocol is proposed in this paper. In the protocol, two participants can deduce the measurement results of each other’s initial quantum states in terms of the measurement correlation property of four-particle entangled states. According to the corresponding initial quantum states deduced by themselves, two parties can extract the secret keys of each other by using the publicly announced value or by performing the delayed measurement, respectively. This guarantees the fair establishment of a shared key. Since each particle in quantum channel is transmitted only once, the protocol is congenitally free from the Trojan horse attacks. The security analysis shows that the protocol not only can resist against both participant and outsider attacks but also has no information leakage problem. Moreover, it has high qubit efficiency.

  8. Advanced quantum communication systems

    Science.gov (United States)

    Jeffrey, Evan Robert

    Quantum communication provides several examples of communication protocols which cannot be implemented securely using only classical communication. Currently, the most widely known of these is quantum cryptography, which allows secure key exchange between parties sharing a quantum channel subject to an eavesdropper. This thesis explores and extends the realm of quantum communication. Two new quantum communication protocols are described. The first is a new form of quantum cryptography---relativistic quantum cryptography---which increases communication efficiency by exploiting a relativistic bound on the power of an eavesdropper, in addition to the usual quantum mechanical restrictions intrinsic to quantum cryptography. By doing so, we have observed over 170% improvement in communication efficiency over a similar protocol not utilizing relativity. A second protocol, Quantum Orienteering, allows two cooperating parties to communicate a specific direction in space. This application shows the possibility of using joint measurements, or projections onto an entangled state, in order to extract the maximum useful information from quantum bits. For two-qubit communication, the maximal fidelity of communication using only separable operations is 73.6%, while joint measurements can improve the efficiency to 78.9%. In addition to implementing these protocols, we have improved several resources for quantum communication and quantum computing. Specifically, we have developed improved sources of polarization-entangled photons, a low-loss quantum memory for polarization qubits, and a quantum random number generator. These tools may be applied to a wide variety of future quantum and classical information systems.

  9. Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems.

    Directory of Open Access Journals (Sweden)

    Ram Samudrala

    2009-04-01

    Full Text Available The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates--effector proteins--are not. We have used a novel computational approach to confidently identify new secreted effectors by integrating protein sequence-based features, including evolutionary measures such as the pattern of homologs in a range of other organisms, G+C content, amino acid composition, and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from the plant pathogen Pseudomonas syringae and validated on a set of effectors from the animal pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium after eliminating effectors with detectable sequence similarity. We show that this approach can predict known secreted effectors with high specificity and sensitivity. Furthermore, by considering a large set of effectors from multiple organisms, we computationally identify a common putative secretion signal in the N-terminal 20 residues of secreted effectors. This signal can be used to discriminate 46 out of 68 total known effectors from both organisms, suggesting that it is a real, shared signal applicable to many type III secreted effectors. We use the method to make novel predictions of secreted effectors in S. Typhimurium, some of which have been experimentally validated. We also apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis, identifying the majority of known secreted proteins in addition to providing a number of novel predictions. This approach provides a new way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.

  10. Information partnerships--shared data, shared scale.

    Science.gov (United States)

    Konsynski, B R; McFarlan, F W

    1990-01-01

    How can one company gain access to another's resources or customers without merging ownership, management, or plotting a takeover? The answer is found in new information partnerships, enabling diverse companies to develop strategic coalitions through the sharing of data. The key to cooperation is a quantum improvement in the hardware and software supporting relational databases: new computer speeds, cheaper mass-storage devices, the proliferation of fiber-optic networks, and networking architectures. Information partnerships mean that companies can distribute the technological and financial exposure that comes with huge investments. For the customer's part, partnerships inevitably lead to greater simplification on the desktop and more common standards around which vendors have to compete. The most common types of partnership are: joint marketing partnerships, such as American Airline's award of frequent flyer miles to customers who use Citibank's credit card; intraindustry partnerships, such as the insurance value-added network service (which links insurance and casualty companies to independent agents); customer-supplier partnerships, such as Baxter Healthcare's electronic channel to hospitals for medical and other equipment; and IT vendor-driven partnerships, exemplified by ESAB (a European welding supplies and equipment company), whose expansion strategy was premised on a technology platform offered by an IT vendor. Partnerships that succeed have shared vision at the top, reciprocal skills in information technology, concrete plans for an early success, persistence in the development of usable information for all partners, coordination on business policy, and a new and imaginative business architecture.

  11. Serial interpolation for secure membership testing and matching in a secret-split archive

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, Thomas M.; Benson, Thomas R.

    2016-12-06

    The various technologies presented herein relate to analyzing a plurality of shares stored at a plurality of repositories to determine whether a secret from which the shares were formed matches a term in a query. A threshold number of shares are formed with a generating polynomial operating on the secret. A process of serially interpolating the threshold number of shares can be conducted whereby a contribution of a first share is determined, a contribution of a second share is determined while seeded with the contribution of the first share, etc. A value of a final share in the threshold number of shares can be determined and compared with the search term. In the event of the value of the final share and the search term matching, the search term matches the secret in the file from which the shares are formed.

  12. General benchmarks for quantum repeaters

    CERN Document Server

    Pirandola, Stefano

    2015-01-01

    Using a technique based on quantum teleportation, we simplify the most general adaptive protocols for key distribution, entanglement distillation and quantum communication over a wide class of quantum channels in arbitrary dimension. Thanks to this method, we bound the ultimate rates for secret key generation and quantum communication through single-mode Gaussian channels and several discrete-variable channels. In particular, we derive exact formulas for the two-way assisted capacities of the bosonic quantum-limited amplifier and the dephasing channel in arbitrary dimension, as well as the secret key capacity of the qubit erasure channel. Our results establish the limits of quantum communication with arbitrary systems and set the most general and precise benchmarks for testing quantum repeaters in both discrete- and continuous-variable settings.

  13. Multi secret image color visual cryptography schemes for general access structures

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In the proposed visual cryptography schemes for general access structures, the single secret image black-and-white visual cryptography schemes with meaningful shares have been constructed, in which the shares are innocent looking images. The meaningful shares have not been realized in single secret image color schemes; neither have the multi secret images color schemes. In this paper, the multi secret images color visual cryptography schemes for general access structures with meaningful shares are constructed by the method of matrix concatenation, the pixel expansion is obtained, and the validity of the scheme is proven. In our scheme, the different combination of meaningful color shares can be used to recover distinct color secret images. The multi secret images black-and-white visual cryptography scheme is a special case of our color scheme.

  14. Quantum dice

    Energy Technology Data Exchange (ETDEWEB)

    Sassoli de Bianchi, Massimiliano, E-mail: autoricerca@gmail.com

    2013-09-15

    In a letter to Born, Einstein wrote [42]: “Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the ‘old one.’ I, at any rate, am convinced that He does not throw dice.” In this paper we take seriously Einstein’s famous metaphor, and show that we can gain considerable insight into quantum mechanics by doing something as simple as rolling dice. More precisely, we show how to perform measurements on a single die, to create typical quantum interference effects, and how to connect (entangle) two identical dice, to maximally violate Bell’s inequality. -- Highlights: •Rolling a die is a quantum process admitting a Hilbert space representation. •Rolling experiments with a single die can produce interference effects. •Two connected dice can violate Bell’s inequality. •Correlations need to be created by the measurement, to violate Bell’s inequality.

  15. Fault tolerant quantum secure direct communication with quantum encryption against collective noise

    Institute of Scientific and Technical Information of China (English)

    Huang Wei; Wen Qiao-Yan; Jia Heng-Yue; Qin Su-Juan; Gao Fei

    2012-01-01

    We present two novel quantum secure direct communication (QSDC) protocols over different collective-noise channels.Different from the previous QSDC schemes over collective-noise channels,which are all source-encrypting protocols,our two protocols are based on channel-encryption. In both schemes,two authorized users first share a sequence of EPR pairs as their reusable quantum key.Then they use their quantum key to encrypt and decrypt the secret message carried by the decoherence-free states over the collective-noise channel.In theory,the intrinsic efficiencies of both protocols are high since there is no need to consume any entangled states including both the quantum key and the information carriers except the ones used for eavesdropping checks.For checking eavesdropping,the two parties only need to perform two-particle measurements on the decoy states during each round.Finally,we make a security analysis of our two protocols and demonstrate that they are secure.

  16. Sharing values, sharing a vision

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    Teamwork, partnership and shared values emerged as recurring themes at the Third Technology Transfer/Communications Conference. The program drew about 100 participants who sat through a packed two days to find ways for their laboratories and facilities to better help American business and the economy. Co-hosts were the Lawrence Livermore National Laboratory and the Lawrence Berkeley Laboratory, where most meetings took place. The conference followed traditions established at the First Technology Transfer/Communications Conference, conceived of and hosted by the Pacific Northwest Laboratory in May 1992 in Richmond, Washington, and the second conference, hosted by the National Renewable Energy Laboratory in January 1993 in Golden, Colorado. As at the other conferences, participants at the third session represented the fields of technology transfer, public affairs and communications. They came from Department of Energy headquarters and DOE offices, laboratories and production facilities. Continued in this report are keynote address; panel discussion; workshops; and presentations in technology transfer.

  17. Quantum cryptography using optical fibers.

    Science.gov (United States)

    Franson, J D; Lives, H

    1994-05-10

    Quantum cryptography permits the transmission of secret information whose security is guaranteed by the uncertainty principle. An experimental system for quantum crytography is implemented based on the linear polarization of single photons transmitted by an optical fiber. Polarization-preserving optical fiber and a feedback loop are employed to maintain the state of polarization. Error rates of less than 0.5% are obtained.

  18. Finite key analysis in quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.

    2007-10-31

    the obtainable key rate for any finite number of input signals, without making any approximations. As an application, we investigate the so-called ''Tomographic Protocol'', which is based on the Six-State Protocol and where Alice and Bob can obtain the additional information which quantum state they share after the distribution step of the protocol. We calculate the obtainable secret key rate under the assumption that the eavesdropper only conducts collective attacks and give a detailed analysis of the dependence of the key rate on various parameters: The number of input signals (the block size), the error rate in the sifted key (the QBER), and the security parameter. Furthermore, we study the influence of multi-photon events which naturally occur in a realistic implementation (orig.)

  19. Long-distance quantum key distribution with imperfect devices

    Energy Technology Data Exchange (ETDEWEB)

    Lo Piparo, Nicoló; Razavi, Mohsen [School of Electronic and Electrical Engineering, University of Leeds (United Kingdom)

    2014-12-04

    Quantum key distribution over probabilistic quantum repeaters is addressed. We compare, under practical assumptions, two such schemes in terms of their secure key generation rate per memory, R{sub QKD}. The two schemes under investigation are the one proposed by Duan et al. in [Nat. 414, 413 (2001)] and that of Sangouard et al. proposed in [Phys. Rev. A 76, 050301 (2007)]. We consider various sources of imperfections in the latter protocol, such as a nonzero double-photon probability for the source, dark count per pulse, channel loss and inefficiencies in photodetectors and memories, to find the rate for different nesting levels. We determine the maximum value of the double-photon probability beyond which it is not possible to share a secret key anymore. We find the crossover distance for up to three nesting levels. We finally compare the two protocols.

  20. Orthogonal Frequency-Division Multiplexed Quantum Key Distribution

    Science.gov (United States)

    Bahrani, Sima; Razavi, Mohsen; Salehi, Jawad A.

    2015-12-01

    We propose orthogonal frequency division multiplexing (OFDM), as a spectrally efficient multiplexing technique, for quantum key distribution (QKD) at the core of trustednode quantum networks. Two main schemes are proposed and analyzed in detail, considering system imperfections, specifically, time misalignment issues. It turns out that while multiple service providers can share the network infrastructure using the proposed multiplexing techniques, no gain in the total secret key generation rate is obtained if one uses conventional all-optical passive OFDM decoders. To achieve a linear increase in the key rate with the number of channels, an alternative active setup for OFDM decoding is proposed, which employs an optical switch in addition to conventional passive circuits. We show that by using our proposed decoder the bandwidth utilization is considerably improved as compared to conventional wavelength division multiplexing techniques.

  1. Long-distance quantum key distribution with imperfect devices

    Science.gov (United States)

    Lo Piparo, Nicoló; Razavi, Mohsen

    2014-12-01

    Quantum key distribution over probabilistic quantum repeaters is addressed. We compare, under practical assumptions, two such schemes in terms of their secure key generation rate per memory, RQKD. The two schemes under investigation are the one proposed by Duan et al. in [Nat. 414, 413 (2001)] and that of Sangouard et al. proposed in [Phys. Rev. A 76, 050301 (2007)]. We consider various sources of imperfections in the latter protocol, such as a nonzero double-photon probability for the source, dark count per pulse, channel loss and inefficiencies in photodetectors and memories, to find the rate for different nesting levels. We determine the maximum value of the double-photon probability beyond which it is not possible to share a secret key anymore. We find the crossover distance for up to three nesting levels. We finally compare the two protocols.

  2. High-efficiency reconciliation for continuous variable quantum key distribution

    Science.gov (United States)

    Bai, Zengliang; Yang, Shenshen; Li, Yongmin

    2017-04-01

    Quantum key distribution (QKD) is the most mature application of quantum information technology. Information reconciliation is a crucial step in QKD and significantly affects the final secret key rates shared between two legitimate parties. We analyze and compare various construction methods of low-density parity-check (LDPC) codes and design high-performance irregular LDPC codes with a block length of 106. Starting from these good codes and exploiting the slice reconciliation technique based on multilevel coding and multistage decoding, we realize high-efficiency Gaussian key reconciliation with efficiency higher than 95% for signal-to-noise ratios above 1. Our demonstrated method can be readily applied in continuous variable QKD.

  3. Shared Memories?

    DEFF Research Database (Denmark)

    Wæhrens, Anne

    2011-01-01

    This paper analyses how the memory of the Holocaust has been addressed in the European Parliament from 1989 to 2009. I identify two major changes that occurred in the 1990s and after the 2004 enlargement of the European Union respectively. In the 1990s the war in Bosnia and the question of restit......This paper analyses how the memory of the Holocaust has been addressed in the European Parliament from 1989 to 2009. I identify two major changes that occurred in the 1990s and after the 2004 enlargement of the European Union respectively. In the 1990s the war in Bosnia and the question...... of restitution universalised the memory of the Holocaust and made it present. The 2004 enlargement brought the memory of Soviet Communism into the Union and made it a central task to construct a community of memory that includes both the memory of the Holocaust and of Soviet Communism. The analysis also...... identifies what seems to be a political memory split between Left and Right; and it shows that the time might not be ripe for a shared European memory....

  4. Accurate prediction of secreted substrates and identification of a conserved putative secretion signal for type III secretion systems

    Energy Technology Data Exchange (ETDEWEB)

    Samudrala, Ram; Heffron, Fred; McDermott, Jason E.

    2009-04-24

    The type III secretion system is an essential component for virulence in many Gram-negative bacteria. Though components of the secretion system apparatus are conserved, its substrates, effector proteins, are not. We have used a machine learning approach to identify new secreted effectors. The method integrates evolutionary measures, such as the pattern of homologs in a range of other organisms, and sequence-based features, such as G+C content, amino acid composition and the N-terminal 30 residues of the protein sequence. The method was trained on known effectors from Salmonella typhimurium and validated on a corresponding set of effectors from Pseudomonas syringae, after eliminating effectors with detectable sequence similarity. The method was able to identify all of the known effectors in P. syringae with a specificity of 84% and sensitivity of 82%. The reciprocal validation, training on P. syringae and validating on S. typhimurium, gave similar results with a specificity of 86% when the sensitivity level was 87%. These results show that type III effectors in disparate organisms share common features. We found that maximal performance is attained by including an N-terminal sequence of only 30 residues, which agrees with previous studies indicating that this region contains the secretion signal. We then used the method to define the most important residues in this putative secretion signal. Finally, we present novel predictions of secreted effectors in S. typhimurium, some of which have been experimentally validated, and apply the method to predict secreted effectors in the genetically intractable human pathogen Chlamydia trachomatis. This approach is a novel and effective way to identify secreted effectors in a broad range of pathogenic bacteria for further experimental characterization and provides insight into the nature of the type III secretion signal.

  5. Classical Cryptography v/s Quantum Cryptography A Comparative Study

    Directory of Open Access Journals (Sweden)

    Minakshi Bhatt

    2012-01-01

    Full Text Available In this era of information technology, the need for security has attained paramount importance. As most of our sensitive information is stored in computers the need of data security becomes increasingly important. Protecting this information against unauthorized access is therefore a major concern for both operating systems and users alike. Cryptography is one such method of safeguarding sensitive data from being stolen or intercepted by unwanted third parties. Traditional cryptology is certainly clever, but as with all encoding methods in code-breaking history, it's being phased out. Quantum cryptography uses quantum mechanics to guarantee secure communication. It enables two parties to produce a shared random bit string known only to them, which can be used as a key to encrypt and decrypt messages. By harnessing the unpredictable nature of matter at the quantum level, physicists have figured out a way to exchange information on secret keys. Attaching information to the photons spin is the essence of Quantum Cryptology. In brief, the processes of encoding (cryptography and decoding (crypto analysis information or messages (called plaintext into an otherwise meaningless data (cipher text combined are cryptology. And when the keys used for this process are photons, it’s called Quantum Cryptology.

  6. Stability assessment of QKD procedures in commercial quantum cryptography systems versus quality of dark channel

    Science.gov (United States)

    Jacak, Monika; Melniczuk, Damian; Jacak, Janusz; Jóźwiak, Ireneusz; Gruber, Jacek; Jóźwiak, Piotr

    2015-02-01

    In order to assess the susceptibility of the quantum key distribution (QKD) systems to the hacking attack including simultaneous and frequent system self-decalibrations, we analyze the stability of the QKD transmission organized in two commercially available systems. The first one employs non-entangled photons as flying qubits in the dark quantum channel for communication whereas the second one utilizes the entangled photon pairs to secretly share the cryptographic key. Applying standard methods of the statistical data analysis to the characteristic indicators of the quality of the QKD communication (the raw key exchange rate [RKER] and the quantum bit error rate [QBER]), we have estimated the pace of the self-decalibration of both systems and the repeatability rate in the case of controlled worsening of the dark channel quality.

  7. Two-party quantum key agreement with five-particle entangled states

    Science.gov (United States)

    He, Ye-Feng; Ma, Wen-Ping

    A two-party quantum key agreement protocol is proposed with five-particle entangled states and the delayed measurement technique. According to the measurement correlation property of five-particle entangled states, two participants can deduce the measurement results of each other’s initial quantum states. As a result, two parties can extract the secret keys of each other by using the publicly announced value or by performing the delayed measurement, respectively. Thus, a shared key is fairly established. Since each particle is transmitted only once in quantum channel, the protocol is congenitally free from the Trojan horse attacks. It is shown that the protocol not only is secure against both participant and outsider attacks but also has no information leakage problem. Moreover, it has high qubit efficiency.

  8. The role of quantum discord in quantum information theory

    Energy Technology Data Exchange (ETDEWEB)

    Streltsov, Alexander [ICFO - The Institute of Photonic Sciences, Castelldefels (Spain)

    2014-07-01

    Quantum correlations beyond entanglement - in particular represented by quantum discord - have become a major research field in the last few years. In this talk we report on the role of quantum discord in several fundamental tasks in quantum information theory. Starting with the role of quantum discord in the quantum measurement process, we also discuss its role in the tasks of information sharing and entanglement distribution. Finally, we also show the limits of these results and present possible ways to go beyond these limits.

  9. Entanglement sharing: from qubits to Gaussian states

    CERN Document Server

    Adesso, G; Adesso, Gerardo; Illuminati, Fabrizio

    2005-01-01

    It is a central trait of quantum information theory that there exist limitations to the free sharing of quantum correlations among multiple parties. Such {\\em monogamy constraints} have been introduced in a landmark paper by Coffman, Kundu and Wootters, who derived a quantitative inequality expressing a trade-off between the couplewise and the genuine tripartite entanglement for states of three qubits. Since then, a lot of efforts have been devoted to the investigation of distributed entanglement in multipartite quantum systems. In these proceedings we report, in a unifying framework, a bird's eye view of the most relevant results that have been established so far on entanglement sharing in quantum systems. We will take off from the domain of $N$ qubits, graze qudits, and finally land in the almost unexplored territory of multimode Gaussian states of continuous variable systems.

  10. Quantum cryptography without switching.

    Science.gov (United States)

    Weedbrook, Christian; Lance, Andrew M; Bowen, Warwick P; Symul, Thomas; Ralph, Timothy C; Lam, Ping Koy

    2004-10-22

    We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.

  11. Multiparty Quantum Key Agreement Based on Quantum Search Algorithm.

    Science.gov (United States)

    Cao, Hao; Ma, Wenping

    2017-03-23

    Quantum key agreement is an important topic that the shared key must be negotiated equally by all participants, and any nontrivial subset of participants cannot fully determine the shared key. To date, the embed modes of subkey in all the previously proposed quantum key agreement protocols are based on either BB84 or entangled states. The research of the quantum key agreement protocol based on quantum search algorithms is still blank. In this paper, on the basis of investigating the properties of quantum search algorithms, we propose the first quantum key agreement protocol whose embed mode of subkey is based on a quantum search algorithm known as Grover's algorithm. A novel example of protocols with 5 - party is presented. The efficiency analysis shows that our protocol is prior to existing MQKA protocols. Furthermore it is secure against both external attack and internal attacks.

  12. Experiments With Queries Over Encrypted Data Using Secret Sharing

    NARCIS (Netherlands)

    Brinkman, R.; Schoenmakers, B.; Doumen, J.M.; Jonker, W.; Jonker, W.; Petkovic, M.

    2005-01-01

    To avoid insider attacks one cannot rely on access control to protect a database scheme. Encrypting the database is a better option. This paper describes a working prototype of an encrypted database system that allows remote querying over the encrypted data. Experiments with the system show the prac

  13. Experiments with Queries over Encrypted Data Using Secret Sharing

    NARCIS (Netherlands)

    Brinkman, R.; Schoenmakers, B.; Doumen, J.; Jonker, W.

    2005-01-01

    To avoid insider attacks one cannot rely on access control to protect a database scheme. Encrypting the database is a better option. This paper describes a working prototype of an encrypted database system that allows remote querying over the encrypted data. Experiments with the system show the prac

  14. Linear round bit-decomposition of secret-shared values

    NARCIS (Netherlands)

    Veugen, P.J.M.

    2015-01-01

    In the field of signal processing in the encrypted domain, linear operations are usually easy to perform, whereas multiplications, and bitwise operations like comparison, are more costly in terms of computation and communication. These bitwise operations frequently require a decomposition of the sec

  15. Authentication Without Secrets

    Energy Technology Data Exchange (ETDEWEB)

    Pierson, Lyndon G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    This work examines a new approach to authentication, which is the most fundamental security primitive that underpins all cyber security protections. Current Internet authentication techniques require the protection of one or more secret keys along with the integrity protection of the algorithms/computations designed to prove possession of the secret without actually revealing it. Protecting a secret requires physical barriers or encryption with yet another secret key. The reason to strive for "Authentication without Secret Keys" is that protecting secrets (even small ones only kept in a small corner of a component or device) is much harder than protecting the integrity of information that is not secret. Promising methods are examined for authentication of components, data, programs, network transactions, and/or individuals. The successful development of authentication without secret keys will enable far more tractable system security engineering for high exposure, high consequence systems by eliminating the need for brittle protection mechanisms to protect secret keys (such as are now protected in smart cards, etc.). This paper is a re-release of SAND2009-7032 with new figures numerous edits.

  16. Free-space Quantum Key Distribution over 10 km in Daylight and at Night

    Science.gov (United States)

    Hughes, Richard; Nordholt, Jane; Peterson, Charles

    2002-05-01

    In quantum key distribution (QKD) single-photon transmissions transfer the shared, secret random number sequences, known as cryptographic keys that are used to encrypt and decrypt secret communications. Because the security of QKD is based on principles of quantum physics and information theory an adversary can neither successfully tap the key transmissions, nor evade detection. We have performed QKD using the four-state Â"BB84Â" protocol with non-orthogonal photon polarization states across a 10-km line-of-sight path in daylight and at night [1]. We transferred secret, cryptographic quality random numbers at practical rates with security against technologically feasible eavesdropping strategies. By relating the secrecy capacity (secret bits transferred per transmitted bit), which had values up to 10-3, to properties of the atmospheric channel we are able to infer the secrecy capacity of free-space QKD under other atmospheric conditions and over other, longer transmission distances. 1. R. J. Hughes, J. E. Nordholt, D. Derkacs and C. G. Peterson, Los Alamos report LA-UR-02-449.

  17. Secret Key Generation for a Pairwise Independent Network Model

    CERN Document Server

    Nitinawarat, Sirin; Barg, Alexander; Narayan, Prakash; Reznik, Alex

    2010-01-01

    We consider secret key generation for a "pairwise independent network" model in which every pair of terminals observes correlated sources that are independent of sources observed by all other pairs of terminals. The terminals are then allowed to communicate publicly with all such communication being observed by all the terminals. The objective is to generate a secret key shared by a given subset of terminals at the largest rate possible, with the cooperation of any remaining terminals. Secrecy is required from an eavesdropper that has access to the public interterminal communication. A (single-letter) formula for secret key capacity brings out a natural connection between the problem of secret key generation and a combinatorial problem of maximal packing of Steiner trees in an associated multigraph. An explicit algorithm is proposed for secret key generation based on a maximal packing of Steiner trees in a multigraph; the corresponding maximum rate of Steiner tree packing is thus a lower bound for the secret ...

  18. New Eavesdropper Detection Method in Quantum Cryptograph

    Directory of Open Access Journals (Sweden)

    Cătălin Anghel

    2011-12-01

    Full Text Available ecurity of quantum cryptographic algorithms is one of the main research directions in quantum cryptography. Security growth of the quantum key distribution systems can be realized by detecting the eavesdropper quickly, precisely and without letting any secret information in the hands of the enemy. This paper proposes a new method, named QBTT, to detect the enemy who try to tap the communication channel. The QBTT method can be implemented in every type of quantum key distribution scheme.

  19. Finite-key analysis of a practical decoy-state high-dimensional quantum key distribution

    Science.gov (United States)

    Bao, Haize; Bao, Wansu; Wang, Yang; Zhou, Chun; Chen, Ruike

    2016-05-01

    Compared with two-level quantum key distribution (QKD), high-dimensional QKD enables two distant parties to share a secret key at a higher rate. We provide a finite-key security analysis for the recently proposed practical high-dimensional decoy-state QKD protocol based on time-energy entanglement. We employ two methods to estimate the statistical fluctuation of the postselection probability and give a tighter bound on the secure-key capacity. By numerical evaluation, we show the finite-key effect on the secure-key capacity in different conditions. Moreover, our approach could be used to optimize parameters in practical implementations of high-dimensional QKD.

  20. Immunoglobins in mammary secretions

    DEFF Research Database (Denmark)

    Hurley, W L; Theil, Peter Kappel

    2013-01-01

    Immunoglobulins secreted in colostrum and milk by the lactating mammal are major factors providing immune protection to the newborn. Immunoglobulins in mammary secretions represent the cumulative immune response of the lactating animal to exposure to antigenic stimulation that occurs through inte...

  1. ASYNCHRONOUS BYZANTINE AGREEMENT PROTOCOL BASED ON VERIFIABLE SIGNATURE SHARING

    Institute of Scientific and Technical Information of China (English)

    Ji Dongyao; Feng Dengguo

    2006-01-01

    An ([n / 3]- 1 )-resilient Asynchronous Byzantine Agreement Protocol (ABAP) that combines verifiable signature sharing and random secret sharing is proposed. The protocol works in the asynchronous network environment and produces Byzantine agreement within a fixed expected number of computational rounds. The correctness of the protocol is proved in theory.

  2. ACTH-Secreting Pheochromocytoma. Case report

    Directory of Open Access Journals (Sweden)

    N S Kuznetsov

    2012-12-01

    Full Text Available Ectopic hormone-secreting pheochromocytomas are rare. Only case reports exist in the literature. Despite the large number of guides on diagnosis and treatment of pheochromocytoma, and Cushing syndrome, the extreme rarity of ectopic ACTH-syndrome caused by pheochromocytoma, and complexity of clinical cause numerous diagnostic errors leading to treatment failure. Therefore, we belive it appropriate to share our experience of this group of patients.

  3. Bulk Locality and Quantum Error Correction in AdS/CFT

    CERN Document Server

    Almheiri, Ahmed; Harlow, Daniel

    2014-01-01

    We point out a connection between the emergence of bulk locality in AdS/CFT and the theory of quantum error correction. Bulk notions such as Bogoliubov transformations, location in the radial direction, and the holographic entropy bound all have natural CFT interpretations in the language of quantum error correction. We also show that the question of whether bulk operator reconstruction works only in the causal wedge or all the way to the extremal surface is related to the question of whether or not the quantum error correcting code realized by AdS/CFT is also a "quantum secret sharing scheme", and suggest a tensor network calculation that may settle the issue. Interestingly, the version of quantum error correction which is best suited to our analysis is the somewhat nonstandard "operator algebra quantum error correction" of Beny, Kempf, and Kribs. Our proposal gives a precise formulation of the idea of "subregion-subregion" duality in AdS/CFT, and clarifies the limits of its validity.

  4. Incretin secretion: direct mechanisms

    DEFF Research Database (Denmark)

    Balk-Møller, Emilie; Holst, Jens Juul; Kuhre, Rune Ehrenreich

    2014-01-01

    The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are secreted from gastro-intestinal K- and L-cells, respectively, and play an important role in post-prandial blood glucose regulation. They do this by direct stimulation of the pancreatic β...... enzyme responsible for incretin degradation (dipeptidyl peptidase-4) is inhibited (drugs are already on the market) while the secretion of endogenous GLP-1 secretion is stimulated at the same time may prove particularly rewarding. In this section we review current knowledge on the mechanisms for direct...

  5. Type VI secretion system.

    Science.gov (United States)

    Salomon, Dor; Orth, Kim

    2015-03-30

    Bacteria employ a variety of tools to survive in a competitive environment. Salomon and Orth describe one such tool-the Type 6 Secretion Systems used by bacteria to deliver a variety of toxins into competing cells.

  6. Quantum Dialogue Revisited

    Institute of Scientific and Technical Information of China (English)

    MAN Zhong-Xiao; ZHANG Zhan-Jun; LI Yong

    2005-01-01

    @@ An entanglement-based quantum dialogue protocol [Phys. Lett. A 328 (2004) 6] is proven to be insecure: that is, in the protocol an eavesdropper can steal the secret messages without being detected provided that he/she adopts the intercept-and-resend attack strategy. We modify the protocol, I.e. In the control mode, by introducing and randomly choosing two sets of measuring basis: the intercept-and-resend attack can be accordingly detected. Hence, within the present version two users can securely and simultaneously exchange their secret messages.

  7. Remote implementation of quantum operations

    Energy Technology Data Exchange (ETDEWEB)

    Huelga, Susana F [Quantum Physics Group, STRI, Department of Physics, Astrophysics and Mathematics, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Plenio, Martin B [QOLS, Blackett Laboratory, Imperial College London, London SW7 2BW (United Kingdom); Xiang Guoyong [Key Laboratory of Quantum Information and Department of Physics, University of Science and Technology of China, Hefei 230026 (China); Li Jian [Key Laboratory of Quantum Information and Department of Physics, University of Science and Technology of China, Hefei 230026 (China); Guo Guangcan [Key Laboratory of Quantum Information and Department of Physics, University of Science and Technology of China, Hefei 230026 (China)

    2005-10-01

    Shared entanglement allows, under certain conditions, the remote implementation of quantum operations. We revise and extend recent theoretical results on the remote control of quantum systems as well as experimental results on the remote manipulation of photonic qubits via linear optical elements.

  8. Remote Implementation of Quantum Operations

    CERN Document Server

    Huelga, S F; Xiang, G Y; Guo, J L G C; Huelga, Susana F.; Plenio, Martin B.; Xiang, Guo-Yong; Guo, Jian Li}and Guang-Can

    2005-01-01

    Shared entanglement allows, under certain conditions, the remote implementation of quantum operations. We revise and extend recent theoretical results on the remote control of quantum systems as well as experimental results on the remote manipulation of photonic qubits via linear optical elements.

  9. Quantum computing

    OpenAIRE

    Li, Shu-Shen; Long, Gui-lu; Bai, Feng-Shan; Feng, Song-Lin; Zheng, Hou-Zhi

    2001-01-01

    Quantum computing is a quickly growing research field. This article introduces the basic concepts of quantum computing, recent developments in quantum searching, and decoherence in a possible quantum dot realization.

  10. Share your Sweets

    DEFF Research Database (Denmark)

    Byrnit, Jill; Høgh-Olesen, Henrik; Makransky, Guido

    2015-01-01

    as sharing in which group members were allowed to co-feed or remove food from the stock of the food possessor, and the introduction of high-value food resulted in more sharing, not less. Food sharing behavior differed between species in that chimpanzees displayed significantly more begging behavior than......All over the world, humans (Homo sapiens) display resource-sharing behavior, and common patterns of sharing seem to exist across cultures. Humans are not the only primates to share, and observations from the wild have long documented food sharing behavior in our closest phylogenetic relatives......, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). However, few controlled studies have been made where groups of Pan are introduced to food items that may be shared or monopolized by a first food possessor, and very few studies have examined what happens to these sharing patterns if the food...

  11. Unknown Quantum States The Quantum de Finetti Representation

    CERN Document Server

    Caves, C M; Schack, R; Caves, Carlton M.; Fuchs, Christopher A.; Schack, Ruediger

    2002-01-01

    We present an elementary proof of the quantum de Finetti representation theorem, a quantum analogue of de Finetti's classical theorem on exchangeable probability assignments. This contrasts with the original proof of Hudson and Moody [Z. Wahrschein. verw. Geb. 33, 343 (1976)], which relies on advanced mathematics and does not share the same potential for generalization. The classical de Finetti theorem provides an operational definition of the concept of an unknown probability in Bayesian probability theory, where probabilities are taken to be degrees of belief instead of objective states of nature. The quantum de Finetti theorem, in a closely analogous fashion, deals with exchangeable density-operator assignments and provides an operational definition of the concept of an ``unknown quantum state'' in quantum-state tomography. This result is especially important for information-based interpretations of quantum mechanics, where quantum states, like probabilities, are taken to be states of knowledge rather than...

  12. Robust Anti-Collective Noise Quantum Secure Direct Dialogue Using Logical Bell States

    Science.gov (United States)

    Wu, Di; Lv, Hong-Jun; Xie, Guang-Jun

    2016-01-01

    In this paper we propose two quantum secure direct dialogue (QSDD) schemes with logical Bell states which can resist collective noise. The two users Alice and Bob encode their secret messages with the help of unitary operations. Compared with many quantum secure direct communication (QSDC), there is no strict information sender and receiver in these schemes, one logical Bell state can be operated twice by Alice and Bob based on what messages they prefer to encode. As a result, the two users are able to share their messages mutually, so the efficiency of communication is improved. By rearranging the order of particles and inserting decoy photons, our protocols are able to avoid the information leakage and detect eavesdropping, and they can be proved to have unconditional security.

  13. Unconventional protein secretion.

    Science.gov (United States)

    Ding, Yu; Wang, Juan; Wang, Junqi; Stierhof, York-Dieter; Robinson, David G; Jiang, Liwen

    2012-10-01

    It is generally believed that protein secretion or exocytosis is achieved via a conventional ER (endoplasmic reticulum)-Golgi-TGN (trans-Golgi network)-PM (plasma membrane) pathway in the plant endomembrane system. However, such signal peptide (SP)-dependent protein secretion cannot explain the increasing number of SP-lacking proteins which are found outside of the PM in plant cells. The process by which such leaderless secretory proteins (LSPs) gain access to the cell exterior is termed unconventional protein secretion (UPS) and has been well-studied in animal and yeast cells, but largely ignored by the plant community. Here, we review the evidence for UPS in plants especially in regard to the recently discovered EXPO (exocyst-positive-organelle).

  14. Quantum red-green-blue image steganography

    Science.gov (United States)

    Heidari, Shahrokh; Pourarian, Mohammad Rasoul; Gheibi, Reza; Naseri, Mosayeb; Houshmand, Monireh

    One of the most considering matters in the field of quantum information processing is quantum data hiding including quantum steganography and quantum watermarking. This field is an efficient tool for protecting any kind of digital data. In this paper, three quantum color images steganography algorithms are investigated based on Least Significant Bit (LSB). The first algorithm employs only one of the image’s channels to cover secret data. The second procedure is based on LSB XORing technique, and the last algorithm utilizes two channels to cover the color image for hiding secret quantum data. The performances of the proposed schemes are analyzed by using software simulations in MATLAB environment. The analysis of PSNR, BER and Histogram graphs indicate that the presented schemes exhibit acceptable performances and also theoretical analysis demonstrates that the networks complexity of the approaches scales squarely.

  15. LSB Based Quantum Image Steganography Algorithm

    Science.gov (United States)

    Jiang, Nan; Zhao, Na; Wang, Luo

    2016-01-01

    Quantum steganography is the technique which hides a secret message into quantum covers such as quantum images. In this paper, two blind LSB steganography algorithms in the form of quantum circuits are proposed based on the novel enhanced quantum representation (NEQR) for quantum images. One algorithm is plain LSB which uses the message bits to substitute for the pixels' LSB directly. The other is block LSB which embeds a message bit into a number of pixels that belong to one image block. The extracting circuits can regain the secret message only according to the stego cover. Analysis and simulation-based experimental results demonstrate that the invisibility is good, and the balance between the capacity and the robustness can be adjusted according to the needs of applications.

  16. Quantum Locality in Game Strategy

    Science.gov (United States)

    Melo-Luna, Carlos A.; Susa, Cristian E.; Ducuara, Andrés F.; Barreiro, Astrid; Reina, John H.

    2017-03-01

    Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players’ input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage.

  17. Quantum Locality in Game Strategy.

    Science.gov (United States)

    Melo-Luna, Carlos A; Susa, Cristian E; Ducuara, Andrés F; Barreiro, Astrid; Reina, John H

    2017-03-22

    Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players' input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage.

  18. Quantum Distinction: Quantum Distinctiones!

    OpenAIRE

    Zeps, Dainis

    2009-01-01

    10 pages; How many distinctions, in Latin, quantum distinctiones. We suggest approach of anthropic principle based on anthropic reference system which should be applied equally both in theoretical physics and in mathematics. We come to principle that within reference system of life subject of mathematics (that of thinking) should be equated with subject of physics (that of nature). For this reason we enter notions of series of distinctions, quantum distinction, and argue that quantum distinct...

  19. Covert Quantum Communication

    Science.gov (United States)

    Arrazola, Juan Miguel; Scarani, Valerio

    2016-12-01

    We extend covert communication to the quantum regime by showing that covert quantum communication is possible over optical channels with noise arising either from the environment or from the sender's lab. In particular, we show that sequences of qubits can be transmitted covertly by using both a single photon and a coherent state encoding. We study the possibility of performing covert quantum key distribution (QKD) and show that positive key rates and covertness can be achieved simultaneously. Covert communication requires a secret key between the sender and receiver, which raises the problem of how this key can be regenerated covertly. We show that covert QKD consumes more secret bits than it can generate and propose instead a hybrid protocol for covert key regeneration that uses pseudorandom number generators (PRNGs) together with covert QKD to regenerate secret keys. The security of the new key is guaranteed by QKD while the security of the covert communication is at least as strong as the security of the PRNG.

  20. A Practical Trojan Horse for Bell-inequality-based Quantum Cryptography

    CERN Document Server

    Larsson, J A

    2002-01-01

    Quantum Cryptography, or more accurately, Quantum Key Distribution (QKD) is based on using an unconditionally secure ``quantum channel'' to share a secret key among two users. A manufacturer of QKD devices could, intentionally or not, use a (semi-)classical channel instead of the quantum channel, which would remove the supposedly unconditional security. One example is the BB84 protocol, where the quantum channel can be implemented in polarization of single photons. Here, use of several photons instead of one to encode each bit of the key provides a similar but insecure system. For protocols based on violation of a Bell inequality (e.g., the Ekert protocol), such a modification is generally thought to be impossible. However, a counterexample will be given here using an identical physical setup as is used in photon-polarization Ekert QKD. Since the physical implementation is identical, a manufacturer may include this modification as a Trojan Horse in manufactured systems, to be activated at will by an eavesdrop...

  1. Urban sharing culture

    DEFF Research Database (Denmark)

    Fjalland, Emmy Laura Perez

    In urban areas sharing cultures, services and economies are rising. People share, rent and recycle their homes, cars, bikes, rides, tools, cloths, working space, knowhow and so on. The sharing culture can be understood as mobilities (Kesselring and Vogl 2013) of goods, values and ideas reshaping...... our cities. The sharing economy has the power to democratise access the urban space, resources and raw materials (Steen Nielsen 2008; Harvey 2000); it holds the ability to change the current dominant understandings and structures of economy and growth (Steen Nielsen 2008); solve emerging environmental...... and trust. (Thomsen 2013; Bauman 2000; Beck 1992; Giddens 1991). The sharing economy is currently hyper trendy but before claiming capitalism as dead we need to understand the basics of the sharing economies and cultures asking who can share and what will we share. Furthermore it is crucial to study what...

  2. Charting Secrets Stop Reading Start Practicing

    CERN Document Server

    Bedford, Louise

    2012-01-01

    It is a common myth that the sharemarket is a fast ticket to the easy life. Buy a few shares and watch them go up. Call your broker for up-to-the-minute price information as you drive the Porsche to the golf club. Yell 'Sell! Sell! Sell' into your mobile as you ski through the Swiss Alps. Nothing could be further from the truth. Louise Bedford believes that the only way to be successful in the market is to spend time studying and putting in the hard work, just like any other job. With this in mind, she has written Charting Secrets. Not just another trading book, Charting Secrets is a workbook

  3. Phase-remapping attack in practical quantum-key-distribution systems

    Science.gov (United States)

    Fung, Chi-Hang Fred; Qi, Bing; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2007-03-01

    Quantum key distribution (QKD) can be used to generate secret keys between two distant parties. Even though QKD has been proven unconditionally secure against eavesdroppers with unlimited computation power, practical implementations of QKD may contain loopholes that may lead to the generated secret keys being compromised. In this paper, we propose a phase-remapping attack targeting two practical bidirectional QKD systems (the “plug-and-play” system and the Sagnac system). We showed that if the users of the systems are unaware of our attack, the final key shared between them can be compromised in some situations. Specifically, we showed that, in the case of the Bennett-Brassard 1984 (BB84) protocol with ideal single-photon sources, when the quantum bit error rate (QBER) is between 14.6% and 20%, our attack renders the final key insecure, whereas the same range of QBER values has been proved secure if the two users are unaware of our attack; also, we demonstrated three situations with realistic devices where positive key rates are obtained without the consideration of Trojan horse attacks but in fact no key can be distilled. We remark that our attack is feasible with only current technology. Therefore, it is very important to be aware of our attack in order to ensure absolute security. In finding our attack, we minimize the QBER over individual measurements described by a general POVM, which has some similarity with the standard quantum state discrimination problem.

  4. Secrets of Successful Homeschooling

    Science.gov (United States)

    Rivero, Lisa

    2011-01-01

    Parents who homeschool gifted children often find the daily practice of home education very different from what they had imagined. Gifted children are complex in both personality and learning styles. Parents who say that homeschooling works well for their gifted children have learned from others or discovered on their own several secrets that make…

  5. Physiology of bile secretion

    Institute of Scientific and Technical Information of China (English)

    Alejandro Esteller

    2008-01-01

    The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment,in different situations,results in the syndrome of cholestasis.The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed.Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane.This review summarizes recent data on the molecular determinants of this primary bile formation.The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bileduct epithelial cells (cholangiocytes) as bile passes through bile ducts.The mechanisms of fluid and solute transport in cholangiocytes will also be discussed.In contrast to hepatocytes where secretion is constant and poorly controlled,cholangiocyte secretion is regulated by hormones and nerves.A short section dedicated to these regulatory mechanisms of bile secretion has been included.The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology.

  6. Salivary Gland Secretion.

    Science.gov (United States)

    Dorman, H. L.; And Others

    1981-01-01

    Describes materials and procedures for an experiment utilizing a live dog to demonstrate: (1) physiology of the salivary gland; (2) parasympathetic control of the salivary gland; (3) influence of varying salivary flow rates on sodium and potassium ions, osmolarity and pH; and (4) salivary secretion as an active process. (DS)

  7. Satisfaction and 'comparison sharing'

    DEFF Research Database (Denmark)

    Amilon, Anna

    2009-01-01

    the probability of satisfaction. Results show that comparison sharing impacts satisfaction for women, and that those women who share more equally than their peers are more likely to be satisfied, whereas comparison sharing has no influence on satisfaction for men. Also, parents are less likely to be satisfied...

  8. A Quick Glance at Quantum Cryptography

    CERN Document Server

    Lomonaco, S J

    1998-01-01

    The recent application of the principles of quantum mechanics to cryptography has led to a remarkable new dimension in secret communication. As a result of these new developments, it is now possible to construct cryptographic communication systems which detect unauthorized eavesdropping should it occur, and which give a guarantee of no eavesdropping should it not occur. CONTENTS P3....Cryptographic systems before quantum cryptography P7....Preamble to quantum cryptography P10..The BB84 quantum cryptographic protocol without noise P16..The BB84 quantum cryptographic protocol with noise P19..The B92 quantum cryptographic protocol P21..EPR quantum cryptographic protocols P25..Other protocols P25..Eavesdropping stategies and counter measures P26..Conclusion P29..Appendix A. The no cloning theorem P30..Appendix B. Proof that an undetectable eavesdropper can obtain no information from the B92 protocol P31..Appendix C. Part of a Rosetta stone for quantum mechanics P44..References

  9. Are Secrets Immoral? The Construction of Secrets in Everyday Conversation.

    Science.gov (United States)

    Gunthner, Susanne; Luckmann, Thomas

    1998-01-01

    Investigates the communicative treatment of secrets, presenting examples from recorded communicative interactions in a wide range of social milieus and settings in which the participants revealed knowledge of secrets, tried to dig out old secrets without appearing to be doing so, and occasionally, appeared to be hiding some items of knowledge from…

  10. The physical underpinning of security proofs for quantum key distribution

    Science.gov (United States)

    Boileau, Jean Christian

    The dawn of quantum technology unveils a plethora of new possibilities and challenges in the world of information technology, one of which is the quest for secure information transmission. A breakthrough in classical algorithm or the development of a quantum computer could threaten the security of messages encoded using public key cryptosystems based on one-way function such as RSA. Quantum key distribution (QKD) offers an unconditionally secure alternative to such schemes, even in the advent of a quantum computer, as it does not rely on mathematical or technological assumptions, but rather on the universality of the laws of quantum mechanics. Physical concepts associated with quantum mechanics, like the uncertainty principle or entanglement, paved the way to the first successful security proof for QKD. Ever since, further development in security proofs for QKD has been remarkable. But the connection between entanglement distillation and the uncertainty principle has remained hidden under a pile of mathematical burden. Our main goal is to dig the physics out of the new advances in security proofs for QKD. By introducing an alternative definition of private state, which elaborates the ideas of Mayers and Koashi, we explain how the security of all QKD protocols follows from an entropic uncertainty principle. We show explicitly how privacy amplification protocol can be reduced to a private state distillation protocol constructed from our observations about the uncertainty principle. We also derive a generic security proof for one-way permutation-invariant QKD protocols. Considering collective attack, we achieve the same secret key generation rate as the Devetak-Winter's bound. Generalizing an observation from Kraus, Branciard and Renner, we have provided an improved version of the secret key generation rates by considering a different symmetrization. In certain situations, we argue that Azuma's inequality can simplify the security proof considerably, and we explain

  11. Secret-Key Generation using Correlated Sources and Channels

    CERN Document Server

    Khisti, Ashish; Wornell, Gregory

    2009-01-01

    We study the problem of generating a shared secret key between two terminals in a joint source-channel setup -- the sender communicates to the receiver over a discrete memoryless wiretap channel and additionally the terminals have access to correlated discrete memoryless source sequences. We establish lower and upper bounds on the secret-key capacity. These bounds coincide, establishing the capacity, when the underlying channel consists of independent, parallel and reversely degraded wiretap channels. In the lower bound, the equivocation terms of the source and channel components are functionally additive. The secret-key rate is maximized by optimally balancing the the source and channel contributions. This tradeoff is illustrated in detail for the Gaussian case where it is also shown that Gaussian codebooks achieve the capacity. When the eavesdropper also observes a source sequence, the secret-key capacity is established when the sources and channels of the eavesdropper are a degraded version of the legitima...

  12. Extracellular secretion of recombinant proteins

    Science.gov (United States)

    Linger, Jeffrey G.; Darzins, Aldis

    2014-07-22

    Nucleic acids encoding secretion signals, expression vectors containing the nucleic acids, and host cells containing the expression vectors are disclosed. Also disclosed are polypeptides that contain the secretion signals and methods of producing polypeptides, including methods of directing the extracellular secretion of the polypeptides. Exemplary embodiments include cellulase proteins fused to secretion signals, methods to produce and isolate these polypeptides, and methods to degrade lignocellulosic biomass.

  13. Bucarest, Strictement Secret

    Directory of Open Access Journals (Sweden)

    Ionela Mihai

    2010-07-01

    Full Text Available L’émission Bucarest, strictement secret représente un documentaire organisésous la forme d’une série télé, qui dépeint le Bucarest à partir de deux perspectives: de l’histoire, de la conte et du lieu. La valeur d’une cité réside dans l’existence d’une mystique, d’un romantisme abscons, à part et des caractères empruntés de drames de Shakespeare, mystérieux, serrés d’angoisse et des secrets qui assombrissent leur existence. Par conséquence, le rôle du metteur en scène est de dévoiler leur vraie identité et de remettre en place, autant que possible, la vérité.

  14. Do quantum strategies always win?

    Science.gov (United States)

    Anand, Namit; Benjamin, Colin

    2015-11-01

    In a seminal paper, Meyer (Phys Rev Lett 82:1052, 1999) described the advantages of quantum game theory by looking at the classical penny flip game. A player using a quantum strategy can win against a classical player almost 100 % of the time. Here we make a slight modification to the quantum game, with the two players sharing an entangled state to begin with. We then analyze two different scenarios: First in which quantum player makes unitary transformations to his qubit, while the classical player uses a pure strategy of either flipping or not flipping the state of his qubit. In this case, the quantum player always wins against the classical player. In the second scenario, we have the quantum player making similar unitary transformations, while the classical player makes use of a mixed strategy wherein he either flips or not with some probability " p." We show that in the second scenario, 100 % win record of a quantum player is drastically reduced and for a particular probability " p" the classical player can even win against the quantum player. This is of possible relevance to the field of quantum computation as we show that in this quantum game of preserving versus destroying entanglement a particular classical algorithm can beat the quantum algorithm.

  15. Secret Key Crypto Implementations

    Science.gov (United States)

    Bertoni, Guido Marco; Melzani, Filippo

    This chapter presents the algorithm selected in 2001 as the Advanced Encryption Standard. This algorithm is the base for implementing security and privacy based on symmetric key solutions in almost all new applications. Secret key algorithms are used in combination with modes of operation to provide different security properties. The most used modes of operation are presented in this chapter. Finally an overview of the different techniques of software and hardware implementations is given.

  16. Quantum stochastics

    CERN Document Server

    Chang, Mou-Hsiung

    2015-01-01

    The classical probability theory initiated by Kolmogorov and its quantum counterpart, pioneered by von Neumann, were created at about the same time in the 1930s, but development of the quantum theory has trailed far behind. Although highly appealing, the quantum theory has a steep learning curve, requiring tools from both probability and analysis and a facility for combining the two viewpoints. This book is a systematic, self-contained account of the core of quantum probability and quantum stochastic processes for graduate students and researchers. The only assumed background is knowledge of the basic theory of Hilbert spaces, bounded linear operators, and classical Markov processes. From there, the book introduces additional tools from analysis, and then builds the quantum probability framework needed to support applications to quantum control and quantum information and communication. These include quantum noise, quantum stochastic calculus, stochastic quantum differential equations, quantum Markov semigrou...

  17. Quantum Computing

    CERN Document Server

    Steane, A M

    1998-01-01

    The subject of quantum computing brings together ideas from classical information theory, computer science, and quantum physics. This review aims to summarise not just quantum computing, but the whole subject of quantum information theory. It turns out that information theory and quantum mechanics fit together very well. In order to explain their relationship, the review begins with an introduction to classical information theory and computer science, including Shannon's theorem, error correcting codes, Turing machines and computational complexity. The principles of quantum mechanics are then outlined, and the EPR experiment described. The EPR-Bell correlations, and quantum entanglement in general, form the essential new ingredient which distinguishes quantum from classical information theory, and, arguably, quantum from classical physics. Basic quantum information ideas are described, including key distribution, teleportation, data compression, quantum error correction, the universal quantum computer and qua...

  18. High-rate measurement-device-independent quantum cryptography

    DEFF Research Database (Denmark)

    Pirandola, Stefano; Ottaviani, Carlo; Spedalieri, Gaetana

    2015-01-01

    Quantum cryptography achieves a formidable task - the remote distribution of secret keys by exploiting the fundamental laws of physics. Quantum cryptography is now headed towards solving the practical problem of constructing scalable and secure quantum networks. A significant step in this direction...... than those currently achieved. Our protocol could be employed to build high-rate quantum networks where devices securely connect to nearby access points or proxy servers....

  19. The Sharing Economy

    DEFF Research Database (Denmark)

    Avital, Michel; Carroll, John M.; Hjalmarsson, Anders

    2015-01-01

    The sharing economy is spreading rapidly worldwide in a number of industries and markets. The disruptive nature of this phenomenon has drawn mixed responses ranging from active conflict to adoption and assimilation. Yet, in spite of the growing attention to the sharing economy, we still do not know...... much about it. With the abundant enthusiasm about the benefits that the sharing economy can unleash and the weekly reminders about its dark side, further examination is required to determine the potential of the sharing economy while mitigating its undesirable side effects. The panel will join...... the ongoing debate about the sharing economy and contribute to the discourse with insights about how digital technologies are critical in shaping this turbulent ecosystem. Furthermore, we will define an agenda for future research on the sharing economy as it becomes part of the mainstream society as well...

  20. Quantum Blobs

    OpenAIRE

    Gosson, Maurice A. de

    2012-01-01

    Quantum blobs are the smallest phase space units of phase space compatible with the uncertainty principle of quantum mechanics and having the symplectic group as group of symmetries. Quantum blobs are in a bijective correspondence with the squeezed coherent states from standard quantum mechanics, of which they are a phase space picture. This allows us to propose a substitute for phase space in quantum mechanics. We study the relationship between quantum blobs with a certain class of level set...

  1. Network-Centric Quantum Communications

    Science.gov (United States)

    Hughes, Richard

    2014-03-01

    Single-photon quantum communications (QC) offers ``future-proof'' cryptographic security rooted in the laws of physics. Today's quantum-secured communications cannot be compromised by unanticipated future technological advances. But to date, QC has only existed in point-to-point instantiations that have limited ability to address the cyber security challenges of our increasingly networked world. In my talk I will describe a fundamentally new paradigm of network-centric quantum communications (NQC) that leverages the network to bring scalable, QC-based security to user groups that may have no direct user-to-user QC connectivity. With QC links only between each of N users and a trusted network node, NQC brings quantum security to N2 user pairs, and to multi-user groups. I will describe a novel integrated photonics quantum smartcard (``QKarD'') and its operation in a multi-node NQC test bed. The QKarDs are used to implement the quantum cryptographic protocols of quantum identification, quantum key distribution and quantum secret splitting. I will explain how these cryptographic primitives are used to provide key management for encryption, authentication, and non-repudiation for user-to-user communications. My talk will conclude with a description of a recent demonstration that QC can meet both the security and quality-of-service (latency) requirements for electric grid control commands and data. These requirements cannot be met simultaneously with present-day cryptography.

  2. Factors Impacting Knowledge Sharing

    DEFF Research Database (Denmark)

    Schulzmann, David; Slepniov, Dmitrij

    The purpose of this paper is to examine various factors affecting knowledge sharing at the R&D center of a Western MNE in China. The paper employs qualitative methodology and is based on the action research and case study research techniques. The findings of the paper advance our understanding...... about factors that affect knowledge sharing. The main emphasis is given to the discussion on how to improve knowledge sharing in global R&D organizations....

  3. Facilitating Knowledge Sharing

    DEFF Research Database (Denmark)

    Holdt Christensen, Peter

    Abstract This paper argues that knowledge sharing can be conceptualized as different situations of exchange in which individuals relate to each other in different ways, involving different rules, norms and traditions of reciprocity regulating the exchange. The main challenge for facilitating...... and the intermediaries regulating the exchange, and facilitating knowledge sharing should therefore be viewed as a continuum of practices under the influence of opportunistic behaviour, obedience or organizational citizenship behaviour. Keywords: Knowledge sharing, motivation, organizational settings, situations...

  4. Facilitating Knowledge Sharing

    OpenAIRE

    Holdt Christensen, Peter

    2005-01-01

    Abstract This paper argues that knowledge sharing can be conceptualized as different situations of exchange in which individuals relate to each other in different ways, involving different rules, norms and traditions of reciprocity regulating the exchange. The main challenge for facilitating knowledge sharing is to ensure that the exchange is seen as equitable for the parties involved, and by viewing the problems of knowledge sharing as motivational problems situated in different organization...

  5. Dynamic secrets in communication security

    CERN Document Server

    Xiao, Sheng; Towsley, Donald

    2013-01-01

    Dynamic secrets are constantly generated and updated from messages exchanged between two communication users. When dynamic secrets are used as a complement to existing secure communication systems, a stolen key or password can be quickly and automatically reverted to its secret status without disrupting communication. 'Dynamic Secrets in Communication Security' presents unique security properties and application studies for this technology. Password theft and key theft no longer pose serious security threats when parties frequently use dynamic secrets. This book also illustrates that a dynamic

  6. A Data Sharing Story

    Directory of Open Access Journals (Sweden)

    Mercè Crosas

    2012-01-01

    Full Text Available From the early days of modern science through this century of Big Data, data sharing has enabled some of the greatest advances in science. In the digital age, technology can facilitate more effective and efficient data sharing and preservation practices, and provide incentives for making data easily accessible among researchers. At the Institute for Quantitative Social Science at Harvard University, we have developed an open-source software to share, cite, preserve, discover and analyze data, named the Dataverse Network. We share here the project’s motivation, its growth and successes, and likely evolution.

  7. Phenomenology of experiential sharing

    DEFF Research Database (Denmark)

    León, Felipe; Zahavi, Dan

    2016-01-01

    The chapter explores the topic of experiential sharing by drawing on the early contributions of the phenomenologists Alfred Schutz and Gerda Walther. It is argued that both Schutz and Walther support, from complementary perspectives, an approach to experiential sharing that has tended...... to be overlooked in current debates. This approach highlights specific experiential interrelations taking place among individuals who are jointly engaged and located in a common environment, and situates this type of sharing within a broader and richer spectrum of sharing phe- nomena. Whereas Schutz’ route...

  8. Phenomenology of experiential sharing

    DEFF Research Database (Denmark)

    León, Felipe; Zahavi, Dan

    2016-01-01

    The chapter explores the topic of experiential sharing by drawing on the early contributions of the phenomenologists Alfred Schutz and Gerda Walther. It is argued that both Schutz and Walther support, from complementary perspectives, an approach to experiential sharing that has tended to be overl......The chapter explores the topic of experiential sharing by drawing on the early contributions of the phenomenologists Alfred Schutz and Gerda Walther. It is argued that both Schutz and Walther support, from complementary perspectives, an approach to experiential sharing that has tended...

  9. Quantum relay schemes for continuous-variable quantum key distribution

    Science.gov (United States)

    Guo, Ying; Liao, Qin; Huang, Duan; Zeng, Guihua

    2017-04-01

    We propose several concatenated quantum relay continuous-variable quantum key distribution schemes based on the parametric amplifier (PA) and the beam splitter (BS). Instead of using only one BS in the traditional relay scheme, the proposed schemes provide two operations that involve both PA and BS, activating the beam splitting and recombining operations in turn. These schemes would benefit the system performance improvement by providing signal amplification and establishing quantum correlations. We show that the different effects of the relay schemes will cause different system performances because of the varied signal-to-noise ratio (SNR) of output fields. The system's secret key rate will be increased when equipping with the PA-BS relay scheme, because the output fields of the PA are entangled with the correlated quantum noises while input fields of the BS are superimposed, subsequently leading to the quantum noise reduction of the total output fields of relay station, while the reversed BS-PA relay scheme has little advantage over the traditional counterpart that contains only one BS in relay data postprocessing because it will not cause any SNR improvement. Moreover, the reinforced PA-PA relay scheme results in a slight improvement due to the increased SNR. These quantum relay schemes can be performed through the beam splitting, the recombining operations, and the relay data postprocessing, such that it would be suitable for secret information exchange in complex networks with intermediate stations.

  10. Quantum Key Distribution with Fibonacci Orbital Angular Momentum States

    OpenAIRE

    Simon, David S.; Lawrence, Nate; Trevino, Jacob; Negro, Luca Dal; Sergienko, Alexander V.

    2012-01-01

    Quantum cryptography and quantum key distribution (QKD) have been the most successful applications of quantum information processing, highlighting the unique capability of quantum mechanics, through the no-cloning theorem, to protect the security of shared encryption keys. Here we present a new and fundamentally different approach to high-capacity, high-efficiency QKD by exploiting interplay between cross-disciplinary ideas from quantum information and light scattering of aperiodic photonic m...

  11. Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons

    OpenAIRE

    Kröger, H.

    2003-01-01

    We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.

  12. Nonlinear Dynamics In Quantum Physics -- Quantum Chaos and Quantum Instantons

    OpenAIRE

    Kröger, H.

    2003-01-01

    We discuss the recently proposed quantum action - its interpretation, its motivation, its mathematical properties and its use in physics: quantum mechanical tunneling, quantum instantons and quantum chaos.

  13. Schrödinger's killer app race to build the world's first quantum computer

    CERN Document Server

    Dowling, Jonathan P

    2013-01-01

    The race is on to construct the first quantum code breaker, as the winner will hold the key to the entire Internet. From international, multibillion-dollar financial transactions to top-secret government communications, all would be vulnerable to the secret-code-breaking ability of the quantum computer. Written by a renowned quantum physicist closely involved in the U.S. government's development of quantum information science, Schrodinger's Killer App: Race to Build the World's First Quantum Computer presents an inside look at the government's quest to build a quantum computer capable of solvi

  14. Choice of measurement as the secret

    Science.gov (United States)

    Liu, Bin; Gao, Fei; Qin, Su-Juan; Huang, Wei; Liu, Feng; Wen, Qiao-Yan

    2014-04-01

    Recently, Kalev et al. [A. Kalev, A. Mann, and M. Revzen, Phys. Rev. Lett. 110, 260502 (2013)., 10.1103/PhysRevLett.110.260502] proposed a quantum (public) communication protocol with an interesting encoding style, where the signal is encoded in the choice of the measurement basis of one of the communicating parties (Bob) and Bob's measurement results are irrelevant for the communication. As we know, one of the main advantages of quantum technique in communication over the classical one is the higher security. Therefore, as Kalev et al. have mentioned in their paper, an interesting open question is whether one could and how to utilize this new encoding style to design a secure communication protocol, i.e., translate the choice of measurement into the secret. Here we propose a quantum key distribution protocol, which is a secure communication protocol, with this encoding style, where Bob's measurement results are still irrelevant. Furthermore, the security of the proposed protocol in the zero-error case has been proved.

  15. Prospects for quantum computation with trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, R.J.; James, D.F.V.

    1997-12-31

    Over the past decade information theory has been generalized to allow binary data to be represented by two-state quantum mechanical systems. (A single two-level system has come to be known as a qubit in this context.) The additional freedom introduced into information physics with quantum systems has opened up a variety of capabilities that go well beyond those of conventional information. For example, quantum cryptography allows two parties to generate a secret key even in the presence of eavesdropping. But perhaps the most remarkable capabilities have been predicted in the field of quantum computation. Here, a brief survey of the requirements for quantum computational hardware, and an overview of the in trap quantum computation project at Los Alamos are presented. The physical limitations to quantum computation with trapped ions are discussed.

  16. Autotransporter protein secretion.

    Science.gov (United States)

    Tame, Jeremy R H

    2011-12-01

    Autotransporter proteins are a large family of virulence factors secreted from Gram-negative bacteria by a unique mechanism. First described in the 1980s, these proteins have a C-terminal region that folds into a β-barrel in the bacterial outer membrane. The so-called passenger domain attached to this barrel projects away from the cell surface and may be liberated from the cell by self-cleavage or surface proteases. Although the majority of passenger domains have a similar β-helical structure, they carry a variety of sub-domains, allowing them to carry out widely differing functions related to pathogenesis. Considerable biochemical and structural characterisation of the barrel domain has shown that 'autotransporters' in fact require a conserved and essential protein complex in the outer membrane for correct folding. Although the globular domains of this complex projecting into the periplasmic space have also been structurally characterised, the overall secretion pathway of the autotransporters remains highly puzzling. It was presumed for many years that the passenger domain passed through the centre of the barrel domain to reach the cell surface, driven at least in part by folding. This picture is complicated by conflicting data, and there is currently little hard information on the true nature of the secretion intermediates. As well as their medical importance therefore, autotransporters are proving to be an excellent system to study the folding and membrane insertion of outer membrane proteins in general. This review focuses on structural aspects of autotransporters; their many functions in pathogenesis are beyond its scope.

  17. Experimental quantum data locking

    Science.gov (United States)

    Liu, Yang; Cao, Zhu; Wu, Cheng; Fukuda, Daiji; You, Lixing; Zhong, Jiaqiang; Numata, Takayuki; Chen, Sijing; Zhang, Weijun; Shi, Sheng-Cai; Lu, Chao-Yang; Wang, Zhen; Ma, Xiongfeng; Fan, Jingyun; Zhang, Qiang; Pan, Jian-Wei

    2016-08-01

    Classical correlation can be locked via quantum means: quantum data locking. With a short secret key, one can lock an exponentially large amount of information in order to make it inaccessible to unauthorized users without the key. Quantum data locking presents a resource-efficient alternative to one-time pad encryption which requires a key no shorter than the message. We report experimental demonstrations of a quantum data locking scheme originally proposed by D. P. DiVincenzo et al. [Phys. Rev. Lett. 92, 067902 (2004), 10.1103/PhysRevLett.92.067902] and a loss-tolerant scheme developed by O. Fawzi et al. [J. ACM 60, 44 (2013), 10.1145/2518131]. We observe that the unlocked amount of information is larger than the key size in both experiments, exhibiting strong violation of the incremental proportionality property of classical information theory. As an application example, we show the successful transmission of a photo over a lossy channel with quantum data (un)locking and error correction.

  18. The Sharing Economy

    DEFF Research Database (Denmark)

    Avital, Michel; Carroll, John M.; Hjalmarsson, Anders;

    2015-01-01

    The sharing economy is spreading rapidly worldwide in a number of industries and markets. The disruptive nature of this phenomenon has drawn mixed responses ranging from active conflict to adoption and assimilation. Yet, in spite of the growing attention to the sharing economy, we still do not kn...

  19. Limitations to sharing entanglement

    CERN Document Server

    Kim, Jeong San; Sanders, Barry C

    2011-01-01

    We discuss limitations to sharing entanglement known as monogamy of entanglement. Our pedagogical approach commences with simple examples of limited entanglement sharing for pure three-qubit states and progresses to the more general case of mixed-state monogamy relations with multiple qudits.

  20. 5G Spectrum Sharing

    OpenAIRE

    Nekovee, Maziar; Rudd, Richard

    2017-01-01

    In this paper an overview is given of the current status of 5G industry standards, spectrum allocation and use cases, followed by initial investigations of new opportunities for spectrum sharing in 5G using cognitive radio techniques, considering both licensed and unlicensed scenarios. A particular attention is given to sharing millimeter-wave frequencies, which are of prominent importance for 5G.

  1. Shared Parenting Dysfunction.

    Science.gov (United States)

    Turkat, Ira Daniel

    2002-01-01

    Joint custody of children is the most prevalent court ordered arrangement for families of divorce. A growing body of literature indicates that many parents engage in behaviors that are incompatible with shared parenting. This article provides specific criteria for a definition of the Shared Parenting Dysfunction. Clinical aspects of the phenomenon…

  2. Windows 8 secrets

    CERN Document Server

    Thurrott, Paul

    2012-01-01

    Tips, tricks, treats, and secrets revealed on Windows 8 Microsoft is introducing a major new release of its Windows operating system, Windows 8, and what better way to learn all its ins and outs than from two internationally recognized Windows experts and Microsoft insiders, authors Paul Thurrott and Rafael Rivera? They cut through the hype to get at useful information you'll not find anywhere else, including what role this new OS plays in a mobile and tablet world. Regardless of your level of knowledge, you'll discover little-known facts about how things work, what's new and different, and h

  3. Effects of nuclei ambiguus and dorsal motor nuclei of vagus on gastric H+ and HCO3- secretion in rats

    Institute of Scientific and Technical Information of China (English)

    Xue-Ying Zhang; Hong-Bin Ai; Xi-Yun Cui

    2006-01-01

    AIM: To determine the effects of electrical stimulation of nucleus ambiguus (NA) and dorsal motor nuclei of vagus (DMV) on gastric acid and bicarbonate secretion in rats.METHODS: NA and DMV in rats were electrically stimulated. Pylorus ligation or esophagus perfusion was used to collect the gastric secretion. The titratable H+ quantum, H+ concentration, HCO3- secretion quantum were measured.RESULTS: Electrical stimulation of NA had no effects on the volume of gastric juice, titratable acidity and acid concentration, but elicited a pronounced increase in the total bicarbonate. However, electrical stimulation of DMV significantly increased the titratable acidity, the volume of gastric juice and the acid concentration. Similarly,electrical stimulation of either NA or DMV decreased the respiratory frequency and sinus bradycardia.CONCLUSION: NA in rats can not control the secretion of gastric acid but the secretion of bicarbonate in gastric juice, while DMV controls the secretion of gastric acid.

  4. Fast and simple high-capacity quantum cryptography with error detection

    Science.gov (United States)

    Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Zhang, Jun; Pan, Lei; Li, Shudong; Orgun, Mehmet A.

    2017-04-01

    Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth.

  5. Exploring the Sharing Economy

    DEFF Research Database (Denmark)

    Netter, Sarah

    tensions experience by sharing platforms by looking at the case of mobile fashion reselling and swapping markets. The final paper combines the perspectives of different sharing economy stakeholders and outlines some of the micro and macro tensions arising in and influencing the organization of these multi...... and to provide a more nuanced understanding of the micro- and macro-level tensions that characterize the sharing economy. This thesis consists of four research papers, each using different literature, methodology, and data sets. The first paper investigates how the sharing economy is diffused and is ‘talked...... into existence’ by the communicative acts of a number of different actors. The second paper looks at how the reality of these narratives is actually experienced by the representatives of one type of sharing platform, i.e., fashion libraries. The third paper further expands the understanding of micro-level...

  6. Exploring the Sharing Economy

    DEFF Research Database (Denmark)

    Netter, Sarah

    Despite the growing interest on the part of proponents and opponents - ranging from business, civil society, media, to policy-makers alike - there is still limited knowledge about the working mechanisms of the sharing economy. The thesis is dedicated to explore this understudied phenomenon...... and to provide a more nuanced understanding of the micro- and macro-level tensions that characterize the sharing economy. This thesis consists of four research papers, each using different literature, methodology, and data sets. The first paper investigates how the sharing economy is diffused and is ‘talked......-level tensions experience by sharing platforms by looking at the case of mobile fashion reselling and swapping markets. The final paper combines the perspectives of different sharing economy stakeholders and outlines some of the micro and macro tensions arising in and influencing the organization of these multi...

  7. Ghrelin and gastric acid secretion

    Institute of Scientific and Technical Information of China (English)

    Koji Yakabi; Junichi Kawashima; Shingo Kato

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric add secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  8. Ghrelin and gastric acid secretion.

    Science.gov (United States)

    Yakabi, Koji; Kawashima, Junichi; Kato, Shingo

    2008-11-07

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-induced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric acid secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  9. Quantum radar

    CERN Document Server

    Lanzagorta, Marco

    2011-01-01

    This book offers a concise review of quantum radar theory. Our approach is pedagogical, making emphasis on the physics behind the operation of a hypothetical quantum radar. We concentrate our discussion on the two major models proposed to date: interferometric quantum radar and quantum illumination. In addition, this book offers some new results, including an analytical study of quantum interferometry in the X-band radar region with a variety of atmospheric conditions, a derivation of a quantum radar equation, and a discussion of quantum radar jamming.This book assumes the reader is familiar w

  10. Quantum Blobs

    CERN Document Server

    de Gosson, Maurice A

    2011-01-01

    Quantum blobs are the smallest phase space units of phase space compatible with the uncertainty principle of quantum mechanics and having the symplectic group as group of symmetries. Quantum blobs are in a bijective correspondence with the squeezed coherent states from standard quantum mechanics, of which they are a phase space picture. This allows us to propose a substitute for phase space in quantum mechanics. We study the relationship between quantum blobs with a certain class of level sets defined by Fermi for the purpose of representing geometrically quantum states.

  11. Quantum Malware

    CERN Document Server

    Wu, L A; Wu, Lian-Ao; Lidar, Daniel

    2005-01-01

    Quantum computation and communication offer unprecedented advantages compared to classical information processing. Currently, quantum communication is moving from laboratory prototypes into real-life applications. When quantum communication networks become more widespread it is likely that they will be subject to attacks by hackers, virus makers, and other malicious intruders. Here we introduce the concept of "quantum malware" to describe such human-made intrusions. We offer a simple solution for storage of quantum information in a manner which protects quantum networks from quantum malware.

  12. Large payload quantum steganography based on cavity quantum electrodynamics

    Institute of Scientific and Technical Information of China (English)

    Ye Tian-Yu; Jiang Li-Zhen

    2013-01-01

    A large payload quantum steganography protocol based on cavity quantum electrodynamics (QED) is presented in this paper,which effectively uses the evolutionary law of atoms in cavity QED.The protocol builds up a hidden channel to transmit secret messages using entanglement swapping between one GHZ state and one Bell state in cavity QED together with the Hadamard operation.The quantum steganography protocol is insensitive to cavity decay and the thermal field.The capacity,imperceptibility and security against eavesdropping are analyzed in detail in the protocol.It turns out that the protocol not only has good imperceptibility but also possesses good security against eavesdropping.In addition,its capacity for a hidden channel achieves five bits,larger than most of the previous quantum steganography protocols.

  13. Chimpanzees share forbidden fruit.

    Directory of Open Access Journals (Sweden)

    Kimberley J Hockings

    Full Text Available The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a 'social tool' for nurturing alliances and social bonds. Here we report the only recorded example of regular sharing of plant foods by unrelated, non-provisioned wild chimpanzees, and the contexts in which these sharing behaviours occur. From direct observations, adult chimpanzees at Bossou (Republic of Guinea, West Africa very rarely transferred wild plant foods. In contrast, they shared cultivated plant foods much more frequently (58 out of 59 food sharing events. Sharing primarily consists of adult males allowing reproductively cycling females to take food that they possess. We propose that hypotheses focussing on 'food-for-sex and -grooming' and 'showing-off' strategies plausibly account for observed sharing behaviours. A changing human-dominated landscape presents chimpanzees with fresh challenges, and our observations suggest that crop-raiding provides adult male chimpanzees at Bossou with highly desirable food commodities that may be traded for other currencies.

  14. Secure quantum communication using classical correlated channel

    Science.gov (United States)

    Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.

    2016-10-01

    We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.

  15. Quantum cloning

    OpenAIRE

    Scarani, Valerio; Iblisdir, Sofyan; Gisin, Nicolas; Acin, Antonio

    2005-01-01

    The impossibility of perfectly copying (or cloning) an arbitrary quantum state is one of the basic rules governing the physics of quantum systems. The processes that perform the optimal approximate cloning have been found in many cases. These "quantum cloning machines" are important tools for studying a wide variety of tasks, e.g. state estimation and eavesdropping on quantum cryptography. This paper provides a comprehensive review of quantum cloning machines (both for discrete-dimensional an...

  16. Complementarity and Entanglement in Quantum Information Theory

    CERN Document Server

    Tessier, T E

    2004-01-01

    The restrictions that nature places on the distribution of correlations in a multipartite quantum system play fundamental roles in the evolution of such systems, and yield vital insights into the design of protocols for the quantum control of ensembles with potential applications in the field of quantum computing. We show how this entanglement sharing behavior may be studied in increasingly complex systems of both theoretical and experimental significance and demonstrate that entanglement sharing, as well as other unique features of entanglement, e.g. the fact that maximal information about a multipartite quantum system does not necessarily entail maximal information about its component subsystems, may be understood as specific consequences of the phenomenon of complementarity extended to composite quantum systems. We also present a local hidden-variable model supplemented by an efficient amount of classical communication that reproduces the quantum-mechanical predictions for the entire class of Gottesman-Kni...

  17. Knowledge grows when shared

    DEFF Research Database (Denmark)

    Elbæk, Mikael Karstensen

    2010-01-01

    Knowledge is one of the few commodities that don’t devalue when used. Actually knowledge grows when shared and the free online access to peer-reviewed scientific publications is a potent ingredient the process of sharing. The sharing of knowledge is facilitated by the Open Access Movement. However...... infrastructure for Open Access was launched in Ghent, Belgium. This project and initiative is facilitating the success of the Open Access Pilot in FP7 as presented earlier in this journal. In this brief article I will present some of the most interesting issues that were discussed during the first session...

  18. Global resource sharing

    CERN Document Server

    Frederiksen, Linda; Nance, Heidi

    2011-01-01

    Written from a global perspective, this book reviews sharing of library resources on a global scale. With expanded discovery tools and massive digitization projects, the rich and extensive holdings of the world's libraries are more visible now than at any time in the past. Advanced communication and transmission technologies, along with improved international standards, present a means for the sharing of library resources around the globe. Despite these significant improvements, a number of challenges remain. Global Resource Sharing provides librarians and library managers with a comprehensive

  19. Too Much Information Sharing?

    DEFF Research Database (Denmark)

    Ganuza, Juan José; Jansen, Jos

    2013-01-01

    By using general information structures and precision criteria based on the dispersion of conditional expectations, we study how oligopolists’ information acquisition decisions may change the effects of information sharing on the consumer surplus. Sharing information about individual cost...... parameters gives the following trade-off in Cournot oligopoly. On the one hand, it decreases the expected consumer surplus for a given information precision, as the literature shows. On the other hand, information sharing increases the firms’ incentives to acquire information, and the consumer surplus...... increases in the precision of the firms’ information. Interestingly, the latter effect may dominate the former effect....

  20. Getting Behind B Shares

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China Ocean Shipping(Group)Co.(COSCO) employs an experimental strategy of making acquisitions through the purchase of B shares COSCO Pacific Ltd.and its affili- ated companies held 4.5 million shares of China International Marine Containers(Grouo)Co.Ltd.(CIMC) as of March 6. Four months ago,the board of direc- tors of COSCO Container Industries Ltd. (COSCO Container)decided to buy more B shares of CIMC through the securities mar- ket.COSCO Container is a shell company registered in the British Virgin Islands with a

  1. Quantum CPU and Quantum Algorithm

    OpenAIRE

    Wang, An Min

    1999-01-01

    Making use of an universal quantum network -- QCPU proposed by me\\upcite{My1}, it is obtained that the whole quantum network which can implement some the known quantum algorithms including Deutsch algorithm, quantum Fourier transformation, Shor's algorithm and Grover's algorithm.

  2. Quantum Computer Games: Quantum Minesweeper

    Science.gov (United States)

    Gordon, Michal; Gordon, Goren

    2010-01-01

    The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…

  3. Quantum Computer Games: Quantum Minesweeper

    Science.gov (United States)

    Gordon, Michal; Gordon, Goren

    2010-01-01

    The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…

  4. Catalytic quantum error correction

    CERN Document Server

    Brun, T; Hsieh, M H; Brun, Todd; Devetak, Igor; Hsieh, Min-Hsiu

    2006-01-01

    We develop the theory of entanglement-assisted quantum error correcting (EAQEC) codes, a generalization of the stabilizer formalism to the setting in which the sender and receiver have access to pre-shared entanglement. Conventional stabilizer codes are equivalent to dual-containing symplectic codes. In contrast, EAQEC codes do not require the dual-containing condition, which greatly simplifies their construction. We show how any quaternary classical code can be made into a EAQEC code. In particular, efficient modern codes, like LDPC codes, which attain the Shannon capacity, can be made into EAQEC codes attaining the hashing bound. In a quantum computation setting, EAQEC codes give rise to catalytic quantum codes which maintain a region of inherited noiseless qubits. We also give an alternative construction of EAQEC codes by making classical entanglement assisted codes coherent.

  5. 量子直接通信%Quantum secure direct communication

    Institute of Scientific and Technical Information of China (English)

    李熙涵

    2015-01-01

    量子直接通信是量子通信中的一个重要分支,它是一种不需要事先建立密钥而直接传输机密信息的新型通信模式。本综述将介绍量子直接通信的基本原理,回顾量子直接通信的发展历程,从最早的高效量子直接通信协议、两步量子直接通信模型、量子一次一密直接通信模型等,到抗噪声的量子直接通信模型以及基于单光子多自由度量子态及超纠缠态的量子直接通信模型,最后介绍量子直接通信的研究现状并展望其发展未来。%Quantum secure direct communication (QSDC) is one of the most important branches of quantum communication. In contrast to the quantum key distribution (QKD) which distributes a secure key between distant parties, QSDC directly transmits secret message instead of sharing key in advance. To establish a secure QSDC protocol, on the one hand, the security of the quantum channel should be confirmed before the exchange of the secret message. On the other hand, the quantum state should be transmitted in a quantum data block since the security of QSDC is based on the error rate analysis in the theories on statistics. Compared with the deterministic quantum key distribution (DQKD) which can also be used to transmit deterministic information, QSDC schemes do not need extra classical bits to read the secret message except for public discussion. In this article, we introduce the basic principles of QSDC and review the development in this field by introducing typical QSDC protocols chronologically. The first QSDC protocol was proposed by Long and Liu, which can be used to establish a common key between distant parties. In their scheme, the method for transmitting quantum states in a block by block way and in multiple steps was proposed and the information leakage before eavesdropping detection was solved. Subsequently, Deng et al. presented two pioneering QSDC schemes, an entangled-state-based two-step QSDC scheme and a

  6. RIC-7 promotes neuropeptide secretion.

    Directory of Open Access Journals (Sweden)

    Yingsong Hao

    2012-01-01

    Full Text Available Secretion of neurotransmitters and neuropeptides is mediated by exocytosis of distinct secretory organelles, synaptic vesicles (SVs and dense core vesicles (DCVs respectively. Relatively little is known about factors that differentially regulate SV and DCV secretion. Here we identify a novel protein RIC-7 that is required for neuropeptide secretion in Caenorhabditis elegans. The RIC-7 protein is expressed in all neurons and is localized to presynaptic terminals. Imaging, electrophysiology, and behavioral analysis of ric-7 mutants indicates that acetylcholine release occurs normally, while neuropeptide release is significantly decreased. These results suggest that RIC-7 promotes DCV-mediated secretion.

  7. Salmonella-secreted Virulence Factors

    Energy Technology Data Exchange (ETDEWEB)

    Heffron, Fred; Niemann, George; Yoon, Hyunjin; Kidwai, Afshan S.; Brown, Roslyn N.; McDermott, Jason E.; Smith, Richard D.; Adkins, Joshua N.

    2011-05-01

    In this short review we discuss secreted virulence factors of Salmonella, which directly affect Salmonella interaction with its host. Salmonella secretes protein to subvert host defenses but also, as discussed, to reduce virulence thereby permitting the bacteria to persist longer and more successfully disperse. The type III secretion system (TTSS) is the best known and well studied of the mechanisms that enable secretion from the bacterial cytoplasm to the host cell cytoplasm. Other secretion systems include outer membrane vesicles, which are present in all Gram-negative bacteria examined to date, two-partner secretion, and type VI secretion will also be addressed. Excellent reviews of Salmonella secreted effectors have focused on themes such as actin rearrangements, vesicular trafficking, ubiquitination, and the activities of the virulence factors themselves. This short review is based on S. Typhimurium infection of mice because it is a model of typhoid like disease in humans. We have organized effectors in terms of events that happen during the infection cycle and how secreted effectors may be involved.

  8. Shared decision making

    Science.gov (United States)

    ... the rest of your life Having major surgery Getting genetic or cancer screening tests Talking together about your options helps your provider know how you feel and what you value. How Shared Decision Making Works When facing a decision, your ...

  9. A Public Secret

    DEFF Research Database (Denmark)

    Bregnbæk, Susanne

    2011-01-01

    This article is based on anthropological fieldwork undertaken at two elite universities in Beijing. It addresses the paradoxical situation of the many instances of suicide among Chinese elite university students in Beijing, which constitute a public secret. The pressure of education weighs heavily...... on the shoulders of China’s only child in each family, known as the generation of little emperors and little empresses. Since the 1980s, the suzhi jiaoyu reforms (education for quality) have involved various attempts to reduce the pressure of education. However, simultaneously the aim is to increase...... the competitiveness of individuals. Drawing on existential and phenomenological thought, I suggest that the discourse seems to objectify and quantify a concern for well-being, rather than recognising its intersubjective character. Finally, I argue that the suicides are controversial since they are seen as a form...

  10. A quantum network of clocks

    Science.gov (United States)

    Kómár, P.; Kessler, E. M.; Bishof, M.; Jiang, L.; Sørensen, A. S.; Ye, J.; Lukin, M. D.

    2014-08-01

    The development of precise atomic clocks plays an increasingly important role in modern society. Shared timing information constitutes a key resource for navigation with a direct correspondence between timing accuracy and precision in applications such as the Global Positioning System. By combining precision metrology and quantum networks, we propose a quantum, cooperative protocol for operating a network of geographically remote optical atomic clocks. Using nonlocal entangled states, we demonstrate an optimal utilization of global resources, and show that such a network can be operated near the fundamental precision limit set by quantum theory. Furthermore, the internal structure of the network, combined with quantum communication techniques, guarantees security both from internal and external threats. Realization of such a global quantum network of clocks may allow construction of a real-time single international time scale (world clock) with unprecedented stability and accuracy.

  11. Sharing resources@CERN

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The library is launching a 'sharing resources@CERN' campaign, aiming to increase the library's utility by including the thousands of books bought by individual groups at CERN. This will improve sharing of information among CERN staff and users. Photo 01: L. to r. Eduardo Aldaz, from the PS division, Corrado Pettenati, Head Librarian, and Isabel Bejar, from the ST division, read their divisional copies of the same book.

  12. The Tradable Shares Puzzle

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A huge number of restricted shares were made tradable in March in the mainland stock market,testing the capability of the fragile capital market Ping An of China has been made the main scapegoat of this year s stock market plunge.A month after its refinancing plan announcement- equivalent to recreating a new Ping An- its 3.12 billion restricted shares were made tradable on March 3,accounting for almost

  13. Performing the sharing economy.

    OpenAIRE

    Richardson, L

    2015-01-01

    The sharing economy converges around activities facilitated through digital platforms that enable peer-to-peer access to goods and services. It constitutes an apparent paradox, framed as both part of the capitalist economy and as an alternative. This duplicity necessitates focusing on the performances of the sharing economy: how it simultaneously constructs diverse economic activities whilst also inviting the deconstruction of ongoing practices of dominance. Such performances hold open the qu...

  14. Quantum memristors

    Science.gov (United States)

    Pfeiffer, P.; Egusquiza, I. L.; di Ventra, M.; Sanz, M.; Solano, E.

    2016-07-01

    Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the known quantized models of passive circuit elements, such as inductors, capacitors or resistors, the design and realization of a quantum memristor is still missing. Here, we introduce the concept of a quantum memristor as a quantum dissipative device, whose decoherence mechanism is controlled by a continuous-measurement feedback scheme, which accounts for the memory. Indeed, we provide numerical simulations showing that memory effects actually persist in the quantum regime. Our quantization method, specifically designed for superconducting circuits, may be extended to other quantum platforms, allowing for memristor-type constructions in different quantum technologies. The proposed quantum memristor is then a building block for neuromorphic quantum computation and quantum simulations of non-Markovian systems.

  15. Regulating the sharing economy

    Directory of Open Access Journals (Sweden)

    Kristofer Erickson

    2016-06-01

    Full Text Available In this introductory essay, we explore definitions of the ‘sharing economy’, a concept indicating both social (relational, communitarian and economic (allocative, profit-seeking aspects which appear to be in tension. We suggest combining the social and economic logics of the sharing economy to focus on the central features of network enabled, aggregated membership in a pool of offers and demands (for goods, services, creative expressions. This definition of the sharing economy distinguishes it from other related peer-to-peer and collaborative forms of production. Understanding the social and economic motivations for and implications of participating in the sharing economy is important to its regulation. Each of the papers in this special issue contributes to knowledge by linking the social and economic aspects of sharing economy practices to regulatory norms and mechanisms. We conclude this essay by suggesting future research to further clarify and render intelligible the sharing economy, not as a contradiction in terms but as an empirically observable realm of socio-economic activity.

  16. Quantum trajectories

    CERN Document Server

    Chattaraj, Pratim Kumar

    2010-01-01

    The application of quantum mechanics to many-particle systems has been an active area of research in recent years as researchers have looked for ways to tackle difficult problems in this area. The quantum trajectory method provides an efficient computational technique for solving both stationary and time-evolving states, encompassing a large area of quantum mechanics. Quantum Trajectories brings the expertise of an international panel of experts who focus on the epistemological significance of quantum mechanics through the quantum theory of motion.Emphasizing a classical interpretation of quan

  17. Memory attacks on device-independent quantum cryptography.

    Science.gov (United States)

    Barrett, Jonathan; Colbeck, Roger; Kent, Adrian

    2013-01-01

    Device-independent quantum cryptographic schemes aim to guarantee security to users based only on the output statistics of any components used, and without the need to verify their internal functionality. Since this would protect users against untrustworthy or incompetent manufacturers, sabotage, or device degradation, this idea has excited much interest, and many device-independent schemes have been proposed. Here we identify a critical weakness of device-independent protocols that rely on public communication between secure laboratories. Untrusted devices may record their inputs and outputs and reveal information about them via publicly discussed outputs during later runs. Reusing devices thus compromises the security of a protocol and risks leaking secret data. Possible defenses include securely destroying or isolating used devices. However, these are costly and often impractical. We propose other more practical partial defenses as well as a new protocol structure for device-independent quantum key distribution that aims to achieve composable security in the case of two parties using a small number of devices to repeatedly share keys with each other (and no other party).

  18. Review of novel aspects of the regulation of ghrelin secretion.

    Science.gov (United States)

    Al Massadi, Omar; Lear, Pamela V; Muller, Timo D; Lopez, Miguel; Dieguez, Carlos; Tschop, Matthias H; Nogueiras, Ruben

    2014-01-01

    The role of ghrelin in regulating metabolism and energy balance has been a subject of intense focus ever since its discovery. Ghrelin regulates energy balance in the short term by induction of appetite and in the longer term by increasing body weight and adiposity. It is the only known peripheral orexigenic hormone and one of the most potent endogenous orexigenic factors discovered to date. However, whilst extensively studied, the mechanism of ghrelin secretion is not well understood. A better understanding of the pathways controlling ghrelin secretion could be useful in the development of new therapeutic approaches to appetite-related disorders. Here, we discuss current knowledge of the processes that control ghrelin secretion, focusing on neural, chemical and hormonal stimuli. In addition, we share our view on the potential of targeting ghrelin for the treatment of eating disorders such as obesity, anorexia nervosa and cachexia.

  19. Yohimbine increases human salivary secretion.

    Science.gov (United States)

    Chatelut, E; Rispail, Y; Berlan, M; Montastruc, J L

    1989-01-01

    The effect of oral yohimbine (14 mg) on salivary secretion was evaluated in healthy volunteers. Yohimbine significantly increased salivary secretion when compared with placebo. This effect was significant from 60 min until 180 min after administration under our experimental conditions. Yohimbine (or alpha 2-adrenoceptor blocking agents) could have a potential interest in the treatment of dry mouths. PMID:2789932

  20. Interactive simulations for quantum key distribution

    CERN Document Server

    Kohnle, Antje

    2016-01-01

    Secure communication protocols are becoming increasingly important, e.g. for internet-based communication. Quantum key distribution allows two parties, commonly called Alice and Bob, to generate a secret sequence of 0s and 1s called a key that is only known to themselves. Classically, Alice and Bob could never be certain that their communication was not compromised by a malicious eavesdropper. Quantum mechanics however makes secure communication possible. The fundamental principle of quantum mechanics that taking a measurement perturbs the system (unless the measurement is compatible with the quantum state) also applies to an eavesdropper. Using appropriate protocols to create the key, Alice and Bob can detect the presence of an eavesdropper by errors in their measurements. As part of the QuVis Quantum Mechanics Visualization Project, we have developed a suite of four interactive simulations that demonstrate the basic principles of three different quantum key distribution protocols. The simulations use either...

  1. Quantum cobwebs: Universal entangling of quantum states

    Indian Academy of Sciences (India)

    Arun Kumar Pati

    2002-08-01

    Entangling an unknown qubit with one type of reference state is generally impossible. However, entangling an unknown qubit with two types of reference states is possible. To achieve this, we introduce a new class of states called zero sum amplitude (ZSA) multipartite, pure entangled states for qubits and study their salient features. Using shared-ZSA states, local operations and classical communication, we give a protocol for creating multipartite entangled states of an unknown quantum state with two types of reference states at remote places. This provides a way of encoding an unknown pure qubit state into a multiqubit entangled state.

  2. Quantum Key Distribution Protocol with User Authentication

    CERN Document Server

    Lee, H; Lee, D; Lim, J; Yang, H J; Lee, Hwayean; Lee, Sangjin; Lee, Donghoon; Lim, Jongin; Yang, HyungJin

    2005-01-01

    We propose a quantum key distribution protocol with quantum based user authentication. User authentication is executed by validating the correlation of GHZ states. Alice and Bob can distribute a secure key using the remaining GHZ states after authentication. This secret key does not leak even to the arbitrator by the properties of the entanglement. We will show that our protocol is secure against the cloning attack.

  3. Failure of Kak quantum key distribution protocol

    Indian Academy of Sciences (India)

    Ching-Nung Yang; Su-Hsuan Chu; Bing-Ling Lu

    2005-01-01

    Kak's quantum key distribution (QKD) protocol provides not only the distribution but also the integrity of secret key simultaneously in quantum channel. Consequently the additional exchange of information, used to check whether an eavesdropper exists, is unnecessary. In this comment, we will point out the failure of Kak's protocol and show that Kak's protocol does not have the joint distribution and integration that the author declares in [1].

  4. Security Proof for Quantum Key Distribution Using Qudit Systems

    CERN Document Server

    Sheridan, Lana

    2010-01-01

    We provide security bounds against coherent attacks for two families of quantum key distribution protocols that use $d$-dimensional quantum systems. In the asymptotic regime, both the secret key rate for fixed noise and the robustness to noise increase with $d$. The finite-key corrections are found to be almost insensitive to $d\\lesssim 20$.

  5. How to teach quantum physics to your dog

    CERN Document Server

    Orzel, Chad

    2010-01-01

    In this international bestseller, Orzel explains the key theories of quantum physics, taking his dog Emmy's anarchic behaviour as a starting point. Could she use quantum tunnelling to get through the neighbour's fence? How about diffracting round a tree to chase squirrels? From quarks and gluons to Heisenberg's uncertainty principle, this is a uniquely entertaining way to unlock the secrets of the universe.

  6. Labia Majora Share

    Science.gov (United States)

    Lee, Hanjing; Yap, Yan Lin; Low, Jeffrey Jen Hui

    2017-01-01

    Defects involving specialised areas with characteristic anatomical features, such as the nipple, upper eyelid, and lip, benefit greatly from the use of sharing procedures. The vulva, a complex 3-dimensional structure, can also be reconstructed through a sharing procedure drawing upon the contralateral vulva. In this report, we present the interesting case of a patient with chronic, massive, localised lymphedema of her left labia majora that was resected in 2011. Five years later, she presented with squamous cell carcinoma over the left vulva region, which is rarely associated with chronic lymphedema. To the best of our knowledge, our management of the radical vulvectomy defect with a labia majora sharing procedure is novel and has not been previously described. The labia major flap presented in this report is a shared flap; that is, a transposition flap based on the dorsal clitoral artery, which has consistent vascular anatomy, making this flap durable and reliable. This procedure epitomises the principle of replacing like with like, does not interfere with leg movement or patient positioning, has minimal donor site morbidity, and preserves other locoregional flap options for future reconstruction. One limitation is the need for a lax contralateral vulva. This labia majora sharing procedure is a viable option in carefully selected patients. PMID:28194353

  7. A noise immunity controlled quantum teleportation protocol

    Science.gov (United States)

    Li, Dong-fen; Wang, Rui-jin; Zhang, Feng-li; Baagyere, Edward; Qin, Zhen; Xiong, Hu; Zhan, Huayi

    2016-08-01

    With the advent of the Internet and information and communication technology, quantum teleportation has become an important field in information security and its application areas. This is because quantum teleportation has the ability to attain a timely secret information delivery and offers unconditional security. And as such, the field of quantum teleportation has become a hot research topic in recent years. However, noise has serious effect on the safety of quantum teleportation within the aspects of information fidelity, channel capacity and information transfer. Therefore, the main purpose of this paper is to address these problems of quantum teleportation. Firstly, in order to resist collective noise, we construct a decoherence-free subspace under different noise scenarios to establish a two-dimensional fidelity quantum teleportation models. And also create quantum teleportation of multiple degree of freedom, and these models ensure the accuracy and availability of the exchange of information and in multiple degree of freedom. Secondly, for easy preparation, measurement and implementation, we use super dense coding features to build an entangled quantum secret exchange channel. To improve the channel utilization and capacity, an efficient super dense coding method based on ultra-entanglement exchange is used. Thirdly, continuous variables of the controlled quantum key distribution were designed for quantum teleportation; in addition, we perform Bell-basis measurement under the collective noise and also prepare the storage technology of quantum states to achieve one-bit key by three-photon encoding to improve its security and efficiency. We use these two methods because they conceal information, resist a third party attack and can detect eavesdropping. Our proposed methods, according to the security analysis, are able to solve the problems associated with the quantum teleportation under various noise environments.

  8. A noise immunity controlled quantum teleportation protocol

    Science.gov (United States)

    Li, Dong-fen; Wang, Rui-jin; Zhang, Feng-li; Baagyere, Edward; Qin, Zhen; Xiong, Hu; Zhan, Huayi

    2016-11-01

    With the advent of the Internet and information and communication technology, quantum teleportation has become an important field in information security and its application areas. This is because quantum teleportation has the ability to attain a timely secret information delivery and offers unconditional security. And as such, the field of quantum teleportation has become a hot research topic in recent years. However, noise has serious effect on the safety of quantum teleportation within the aspects of information fidelity, channel capacity and information transfer. Therefore, the main purpose of this paper is to address these problems of quantum teleportation. Firstly, in order to resist collective noise, we construct a decoherence-free subspace under different noise scenarios to establish a two-dimensional fidelity quantum teleportation models. And also create quantum teleportation of multiple degree of freedom, and these models ensure the accuracy and availability of the exchange of information and in multiple degree of freedom. Secondly, for easy preparation, measurement and implementation, we use super dense coding features to build an entangled quantum secret exchange channel. To improve the channel utilization and capacity, an efficient super dense coding method based on ultra-entanglement exchange is used. Thirdly, continuous variables of the controlled quantum key distribution were designed for quantum teleportation; in addition, we perform Bell-basis measurement under the collective noise and also prepare the storage technology of quantum states to achieve one-bit key by three-photon encoding to improve its security and efficiency. We use these two methods because they conceal information, resist a third party attack and can detect eavesdropping. Our proposed methods, according to the security analysis, are able to solve the problems associated with the quantum teleportation under various noise environments.

  9. Quantum robots and quantum computers

    Energy Technology Data Exchange (ETDEWEB)

    Benioff, P.

    1998-07-01

    Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.

  10. Quantum Darwinism

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, Wojciech H [Los Alamos National Laboratory

    2008-01-01

    Quantum Darwinism - proliferation, in the environment, of multiple records of selected states of the system (its information-theoretic progeny) - explains how quantum fragility of individual state can lead to classical robustness of their multitude.

  11. Quantum music

    CERN Document Server

    Putz, Volkmar

    2015-01-01

    We consider ways of conceptualizing, rendering and perceiving quantum music, and quantum art in general. Thereby we give particular emphasis to its non-classical aspects, such as coherent superposition and entanglement.

  12. Least significant qubit algorithm for quantum images

    Science.gov (United States)

    Sang, Jianzhi; Wang, Shen; Li, Qiong

    2016-11-01

    To study the feasibility of the classical image least significant bit (LSB) information hiding algorithm on quantum computer, a least significant qubit (LSQb) information hiding algorithm of quantum image is proposed. In this paper, we focus on a novel quantum representation for color digital images (NCQI). Firstly, by designing the three qubits comparator and unitary operators, the reasonability and feasibility of LSQb based on NCQI are presented. Then, the concrete LSQb information hiding algorithm is proposed, which can realize the aim of embedding the secret qubits into the least significant qubits of RGB channels of quantum cover image. Quantum circuit of the LSQb information hiding algorithm is also illustrated. Furthermore, the secrets extracting algorithm and circuit are illustrated through utilizing control-swap gates. The two merits of our algorithm are: (1) it is absolutely blind and (2) when extracting secret binary qubits, it does not need any quantum measurement operation or any other help from classical computer. Finally, simulation and comparative analysis show the performance of our algorithm.

  13. Quantum State Detection Via Elimination

    CERN Document Server

    Ettinger, J M; Hoyer, Peter

    1999-01-01

    We present the view of quantum algorithms as a search-theoretic problem. We show that the Fourier transform, used to solve the Abelian hidden subgroup problem, is an example of an efficient elimination observable which eliminates a constant fraction of the candidate secret states with high probability. Finally, we show that elimination observables do not always exist by considering the geometry of the hidden subgroup states of the dihedral group D_N.

  14. Multiple Ca2+ sensors in secretion

    DEFF Research Database (Denmark)

    Walter, Alexander M; Groffen, Alexander J; Sørensen, Jakob Balslev;

    2011-01-01

    Regulated neurotransmitter secretion depends on Ca(2+) sensors, C2 domain proteins that associate with phospholipids and soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE) complexes to trigger release upon Ca(2+) binding. Ca(2+) sensors are thought to prevent spontaneous...... fusion at rest (clamping) and to promote fusion upon Ca(2+) activation. At least eight, often coexpressed, Ca(2+) sensors have been identified in mammals. Accumulating evidence suggests that multiple Ca(2+) sensors interact, rather than work autonomously, to produce the complex secretory response...... observed in neurons and secretory cells. In this review, we present several working models to describe how different sensors might be arranged to mediate synchronous, asynchronous and spontaneous neurotransmitter release. We discuss the scenario that different Ca(2+) sensors typically act on one shared...

  15. Secrets of mlearning failures: confronting reality

    Directory of Open Access Journals (Sweden)

    Thomas Cochrane

    2012-08-01

    Full Text Available Having implemented and evaluated over 35 mlearning projects in a variety of contexts in higher education over the past 6 years the researcher is ready to share the untold secret: not all mlearning projects succeed! This article critiques three of the researcher's mlearning projects that can be classed as “failures” and compares them to successful projects to draw out critical implications for mlearning project design and implementation to avoid common pitfalls leading to potential project failure. This article uses the researcher's six critical success factors identified across the 35 mlearning projects to evaluate these three projects, and concludes that projects resulting in “no significant difference” in pedagogical outcomes are the result of attempts to shoehorn old pedagogies into new technologies. Lecturer professional development and sustained collaborative support are critical to fostering new pedagogies utilising the unique affordances of mobile devices.

  16. Pheochromocytomas and secreting paragangliomas

    Directory of Open Access Journals (Sweden)

    Gimenez-Roqueplo Anne-Paule

    2006-12-01

    Full Text Available Abstract Catecholamine-producing tumors may arise in the adrenal medulla (pheochromocytomas or in extraadrenal chromaffin cells (secreting paragangliomas. Their prevalence is about 0.1% in patients with hypertension and 4% in patients with a fortuitously discovered adrenal mass. An increase in the production of catecholamines causes symptoms (mainly headaches, palpitations and excess sweating and signs (mainly hypertension, weight loss and diabetes reflecting the effects of epinephrine and norepinephrine on α- and β-adrenergic receptors. Catecholamine-producing tumors mimic paroxysmal conditions with hypertension and/or cardiac rhythm disorders, including panic attacks, in which sympathetic activation linked to anxiety reproduces the same signs and symptoms. These tumors may be sporadic or part of any of several genetic diseases: familial pheochromocytoma-paraganglioma syndromes, multiple endocrine neoplasia type 2, neurofibromatosis 1 and von Hippel-Lindau disease. Familial cases are diagnosed earlier and are more frequently bilateral and recurring than sporadic cases. The most specific and sensitive diagnostic test for the tumor is the determination of plasma or urinary metanephrines. The tumor can be located by computed tomography, magnetic resonance imaging and metaiodobenzylguanidine scintigraphy. Treatment requires resection of the tumor, generally by laparoscopic surgery. About 10% of tumors are malignant either at first operation or during follow-up, malignancy being diagnosed by the presence of lymph node, visceral or bone metastases. Recurrences and malignancy are more frequent in cases with large or extraadrenal tumors. Patients, especially those with familial or extraadrenal tumors, should be followed-up indefinitely.

  17. Ergodic Secret Alignment

    CERN Document Server

    Bassily, Raef

    2010-01-01

    In this paper, we introduce two new achievable schemes for the fading multiple access wiretap channel (MAC-WT). In the model that we consider, we assume that perfect knowledge of the state of all channels is available at all the nodes in a causal fashion. Our schemes use this knowledge together with the time varying nature of the channel model to align the interference from different users at the eavesdropper perfectly in a one-dimensional space while creating a higher dimensionality space for the interfering signals at the legitimate receiver hence allowing for better chance of recovery. While we achieve this alignment through signal scaling at the transmitters in our first scheme (scaling based alignment (SBA)), we let nature provide this alignment through the ergodicity of the channel coefficients in the second scheme (ergodic secret alignment (ESA)). For each scheme, we obtain the resulting achievable secrecy rate region. We show that the secrecy rates achieved by both schemes scale with SNR as 1/2log(SNR...

  18. Quantum Abacus

    CERN Document Server

    Cheon, T

    2004-01-01

    We show that the U(2) family of point interactions on a line can be utilized to provide the U(2) family of qubit operations for quantum information processing. Qubits are realized as localized states in either side of the point interaction which represents a controllable gate. The manipulation of qubits proceeds in a manner analogous to the operation of an abacus. Keywords: quantum computation, quantum contact interaction, quantum wire

  19. Quantum Econophysics

    OpenAIRE

    Esteban Guevara

    2006-01-01

    The relationships between game theory and quantum mechanics let us propose certain quantization relationships through which we could describe and understand not only quantum but also classical, evolutionary and the biological systems that were described before through the replicator dynamics. Quantum mechanics could be used to explain more correctly biological and economical processes and even it could encloses theories like games and evolutionary dynamics. This could make quantum mechanics a...

  20. Quantum Nanomechanics

    OpenAIRE

    2008-01-01

    Quantum Nanomechanics is the emerging field which pertains to the mechanical behavior of nanoscale systems in the quantum domain. Unlike the conventional studies of vibration of molecules and phonons in solids, quantum nanomechanics is defined as the quantum behavior of the entire mechanical structure, including all of its constituents--the atoms, the molecules, the ions, the electrons as well as other excitations. The relevant degrees of freedom of the system are described by macroscopic var...

  1. Shared care (comanagement).

    Science.gov (United States)

    Montero Ruiz, E

    2016-01-01

    Surgical departments have increasing difficulties in caring for their hospitalised patients due to the patients' advanced age and comorbidity, the growing specialisation in medical training and the strong political-healthcare pressure that a healthcare organisation places on them, where surgical acts take precedence over other activities. The pressure exerted by these departments on the medical area and the deficient response by the interconsultation system have led to the development of a different healthcare organisation model: Shared care, which includes perioperative medicine. In this model, 2 different specialists share the responsibility and authority in caring for hospitalised surgical patients. Internal Medicine is the most appropriate specialty for shared care. Internists who exercise this responsibility should have certain characteristics and must overcome a number of concerns from the surgeon and anaesthesiologist. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  2. Sharing big biomedical data.

    Science.gov (United States)

    Toga, Arthur W; Dinov, Ivo D

    The promise of Big Biomedical Data may be offset by the enormous challenges in handling, analyzing, and sharing it. In this paper, we provide a framework for developing practical and reasonable data sharing policies that incorporate the sociological, financial, technical and scientific requirements of a sustainable Big Data dependent scientific community. Many biomedical and healthcare studies may be significantly impacted by using large, heterogeneous and incongruent datasets; however there are significant technical, social, regulatory, and institutional barriers that need to be overcome to ensure the power of Big Data overcomes these detrimental factors. Pragmatic policies that demand extensive sharing of data, promotion of data fusion, provenance, interoperability and balance security and protection of personal information are critical for the long term impact of translational Big Data analytics.

  3. Quantum secure direct communication over the collective amplitude damping channel

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An efficient quantum secure direct communication protocol is presented over the amplitude damping channel.The protocol encodes logical bits in two-qubit noiseless states,and so it can function over a quantum channel subjected to collective amplitude damping.The feature of this protocol is that the sender encodes the secret directly on the quantum states,the receiver decodes the secret by performing determinate measurements,and there is no basis mismatch.The transmission’s safety is ensured by the nonorthogonality of the noiseless states traveling forward and backward on the quantum channel.Moreover,we construct the efficient quantum circuits to implement channel encoding and information encoding by means of primitive operations in quantum computation.

  4. Multi-state Quantum Teleportation via One Entanglement State

    Institute of Scientific and Technical Information of China (English)

    GUO Ying; ZENG Gui-Hua; Moon Ho Lee

    2008-01-01

    A multi-sender-controlled quantum teleportation scheme is proposed to teleport several secret quan-tum states from different senders to a distance receiver based on only one Einstein-Podolsky-Rosen (EPR) pair with controlled-NOT (CNOT) gates. In the present scheme, several secret single-qubit quantum states are encoded into a multi-qubit entangled quantum state. Two communication modes, i.e., the detecting mode and the message mode, are employed so that the eavesdropping can be detected easily and the teleported message may be recovered efficiently. It has an advantage over teleporting several different quantum states for one scheme run with more efficiency than the previous quantum teleportation schemes.

  5. Quantum secure direct communication over the collective amplitude damping channel

    Institute of Scientific and Technical Information of China (English)

    QIN Suduan; WEN QiaoYan; MENG LuoMing; ZHU FuChen

    2009-01-01

    An efficient quantum secure direct communication protocol is presented over the amplitude damping channel. The protocol encodes logical bits in two-qubit noiseless states, and so it can function over a quantum channel subjected to collective amplitude damping. The feature of this protocol is that the sender encodes the secret directly on the quantum states, the receiver decodes the secret by per-forming determinate measurements, and there is no basis mismatch. The transmission's safely is en-sured by the nonorthogonality of the noiseless states traveling forward and backward on the quantum channel. Moreover, we construct the efficient quantum circuits to implement channel encoding and information enooding by means of primitive operations in quantum computation.

  6. Quantum cryptography

    NARCIS (Netherlands)

    Fehr, S.

    2010-01-01

    Quantum cryptography makes use of the quantum-mechanical behavior of nature for the design and analysis of cryptographic schemes. Optimally (but not always), quantum cryptography allows for the design of cryptographic schemes whose security is guaranteed solely by the laws of nature. This is in shar

  7. Ultimate precision of adaptive quantum metrology

    CERN Document Server

    Pirandola, Stefano

    2016-01-01

    We consider the problem of estimating a classical parameter encoded in a quantum channel, assuming the most general strategy allowed by quantum mechanics. This strategy is based on the exploitation of an unlimited amount of pre-shared entanglement plus the use of adaptive probings, where the input of the channel is interactively updated during the protocol. We show that, for the wide class of teleportation-stretchable channels in finite dimension, including all Pauli channels and erasure channels, the quantum Fisher information cannot exceed an ultimate bound given by the Choi matrix of the encoding channel. We also extend our methods and results to quantum channel discrimination, finding a corresponding ultimate bound for the minimum error probability. Thus, our findings establish the ultimate precision limits that are achievable in quantum metrology and quantum discrimination for the most basic models of discrete-variable quantum channels.

  8. Sharing the dance -

    DEFF Research Database (Denmark)

    He, Jing; Ravn, Susanne

    2017-01-01

    to the highly specialized field of elite sports dance, we aim at exploring the way in which reciprocity unfolds in intensive deliberate practices of movement. In our analysis, we specifically argue that the ongoing dynamics of two separate flows of movement constitute a shared experience of dancing together....... In this sense, moving together, in sports dance, is a practical way of understanding each other. In agreement with Zahavi, our analysis emphasizes the bi-directed nature of sharing. However, at the same time, we contribute to Zahavi’s ongoing endeavour as the special case of sports dance reveals how reciprocity...

  9. Towards A Shared Mission

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen; Orth Gaarn-Larsen, Carsten

    A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome of the univer......A mission shared by stakeholders, management and employees is a prerequisite for an engaging dialog about the many and substantial changes and challenges currently facing universities. Too often this essen-tial dialog reveals mistrust and misunderstandings about the role and outcome...

  10. Shared values and normality

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-hua; PANG Xue-cheng

    2006-01-01

    This paper investigates the relationship between the normality and the shared values for a meromorphic function on the unit disc △.Based on Marty's normality criterion and through a detailed analysis of the meromorphic functions,it is shown that if for every f∈F,f and f(k) share a and b on △ and the zeros of f(z)-a are of multiplicity k≥3,then F is normal on △,where F is a family of meromorphic functions on the unit disc △,and a and b are distinct values.

  11. PREFACE: International Conference on Quantum Optics and Quantum Information (icQoQi) 2013

    Science.gov (United States)

    2014-11-01

    Quantum Information can be understood as being naturally derived from a new understanding of information theory when quantum systems become information carriers and quantum effects become non negligible. Experiments and the realization of various interesting phenomena in quantum information within the established field of quantum optics have been reported, which has provided a very convenient framework for the former. Together, quantum optics and quantum information are among the most exciting areas of interdisciplinary research in modern day science which cover a broad spectrum of topics, from the foundations of quantum mechanics and quantum information science to the introduction of new types of quantum technologies and metrology. The International Conference on Quantum Optics and Quantum Information (icQoQi) 2013 was organized by the Faculty of Science, International Islamic University Malaysia with the objective of bringing together leading academic scientists, researchers and scholars in the domain of interest from around the world to share their experiences and research results about all aspects of quantum optics and quantum information. While the event was organized on a somewhat modest scale, it was in fact a rather fruitful meeting for established researchers and students as well, especially for the local scene where the field is relatively new. We would therefore, like to thank the organizing committee, our advisors and all parties for having made this event successful and last but not least would extend our sincerest gratitude to IOP for publishing these selected papers from icQoQi2013 in Journal of Physics: Conference Series.

  12. Dynamical Equations for Quantum Information and Application in Information Channel

    Institute of Scientific and Technical Information of China (English)

    BI Qiao; XING Xiu-San; H. E. Ruda

    2005-01-01

    @@ We establish several dynamical equations for quantum information density. It is demonstrated that quantum information density shares the same formalism of the Liouville equation, subdynamics kinetic equation and Fokker-Planck equation as the density operator and also possesses the superposition property. These allow one to use quantum information density directly to model quantum information. The kinetic equations for quantum information density reveal that the dynamical process of quantum information may be related to dissipative,Markovian, or diffusional information flows, together causing irreversibility. Finally, we discuss superposition of quantum information density, which allows us to construct a quantum information channel in the coherent state representation using harmonic oscillator based encoded quantum information, and obtain a formula for quantum dynamical mutual information.

  13. Helicobacter pylori in lacrimal secretions.

    Science.gov (United States)

    Batioglu-Karaaltin, Aysegul; Saatci, Ozlem; Akpinar, Meltem; Celik, Melih Ozgür; Develioglu, Omer; Yigit, Ozgur; Külekçi, Mehmet; Akarsubaşı, Alper Tunga

    2016-03-01

    The aim of this study was to investigate the presence of Helicobacter pylori in human lacrimal and nasal secretions. Eighty patients with complaints of dyspepsia who had undergone endoscopies and gastric antrum biopsies were included in the study. A total of five specimens, including 2 lacrimal secretion samples, 2 nasal mucosal swab samples, and 1 gastric antrum biopsy, were collected from each patient and investigated with polymerase chain reaction (PCR) methods consisting of the urease enzyme coding gene GlmM (UreC) and the H pylori-specific 16S rRNA coding gene. The Reflux Symptom Index and ophthalmologic complaints of the patients were recorded. The detected positivity rates of the H pylori 16S rRNA coding gene in gastric biopsies and nasal mucous and lacrimal secretions were 55, 11.2, and 20%, respectively. The patients were grouped as gastric-antrum-biopsy-negative (Group I [n = 36]) and -positive (Group II [n = 44). In Group II, H pylori positivity in the lacrimal and nasal mucous secretions was 36.3 and 18%, respectively. A comparison between the groups in terms of H pylori presence in nasal mucous and lacrimal secretions yielded statistically significant differences (p = 0.0001, p = 0.003). The simultaneous presence of H pylori in nasal mucous and lacrimal secretions was 13.6% in Group II. H pylori positivity in nasal mucous and lacrimal secretions had a positive moderate correlation (r = 0.40; p = 0.0003). The present study is the first report on the presence of H pylori in lacrimal secretions through nested PCR, which suggested the presence of a number of mechanisms for H pylori transmission to lacrimal secretions.

  14. Quantum Computing for Quantum Chemistry

    Science.gov (United States)

    2010-09-01

    This three-year project consisted on the development and application of quantum computer algorithms for chemical applications. In particular, we developed algorithms for chemical reaction dynamics, electronic structure and protein folding. The first quantum computing for

  15. Quantum Operations as Quantum States

    CERN Document Server

    Arrighi, P; Arrighi, Pablo; Patricot, Christophe

    2004-01-01

    In this article we formalize the correspondence between quantum states and quantum operations, and harness its consequences. This correspondence was already implicit in Choi's proof of the operator sum representation of Completely Positive-preserving linear maps; we go further and show that all of the important theorems concerning quantum operations can be derived as simple corollaries of those concerning quantum states. As we do so the discussion first provides an elegant and original review of the main features of quantum operations. Next (in the second half of the paper) we search for more results to arise from the correspondence. Thus we propose a factorizability condition and an extremal trace-preservedness condition for quantum operations, give two novel Schmidt-type decompositions of bipartite pure states and two interesting composition laws for which the set of quantum operations and quantum states remain stable. The latter enables us to define a group structure upon the set of totally entangled state...

  16. Quantum memory in quantum cryptography

    CERN Document Server

    Mor, T

    1999-01-01

    [Shortened abstract:] This thesis investigates the importance of quantum memory in quantum cryptography, concentrating on quantum key distribution schemes. In the hands of an eavesdropper -- a quantum memory is a powerful tool, putting in question the security of quantum cryptography; Classical privacy amplification techniques, used to prove security against less powerful eavesdroppers, might not be effective when the eavesdropper can keep quantum states for a long time. In this work we suggest a possible direction for approaching this problem. We define strong attacks of this type, and show security against them, suggesting that quantum cryptography is secure. We start with a complete analysis regarding the information about a parity bit (since parity bits are used for privacy amplification). We use the results regarding the information on parity bits to prove security against very strong eavesdropping attacks, which uses quantum memories and all classical data (including error correction codes) to attack th...

  17. Characterization of a secreted Chlamydia protease

    DEFF Research Database (Denmark)

    Shaw, Allan C; Vandahl, Brian; Larsen, Martin Røssel

    2002-01-01

    Chlamydiae are obligate intracellular bacteria that are important human pathogens. The Chlamydia genomes contain orthologues to secretion apparatus proteins from other intracellular bacteria, but only a few secreted proteins have been identified. Most likely, effector proteins are secreted in ord...

  18. A conditional quantum phase gate between two 3-state atoms

    CERN Document Server

    Yi, X X; You, L

    2002-01-01

    We propose a scheme for conditional quantum logic between two 3-state atoms that share a quantum data-bus such as a single mode optical field in cavity QED systems, or a collective vibrational state of trapped ions. Making use of quantum interference, our scheme achieves successful conditional phase evolution without any real transitions of atomic internal states or populating the quantum data-bus. In addition, it only requires common addressing of the two atoms by external laser fields.

  19. Conditional quantum phase gate between two 3-state atoms.

    Science.gov (United States)

    Yi, X X; Su, X H; You, L

    2003-03-07

    We propose a scheme for conditional quantum logic between two 3-state atoms that share a quantum data bus such as a single mode optical field in cavity QED systems, or a collective vibrational state of trapped ions. Making use of quantum interference, our scheme achieves successful conditional phase evolution without any real transitions of atomic internal states or populating the quantum data bus. In addition, it requires only common addressing of the two atoms by external laser fields.

  20. Efficient quantum secure communication with a publicly known key

    Institute of Scientific and Technical Information of China (English)

    Li Chun-Yan; Li Xi-Han; Deng Fu-Guo; Zhou Hong-Yu

    2008-01-01

    This paper presents a simple way for an eavesdropper to eavesdrop freely the secret message in the experimental realization of quantum communication protocol proposed by Beige et al (2002 Acta Phys. Pol. A 101 357). Moreover, it introduces an efficient quantum secure communication protocol based on a publicly known key with decoy photons and two biased bases by modifying the original protocol. The total efficiency of this new protocol is double that of the original one. With a low noise quantum channel, this protocol can be used for transmitting a secret message. At present, this protocol is good for generating a private key efficiently.

  1. Ghrelin and gastric acid secretion

    OpenAIRE

    Yakabi, Koji; Kawashima, Junichi; Kato, Shingo

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in in-vivo experiment. In t...

  2. A common assembly module in injectisome and flagellar type III secretion sorting platforms.

    Science.gov (United States)

    Notti, Ryan Q; Bhattacharya, Shibani; Lilic, Mirjana; Stebbins, C Erec

    2015-05-21

    Translocating proteins across the double membrane of Gram-negative bacteria, type III secretion systems (T3SS) occur in two evolutionarily related forms: injectisomes, delivering virulence factors into host cells, and the flagellar system, secreting the polymeric filament used for motility. While both systems share related elements of a cytoplasmic sorting platform that facilitates the hierarchical secretion of protein substrates, its assembly and regulation remain unclear. Here we describe a module mediating the assembly of the sorting platform in both secretion systems, and elucidate the structural basis for segregation of homologous components among these divergent T3SS subtypes sharing a common cytoplasmic milieu. These results provide a foundation for the subtype-specific assembly of T3SS sorting platforms and will support further mechanistic analysis and anti-virulence drug design.

  3. MULTI-LEVEL KEY DISTRIBUTION ALGORITHM FOR SECRET KEY RECOVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    TANAPAT MAHAVEERAWAT

    2015-02-01

    Full Text Available Most of Multi Agent Key Recovery Systems are proposed from the assumption that Key Recovery Agents in the system have same availability of security service levelagreement and trust. Which mean, secret key will be shared to each Key Recovery Agent in equal secret’s portion. Practically, each Key Recovery Agent may have their own limitation in terms of securityservice level agreement according to economic cost, complexity and risks. This paper proposedMulti Level Key Distribution Algorithm,which the secret key can be managed into portionsharing and assignto each Key Recovery Agent (KRA according to user’s trust. Withproposed algorithm, the experimental result had shown the advantage in secret sharing size and the system had improved initssecurity from the advantage of multilevel secret key distribution capability.

  4. Quantum Darwinism

    Science.gov (United States)

    Zurek, Wojciech Hubert

    2009-03-01

    Quantum Darwinism describes the proliferation, in the environment, of multiple records of selected states of a quantum system. It explains how the quantum fragility of a state of a single quantum system can lead to the classical robustness of states in their correlated multitude; shows how effective `wave-packet collapse' arises as a result of the proliferation throughout the environment of imprints of the state of the system; and provides a framework for the derivation of Born's rule, which relates the probabilities of detecting states to their amplitudes. Taken together, these three advances mark considerable progress towards settling the quantum measurement problem.

  5. SharedSpaces mingle

    NARCIS (Netherlands)

    Handberg, L.; Gullström, C.; Kort, J.; Nyström, J.

    2016-01-01

    SharedSpaces is a WebRTC design prototype that creates a virtual media space where people can mingle and interact. Although you are in different locations, you appear side by side in front of a chosen backdrop. This interactive installation addresses spatial and social connectedness, stressing the

  6. Shared goals and development

    DEFF Research Database (Denmark)

    Blomberg, Olle

    2015-01-01

    undemanding for children to engage in, and therefore has the potential to play a part in fostering their understanding of other minds. Part of the functional role of shared goals is to enable agents to choose means that are appropriate to realising a goal with others rather than individually. By offering...

  7. Shared Oral Care

    DEFF Research Database (Denmark)

    Hede, Børge; Elmelund Poulsen,, Johan; Christophersen, Rasmus

    2014-01-01

    Shared Oral Care - Forebyggelse af orale sygdomme på plejecentre Introduktion og formål: Mangelfuld mundhygiejne hos plejekrævende ældre er et alment og veldokumenteret sundhedsproblem, der kan føre til massiv udvikling af tandsygdomme, og som yderligere kan være medvirkende årsag til alvorlige...

  8. Shared Care in Diabetes?

    DEFF Research Database (Denmark)

    Bødker, Keld

    2006-01-01

    The Danish National Board of Health has recently released a report that is intended to mark the start of a new project to establish it support for shared care in diabetes. In this paper I raise a number of concerns where lack of attention towards participation from prospective users constitute...

  9. Sharing Expertise: Consulting

    Science.gov (United States)

    Graves, Bill

    2011-01-01

    A special breed of superintendents who have developed expertise in a particular area find ways of sharing it in other venues as outside consultants. They pull extra duty to put their special skills into practice, to give back to their communities, to stay current and grounded in the field, or to enhance their professional reputations. They teach…

  10. 'Smart Power' for' Sharing'

    Institute of Scientific and Technical Information of China (English)

    Wang Ting

    2010-01-01

    @@ As an attitude of life The Interstoff Asia Essential Spring will be held from March 17th to 19th,2010,in Hong Kong Convention & Exhibition Centre.During this exhibition,the Interstoff Asia Directions trend committee will present its apparel fabric trend forecast for next season's wardrobes,unfolding a story of'Smart Power' of 'Sharing'.

  11. Decreasing serial cost sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Østerdal, Lars Peter Raahave

    2009-01-01

    The increasing serial cost sharing rule of Moulin and Shenker (Econometrica 60:1009-1037, 1992) and the decreasing serial rule of de Frutos (J Econ Theory 79:245-275, 1998) are known by their intuitive appeal and striking incentive properties. An axiomatic characterization of the increasing serial...

  12. Promoting teachers’ knowledge sharing

    NARCIS (Netherlands)

    Runhaar, P.R.; Sanders, K.

    2016-01-01

    Teachers’ professional development is nowadays seen as key in efforts to improve education. Knowledge sharing is a learning activity with which teachers not only professionalize themselves, but contribute to the professional development of their colleagues as well. This paper presents two studies,

  13. Decreasing Serial Cost Sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Østerdal, Lars Peter

    The increasing serial cost sharing rule of Moulin and Shenker [Econometrica 60 (1992) 1009] and the decreasing serial rule of de Frutos [Journal of Economic Theory 79 (1998) 245] have attracted attention due to their intuitive appeal and striking incentive properties. An axiomatic characterization...

  14. Sharing Research Results

    Science.gov (United States)

    Ashbrook, Peggy

    2011-01-01

    There are many ways to share a collection of data and students' thinking about that data. Explaining the results of science inquiry is important--working scientists and amateurs both contribute information to the body of scientific knowledge. Students can collect data about an activity that is already happening in a classroom (e.g., the qualities…

  15. Promoting teachers’ knowledge sharing

    NARCIS (Netherlands)

    Runhaar, P.R.; Sanders, K.

    2016-01-01

    Teachers’ professional development is nowadays seen as key in efforts to improve education. Knowledge sharing is a learning activity with which teachers not only professionalize themselves, but contribute to the professional development of their colleagues as well. This paper presents two studies, a

  16. Share the Fruits

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Procter & Gamble Co,extends its employee stock ownership plan to benefit its Chinese employees The Procter & Gamble Co.(P&G) launched its Chinese employee stock ownership plan(ESOP)on April 1 after five years of preparation.The plan entitles its more than 7,000 employees in China to buy P&G stocks and share its growth benefits.

  17. Beyond processor sharing

    NARCIS (Netherlands)

    Aalto, S.; Ayesta, U.; Borst, S.C.; Misra, V.; Núñez Queija, R.

    2007-01-01

    While the (Egalitarian) Processor-Sharing (PS) discipline offers crucial insights in the performance of fair resource allocation mechanisms, it is inherently limited in analyzing and designing differentiated scheduling algorithms such as Weighted Fair Queueing and Weighted Round-Robin. The Discrimin

  18. Power Sharing Courts

    Directory of Open Access Journals (Sweden)

    Stefan Graziadei

    2016-06-01

    Full Text Available In this paper, I introduce a novel concept, the one of power sharing courts. Scholars of judicial politics look at the reasons behind judicial selection and the patterns of decision making within courts through the lens of ideology (left-right. However, the resulting fertile scholarly analysis has not been extended to divided societies, where the main cleavages are not partisan but ethno-national. In these societies, the liberal model of selecting judges and taking decisions within an apex court is often corrected to specifically include politically salient ascriptive cleavages (such as ethnicity/nationality/language/religion. The main thrust of my argument is that there is a model of selecting judges, taking decisions and sharing posts of influence within apex courts in divided societies that has not yet been conceptually captured: power sharing courts. In analogy to consociationalism in the political system, power sharing in the judiciary aims to solve salient inter-community conflicts by including all relevant groups in these bodies on a basis of parity or proportionality. The paper is of equal interest to scholars of constitutional courts, consociationalists, comparatists, as well as country specialists.

  19. The Sharing Economy

    DEFF Research Database (Denmark)

    Hamari, Juho; Sjöklint, Mimmi; Ukkonen, Antti

    2016-01-01

    Information and communications technologies (ICTs) have enabled the rise of so-called “Collaborative Consumption” (CC): the peer-to-peer-based activity of obtaining, giving, or sharing the access to goods and services, coordinated through community-based online services. CC has been expected...

  20. Promoting teachers’ knowledge sharing

    NARCIS (Netherlands)

    Runhaar, P.R.; Sanders, K.

    2016-01-01

    Teachers’ professional development is nowadays seen as key in efforts to improve education. Knowledge sharing is a learning activity with which teachers not only professionalize themselves, but contribute to the professional development of their colleagues as well. This paper presents two studies, a