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Sample records for cryptography annegret weng

  1. 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.

  2. 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

  3. Calculator Cryptography.

    Science.gov (United States)

    Hall, Matthew

    2003-01-01

    Uses cryptography to demonstrate the importance of algebra and the use of technology as an effective real application of mathematics. Explains simple encoding and decoding of messages for student learning of modular arithmetic. This elementary encounter with cryptography along with its historical and modern background serves to motivate student…

  4. Contemporary cryptography

    CERN Document Server

    Oppliger, Rolf

    2011-01-01

    Whether you're new to the field or looking to broaden your knowledge of contemporary cryptography, this newly revised edition of an Artech House classic puts all aspects of this important topic into perspective. Delivering an accurate introduction to the current state-of-the-art in modern cryptography, the book offers you an in-depth understanding of essential tools and applications to help you with your daily work. The second edition has been reorganized and expanded, providing mathematical fundamentals and important cryptography principles in the appropriate appendixes, rather than summarize

  5. Conventional Cryptography.

    Science.gov (United States)

    Wright, Marie A.

    1993-01-01

    Cryptography is the science that renders data unintelligible to prevent its unauthorized disclosure or modification. Presents an application of matrices used in linear transformations to illustrate a cryptographic system. An example is provided. (17 references) (MDH)

  6. Quantum cryptography

    CERN Document Server

    Gilbert, Gerald; Hamrick, Michael

    2013-01-01

    This book provides a detailed account of the theory and practice of quantum cryptography. Suitable as the basis for a course in the subject at the graduate level, it crosses the disciplines of physics, mathematics, computer science and engineering. The theoretical and experimental aspects of the subject are derived from first principles, and attention is devoted to the practical development of realistic quantum communications systems. The book also includes a comprehensive analysis of practical quantum cryptography systems implemented in actual physical environments via either free-space or fiber-optic cable quantum channels. This book will be a valuable resource for graduate students, as well as professional scientists and engineers, who desire an introduction to the field that will enable them to undertake research in quantum cryptography. It will also be a useful reference for researchers who are already active in the field, and for academic faculty members who are teaching courses in quantum information s...

  7. Cryptography Basics

    DEFF Research Database (Denmark)

    Förster, Klaus-Tycho

    2017-01-01

    Public-key cryptography is one of the biggest scientific achievements of the last century. Two people that never met before can establish a common secret in plain sight? Sounds like pure magic! The idea of this chapter is to reveal some of the tricks of this “crypto magic”. This chapter...

  8. New field of cryptography: DNA cryptography

    Institute of Scientific and Technical Information of China (English)

    XIAO Guozhen; LU Mingxin; QIN Lei; LAI Xuejia

    2006-01-01

    DNA cryptography is a new born cryptographic field emerged with the research of DNA computing, in which DNA is used as information carrier and the modern biological technology is used as implementation tool. The vast parallelism and extraordinary information density inherent in DNA molecules are explored for cryptographic purposes such as encryption, authentication, signature, and so on. In this paper, we briefly introduce the biological background of DNA cryptography and the principle of DNA computing, summarize the progress of DNA cryptographic research and several key problems, discuss the trend of DNA cryptography, and compare the status, security and application fields of DNA cryptography with those of traditional cryptography and quantum cryptography. It is pointed out that all the three kinds of cryptography have their own advantages and disadvantages and complement each other in future practical application. The current main difficulties of DNA cryptography are the absence of effective secure theory and simple realizable method. The main goal of the research of DNA cryptography is exploring characteristics of DNA molecule and reaction, establishing corresponding theories, discovering possible development directions, searching for simple methods of realizing DNA cryptography, and laying the basis for future development.

  9. Quantum cryptography: a view from classical cryptography

    Science.gov (United States)

    Buchmann, Johannes; Braun, Johannes; Demirel, Denise; Geihs, Matthias

    2017-06-01

    Much of digital data requires long-term protection of confidentiality, for example, medical health records. Cryptography provides such protection. However, currently used cryptographic techniques such as Diffe-Hellman key exchange may not provide long-term security. Such techniques rely on certain computational assumptions, such as the hardness of the discrete logarithm problem that may turn out to be incorrect. On the other hand, quantum cryptography---in particular quantum random number generation and quantum key distribution---offers information theoretic protection. In this paper, we explore the challenge of providing long-term confidentiality and we argue that a combination of quantum cryptography and classical cryptography can provide such protection.

  10. Chocolate Key Cryptography

    Science.gov (United States)

    Bachman, Dale J.; Brown, Ezra A.; Norton, Anderson H.

    2010-01-01

    Cryptography is the science of hidden or secret writing. More generally, cryptography refers to the science of safeguarding information. Cryptography allows people to use a public medium such as the Internet to transmit private information securely, thus enabling a whole range of conveniences, from online shopping to personally printed movie…

  11. Chocolate Key Cryptography

    Science.gov (United States)

    Bachman, Dale J.; Brown, Ezra A.; Norton, Anderson H.

    2010-01-01

    Cryptography is the science of hidden or secret writing. More generally, cryptography refers to the science of safeguarding information. Cryptography allows people to use a public medium such as the Internet to transmit private information securely, thus enabling a whole range of conveniences, from online shopping to personally printed movie…

  12. Broadband Quantum Cryptography

    CERN Document Server

    Rogers, Daniel

    2010-01-01

    Quantum cryptography is a rapidly developing field that draws from a number of disciplines, from quantum optics to information theory to electrical engineering. By combining some fundamental quantum mechanical principles of single photons with various aspects of information theory, quantum cryptography represents a fundamental shift in the basis for security from numerical complexity to the fundamental physical nature of the communications channel. As such, it promises the holy grail of data security: theoretically unbreakable encryption. Of course, implementing quantum cryptography in real br

  13. Introduction to modern cryptography

    CERN Document Server

    Katz, Jonathan

    2014-01-01

    Praise for the First Edition:""This book is a comprehensive, rigorous introduction to what the authors name 'modern' cryptography. … a novel approach to how cryptography is taught, replacing the older, construction-based approach. … The concepts are clearly stated, both in an intuitive fashion and formally. … I would heartily recommend this book to anyone who is interested in cryptography. … The exercises are challenging and interesting, and can benefit readers of all academic levels.""-IACR Book Reviews, January 2010""Over the past 30 years, cryptography has been transformed from a mysterious

  14. Selected areas in cryptography

    CERN Document Server

    Oorschot, Paul

    1997-01-01

    Selected Areas in Cryptography brings together in one place important contributions and up-to-date research results in this fast moving area. Selected Areas in Cryptography serves as an excellent reference, providing insight into some of the most challenging research issues in the field.

  15. Microtubular metazoan fossils with multi-branches in Weng'an Biota

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Microtubular metazoan fossils with multi- branches are found at least 4 times from the Sinian (Ediacarian) Doushantuo Formation at Weng'an, Guizhou, China. Their living mode should be the benthonic colony with higher ability of asexual reproduction. The inner of the tube with cross-walls and chamber shows that these fossils are basal or stem- group cnidarians, similar to extinct tabulates. The multi-branching microtubular fossils are real metazoan found from Weng'an biota, which is very important for studying the origin and evolvement of metazoan.

  16. Public Key Cryptography.

    Science.gov (United States)

    Tapson, Frank

    1996-01-01

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

  17. Neural cryptography with feedback

    Science.gov (United States)

    Ruttor, Andreas; Kinzel, Wolfgang; Shacham, Lanir; Kanter, Ido

    2004-04-01

    Neural cryptography is based on a competition between attractive and repulsive stochastic forces. A feedback mechanism is added to neural cryptography which increases the repulsive forces. Using numerical simulations and an analytic approach, the probability of a successful attack is calculated for different model parameters. Scaling laws are derived which show that feedback improves the security of the system. In addition, a network with feedback generates a pseudorandom bit sequence which can be used to encrypt and decrypt a secret message.

  18. Neural cryptography with feedback.

    Science.gov (United States)

    Ruttor, Andreas; Kinzel, Wolfgang; Shacham, Lanir; Kanter, Ido

    2004-04-01

    Neural cryptography is based on a competition between attractive and repulsive stochastic forces. A feedback mechanism is added to neural cryptography which increases the repulsive forces. Using numerical simulations and an analytic approach, the probability of a successful attack is calculated for different model parameters. Scaling laws are derived which show that feedback improves the security of the system. In addition, a network with feedback generates a pseudorandom bit sequence which can be used to encrypt and decrypt a secret message.

  19. Halftone visual cryptography.

    Science.gov (United States)

    Zhou, Zhi; Arce, Gonzalo R; Di Crescenzo, Giovanni

    2006-08-01

    Visual cryptography encodes a secret binary image (SI) into n 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 n shares, however, have no visual meaning and hinder the objectives of visual cryptography. Extended visual cryptography [1] was proposed recently to construct meaningful binary images as shares using hypergraph colourings, but the visual quality is poor. In this paper, a novel technique named halftone visual cryptography is proposed to achieve visual cryptography via halftoning. Based on the blue-noise dithering principles, the proposed method utilizes the void and cluster algorithm [2] to encode a secret binary image into n halftone shares (images) carrying significant visual information. The simulation shows that the visual quality of the obtained halftone shares are observably better than that attained by any available visual cryptography method known to date.

  20. Quantum cryptography communication technology

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jai Wan; Choi, Young Soo; Lee, Jae Chul; Choi, Yu Rak; Jung, Gwang Il; Jung, Jong Eun; Hong, Seok Boong; Koo, In Soo

    2007-09-15

    Quantum cryptography communication based on quantum mechanics provides and unconditional security between two users. Even though huge advance has been done since the 1984, having a complete system is still far away. In the case of real quantum cryptography communication systems, an unconditional security level is lowered by the imperfection of the communication unit. It is important to investigate the unconditional security of quantum communication protocols based on these experimental results and implementation examples for the advanced spread all over the world. The Japanese report, titled, 'Investigation report on the worldwide trends of quantum cryptography communications systems' was translated and summarized in this report. An unconditional security theory of the quantum cryptography and real implementation examples in the domestic area are investigated also. The goal of the report is to make quantum cryptography communication more useful and reliable alternative telecommunication infrastructure as the one of the cyber security program of the class 1-E communication system of nuclear power plant. Also another goal of this report is to provide the quantitative decision basis on the quantum cryptography communication when this secure communication system will be used in class 1-E communication channel of the nuclear power plant.

  1. Quantum cryptography in free space.

    Science.gov (United States)

    Jacobs, B C; Franson, J D

    1996-11-15

    The range of quantum cryptography systems using optical fibers is limited to roughly 30 km because amplifiers cannot be used. A fully operational system for quantum cryptography based on the transmission of single photons in free space under daylight conditions has been demonstrated. The feasibility of a global system for quantum cryptography based on a network of ground stations and satellites is discussed.

  2. Quantum Computational Cryptography

    Science.gov (United States)

    Kawachi, Akinori; Koshiba, Takeshi

    As computational approaches to classical cryptography have succeeded in the establishment of the foundation of the network security, computational approaches even to quantum cryptography are promising, since quantum computational cryptography could offer richer applications than the quantum key distribution. Our project focused especially on the quantum one-wayness and quantum public-key cryptosystems. The one-wayness of functions (or permutations) is one of the most important notions in computational cryptography. First, we give an algorithmic characterization of quantum one-way permutations. In other words, we show a necessary and sufficient condition for quantum one-way permutations in terms of reflection operators. Second, we introduce a problem of distinguishing between two quantum states as a new underlying problem that is harder to solve than the graph automorphism problem. The new problem is a natural generalization of the distinguishability problem between two probability distributions, which are commonly used in computational cryptography. We show that the problem has several cryptographic properties and they enable us to construct a quantum publickey cryptosystem, which is likely to withstand any attack of a quantum adversary.

  3. Post-Quantum Cryptography

    DEFF Research Database (Denmark)

    Gauthier Umana, Valérie

    The security of almost all the public-key cryptosystems used in practice depends on the fact that the prime factorization of a number and the discrete logarithm are hard problems to solve. In 1994, Peter Shor found a polynomial-time algorithm which solves these two problems using quantum computers....... The public key cryptosystems that can resist these emerging attacks are called quantum resistant or post-quantum cryptosystems. There are mainly four classes of public-key cryptography that are believed to resist classical and quantum attacks: code-based cryptography, hash-based cryptography, lattice......-cyclic alternant codes and quasi-dyadic codes (joint work with Gregor Leander). We also present a deterministic polynomial-time algorithm to solve the Goppa Code Distinguisher problem for high rate codes (joint work with Jean-Charles Faugere, Ayoub Otmani, Ludovic Perret and Jean-Pierre Tillich). In the second...

  4. Quantum Cryptography in Practice

    CERN Document Server

    Elliott, C; Troxel, G; Elliott, Chip; Pearson, David; Troxel, Gregory

    2003-01-01

    BBN, Harvard, and Boston University are building the DARPA Quantum Network, the world's first network that delivers end-to-end network security via high-speed Quantum Key Distribution, and testing that Network against sophisticated eavesdropping attacks. The first network link has been up and steadily operational in our laboratory since December 2002. It provides a Virtual Private Network between private enclaves, with user traffic protected by a weak-coherent implementation of quantum cryptography. This prototype is suitable for deployment in metro-size areas via standard telecom (dark) fiber. In this paper, we introduce quantum cryptography, discuss its relation to modern secure networks, and describe its unusual physical layer, its specialized quantum cryptographic protocol suite (quite interesting in its own right), and our extensions to IPsec to integrate it with quantum cryptography.

  5. QUANTUM CRYPTOGRAPHY: Single Photons.

    Science.gov (United States)

    Benjamin, S

    2000-12-22

    Quantum cryptography offers the potential of totally secure transfer of information, but as Benjamin discusses in this Perspective, its practical implementation hinges on being able to generate single photons (rather than two or more) at a time. Michler et al. show how this condition can be met in a quantum dot microdisk structure. Single molecules were also recently shown to allow controlled single-photon emission.

  6. Dynamics of neural cryptography.

    Science.gov (United States)

    Ruttor, Andreas; Kinzel, Wolfgang; Kanter, Ido

    2007-05-01

    Synchronization of neural networks has been used for public channel protocols in cryptography. In the case of tree parity machines the dynamics of both bidirectional synchronization and unidirectional learning is driven by attractive and repulsive stochastic forces. Thus it can be described well by a random walk model for the overlap between participating neural networks. For that purpose transition probabilities and scaling laws for the step sizes are derived analytically. Both these calculations as well as numerical simulations show that bidirectional interaction leads to full synchronization on average. In contrast, successful learning is only possible by means of fluctuations. Consequently, synchronization is much faster than learning, which is essential for the security of the neural key-exchange protocol. However, this qualitative difference between bidirectional and unidirectional interaction vanishes if tree parity machines with more than three hidden units are used, so that those neural networks are not suitable for neural cryptography. In addition, the effective number of keys which can be generated by the neural key-exchange protocol is calculated using the entropy of the weight distribution. As this quantity increases exponentially with the system size, brute-force attacks on neural cryptography can easily be made unfeasible.

  7. The microfossils in phosphate deposit in Doushantuo stage, Sinian System, Weng'an, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The aim of this study is to discuss the microfossils in phosphate deposit in the Doushantuo stage, Sinian System, Weng'an, Guizhou Province. Based on the detailed observation in morphology and microstructures, it is considered that those acritarchs with interior spicules probably belong to sponge animals. However, some explanations for a part of soft-tissue are still contrioversial. The reliable conclusion still needs more evidence to study. The scientific significance of this study and the key questions for further studies are suggested here.

  8. On Classical and Quantum Cryptography

    CERN Document Server

    Volovich, I V; Volovich, Ya.I.

    2001-01-01

    Lectures on classical and quantum cryptography. Contents: Private key cryptosystems. Elements of number theory. Public key cryptography and RSA cryptosystem. Shannon`s entropy and mutual information. Entropic uncertainty relations. The no cloning theorem. The BB84 quantum cryptographic protocol. Security proofs. Bell`s theorem. The EPRBE quantum cryptographic protocol.

  9. Data Authentication Using Cryptography

    Directory of Open Access Journals (Sweden)

    Sagar Chouksey

    2013-06-01

    Full Text Available We present a novel approach using cryptographyfor data authentication. The key idea is to provide aencoded quantized data projection as authenticationdata. This can be correctly decoded with the help ofan authentic data using as side information.Cryptography source coding provides the desiredrobustness against legitimate variations whiledetecting illegitimate modification. Additionaladjustments might not change the meaning of thecontent, but could be misclassified as tampering.Users might also beinterested in localizingtampered regions. Distinguishing legitimateencodings with possible adjustments fromtampering and localizing tampering are thechallenges addressed in this paper. We applycryptography source coding and statistical methodsto solve the data authentication problem.Experimental results have been presented for dataauthentication.

  10. Single photon quantum cryptography

    CERN Document Server

    Beveratos, A; Gacoin, T; Villing, A; Poizat, J P; Grangier, P; Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, Andre; Poizat, Jean-Philippe; Grangier, Philippe

    2002-01-01

    We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy (NV) color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 9500 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

  11. Single photon quantum cryptography.

    Science.gov (United States)

    Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, André; Poizat, Jean-Philippe; Grangier, Philippe

    2002-10-28

    We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

  12. Cryptography cracking codes

    CERN Document Server

    2014-01-01

    While cracking a code might seem like something few of us would encounter in our daily lives, it is actually far more prevalent than we may realize. Anyone who has had personal information taken because of a hacked email account can understand the need for cryptography and the importance of encryption-essentially the need to code information to keep it safe. This detailed volume examines the logic and science behind various ciphers, their real world uses, how codes can be broken, and the use of technology in this oft-overlooked field.

  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. Discovery of phosphatized gastrula fossils from the Doushantuo Formation, Weng'an,Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Globular fossils from Doushantuo phosphorites at the Weng'an area are for the first time identified as a gastrulation stage of phosphatized embryos. They are got from the fossiliferous remains after acetic acid maceration. The fossils are found together with formerly reported animal resting eggs and embryos of the earlier cleavage stage. The oblate-shaped fossils with the same size as those reported embryos and invaginate at the middle part into the embryos, show the characteristics of the late blastula to the early gastrula stage of the embryo development. This discovery convinces the existence of animal embryos at Doushantuo age and offers new facts for the studying of the affinity of related fossils, which are still controversial at present.

  15. New observations on spiculelike structures from Doushantuo phosphorites at Weng'an, Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Doushantuo phosphorites at Weng'an, Guizhou Province, provide a unique opportunity for the study of early evolution of multicellular organisms, including metazoans.Our light microscope and SEM observations, however, do not substantiate a sponge spicule interpretation of spicular structures. No convincing axial canals have been seen in the observed spicule population. Instead, the coexistence of some monaxonal spicules with clearly diagenetic crystal fascicles and dumbbells suggest that these monaxons may also be diagenetic in origin. Our preliminary EDS analyses detect no significant silicon in spicule-containing intraclasts (including abiotic clasts and fragments of sphaeromorphic acritarchs and algal thalii), that contain abundant monaxonal spicular structures. We, therefore, believe that the evidence for a sponge spicule interpretation of the Doushantuo spicular structures are at best ambiguous at present; these alleged sponge spicules are indistinguishable from coexistent diageneric crystals.

  16. Introduction to cryptography

    CERN Document Server

    Buchmann, Johannes A

    2004-01-01

    Cryptography is a key technology in electronic key systems. It is used to keep data secret, digitally sign documents, access control, etc. Therefore, users should not only know how its techniques work, but they must also be able to estimate their efficiency and security. For this new edition, the author has updated the discussion of the security of encryption and signature schemes and recent advances in factoring and computing discrete logarithms. He has also added descriptions of time-memory trade of attacks and algebraic attacks on block ciphers, the Advanced Encryption Standard, the Secure Hash Algorithm, secret sharing schemes, and undeniable and blind signatures. Johannes A. Buchmann is a Professor of Computer Science and Mathematics at the Technical University of Darmstadt, and the Associate Editor of the Journal of Cryptology. In 1985, he received the Feodor Lynen Fellowship of the Alexander von Humboldt Foundation. Furthermore, he has received the most prestigious award in science in Germany, the Leib...

  17. 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.

  18. Estimators in Cryptography

    Directory of Open Access Journals (Sweden)

    CONSTANTINESCU Nicolae

    2009-12-01

    Full Text Available One of the main problems in cryptography is to give criteria to provide good comparators of cipher systems. The security of a cipher system must include the security of the algorithm, the security of the key generator and management module (see [BM94], [CM97],[Mau92a] and the security of the cryptographic key agreement protocol (see [Mau93a],[MC94],[Mau93b],[Mau92b]. This paper gives show the necessary mathematical background to estimate the most important cryptographic measures of the key generators and of the unconditionally key agreement protocols. These cryptographic measures are the Shannon entropy (for the key generator module and Renyi entropy of order  for the key agreement protocol.

  19. Cryptography Engineering Design Principles and Practical Applications

    CERN Document Server

    Ferguson, Niels; Kohno, Tadayoshi

    2012-01-01

    The ultimate guide to cryptography, updated from an author team of the world's top cryptography experts. Cryptography is vital to keeping information safe, in an era when the formula to do so becomes more and more challenging. Written by a team of world-renowned cryptography experts, this essential guide is the definitive introduction to all major areas of cryptography: message security, key negotiation, and key management. You'll learn how to think like a cryptographer. You'll discover techniques for building cryptography into products from the start and you'll examine the many technical chan

  20. Understanding and applying cryptography and data security

    CERN Document Server

    Elbirt, Adam J

    2009-01-01

    Introduction A Brief History of Cryptography and Data Security Cryptography and Data Security in the Modern World Existing Texts Book Organization Symmetric-Key Cryptography Cryptosystem Overview The Modulo Operator Greatest Common Divisor The Ring ZmHomework ProblemsSymmetric-Key Cryptography: Substitution Ciphers Basic Cryptanalysis Shift Ciphers Affine Ciphers Homework ProblemsSymmetric-Key Cryptography: Stream Ciphers Random Numbers The One-Time Pad Key Stream GeneratorsReal-World ApplicationsHomework ProblemsSymmetric-Key Cryptography: Block Ciphers The Data Encryption StandardThe Advance

  1. Coding Theory, Cryptography and Related Areas

    DEFF Research Database (Denmark)

    Buchmann, Johannes; Stichtenoth, Henning; Tapia-Recillas, Horacio

    Proceedings of anInternational Conference on Coding Theory, Cryptography and Related Areas, held in Guanajuato, Mexico. in april 1998......Proceedings of anInternational Conference on Coding Theory, Cryptography and Related Areas, held in Guanajuato, Mexico. in april 1998...

  2. Theory and practice of chaotic cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Amigo, J.M. [Centro de Investigacion Operativa, Universidad Miguel Hernandez, Avda. de la Universidad, 03202 Elche (Spain)]. E-mail: jm.amigo@umh.es; Kocarev, L. [Institute for Nonlinear Science, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0402 (United States)]. E-mail: lkocarev@ucsd.edu; Szczepanski, J. [Institute of Fundamental Technological Research, Polish Academy of Science, Swietokrzyska 21, 00-049 Warsaw (Poland)]. E-mail: jszczepa@ippt.gov.pl

    2007-06-25

    In this Letter we address some basic questions about chaotic cryptography, not least the very definition of chaos in discrete systems. We propose a conceptual framework and illustrate it with different examples from private and public key cryptography. We elaborate also on possible limits of chaotic cryptography.

  3. Coding, cryptography and combinatorics

    CERN Document Server

    Niederreiter, Harald; Xing, Chaoping

    2004-01-01

    It has long been recognized that there are fascinating connections between cod­ ing theory, cryptology, and combinatorics. Therefore it seemed desirable to us to organize a conference that brings together experts from these three areas for a fruitful exchange of ideas. We decided on a venue in the Huang Shan (Yellow Mountain) region, one of the most scenic areas of China, so as to provide the additional inducement of an attractive location. The conference was planned for June 2003 with the official title Workshop on Coding, Cryptography and Combi­ natorics (CCC 2003). Those who are familiar with events in East Asia in the first half of 2003 can guess what happened in the end, namely the conference had to be cancelled in the interest of the health of the participants. The SARS epidemic posed too serious a threat. At the time of the cancellation, the organization of the conference was at an advanced stage: all invited speakers had been selected and all abstracts of contributed talks had been screened by the p...

  4. Quantum Cryptography in Spin Networks

    Institute of Scientific and Technical Information of China (English)

    DENG Hong-Liang; FANG Xi-Ming

    2007-01-01

    In this paper we propose a new scheme of long-distance quantum cryptography based on spin networks with qubits stored in electron spins of quantum dots. By conditional Faraday rotation, single photon polarization measurement, and quantum state transfer, maximal-entangled Bell states for quantum cryptography between two long-distance parties are created. Meanwhile, efficient quantum state transfer over arbitrary distances is obtained in a spin chain by a proper choice of coupling strengths and using spin memory technique improved. We also analyse the security of the scheme against the cloning-based attack which can be also implemented in spin network and discover that this spin network cloning coincides with the optimal fidelity achieved by an eavesdropper for entanglement-based cryptography.

  5. An introduction to mathematical cryptography

    CERN Document Server

    Hoffstein, Jeffrey; Silverman, Joseph H

    2014-01-01

    This self-contained introduction to modern cryptography emphasizes the mathematics behind the theory of public key cryptosystems and digital signature schemes. The book focuses on these key topics while developing the mathematical tools needed for the construction and security analysis of diverse cryptosystems. Only basic linear algebra is required of the reader; techniques from algebra, number theory, and probability are introduced and developed as required. This text provides an ideal introduction for mathematics and computer science students to the mathematical foundations of modern cryptography. The book includes an extensive bibliography and index; supplementary materials are available online. The book covers a variety of topics that are considered central to mathematical cryptography. Key topics include: classical cryptographic constructions, such as Diffie–Hellmann key exchange, discrete logarithm-based cryptosystems, the RSA cryptosystem, and digital signatures; fundamental mathematical tools for cr...

  6. 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...

  7. Use of Cryptography in communication

    Directory of Open Access Journals (Sweden)

    University Junior Assistant Ioana-Julieta Vasile

    2008-05-01

    Full Text Available This work envisages the presentation and analysis of important cryptographic systems in the field as well as the way these systems have been applied during the course of time. The work presents the advantages and disadvantages that derive from the use of cryptography while also emphasizing the importance cryptography has had along the way. Not least, the present article shall analyze the "“Pretty Good Privacy"” model - –a widely used system nowadays, whose decryption key has yet to be found.

  8. Trusted Certificates in Quantum Cryptography

    OpenAIRE

    Perkins, William

    2006-01-01

    This paper analyzes the performance of Kak's three stage quantum cryptographic protocol based on public key cryptography against a man-in-the-middle attack. A method for protecting against such an attack is presented using certificates distributed by a trusted third party.

  9. Finding Cryptography in Object Code

    Energy Technology Data Exchange (ETDEWEB)

    Jason L. Wright

    2008-10-01

    Finding and identifying Cryptography is a growing concern in the malware analysis community. In this paper, a heuristic method for determining the likelihood that a given function contains a cryptographic algorithm is discussed and the results of applying this method in various environments is shown. The algorithm is based on frequency analysis of opcodes that make up each function within a binary.

  10. Lightweight cryptography for constrained devices

    DEFF Research Database (Denmark)

    Alippi, Cesare; Bogdanov, Andrey; Regazzoni, Francesco

    2014-01-01

    Lightweight cryptography is a rapidly evolving research field that responds to the request for security in resource constrained devices. This need arises from crucial pervasive IT applications, such as those based on RFID tags where cost and energy constraints drastically limit the solution...

  11. Cryptography as a Pedagogical Tool

    Science.gov (United States)

    Kaur, Manmohan

    2008-01-01

    In order to get undergraduates interested in mathematics, it is necessary to motivate them, give them good reasons to spend time on a subject that requires hard work, and, if possible, involve them in undergraduate research. This article discusses how cryptography can be used for all these purposes. In particular, a special topics course on…

  12. 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.

  13. 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.

  14. Everyday cryptography fundamental principles and applications

    CERN Document Server

    Martin, Keith M

    2012-01-01

    Cryptography is a vital technology that underpins the security of information in computer networks. This book presents a comprehensive introduction to the role that cryptography plays in providing information security for technologies such as the Internet, mobile phones, payment cards, and wireless local area networks. Focusing on the fundamental principles that ground modern cryptography as they arise in modern applications, it avoids both an over-reliance on transient currenttechnologies and over-whelming theoretical research.Everyday Cryptography is a self-contained and widely accessible in

  15. QUANTUM CRYPTOGRAPHY WITH PHOTON PAIRS

    Directory of Open Access Journals (Sweden)

    Anand Sharma,

    2010-07-01

    Full Text Available Quantum cryptographic systems use quantum mechanical concepts that are based on qubit superposition of states, and on the no cloning or no copying theorem to establish unbreakable cipher keys. The basic idea of quantum cryptography is to send the key in the form of photons over a public channel, encoding the zeros and one on quantum states in such a way that any eavesdropping attempt can be detected. Using optical communications the most commonly quantum mechanical property used is the polarization state of photon. However, in most quantum cryptographic algorithms a random polarization state is required. The photons are ideal for low loss transport, either in free space or in optical fibers, i.e. we have the full arsenal of fiber optic technology at our disposal. In this paper we are describing the process of quantum cryptography with photon pairs.

  16. Cryptography with DNA binary strands.

    Science.gov (United States)

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  17. On Simulation of Quantum Cryptography

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The simulation of quantum cryptography on classical computers is discussed in this paper. The methods to express the preparation and measurement of quantum states on current computers are given and the basic algorithms for simulating the quantum key distribution protocols are presented. All the simulating results of each protocol are given and compared with the theoretic one. It is shown that the simulation results are completely tallied with the theoretic one.

  18. Security, Privacy, and Applied Cryptography Engineering

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the Second International Conference on Security, Privacy and Applied Cryptography Engineering held in Chennai, India, in November 2012. The 11 papers presented were carefully reviewed and selected from 61 submissions. The papers are organized...... and applications, high-performance computing in cryptology and cryptography in ubiquitous devices....

  19. Report of the Public Cryptography Study Group.

    Science.gov (United States)

    American Council on Education, Washington, DC.

    Concerns of the National Security Agency (NSA) that information contained in some articles about cryptography in learned and professional journals and in monographs might be inimical to the national security are addressed. The Public Cryptography Study Group, with one dissenting opinion, recommends that a voluntary system of prior review of…

  20. Rossler Nonlinear Dynamical Machine for Cryptography Applications

    CERN Document Server

    Pandey, Sunil; Shrivastava, Dr S C

    2009-01-01

    In many of the cryptography applications like password or IP address encryption schemes, symmetric cryptography is useful. In these relatively simpler applications of cryptography, asymmetric cryptography is difficult to justify on account of the computational and implementation complexities associated with asymmetric cryptography. Symmetric schemes make use of a single shared key known only between the two communicating hosts. This shared key is used both for the encryption as well as the decryption of data. This key has to be small in size besides being a subset of a potentially large keyspace making it convenient for the communicating hosts while at the same time making cryptanalysis difficult for the potential attackers. In the present work, an abstract Rossler nonlinear dynamical machine has been described first. The Rossler system exhibits chaotic dynamics for certain values of system parameters and initial conditions. The chaotic dynamics of the Rossler system with its apparently erratic and irregular ...

  1. Protocols and plan of quantum cryptography

    Directory of Open Access Journals (Sweden)

    Milorad S. Markagić

    2012-01-01

    Full Text Available Along with the development of confidentiality of data and resources, there is a need to develop systems that would provide confidentiality. Currently, the most used systems are classical cryptographic systems and encryption public key systems. However, none of these systems provides a solution for the famous 'catch 22' of cryptography. Owing to the intensive development of quantum mechanics, in the last 30 years emerged an entirely new kind of cryptography-quantum cryptography. Its greatest contribution is a possibility to discover an intercepted communication channel from a third party. The question is: is this really true? The question arises: 'If the quantum cryptography is so good, why is not widely used?' The aim of this paper is, on the one hand, to define the basic mechanisms of quantum cryptography IP, and, on the other hand, to point to the shortcomings, as they related to the opportunities of today's devices and flaws in protocols.

  2. Cryptography in constant parallel time

    CERN Document Server

    Applebaum, Benny

    2013-01-01

    Locally computable (NC0) functions are 'simple' functions for which every bit of the output can be computed by reading a small number of bits of their input. The study of locally computable cryptography attempts to construct cryptographic functions that achieve this strong notion of simplicity and simultaneously provide a high level of security. Such constructions are highly parallelizable and they can be realized by Boolean circuits of constant depth.This book establishes, for the first time, the possibility of local implementations for many basic cryptographic primitives such as one-way func

  3. Quantum cryptography with entangled photons

    Science.gov (United States)

    Jennewein; Simon; Weihs; Weinfurter; Zeilinger

    2000-05-15

    By realizing a quantum cryptography system based on polarization entangled photon pairs we establish highly secure keys, because a single photon source is approximated and the inherent randomness of quantum measurements is exploited. We implement a novel key distribution scheme using Wigner's inequality to test the security of the quantum channel, and, alternatively, realize a variant of the BB84 protocol. Our system has two completely independent users separated by 360 m, and generates raw keys at rates of 400-800 bits/s with bit error rates around 3%.

  4. Cooperating attackers in neural cryptography.

    Science.gov (United States)

    Shacham, Lanir N; Klein, Einat; Mislovaty, Rachel; Kanter, Ido; Kinzel, Wolfgang

    2004-06-01

    A successful attack strategy in neural cryptography is presented. The neural cryptosystem, based on synchronization of neural networks by mutual learning, has been recently shown to be secure under different attack strategies. The success of the advanced attacker presented here, called the "majority-flipping attacker," does not decay with the parameters of the model. This attacker's outstanding success is due to its using a group of attackers which cooperate throughout the synchronization process, unlike any other attack strategy known. An analytical description of this attack is also presented, and fits the results of simulations.

  5. 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.

  6. Chaos Cryptography with Dynamical Systems

    Science.gov (United States)

    Anderson, Robert; Morse, Jack; Schimmrigk, Rolf

    2001-11-01

    Cryptography is a subject that draws strength from an amazing variety of different mathematical fields, including such deep results as the Weil-Dwork-Deligne theorem on the zeta function. Physical theories have recently entered the subject as well, an example being the subject of quantum cryptography, motivated in part by Shor's insight into the vulnerability of prime number factorization based crypto systems. In this contribution we describe a cryptographic algorithm which is based on the dynamics of a class of physical models that exhibit chaotic behavior. More precisely, we consider dissipative systems which are described by nonlinear three-dimensional systems of differential equations with strange attractor surfaces of non-integer Lyapunov dimension. The time evolution of such systems in part of the moduli space shows unpredictable behavior, which suggests that they might be useful as pseudorandom number generators. We will show that this is indeed the case and illustrate our procedure mainly with the Lorenz attractor, though we also briefly mention the Rössler system. We use this class of nonlinear models to construct an extremely fast stream cipher with a large keyspace, which we test with Marsaglia's battery of DieHard tests.

  7. Cryptography and computational number theory

    CERN Document Server

    Shparlinski, Igor; Wang, Huaxiong; Xing, Chaoping; Workshop on Cryptography and Computational Number Theory, CCNT'99

    2001-01-01

    This volume contains the refereed proceedings of the Workshop on Cryptography and Computational Number Theory, CCNT'99, which has been held in Singapore during the week of November 22-26, 1999. The workshop was organized by the Centre for Systems Security of the Na­ tional University of Singapore. We gratefully acknowledge the financial support from the Singapore National Science and Technology Board under the grant num­ ber RP960668/M. The idea for this workshop grew out of the recognition of the recent, rapid development in various areas of cryptography and computational number the­ ory. The event followed the concept of the research programs at such well-known research institutions as the Newton Institute (UK), Oberwolfach and Dagstuhl (Germany), and Luminy (France). Accordingly, there were only invited lectures at the workshop with plenty of time for informal discussions. It was hoped and successfully achieved that the meeting would encourage and stimulate further research in information and computer s...

  8. Cryptographie quantique à variables continues

    Science.gov (United States)

    Bencheikh, K.; Jankovic, A.; Symul, T.; Levenson, J. A.

    2002-06-01

    Nous avons élaboré un protocole de cryptographie quantique qui permet de générer et de distribuer une clé secrète aléatoire. Le protocole repose sur l'utilisation de paires de champs électromagnétiques dont les quadratures présentent des corrélations quantiques de type Einstein-Podolsky-Rosen. Les fluctuations quantiques instantanése constituent les bits aléatoires de la clé secrète, et la dégradation irréversible des corrélations quantiques des quadratures causée par une tierce personne permet de la détecter et de garantir la sécurité d'échange.

  9. Genetic attack on neural cryptography.

    Science.gov (United States)

    Ruttor, Andreas; Kinzel, Wolfgang; Naeh, Rivka; Kanter, Ido

    2006-03-01

    Different scaling properties for the complexity of bidirectional synchronization and unidirectional learning are essential for the security of neural cryptography. Incrementing the synaptic depth of the networks increases the synchronization time only polynomially, but the success of the geometric attack is reduced exponentially and it clearly fails in the limit of infinite synaptic depth. This method is improved by adding a genetic algorithm, which selects the fittest neural networks. The probability of a successful genetic attack is calculated for different model parameters using numerical simulations. The results show that scaling laws observed in the case of other attacks hold for the improved algorithm, too. The number of networks needed for an effective attack grows exponentially with increasing synaptic depth. In addition, finite-size effects caused by Hebbian and anti-Hebbian learning are analyzed. These learning rules converge to the random walk rule if the synaptic depth is small compared to the square root of the system size.

  10. Cheating prevention in visual cryptography.

    Science.gov (United States)

    Hu, Chih-Ming; Tzeng, Wen-Guey

    2007-01-01

    Visual cryptography (VC) is a method of encrypting a secret image into shares such that stacking a sufficient number of shares reveals the secret image. Shares are usually presented in transparencies. Each participant holds a transparency. Most of the previous research work on VC focuses on improving two parameters: pixel expansion and contrast. In this paper, we studied the cheating problem in VC and extended VC. We considered the attacks of malicious adversaries who may deviate from the scheme in any way. We presented three cheating methods and applied them on attacking existent VC or extended VC schemes. We improved one cheat-preventing scheme. We proposed a generic method that converts a VCS to another VCS that has the property of cheating prevention. The overhead of the conversion is near optimal in both contrast degression and pixel expansion.

  11. Bent functions results and applications to cryptography

    CERN Document Server

    Tokareva, Natalia

    2015-01-01

    Bent Functions: Results and Applications to Cryptography offers a unique survey of the objects of discrete mathematics known as Boolean bent functions. As these maximal, nonlinear Boolean functions and their generalizations have many theoretical and practical applications in combinatorics, coding theory, and cryptography, the text provides a detailed survey of their main results, presenting a systematic overview of their generalizations and applications, and considering open problems in classification and systematization of bent functions. The text is appropriate for novices and advanced

  12. Cryptography with chaos using Chua's system

    Science.gov (United States)

    Oliveira, C. H.; Pizolato, J. C., Jr.

    2011-03-01

    In the last years, chaotic systems have been applied in information security. These systems have a complex and unpredictable behavior, what makes them more attractive for data cryptography applications. In this work, the chaotic behavior of signals generated by Chua's system is combined with the original information in order to obtain a safe cryptographic method. The experimental results demonstrate that the proposed scheme can be used in data cryptography applications.

  13. Classical introduction to cryptography exercise book

    CERN Document Server

    Baigneres, Thomas; Lu, Yi

    2007-01-01

    This is a companion exercise and solution book to A Classical Introduction to Cryptography: Applications for Communications Security (0-387-25464-1). Coverage includes symmetric or public-key cryptography, cryptographic protocols, design, cryptanalysis, and implementation of cryptosystems. Readers should be comfortable with basic facts of discrete probability theory, discrete mathematics, calculus, algebra, and computer science. However, the exercises do not require an extensive background in mathematics, since the most important notions are introduced and discussed in many of them. Exercises

  14. Mathematical Background of Public Key Cryptography

    DEFF Research Database (Denmark)

    Frey, Gerhard; Lange, Tanja

    2005-01-01

    The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material.......The two main systems used for public key cryptography are RSA and protocols based on the discrete logarithm problem in some cyclic group. We focus on the latter problem and state cryptographic protocols and mathematical background material....

  15. Neural Network Approach to Locating Cryptography in Object Code

    Energy Technology Data Exchange (ETDEWEB)

    Jason L. Wright; Milos Manic

    2009-09-01

    Finding and identifying cryptography is a growing concern in the malware analysis community. In this paper, artificial neural networks are used to classify functional blocks from a disassembled program as being either cryptography related or not. The resulting system, referred to as NNLC (Neural Net for Locating Cryptography) is presented and results of applying this system to various libraries are described.

  16. SHAMROCK: A Synthesizable High Assurance Cryptography and Key Management Coprocessor

    Science.gov (United States)

    2016-11-01

    cryptography; key management ; synthesizable. I. INTRODUCTION Modern cryptographic algorithms are designed with Kerckhoffs’ Principle in mind – that...LOCKMA supports good cryptography and key management practices . However, in general a software only solution is insufficient to guarantee the...1 SHAMROCK: A Synthesizable High Assurance Cryptography and Key Management Coprocessor David Whelihan, Michael Vai, Dan Utin, Roger Khazan, Karen

  17. 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.``

  18. 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

  19. GSM Security Using Identity-based Cryptography

    CERN Document Server

    Agarwal, Animesh; Das, Manik Lal

    2009-01-01

    Current security model in Global System for Mobile Communications (GSM) predominantly use symmetric key cryptography. The rapid advancement of Internet technology facilitates online trading, banking, downloading, emailing using resource-constrained handheld devices such as personal digital assistants and cell phones. However, these applications require more security than the present GSM supports. Consequently, a careful design of GSM security using both symmetric and asymmetric key cryptography would make GSM security more adaptable in security intensive applications. This paper presents a secure and efficient protocol for GSM security using identity based cryptography. The salient features of the proposed protocol are (i) authenticated key exchange; (ii) mutual authentication amongst communicating entities; and (iii) user anonymity. The security analysis of the protocol shows its strength against some known threats observed in conventional GSM security.

  20. Quantum cryptography approaching the classical limit.

    Science.gov (United States)

    Weedbrook, Christian; Pirandola, Stefano; Lloyd, Seth; Ralph, Timothy C

    2010-09-10

    We consider the security of continuous-variable quantum cryptography as we approach the classical limit, i.e., when the unknown preparation noise at the sender's station becomes significantly noisy or thermal (even by as much as 10(4) times greater than the variance of the vacuum mode). We show that, provided the channel transmission losses do not exceed 50%, the security of quantum cryptography is not dependent on the channel transmission, and is therefore incredibly robust against significant amounts of excess preparation noise. We extend these results to consider for the first time quantum cryptography at wavelengths considerably longer than optical and find that regions of security still exist all the way down to the microwave.

  1. Color extended visual cryptography using error diffusion.

    Science.gov (United States)

    Kang, InKoo; Arce, Gonzalo R; Lee, Heung-Kyu

    2011-01-01

    Color visual cryptography (VC) encrypts a color secret message into n color halftone image shares. Previous methods in the literature show good results for black and white or gray scale VC schemes, however, they are not sufficient to be applied directly to color shares due to different color structures. Some methods for color visual cryptography are not satisfactory in terms of producing either meaningless shares or meaningful shares with low visual quality, leading to suspicion of encryption. This paper introduces the concept of visual information pixel (VIP) synchronization and error diffusion to attain a color visual cryptography encryption method that produces meaningful color shares with high visual quality. VIP synchronization retains the positions of pixels carrying visual information of original images throughout the color channels and error diffusion generates shares pleasant to human eyes. Comparisons with previous approaches show the superior performance of the new method.

  2. 802.11i Encryption Key Distribution Using Quantum Cryptography

    Directory of Open Access Journals (Sweden)

    Thi Mai Trang Nguyen

    2006-10-01

    Full Text Available Quantum cryptography is a promising solution towards absolute security in long term cryptosystems. While the use of quantum cryptography in fiber optical networks gets significant advances, research on the application of quantum cryptography in mobile wireless network is still premature. In this paper, we analyze the interests of using quantum cryptography in 802.11 wireless networks, and propose a scheme integrating quantum cryptography in 802.11i security mechanisms for the distribution of the encryption keys. The use of an apparatus network to provide alternative line-of-sight paths is also discussed.

  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. Quantum asymmetric cryptography with symmetric keys

    Science.gov (United States)

    Gao, Fei; Wen, Qiaoyan; Qin, Sujuan; Zhu, Fuchen

    2009-12-01

    Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstrated.

  5. Quantum asymmetric cryptography with symmetric keys

    OpenAIRE

    Gao, Fei; Wen, Qiao-Yan; Qin, Su-Juan; Zhu, Fu-Chen

    2008-01-01

    Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstr...

  6. Quantum asymmetric cryptography with symmetric keys

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Based on quantum encryption,we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme,which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore,the state-estimation attack to a prior QPKC scheme is demonstrated.

  7. Quantum asymmetric cryptography with symmetric keys

    Institute of Scientific and Technical Information of China (English)

    GAO Fei; WEN QiaoYan; QIN SuJuan; ZHU FuChen

    2009-01-01

    Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstrated.

  8. A Study of Hyperelliptic Curves in Cryptography

    Directory of Open Access Journals (Sweden)

    Reza Alimoradi

    2016-08-01

    Full Text Available Elliptic curves are some specific type of curves known as hyper elliptic curves. Compared to the integer factorization problem(IFP based systems, using elliptic curve based cryptography will significantly decrease key size of the encryption. Therefore, application of this type of cryptography in systems that need high security and smaller key size has found great attention. Hyperelliptic curves help to make key length shorter. Many investigations are done with regard to improving computations, hardware and software implementation of these curves, their security and resistance against attacks. This paper studies and analyzes researches done about security and efficiency of hyperelliptic curves.

  9. Cryptography, quantum computation and trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard J.

    1998-03-01

    The significance of quantum computation for cryptography is discussed. Following a brief survey of the requirements for quantum computational hardware, an overview of the ion trap quantum computation project at Los Alamos is presented. The physical limitations to quantum computation with trapped ions are analyzed and an assessment of the computational potential of the technology is made.

  10. Quantum cryptography beyond quantum key distribution

    NARCIS (Netherlands)

    A. Broadbent (Anne); C. Schaffner (Christian)

    2016-01-01

    textabstractQuantum cryptography is the art and science of exploiting quantum mechanical effects in order to perform cryptographic tasks. While the most well-known example of this discipline is quantum key distribution (QKD), there exist many other applications such as quantum money, randomness

  11. Quantum cryptography beyond quantum key distribution

    NARCIS (Netherlands)

    Broadbent, A.; Schaffner, C.

    2016-01-01

    Quantum cryptography is the art and science of exploiting quantum mechanical effects in order to perform cryptographic tasks. While the most well-known example of this discipline is quantum key distribution (QKD), there exist many other applications such as quantum money, randomness generation,

  12. Quantum cryptography beyond quantum key distribution

    NARCIS (Netherlands)

    Broadbent, A.; Schaffner, C.

    2016-01-01

    Quantum cryptography is the art and science of exploiting quantum mechanical effects in order to perform cryptographic tasks. While the most well-known example of this discipline is quantum key distribution (QKD), there exist many other applications such as quantum money, randomness generation, secu

  13. Security, Privacy, and Applied Cryptography Engineering

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the Second International Conference on Security, Privacy and Applied Cryptography Engineering held in Chennai, India, in November 2012. The 11 papers presented were carefully reviewed and selected from 61 submissions. The papers are organized...

  14. Number Theory and Public-Key Cryptography.

    Science.gov (United States)

    Lefton, Phyllis

    1991-01-01

    Described are activities in the study of techniques used to conceal the meanings of messages and data. Some background information and two BASIC programs that illustrate the algorithms used in a new cryptographic system called "public-key cryptography" are included. (CW)

  15. Report on Pairing-based Cryptography.

    Science.gov (United States)

    Moody, Dustin; Peralta, Rene; Perlner, Ray; Regenscheid, Andrew; Roginsky, Allen; Chen, Lily

    2015-01-01

    This report summarizes study results on pairing-based cryptography. The main purpose of the study is to form NIST's position on standardizing and recommending pairing-based cryptography schemes currently published in research literature and standardized in other standard bodies. The report reviews the mathematical background of pairings. This includes topics such as pairing-friendly elliptic curves and how to compute various pairings. It includes a brief introduction to existing identity-based encryption (IBE) schemes and other cryptographic schemes using pairing technology. The report provides a complete study of the current status of standard activities on pairing-based cryptographic schemes. It explores different application scenarios for pairing-based cryptography schemes. As an important aspect of adopting pairing-based schemes, the report also considers the challenges inherent in validation testing of cryptographic algorithms and modules. Based on the study, the report suggests an approach for including pairing-based cryptography schemes in the NIST cryptographic toolkit. The report also outlines several questions that will require further study if this approach is followed.

  16. Harry Potter and the Cryptography with Matrices

    Science.gov (United States)

    Chua, Boon Liang

    2006-01-01

    This article describes Cryptography, defined as the science of encrypting and deciphering messages written in secret codes, it has played a vital role in securing information since ancient times. There are several cryptographic techniques and many make extensive use of mathematics to secure information. The author discusses an activity built…

  17. On Weng Wanda’s Frontier Poems%浅论翁万达的边塞诗

    Institute of Scientific and Technical Information of China (English)

    陈作宏

    2015-01-01

    翁万达既是明代嘉靖年间著名的军事家、政治家和国防重臣,也是一位诗人。其所撰《思德堂诗集》中的边塞诗,继承了唐代边塞诗爱国主义和英雄主义的优秀传统,但诗人没有走初盛唐国力强盛时期边塞诗纵横捭阖的浪漫主义诗派之路,其诗作更多地闪耀着积极现实主义的光彩而更为有血有肉。这种风格和特色的形成,似与明代中叶国力中落、频繁应对边患的大环境、翁氏有边塞生活的丰富体验及其既坚毅沉稳又刚介坦直的个性有关。几百年来,翁氏的卓著军功掩盖了他的诗名,其诗作成就长期为诗史家所忽略。%Weng Wanda was a poet as well as a renowned military strategist, statesman and defence min⁃ister in Jiajing’s reign (1521~1567) of Ming Dynasty (1368~1644) . The frontier poems in Sidetang Col⁃lection of Poems by him, following the fine traditional themes of patriotism and heroism depicted in the frontier poems of Tang Dynasty (618~907) , adopted the positive realism to keep true to life instead of the romanti⁃cism popular in the frontier poems written in the early prosperous period of Tang Dynasty. This writing style and characteristic may be formed from the context of the declining national strength and the frequent frontier troubles in Mid Ming Dynasty, Weng’s rich experiences of frontier life and his personality of perseverance, calm, honesty and directness. Weng’s reputation as a poet has been masked by his outstanding military honors for hundreds of years and his achievements in poems have long been ignored in the circle of the poetry history.

  18. Review of Lattice-based Public key Cryptography(Russian)

    OpenAIRE

    Usatyuk, V. S.

    2010-01-01

    This article presets a review of the achievements rapidly developing field of cryptography - public-key cryptography based on the lattice theory. Paper contains the necessary basic concepts and the major problems of the lattice theory, as well as together with the description on the benefits of this cryptography class - the properties of the reliability to quantum computers and full homomorphism, the shortcomings of specific implementations.

  19. 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...

  20. 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.

  1. On the complexity of search for keys in quantum cryptography

    Science.gov (United States)

    Molotkov, S. N.

    2016-03-01

    The trace distance is used as a security criterion in proofs of security of keys in quantum cryptography. Some authors doubted that this criterion can be reduced to criteria used in classical cryptography. The following question has been answered in this work. Let a quantum cryptography system provide an ɛ-secure key such that ½‖ρ XE - ρ U ⊗ ρ E ‖1 cryptography. Bounds for the minimum and maximum numbers of search steps for the determination of the actual key have been presented.

  2. Quantum Cryptography in Existing Telecommunications Infrastructure

    Science.gov (United States)

    Rogers, Daniel; Bienfang, Joshua; Mink, Alan; Hershman, Barry; Nakassis, Anastase; Tang, Xiao; Ma, Lijun; Su, David; Williams, Carl; Clark, Charles

    2006-03-01

    Quantum cryptography has shown the potential for ultra-secure communications. However, all systems demonstrated to date operate at speeds that make them impractical for performing continuous one-time-pad encryption of today's broadband communications. By adapting clock and data recovery techniques from modern telecommunications engineering practice, and by designing and implementing expeditious error correction and privacy amplification algorithms, we have demonstrated error-corrected and privacy-amplified key rates up to 1.0 Mbps over a free-space link with a 1.25 Gbps clock. Using new detectors with improved timing resolution, careful wavelength selection and an increased clock speed, we expect to quadruple the transmission rate over a 1.5 km free-space link. We have identified scalable solutions for delivering sustained one-time-pad encryption at 10 Mbps, thus making it possible to integrate quantum cryptography with first-generation Ethernet protocols.

  3. Asymmetric cryptography based on wavefront sensing.

    Science.gov (United States)

    Peng, Xiang; Wei, Hengzheng; Zhang, Peng

    2006-12-15

    A system of asymmetric cryptography based on wavefront sensing (ACWS) is proposed for the first time to our knowledge. One of the most significant features of the asymmetric cryptography is that a trapdoor one-way function is required and constructed by analogy to wavefront sensing, in which the public key may be derived from optical parameters, such as the wavelength or the focal length, while the private key may be obtained from a kind of regular point array. The ciphertext is generated by the encoded wavefront and represented with an irregular array. In such an ACWS system, the encryption key is not identical to the decryption key, which is another important feature of an asymmetric cryptographic system. The processes of asymmetric encryption and decryption are formulized mathematically and demonstrated with a set of numerical experiments.

  4. Partially Blind Signatures Based on Quantum Cryptography

    Science.gov (United States)

    Cai, Xiao-Qiu; Niu, Hui-Fang

    2012-12-01

    In a partially blind signature scheme, the signer explicitly includes pre-agreed common information in the blind signature, which can improve the availability and performance. We present a new partially blind signature scheme based on fundamental properties of quantum mechanics. In addition, we analyze the security of this scheme, and show it is not possible to forge valid partially blind signatures. Moreover, the comparisons between this scheme and those based on public-key cryptography are also discussed.

  5. Multiphoton entanglement concentration and quantum cryptography.

    Science.gov (United States)

    Durkin, Gabriel A; Simon, Christoph; Bouwmeester, Dik

    2002-05-01

    Multiphoton states from parametric down-conversion can be entangled both in polarization and photon number. Maximal high-dimensional entanglement can be concentrated postselectively from these states via photon counting. This makes them natural candidates for quantum key distribution, where the presence of more than one photon per detection interval has up to now been considered undesirable. We propose a simple multiphoton cryptography protocol for the case of low losses.

  6. Spectral coherent-state quantum cryptography.

    Science.gov (United States)

    Cincotti, Gabriella; Spiekman, Leo; Wada, Naoya; Kitayama, Ken-ichi

    2008-11-01

    A novel implementation of quantum-noise optical cryptography is proposed, which is based on a simplified architecture that allows long-haul, high-speed transmission in a fiber optical network. By using a single multiport encoder/decoder and 16 phase shifters, this new approach can provide the same confidentiality as other implementations of Yuen's encryption protocol, which use a larger number of phase or polarization coherent states. Data confidentiality and error probability for authorized and unauthorized receivers are carefully analyzed.

  7. Gröbner Bases, Coding, and Cryptography

    CERN Document Server

    Sala, Massimiliano; Perret, Ludovic

    2009-01-01

    Coding theory and cryptography allow secure and reliable data transmission, which is at the heart of modern communication. This book offers a comprehensive overview on the application of commutative algebra to coding theory and cryptography. It analyzes important properties of algebraic/geometric coding systems individually.

  8. Position-based quantum cryptography and catalytic computation

    NARCIS (Netherlands)

    Speelman, F.

    2016-01-01

    In this thesis, we present several results along two different lines of research. The first part concerns the study of position-based quantum cryptography, a topic in quantum cryptography. By combining quantum mechanics with special relativity theory, new cryptographic tasks can be developed that us

  9. Comparative Analysis of Cryptography Library in IoT

    Science.gov (United States)

    Kumar, Uday; Borgohain, Tuhin; Sanyal, Sugata

    2015-05-01

    The paper aims to do a survey along with a comparative analysis of the various cryptography libraries that are applicable in the field of Internet of Things (IoT). The first half of the paper briefly introduces the various cryptography libraries available in the field of cryptography along with a list of all the algorithms contained within the libraries. The second half of the paper deals with cryptography libraries specifically aimed for application in the field of Internet of Things. The various libraries and their performance analysis listed down in this paper are consolidated from various sources with the aim of providing a single comprehensive repository for reference to the various cryptography libraries and the comparative analysis of their features in IoT.

  10. Cubic Curves, Finite Geometry and Cryptography

    CERN Document Server

    Bruen, A A; Wehlau, D L

    2011-01-01

    Some geometry on non-singular cubic curves, mainly over finite fields, is surveyed. Such a curve has 9,3,1 or 0 points of inflexion, and cubic curves are classified accordingly. The group structure and the possible numbers of rational points are also surveyed. A possible strengthening of the security of elliptic curve cryptography is proposed using a `shared secret' related to the group law. Cubic curves are also used in a new way to construct sets of points having various combinatorial and geometric properties that are of particular interest in finite Desarguesian planes.

  11. Coding theory and cryptography the essentials

    CERN Document Server

    Hankerson, DC; Leonard, DA; Phelps, KT; Rodger, CA; Wall, JR; Wall, J R

    2000-01-01

    Containing data on number theory, encryption schemes, and cyclic codes, this highly successful textbook, proven by the authors in a popular two-quarter course, presents coding theory, construction, encoding, and decoding of specific code families in an ""easy-to-use"" manner appropriate for students with only a basic background in mathematics offering revised and updated material on the Berlekamp-Massey decoding algorithm and convolutional codes. Introducing the mathematics as it is needed and providing exercises with solutions, this edition includes an extensive section on cryptography, desig

  12. Cryptography with chaos at the physical level

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Romuel F. E-mail: romuelm@iceb.ufop.br; Baptista, Murilo S.; Grebogi, C

    2004-09-01

    In this work, we devise a chaos-based secret key cryptography scheme for digital communication where the encryption is realized at the physical level, that is, the encrypting transformations are applied to the wave signal instead to the symbolic sequence. The encryption process consists of transformations applied to a two-dimensional signal composed of the message carrying signal and an encrypting signal that has to be a chaotic one. The secret key, in this case, is related to the number of times the transformations are applied. Furthermore, we show that due to its chaotic nature, the encrypting signal is able to hide the statistics of the original signal.

  13. Comment on "Cheating prevention in visual cryptography".

    Science.gov (United States)

    Chen, Yu-Chi; Horng, Gwoboa; Tsai, Du-Shiau

    2012-07-01

    Visual cryptography (VC), proposed by Naor and Shamir, has numerous applications, including visual authentication and identification, steganography, and image encryption. In 2006, Horng showed that cheating is possible in VC, where some participants can deceive the remaining participants by forged transparencies. Since then, designing cheating-prevention visual secret-sharing (CPVSS) schemes has been studied by many researchers. In this paper, we cryptanalyze the Hu-Tzeng CPVSS scheme and show that it is not cheating immune. We also outline an improvement that helps to overcome the problem.

  14. Lightweight Cryptography for Passive RFID Tags

    DEFF Research Database (Denmark)

    David, Mathieu

    2012-01-01

    among the smallest in the published literature and aims at being implemented on printed electronics RFID tags. Then, we compare different cryptographic primitives based on their key parameters: throughput, area, power consumption and level of security. Our main concern is the integrability...... of an integrator for a particular application. Finally, we conclude that the research for finding robust cryptographic primitive in the branch of lightweight cryptography still has some nice days ahead, and that providing a secure cryptosystem for printed electronics RFID tags remains an open research topic....

  15. Distinguishability of quantum states and shannon complexity in quantum cryptography

    Science.gov (United States)

    Arbekov, I. M.; Molotkov, S. N.

    2017-07-01

    The proof of the security of quantum key distribution is a rather complex problem. Security is defined in terms different from the requirements imposed on keys in classical cryptography. In quantum cryptography, the security of keys is expressed in terms of the closeness of the quantum state of an eavesdropper after key distribution to an ideal quantum state that is uncorrelated to the key of legitimate users. A metric of closeness between two quantum states is given by the trace metric. In classical cryptography, the security of keys is understood in terms of, say, the complexity of key search in the presence of side information. In quantum cryptography, side information for the eavesdropper is given by the whole volume of information on keys obtained from both quantum and classical channels. The fact that the mathematical apparatuses used in the proof of key security in classical and quantum cryptography are essentially different leads to misunderstanding and emotional discussions [1]. Therefore, one should be able to answer the question of how different cryptographic robustness criteria are related to each other. In the present study, it is shown that there is a direct relationship between the security criterion in quantum cryptography, which is based on the trace distance determining the distinguishability of quantum states, and the criterion in classical cryptography, which uses guesswork on the determination of a key in the presence of side information.

  16. 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.

  17. Lower Bound for Visual Cryptography Schemes

    CERN Document Server

    Cheraghi, Abbas

    2007-01-01

    For a given visual cryptography scheme, it is possible to present a basis matrices for it and most of constructions are based on basis matrices. In this paper we introduce a lower bound for the pixel expansion of visual cryptography schemes with basis matrices. To make the main theorem more flexible, we will introduce a lower bound based on induced matchings of hypergraph of qualified sets. As an application, we present an algebraic proof for the fact that the pixel expansion of basis matrices of any $k$ out of $k$ scheme is at least $2^{k-1}$. In the sequel, we present a lower bound for the pixel expansion of a given graph access structure in term of maximum number of edges in an induced matching. Finally, we show that the minimum pixel expansion of basis matrices of graph access structure $P_n$ is exactly $\\lceil \\frac{n+1}{2}\\rceil$ and this shows the lower bound mentioned in the main theorem is sharp.

  18. IMPROVING TLS SECURITY BY QUANTUM CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mohamed Elboukhari

    2010-07-01

    Full Text Available Quantum Cryptography or Quantum Key Distribution (QKD solves the key distribution problem byallowing the exchange of a cryptographic key between two remote parties with absolute security,guaranteed by the laws of quantum physics. Extensive studies have been undertaken on QKD since it wasnoted that quantum computers could break public key cryptosystems based on number theory. Actually,the progress of research in this field allows the implementation of QKD outside of laboratories. Effortsare made to exploit this technology in the existing communication networks and to improve theperformance and reliability of the implemented technologies. Some research is in progress for theintegration of QKD with the protocols in different layers of OSI model. The examples of such researcheffort are the integration of QKD in point-to-point protocol (PPP OSI layer 2 and the integration ofQKD with IPSEC at OSI layer-3. All these works are moving towards the utilization of QKD technologyfor enhancing the security of modern computing applications on the internet. In this paper, we present anovel extension of the TLS protocol based on QKD. We introduce a scheme for integrating QuantumCryptography in this protocol. Our approach improves the security of the process of authentication anddata encryption. Also, we describe an example to illustrate the feasibility of our scheme’simplementation.

  19. Evaluation of correlation in optical encryption by using visual cryptography

    Science.gov (United States)

    Yi, Sang-Yi; Ryu, Chung-Sang; Ryu, Dae-Hyun; Lee, Seung-Hyun

    2001-03-01

    Visual cryptography made it possible to decrypt the information encrypted by thresholding scheme not with digital system but with human vision system. This method, however, has some limit in it because of the rack of resolution in both the spatial and amplitude domain. Optical visual cryptography, which used laser system instead of human eyesight, was proposed by conjunction of the optical theory with the cryptography. However, it also had some difficulties because it did not overcome the existing problem of visual cryptography completely. The problems occurred in the process of transferring data processing system from visual to optics. Therefore, it is appropriate to approach these problems in terms of optics. The results show that the optical visual cryptograph system has both the effectiveness and reliability as well as real-time implementation property.

  20. The Secrecy Capacity of Practical Quantum Cryptography

    CERN Document Server

    Gilbert, G

    2001-01-01

    Quantum cryptography has attracted much recent attention due to its potential for providing secret communications that cannot be decrypted by any amount of computational effort. This is the first analysis of the secrecy of a practical implementation of the BB84 protocol that simultaneously takes into account and presents the {\\it full} set of complete analytical expressions for effects due to the presence of pulses containing multiple photons in the attenuated output of the laser, the finite length of individual blocks of key material, losses due to error correction, privacy amplification, continuous authentication, errors in polarization detection, the efficiency of the detectors, and attenuation processes in the transmission medium. The analysis addresses eavesdropping attacks on individual photons rather than collective attacks in general. Of particular importance is the first derivation of the necessary and sufficient amount of privacy amplification compression to ensure secrecy against the loss of key ma...

  1. Privacy-Enhancing Auctions Using Rational Cryptography

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Nielsen, Jesper Buus; Triandopoulos, Nikolaos

    2009-01-01

    We consider enhancing with privacy concerns a large class of auctions, which include sealed-bid single-item auctions but also general multi-item multi-winner auctions, our assumption being that bidders primarily care about monetary payoff and secondarily worry about exposing information about...... show how to use rational cryptography to approximately implement any given ex interim individually strictly rational equilibrium of such an auction without a trusted mediator through a cryptographic protocol that uses only point-to-point authenticated channels between the players. By “ex interim...... close to the original equilibrium.Supported by the Center for Algorithmic Game Theory, funded by The Carlsberg Foundation....

  2. 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....

  3. Securing information display by use of visual cryptography.

    Science.gov (United States)

    Yamamoto, Hirotsugu; Hayasaki, Yoshio; Nishida, Nobuo

    2003-09-01

    We propose a secure display technique based on visual cryptography. The proposed technique ensures the security of visual information. The display employs a decoding mask based on visual cryptography. Without the decoding mask, the displayed information cannot be viewed. The viewing zone is limited by the decoding mask so that only one person can view the information. We have developed a set of encryption codes to maintain the designed viewing zone and have demonstrated a display that provides a limited viewing zone.

  4. Block Based Symmetry Key Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Satyendra Nath Mandal

    2012-08-01

    Full Text Available Visual cryptography is a method for protecting image-based secrets that has a computation-free decoding process. In this technique, numbers of shares have been generated from one image. The shares are sent through any channel to the receiver and the receiver can again produce original image by stacking all the shares in proper order. But, this method wastes a lot of bandwidth of the network. The techniques of generating shares have been used in several existing methods which are not unique. The different methods have been used in different types of images like binary, gray and color images. In this paper, a block based symmetry key visual cryptography algorithm has been proposed to convert image in encrypted form and decrypt the encrypted image into original form. The symmetric key has been generated from a real number. The encryption and decryption algorithm have been designed based on symmetry key. The algorithm with key has been used to encrypt image into single share and decrypt the single share into original image. The real number has been used to form the key may be predefined or may be sent by secure channel to the receiver. The proposed algorithm can be applied to any type images i.e. binary, gray scale and color images. A comparison has been made of the proposed algorithm with different existing algorithms like Ceaser cipher, transpose of matrix, bit comp, and transposition cipher based on the performance. The pixels distributed in original and share images have also been tested. Finally, it has shown that breaking of security level of proposed algorithm i.e. to guess the real number is huge time consuming.

  5. PREFACE: Quantum Information, Communication, Computation and Cryptography

    Science.gov (United States)

    Benatti, F.; Fannes, M.; Floreanini, R.; Petritis, D.

    2007-07-01

    The application of quantum mechanics to information related fields such as communication, computation and cryptography is a fast growing line of research that has been witnessing an outburst of theoretical and experimental results, with possible practical applications. On the one hand, quantum cryptography with its impact on secrecy of transmission is having its first important actual implementations; on the other hand, the recent advances in quantum optics, ion trapping, BEC manipulation, spin and quantum dot technologies allow us to put to direct test a great deal of theoretical ideas and results. These achievements have stimulated a reborn interest in various aspects of quantum mechanics, creating a unique interplay between physics, both theoretical and experimental, mathematics, information theory and computer science. In view of all these developments, it appeared timely to organize a meeting where graduate students and young researchers could be exposed to the fundamentals of the theory, while senior experts could exchange their latest results. The activity was structured as a school followed by a workshop, and took place at The Abdus Salam International Center for Theoretical Physics (ICTP) and The International School for Advanced Studies (SISSA) in Trieste, Italy, from 12-23 June 2006. The meeting was part of the activity of the Joint European Master Curriculum Development Programme in Quantum Information, Communication, Cryptography and Computation, involving the Universities of Cergy-Pontoise (France), Chania (Greece), Leuven (Belgium), Rennes1 (France) and Trieste (Italy). This special issue of Journal of Physics A: Mathematical and Theoretical collects 22 contributions from well known experts who took part in the workshop. They summarize the present day status of the research in the manifold aspects of quantum information. The issue is opened by two review articles, the first by G Adesso and F Illuminati discussing entanglement in continuous variable

  6. Integration of Quantum Cryptography through Satellite Networks Transmission

    Directory of Open Access Journals (Sweden)

    Skander Aris

    2011-01-01

    Full Text Available Problem statement: The security of the telecommunications satellite has become a crucial issue. The telecommunications can be set using the classical cryptography. But this so-called classical cryptography provides cryptographic security. This means that security is based on the difficulty of some mathematics problems. On the other hand, quantum cryptography provides security without conditions based on the law of quantum physics. This method, called the theoretic information security is evidenced using the theory of information. Approach: In this study, we study whether quantum cryptography can be applied in the frame of the satellite telecommunications network. To do this in our project, we present theories regarding the following issues: Telecommunications Station and Satellite Communication Networks, Quantum Key Distribution, Open Space and Satellites, Analyses in different Scenarios between the Satellite and Earth station. Results: Quantum communications offers many advantages for secure data transmission, in our implementation study, we presented different scenarios of quantum key exchange between satellites and ground stations for possible approach to subsystem with quantum communication in space, capable of generating and detecting entangled photons as well as faint laser pulses. Conclusion: The use of satellites to distribute quantum photon provides a unique solution for long-distance. Moreover, quantum cryptography is a satisfactory solution to improve the safety problem. So, the quantum transmissions are the future of telecommunications.

  7. Optical scanning cryptography for secure wireless transmission

    Science.gov (United States)

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-01

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

  8. QC-LDPC code-based cryptography

    CERN Document Server

    Baldi, Marco

    2014-01-01

    This book describes the fundamentals of cryptographic primitives based on quasi-cyclic low-density parity-check (QC-LDPC) codes, with a special focus on the use of these codes in public-key cryptosystems derived from the McEliece and Niederreiter schemes. In the first part of the book, the main characteristics of QC-LDPC codes are reviewed, and several techniques for their design are presented, while tools for assessing the error correction performance of these codes are also described. Some families of QC-LDPC codes that are best suited for use in cryptography are also presented. The second part of the book focuses on the McEliece and Niederreiter cryptosystems, both in their original forms and in some subsequent variants. The applicability of QC-LDPC codes in these frameworks is investigated by means of theoretical analyses and numerical tools, in order to assess their benefits and drawbacks in terms of system efficiency and security. Several examples of QC-LDPC code-based public key cryptosystems are prese...

  9. Optical scanning cryptography for secure wireless transmission.

    Science.gov (United States)

    Poon, Ting-Chung; Kim, Taegeun; Doh, Kyu

    2003-11-10

    We propose a method for secure wireless transmission of encrypted information. By use of an encryption key, an image or document is optically encrypted by optical heterodyne scanning and hence encryption is performed on the fly. We call this technique optical scanning cryptography. The output of the heterodyne encrypted signal is at radio frequency and can be directly sent through an antenna to a secure site for digital storage to be prepared for decryption. In the secure site, an identical optical scanning system to that used for encryption is used, together with a decryption key, to generate an electrical signal. The electrical signal is then processed and sent to a computer to be used for decryption. Utilizing the stored information received from the encryption stage and the electrical information from the secure site, a digital decryption unit performs a decryption algorithm. If the encryption key and the decryption key are matched, the decryption unit will decrypt the image or document faithfully. The overall cryptosystem can perform the incoherent optical processing counterpart of the well-known coherent double-random phase-encoding technique. We present computer simulations of the idea.

  10. Proposed System for data hiding using Cryptography and Steganography Proposed System for data hiding using Cryptography and Steganography

    CERN Document Server

    Sarmah, Dipti Kapoor

    2010-01-01

    Steganography and Cryptography are two popular ways of sending vital information in a secret way. One hides the existence of the message and the other distorts the message itself. There are many cryptography techniques available; among them AES is one of the most powerful techniques. In Steganography we have various techniques in different domains like spatial domain, frequency domain etc. to hide the message. It is very difficult to detect hidden message in frequency domain and for this domain we use various transformations like DCT, FFT and Wavelets etc. In this project we are developing a system where we develop a new technique in which Cryptography and Steganography are used as integrated part along with newly developed enhanced security module. In Cryptography we are using AES algorithm to encrypt a message and a part of the message is hidden in DCT of an image; remaining part of the message is used to generate two secret keys which make this system highly secured. Keyword: Cryptography, Steganography, S...

  11. SECOQC White Paper on Quantum Key Distribution and Cryptography

    CERN Document Server

    Alleaume, R; Branciard, C; Debuisschert, T; Dianati, M; Gisin, N; Godfrey, M; Grangier, P; Langer, T; Leverrier, A; Lütkenhaus, N; Painchault, P; Peev, M; Poppe, A; Pornin, T; Rarity, J; Renner, R; Ribordy, G; Riguidel, M; Salvail, L; Shields, A; Weinfurter, H; Zeilinger, A; Alleaume, Romain; Bouda, Jan; Branciard, Cyril; Debuisschert, Thierry; Dianati, Mehrdad; Gisin, Nicolas; Godfrey, Mark; Grangier, Philippe; Langer, Thomas; Leverrier, Anthony; Lutkenhaus, Norbert; Painchault, Philippe; Peev, Momtchil; Poppe, Andreas; Pornin, Thomas; Rarity, John; Renner, Renato; Ribordy, Gregoire; Riguidel, Michel; Salvail, Louis; Shields, Andrew; Weinfurter, Harald; Zeilinger, Anton

    2007-01-01

    The SECOQC White Paper on Quantum Key Distribution and Cryptography is the outcome on a thorough consultation and discussion among the participants of the European project SECOQC (www.secoqc.net). This paper is a review article that attempts to position Quantum Key Distribution (QKD) in terms of cryptographic applications. A detailed comparison of QKD with the solutions currently in use to solve the key distribution problem, based on classical cryptography, is provided. We also detail how the work on QKD networks lead within SECOQC will allow the deployment of long-distance secure communication infrastructures based on quantum cryptography. The purpose of the White Paper is finally to promote closer collaboration between classical and quantum cryptographers. We believe that very fruitful research, involving both communities, could emerge in the future years and try to sketch what may be the next challenges in this direction.

  12. Fast, parallel and secure cryptography algorithm using Lorenz's attractor

    CERN Document Server

    Marco, Anderson Gonçalves; Bruno, Odemir Martinez; 10.1142/S0129183110015166

    2012-01-01

    A novel cryptography method based on the Lorenz's attractor chaotic system is presented. The proposed algorithm is secure and fast, making it practical for general use. We introduce the chaotic operation mode, which provides an interaction among the password, message and a chaotic system. It ensures that the algorithm yields a secure codification, even if the nature of the chaotic system is known. The algorithm has been implemented in two versions: one sequential and slow and the other, parallel and fast. Our algorithm assures the integrity of the ciphertext (we know if it has been altered, which is not assured by traditional algorithms) and consequently its authenticity. Numerical experiments are presented, discussed and show the behavior of the method in terms of security and performance. The fast version of the algorithm has a performance comparable to AES, a popular cryptography program used commercially nowadays, but it is more secure, which makes it immediately suitable for general purpose cryptography ...

  13. FRAMEWORK FOR WIRELESS NETWORK SECURITY USING QUANTUM CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Priyanka Bhatia

    2014-12-01

    Full Text Available Data that is transient over an unsecured wireless network is always susceptible to being intercepted by anyone within the range of the wireless signal. Hence providing secure communication to keep the user’s information and devices safe when connected wirelessly has become one of the major concerns. Quantum cryptography provides a solution towards absolute communication security over the network by encoding information as polarized photons, which can be sent through the air. This paper explores on the aspect of application of quantum cryptography in wireless networks. In this paper we present a methodology for integrating quantum cryptography and security of IEEE 802.11 wireless networks in terms of distribution of the encryption keys

  14. A Review on Elliptic Curve Cryptography for Embedded Systems

    CERN Document Server

    Afreen, Rahat

    2011-01-01

    Importance of Elliptic Curves in Cryptography was independently proposed by Neal Koblitz and Victor Miller in 1985.Since then, Elliptic curve cryptography or ECC has evolved as a vast field for public key cryptography (PKC) systems. In PKC system, we use separate keys to encode and decode the data. Since one of the keys is distributed publicly in PKC systems, the strength of security depends on large key size. The mathematical problems of prime factorization and discrete logarithm are previously used in PKC systems. ECC has proved to provide same level of security with relatively small key sizes. The research in the field of ECC is mostly focused on its implementation on application specific systems. Such systems have restricted resources like storage, processing speed and domain specific CPU architecture.

  15. 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.

  16. Quantum discord as a resource for quantum cryptography.

    Science.gov (United States)

    Pirandola, Stefano

    2014-11-07

    Quantum discord is the minimal bipartite resource which is needed for a secure quantum key distribution, being a cryptographic primitive equivalent to non-orthogonality. Its role becomes crucial in device-dependent quantum cryptography, where the presence of preparation and detection noise (inaccessible to all parties) may be so strong to prevent the distribution and distillation of entanglement. The necessity of entanglement is re-affirmed in the stronger scenario of device-independent quantum cryptography, where all sources of noise are ascribed to the eavesdropper.

  17. A New Visual Cryptography Scheme for Color Images

    Directory of Open Access Journals (Sweden)

    B.SaiChandana,

    2010-06-01

    Full Text Available Visual cryptography is a method for protecting image-based secrets that has a computation-free decoding process. In this paper, we proposed a visual cryptographic system which can be used to hide the original image information from an intruder or an unwanted user. The images can be in any standard format. The encrypted image is sent to the destination through the network and then the image is decrypted. We used symmetric key cryptography. Experimental results indicate the proposed method is a simple, practical and effective cryptographicsystem.

  18. Implementation of Elliptic Curve Cryptography in Binary Field

    Science.gov (United States)

    Susantio, D. R.; Muchtadi-Alamsyah, I.

    2016-04-01

    Currently, there is a steadily increasing demand of information security, caused by a surge in information flow. There are many ways to create a secure information channel, one of which is to use cryptography. In this paper, we discuss the implementation of elliptic curves over the binary field for cryptography. We use the simplified version of the ECIES (Elliptic Curve Integrated Encryption Scheme). The ECIES encrypts a plaintext by masking the original message using specified points on the curve. The encryption process is done by separating the plaintext into blocks. Each block is then separately encrypted using the encryption scheme.

  19. Geochemistry of Platinum Group and Rare Earth Elements of the Polymetallic Layer in the Lower Cambrian,Weng'an,Guizhou Province

    Institute of Scientific and Technical Information of China (English)

    FU Yong; WU Chaodong; GUAN Ping; QU Wenjun; CHEN Jiafu

    2009-01-01

    The black shales of the Lower Cambrian Niutitang Formation in Weng'an.on the Yangtze platform of south China,contain voluminous polymetallic sulfide deposits.A comprehensive geochemical investigation of trace,rare earth,and platinum group elements(PGE)has been undertaken in order to discuss its ore genesis and correlation with the tectono.depositional setting.The ore-bearing layers enrich molybdenum(Mo),nickeI(Ni),vanadium(V),lead(Pb),strontium(Sr), bariam(Ba),uranium(U),arsenic(As),and rare earth elements(REE)in abundance.High uranium/thorium(U/Th)ratios(U/Th>1)indicated that mineralization was mainly influenced by the hydrothermal process.The δU value Was above 1.9.showing a reducing sedimentary condition.The REE patterns showed high enrichment in Iight rare earth elements (LREE)(heavy rare earth elements (HREE)(LREE/HREE=5-17),slightly negative europium(EU)and cerium(Ce)anomalies(δEu=0.81-0.93).and positive Ce anomalies(δCe=0.76-1.12).PGE abundance was characterized by the PGE-type distribution patterns,enriching platinum(Pt),palladium(Pd),ruthenium(RuJ and osmium(Os).The Pt,Pd ratio was 0.8.which is close to the ratios of seawater and ultramafic rocks.AII of these geochemical features suggest that the mineralization was triggered by hydrothermal activity in an extensionai setting in the context of break-up of the Rodinian supercontinent.

  20. Twenty Seven Years of Quantum Cryptography!

    Science.gov (United States)

    Hughes, Richard

    2011-03-01

    One of the fundamental goals of cryptographic research is to minimize the assumptions underlying the protocols that enable secure communications between pairs or groups of users. In 1984, building on earlier research by Stephen Wiesner, Charles Bennett and Gilles Brassard showed how quantum physics could be harnessed to provide information-theoretic security for protocols such as the distribution of cryptographic keys, which enables two parties to secure their conventional communications. Bennett and Brassard and colleagues performed a proof-of-principle quantum key distribution (QKD) experiment with single-photon quantum state transmission over a 32-cm air path in 1991. This seminal experiment led other researchers to explore QKD in optical fibers and over line-of-sight outdoor atmospheric paths (``free-space''), resulting in dramatic increases in range, bit rate and security. These advances have been enabled by improvements in sources and single-photon detectors. Also in 1991 Artur Ekert showed how the security of QKD could be related to quantum entanglement. This insight led to a deeper understanding and proof of QKD security with practical sources and detectors in the presence of transmission loss and channel noise. Today, QKD has been implemented over ranges much greater than 100km in both fiber and free-space, multi-node network testbeds have been demonstrated, and satellite-based QKD is under study in several countries. ``Quantum hacking'' researchers have shown the importance of extending security considerations to the classical devices that produce and detect the photon quantum states. New quantum cryptographic protocols such as secure identification have been proposed, and others such as quantum secret splitting have been demonstrated. It is now possible to envision quantum cryptography providing a more secure alternative to present-day cryptographic methods for many secure communications functions. My talk will survey these remarkable developments.

  1. The Characteristics and Significance of Using Allusions In FangWeng Ci-Poem%放翁词中典故运用的特征及其意义

    Institute of Scientific and Technical Information of China (English)

    邢蕊杰

    2011-01-01

    Ci-Poem Using allusions is very popular in South-Song Dynasty. Lu you and Xin qi-ji are the represen- tative writers. Lu you, also named Fang weng, has lots of allusions in his Ci-Poem, which involve the different meaning of history and profound implications. Therefore FangWeng tries to use various ways to express the allu- sions in his Ct-Poem, which as a true portrayal of his inner world, helps him to reflect his life experience and ideas truly. Using allusions in the FangWeng Ci-Poem has the lyric and flexible characteristics, which enhances the elegant and dignified temperament to Ci-Poem. Using allusions reflect the current aesthetic fashion in Song Dy- nasty and also is the result of the Ci-Poem evolution.%词的用典,在南宋词坛渐成风气,以陆游、辛弃疾为代表。陆放翁以典入词,数量多、范围广,熔铸百家,广博精当。放翁词语典内容广泛,事典意蕴深厚,用法灵活多样。典故中的历史积淀形象表达了词人的人生情怀或思想志趣,成为其内心世界的真实写照。放翁词大量用典,抒情言志,增强了词作的书卷气,增添了其风雅相,是时代审美风尚的具体反映以及词体演进的必然结果。

  2. The mathematics of ciphers number theory and RSA cryptography

    CERN Document Server

    Coutinho, S C

    1999-01-01

    This book is an introduction to the algorithmic aspects of number theory and its applications to cryptography, with special emphasis on the RSA cryptosys-tem. It covers many of the familiar topics of elementary number theory, all with an algorithmic twist. The text also includes many interesting historical notes.

  3. Enhancing Undergraduate Mathematics Curriculum via Coding Theory and Cryptography

    Science.gov (United States)

    Aydin, Nuh

    2009-01-01

    The theory of error-correcting codes and cryptography are two relatively recent applications of mathematics to information and communication systems. The mathematical tools used in these fields generally come from algebra, elementary number theory, and combinatorics, including concepts from computational complexity. It is possible to introduce the…

  4. Steganography and Cryptography Inspired Enhancement of Introductory Programming Courses

    Science.gov (United States)

    Kortsarts, Yana; Kempner, Yulia

    2015-01-01

    Steganography is the art and science of concealing communication. The goal of steganography is to hide the very existence of information exchange by embedding messages into unsuspicious digital media covers. Cryptography, or secret writing, is the study of the methods of encryption, decryption and their use in communications protocols.…

  5. 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.

  6. APE: Authenticated Permutation-Based Encryption for Lightweight Cryptography

    NARCIS (Netherlands)

    Andreeva, Elena; Bilgin, Begül; Bogdanov, Andrey; Luykx, Atul; Mennink, Bart; Mouha, Nicky; Yasuda, Kan

    The domain of lightweight cryptography focuses on cryptographic algorithms for extremely constrained devices. It is very costly to avoid nonce reuse in such environments, because this requires either a hardware source of randomness, or non-volatile memory to store a counter. At the same time, a lot

  7. A "proof-reading" of Some Issues in Cryptography

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre

    2007-01-01

    In this paper, we identify some issues in the interplay between practice and theory in cryptography, issues that have repeatedly appeared in different incarnations over the years. These issues are related to fundamental concepts in the eld, e.g., to what extent we can prove that a system is secure...

  8. Optimal eavesdropping in cryptography with three-dimensional quantum states.

    Science.gov (United States)

    Bruss, D; Macchiavello, C

    2002-03-25

    We study optimal eavesdropping in quantum cryptography with three-dimensional systems, and show that this scheme is more secure against symmetric attacks than protocols using two-dimensional states. We generalize the according eavesdropping transformation to arbitrary dimensions, and discuss the connection with optimal quantum cloning.

  9. Phase-modulation transmission system for quantum cryptography.

    Science.gov (United States)

    Mérolla, J M; Mazurenko, Y; Goedgebuer, J P; Porte, H; Rhodes, W T

    1999-01-15

    We describe a new method for quantum key distribution that utilizes phase modulation of sidebands of modulation by use of integrated electro-optic modulators at the transmitting and receiving modules. The system is shown to produce constructive or destructive interference with unity visibility, which should allow quantum cryptography to be carried out with high flexibility by use of conventional devices.

  10. Introduction to Cryptography and the Bitcoin Protocol (1/2)

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The Bitcoin protocol not only supports an electronic currency, but also has the possibility for being (mis)used in other ways. Topics will include the basic operation of how Bitcoin operates including motivations and also such things as block chaining, bitcoin mining, and how financial transactions operate. A knowledge of the topics covered in the Basic Cryptography lecture will be assumed.

  11. Introduction to Cryptography and the Bitcoin Protocol (2/2)

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The Bitcoin protocol not only supports an electronic currency, but also has the possibility for being (mis)used in other ways. Topics will include the basic operation of how Bitcoin operates including motivations and also such things as block chaining, bitcoin mining, and how financial transactions operate. A knowledge of the topics covered in the Basic Cryptography lecture will be assumed.

  12. Implementation of diffie-Hellman key exchange on wireless sensor using elliptic curve cryptography

    DEFF Research Database (Denmark)

    Khajuria, Samant; Tange, Henrik

    2009-01-01

    This work describes a low-cost public key cryptography (PKC) based solution for security services such as authentication as required for wireless sensor networks. We have implemented a software approach using elliptic curve cryptography (ECC) over GF (2m) in order to obtain stronger cryptography....... from Crossbow. Results has shown that the point calculation can be done fairly amount of time with relatively small space consumption......This work describes a low-cost public key cryptography (PKC) based solution for security services such as authentication as required for wireless sensor networks. We have implemented a software approach using elliptic curve cryptography (ECC) over GF (2m) in order to obtain stronger cryptography...

  13. Visual cryptography for image processing and security theory, methods, and applications

    CERN Document Server

    Liu, Feng

    2014-01-01

    This unique book describes the fundamental concepts, theories and practice of visual cryptography. The design, construction, analysis, and application of visual cryptography schemes (VCSs) are discussed in detail. Original, cutting-edge research is presented on probabilistic, size invariant, threshold, concolorous, and cheating immune VCS. Features: provides a thorough introduction to the field; examines various common problems in visual cryptography, including the alignment, flipping, cheating, distortion, and thin line problems; reviews a range of VCSs, including XOR-based visual cryptograph

  14. Integrating identity-based cryptography in IMS service authentication

    CERN Document Server

    Abid, Mohamed; Moustafa, Hassnaa; Afifi, Hossam

    2010-01-01

    Nowadays, the IP Multimedia Subsystem (IMS) is a promising research field. Many ongoing works related to the security and the performances of its employment are presented to the research community. Although, the security and data privacy aspects are very important in the IMS global objectives, they observe little attention so far. Secure access to multimedia services is based on SIP and HTTP digest on top of IMS architecture. The standard deploys AKA-MD5 for the terminal authentication. The third Generation Partnership Project (3GPP) provided Generic Bootstrapping Architecture (GBA) to authenticate the subscriber before accessing multimedia services over HTTP. In this paper, we propose a new IMS Service Authentication scheme using Identity Based cryptography (IBC). This new scheme will lead to better performances when there are simultaneous authentication requests using Identity-based Batch Verification. We analyzed the security of our new protocol and we presented a performance evaluation of its cryptographi...

  15. Electronic Voting Protocol Using Identity-Based Cryptography

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps. PMID:26090515

  16. Electronic Voting Protocol Using Identity-Based Cryptography

    Directory of Open Access Journals (Sweden)

    Gina Gallegos-Garcia

    2015-01-01

    Full Text Available Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC, which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE. With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI. Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps.

  17. Field Experiment on a Robust Hierarchical Metropolitan Quantum Cryptography Network

    CERN Document Server

    Xu, Fangxing; Wang, Shuang; Yin, Zhenqiang; Zhang, Yang; Liu, Yun; Zhou, Zheng; Zhao, Yibo; Li, Hongwei; Liu, Dong; Han, Zhengfu; Guo, Guangcan

    2009-01-01

    A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as the subnet gateway, a two-user subnet and a single-fiber access link, which is realized by the Faraday-Michelson Interferometer set-ups. The techniques of the quantum router, optical switch and trusted relay are assembled here to guarantee the feasibility and expandability of the quantum cryptography network. Five nodes of the network are located in the government departments and the secure keys generated by the quantum key distribution network are utilized to encrypt the instant video, sound, text messages and confidential files transmitting between these bureaus. The whole implementation including the hierarchical quantum cryptographic communication network links and corresponding application software shows a big step toward the practical user-oriented network with high security level.

  18. Electronic Voting Protocol Using Identity-Based Cryptography.

    Science.gov (United States)

    Gallegos-Garcia, Gina; Tapia-Recillas, Horacio

    2015-01-01

    Electronic voting protocols proposed to date meet their properties based on Public Key Cryptography (PKC), which offers high flexibility through key agreement protocols and authentication mechanisms. However, when PKC is used, it is necessary to implement Certification Authority (CA) to provide certificates which bind public keys to entities and enable verification of such public key bindings. Consequently, the components of the protocol increase notably. An alternative is to use Identity-Based Encryption (IBE). With this kind of cryptography, it is possible to have all the benefits offered by PKC, without neither the need of certificates nor all the core components of a Public Key Infrastructure (PKI). Considering the aforementioned, in this paper we propose an electronic voting protocol, which meets the privacy and robustness properties by using bilinear maps.

  19. Development of mechanism for enhancing data security in quantum cryptography

    CERN Document Server

    Singh, Ajit

    2011-01-01

    Nowadays security in communication is increasingly important to the network communication because many categories of data are required restriction on authorization of access, modify, delete and insert. Quantum cryptography is one of the solutions that use property of polarization to ensure that transmitted data is not tampered. The research paper provides the mechanism that enhances the data security in quantum cryptography during exchange of information. In first phase detailed explanation of Quantum key distribution's BB84 protocol is given. BB84 protocol is used as the basis for the mechanism. In next phase the proposed mechanism is explained. The proposed mechanism combines BB84 protocol at two levels, from sender to receiver and then from receiver to sender. Moreover, a logic circuit is used to combine the bits hence to reduce the probability of eavesdropping. The key obtained can be used to exchange the information securely further it can help in encryption and decryption of crucial data. Double level B...

  20. Towards Practical Whitebox Cryptography: Optimizing Efficiency and Space Hardness

    DEFF Research Database (Denmark)

    Bogdanov, Andrey; Isobe, Takanori; Tischhauser, Elmar Wolfgang

    2016-01-01

    Whitebox cryptography aims to provide security for cryptographic algorithms in an untrusted environment where the adversary has full access to their implementation. Typical security goals for whitebox cryptography include key extraction security and decomposition security: Indeed, it should...... such as DES or AES are prone to practical key extraction attacks, there have been two dedicated design approaches for whitebox block ciphers: ASASA by Birykov et al. at ASIACRYPT'14 and SPACE by Bogdanov and Isobe at CCS'15. While ASASA suffers from decomposition attacks, SPACE reduces the security against...... key extraction and decomposition attacks in the white box to the security of a standard block cipher such as AES in the standard blackbox setting. However, due to the security-prioritized design strategy, SPACE imposes a sometimes prohibitive performance overhead in the real world as it needs many AES...

  1. Region Incrementing Visual Cryptography Scheme with Same Contrast

    Institute of Scientific and Technical Information of China (English)

    LI Shundong; LI Jiliang; WANG Daoshun

    2016-01-01

    In binary Region increm enting visual cryptography schemes (RIVCSs), the secrets of multi-ple secrecy regions can be gradually revealed by hu-man visual system. A characteristic of the existing binary RIVCSs different from traditional binary Visual cryptog-raphy schemes (VCSs) is that, the contrasts for different revealed regions are different while traditional binary VCSs have same contrast. To keep the quality (contrast) of re-covered image compatible with the traditional VCS, we use integer linear programming to design a binary (k,n)-RIVCS with same contrast for all secrecy regions in this paper. Experimental results demonstrate that our method is feasible and effective. The trade-off is that our schem e involves a larger pixel expansion.

  2. Public-key cryptography in functional programming context

    CERN Document Server

    Márton, Gyöngyvér

    2010-01-01

    Up to now, for efficiency reasons cryptographic algorithm has been written in an imperative language. But to get acquaintance with a functional programming language a question arises: functional programming offers some new for secure communication or not? This article investigates this question giving an overview on some cryptography algorithms and presents how the RSA encryption in the functional language Clean can be implemented and how can be measured the efficiency of a certain application.

  3. On Some Security Issues in Pervasive Computing - Light Weight Cryptography

    Directory of Open Access Journals (Sweden)

    Rukma Rekha N

    2012-02-01

    Full Text Available Pervasive Computing Environment is a world where technologies fadeout into the background. The technology is invisible to the user and he is least distracted by the technology. This paper tries to focus on the issues of pervasive computing and reveals the security issues in pervasive computing. We try to find out the role of light weight cryptography in pervasive computing and a comparison between traditional and light weight cryptographic approaches was made.

  4. 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.

  5. 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.

  6. Nonlinear laser dynamics from quantum dots to cryptography

    CERN Document Server

    Lüdge, Kathy

    2012-01-01

    A distinctive discussion of the nonlinear dynamical phenomena of semiconductor lasers. The book combines recent results of quantum dot laser modeling with mathematical details and an analytic understanding of nonlinear phenomena in semiconductor lasers and points out possible applications of lasers in cryptography and chaos control. This interdisciplinary approach makes it a unique and powerful source of knowledge for anyone intending to contribute to this field of research.By presenting both experimental and theoretical results, the distinguished authors consider solitary lase

  7. Verification of Quantum Cryptography Protocols by Model Checking

    Directory of Open Access Journals (Sweden)

    Mohamed Elboukhari

    2010-10-01

    Full Text Available Unlike classical cryptography which is based on mathematical functions, Quantum Cryptography orQuantum Key Distribution (QKD exploits the laws of quantum physics to offer unconditionally securecommunication. The progress of research in this field allows the anticipation of QKD to be availableoutside of laboratories within the next few years and efforts are made to improve the performance andreliability of the implemented technologies. But despite this big progress, several challenges remain. Forexample the task of how to test the devices of QKD did not yet receive enough attention. These apparatusesbecome heterogeneous, complex and so demand a big verification effort. In this paper we propose to studyquantum cryptography protocols by applying the technique of probabilistic model checking. Using PRISMtool, we analyze the security of BB84 protocol and we are focused on the specific security property ofeavesdropper's information gain on the key derived from the implementation of this protocol. We show thatthis property is affected by the parameters of the eavesdropper’s power and the quantum channel.

  8. Authentication in Online Banking Systems through Quantum Cryptography

    Directory of Open Access Journals (Sweden)

    Anand Sharma

    2013-06-01

    Full Text Available The new information technology is becoming an important factor in the future development of financial services industry, and especially banking industry. Growing international trading and problems in transferring money have motivated researchers to introduce a new structure. Online banking is the newest delivery channel for retail banking services. Online banking facilitated by various Electronic Commerce technologies, has helped commercial banks to stay competitive through productivity gains, transaction cost reduction and customer service improvement. Security for online banking has changed considerably during the relatively short period that online banking has been in use. In particular, authentication in the early implementations was, and sometimes still is, vulnerable to various attacks such as phishing. It is known that the quantum cryptography protocols are able to detect immediately any attempt to attack the key exchange and the authentication process. This paper presentsan introduction of online banking and quantum cryptography. In this paper we are proposing a model for authentication in online banking system with quantum cryptography.

  9. Survey of Multiple Information Hiding Techniques using Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Bijoy Chhetri

    2015-10-01

    Full Text Available Information now a day‟s seems to have become abundant and the secure transmission and visualization of it has been a challenge. The major security concerns are of Authentication, Confidentiality and Data Integrity.  In regard to this, the various security methodologies have been introduced and Cryptography is one of the schemes where the information is transferred in the disguise form and only authentic user can reveal the exact information. Various Cryptographic techniques has played a very vital role in this regard, among which Visual Cryptographic System(VCS is one of such kind  where the secret data (image, text etc is encoded into multiple images and decoded using Human Visual System(HVS without having to tedious calculations and sound  knowledge of Cryptography. VC  is one of such methodology where the secret information is bifurcated into many disguise images and on super imposing these images, the original secret information is revealed, using Human Visual System(HVS unlike the traditional cryptography where lot of complex mathematical and time consuming calculation are to be performed. In this paper study of various VC techniques has been done based on number of shares, number of secret messages and types of shares in the cases of Grayscale Image.

  10. A Generic Simulation Framework for Non-Entangled based Experimental Quantum Cryptography and Communication: Quantum Cryptography and Communication Simulator (QuCCs)

    Science.gov (United States)

    Buhari, Abudhahir; Zukarnain, Zuriati Ahmad; Khalid, Roszelinda; Zakir Dato', Wira Jaafar Ahmad

    2016-11-01

    The applications of quantum information science move towards bigger and better heights for the next generation technology. Especially, in the field of quantum cryptography and quantum computation, the world already witnessed various ground-breaking tangible product and promising results. Quantum cryptography is one of the mature field from quantum mechanics and already available in the markets. The current state of quantum cryptography is still under various researches in order to reach the heights of digital cryptography. The complexity of quantum cryptography is higher due to combination of hardware and software. The lack of effective simulation tool to design and analyze the quantum cryptography experiments delays the reaching distance of the success. In this paper, we propose a framework to achieve an effective non-entanglement based quantum cryptography simulation tool. We applied hybrid simulation technique i.e. discrete event, continuous event and system dynamics. We also highlight the limitations of a commercial photonic simulation tool based experiments. Finally, we discuss ideas for achieving one-stop simulation package for quantum based secure key distribution experiments. All the modules of simulation framework are viewed from the computer science perspective.

  11. 翁维良教授治疗心血管疾病临床用药经验初探%Initially study on professor WENG Wei-liang's clinical experience of prescription and medication treating cardiovascular diseases

    Institute of Scientific and Technical Information of China (English)

    于大君

    2011-01-01

    翁维良教授从事心血管疾病研究50余年,对该系统疾病的治疗用药积累了丰富经验.他重视运用活血化瘀药,并强调养血活血药的使用,慎用破血药,常用的活血化瘀药有丹参、赤芍、红花、川芎、姜黄、郁金等.翁老治疗心血管疾病以活血化瘀药为中心,根据不同病证配合祛痰除湿药(陈皮、法半夏、白术、茯苓、荷叶等)、益气滋阴药(太子参、生黄芪、北沙参、玉竹、女贞子、生地黄等)、温阳药(炮附子、干姜、肉桂、良姜、补骨脂等).翁老重视药物归经,善用心经药(麦冬、五味子、酸枣仁、夜交藤,远志、莲子心、百合等).他对心律失常的治疗善以散剂配合汤剂治疗,疗效显著.%Professor WENG Wei-Hang has been working on cardiovascular diseases for more than 50 years, and has accumulated lots of experience on treating these diseases. He emphasizes on the more using of promoting blood flow and eliminating phlegm herbs and less using of removing blood stasis with potent herbs. The commonly used promoting blood flow and eliminating phlegm herbs are red sage root, red peony root, safflower, chuanxiong rhizoma. Turmeric root tuber, turmeric root tuber, et al. At the same time, Professor WENG compatibles different herbs according to patient's conditions. The commonly used herbs of removing phlegm are tangerine peel, pinellia tuber, largehead atractylodes rhizome, Indian bread, lotus leaf, etc. Supplementing qi and nourishing yin herbs are heterophylly falsesatarwort root, milkvetch root, glehnia, fragrant solomonseal rhizome, glossy privet fruit, dried rehmannia root, et al. Warming yang herbs are prepared common monkshood daughter root, dried ginger, cassia bark, lesser galangal rhizome, malaytea scurfpea fruit, etc. Professor WENG also thinks highly of channel tropism of herbs. Dwarf lilyturf tuber, Chinese magnolivine fruit, spine date seed, thinleaf milkwort root, lotus plumule and lily bulb are the

  12. EDITORIAL: Focus on Quantum Cryptography: Theory and Practice FOCUS ON QUANTUM CRYPTOGRAPHY: THEORY AND PRACTICE

    Science.gov (United States)

    Lütkenhaus, N.; Shields, A. J.

    2009-04-01

    Quantum cryptography, and especially quantum key distribution (QKD), is steadily progressing to become a viable tool for cryptographic services. In recent years we have witnessed a dramatic increase in the secure bit rate of QKD, as well as its extension to ever longer fibre- and air-based links and the emergence of metro-scale trusted networks. In the foreseeable future even global-scale communications may be possible using quantum repeaters or Earth-satellite links. A handful of start-ups and some bigger companies are already active in the field. The launch of an initiative to form industrial standards for QKD, under the auspices of the European Telecommunication Standards Institute, described in the paper by Laenger and Lenhart in this Focus Issue, can be taken as a sign of the growing commercial interest. Recent progress has seen an increase in the secure bit rate of QKD links, by orders of magnitude, to over 1 Mb s-1. This has resulted mainly from an improvement in the detection technology. Here changes in the way conventional semiconductor detectors are gated, as well as the development of novel devices based on non-linear processes and superconducting materials, are leading the way. Additional challenges for QKD at GHz clock rates include the design of high speed electronics, remote synchronization and high rate random number generation. Substantial effort is being devoted to increasing the range of individual links, which is limited by attenuation and other losses in optical fibres and air links. An important advance in the past few years has been the introduction of protocols with the same scaling as an ideal single-photon set-up. The good news is that these schemes use standard optical devices, such as weak laser pulses. Thanks to these new protocols and improvements in the detection technology, the range of a single fibre link can exceed a few hundred km. Outstanding issues include proving the unconditional security of some of the schemes. Much of the

  13. Multi-pixel Visual Cryptography for color images with Meaningful Shares

    Directory of Open Access Journals (Sweden)

    Ms. KIRAN KUMARI,

    2010-06-01

    Full Text Available The important issue of visual cryptography is visual quality of recovered image. This paper presents Multi-pixel Visual Cryptography for color images to generate two meaningful shares. Some filters are proposed for better visual quality of recovered image and a new simple watermarking algorithm is proposed to generate meaningful shares.

  14. An application of different dioids in public key cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Durcheva, Mariana I., E-mail: mdurcheva66@gmail.com [Technical University of Sofia, Faculty of Applied Mathematics and Informatics, 8 Kliment Ohridski St., Sofia 1000 (Bulgaria)

    2014-11-18

    Dioids provide a natural framework for analyzing a broad class of discrete event dynamical systems such as the design and analysis of bus and railway timetables, scheduling of high-throughput industrial processes, solution of combinatorial optimization problems, the analysis and improvement of flow systems in communication networks. They have appeared in several branches of mathematics such as functional analysis, optimization, stochastic systems and dynamic programming, tropical geometry, fuzzy logic. In this paper we show how to involve dioids in public key cryptography. The main goal is to create key – exchange protocols based on dioids. Additionally the digital signature scheme is presented.

  15. Geometry, algebra and applications from mechanics to cryptography

    CERN Document Server

    Encinas, Luis; Gadea, Pedro; María, Mª

    2016-01-01

    This volume collects contributions written by different experts in honor of Prof. Jaime Muñoz Masqué. It covers a wide variety of research topics, from differential geometry to algebra, but particularly focuses on the geometric formulation of variational calculus; geometric mechanics and field theories; symmetries and conservation laws of differential equations, and pseudo-Riemannian geometry of homogeneous spaces. It also discusses algebraic applications to cryptography and number theory. It offers state-of-the-art contributions in the context of current research trends. The final result is a challenging panoramic view of connecting problems that initially appear distant.

  16. An Online Banking System Based on Quantum Cryptography Communication

    Science.gov (United States)

    Zhou, Ri-gui; Li, Wei; Huan, Tian-tian; Shen, Chen-yi; Li, Hai-sheng

    2014-07-01

    In this paper, an online banking system has been built. Based on quantum cryptography communication, this system is proved unconditional secure. Two sets of GHZ states are applied, which can ensure the safety of purchase and payment, respectively. In another word, three trading participants in each triplet state group form an interdependent and interactive relationship. In the meantime, trading authorization and blind signature is introduced by means of controllable quantum teleportation. Thus, an effective monitor is practiced on the premise that the privacy of trading partners is guaranteed. If there is a dispute or deceptive behavior, the system will find out the deceiver immediately according to the relationship mentioned above.

  17. Watermarking Scheme Based on Wavelet Transformation and Visual Cryptography

    Institute of Scientific and Technical Information of China (English)

    Young-Chang Hou; Shih-Chieh Wei; Hsin-Ju Liu; A-Yu Tseng

    2014-01-01

    Based on the principles of the visual cryptography and the law of large numbers, the unexpanded shares are generated during the processes of embedding and verifying the hidden watermark. The watermark embedding is done in the frequency domain, which can be decoded by the human visual system (HVS) without the necessity of any complicated computation and the help of the original image. Experimental results indicated that our method had a good robustness on darkening, lightening, blurring, sharpening, noise, distorting, jitter, joint photographic experts group (JPEG) compression, and crop attacks.

  18. A Luggage Control System Based on NFC and Homomorphic Cryptography

    Directory of Open Access Journals (Sweden)

    Néstor Álvarez-Díaz

    2017-01-01

    Full Text Available We propose an innovative luggage tracking and management system that can be used to secure airport terminal services and reduce the waiting time of passengers during check-in. This addresses an urgent need to streamline and optimize passenger flows at airport terminals and lowers the risk of terrorist threats. The system employs Near Field Communication (NFC technology and homomorphic cryptography (the Paillier cryptosystem to protect wireless communication and stored data. A security analysis and a performance test show the usability and applicability of the proposed system.

  19. Cyber Security for Smart Grid, Cryptography, and Privacy

    Directory of Open Access Journals (Sweden)

    Swapna Iyer

    2011-01-01

    Full Text Available The invention of “smart grid” promises to improve the efficiency and reliability of the power system. As smart grid is turning out to be one of the most promising technologies, its security concerns are becoming more crucial. The grid is susceptible to different types of attacks. This paper will focus on these threats and risks especially relating to cyber security. Cyber security is a vital topic, since the smart grid uses high level of computation like the IT. We will also see cryptography and key management techniques that are required to overcome these attacks. Privacy of consumers is another important security concern that this paper will deal with.

  20. Implementing SSL/TLS using cryptography and PKI

    CERN Document Server

    Davies, Joshua

    2011-01-01

    Hands-on, practical guide to implementing SSL and TLS protocols for Internet security If you are a network professional who knows C programming, this practical book is for you.  Focused on how to implement Secure Socket Layer (SSL) and Transport Layer Security (TLS), this book guides you through all necessary steps, whether or not you have a working knowledge of cryptography. The book covers SSLv2, TLS 1.0, and TLS 1.2, including implementations of the relevant cryptographic protocols, secure hashing, certificate parsing, certificate generation, and more.  Coverage includes: Underst

  1. Survey paper on different approaches of Threshold Cryptography

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2012-09-01

    Full Text Available A traditional key management service is based on a Certificate Authority or a Trusted Third party. Security solutions for traditional network are not suitable for Mobile ad hoc network. The characteristics of MANET presence a number of challenges to security such as self-configuring, wireless links, infrastructure less nature. Threshold cryptography has proved to be an effective technique for key distribution and management. In this paper we highlight the different approaches used for certificate generation, discovering and authentication of public keys.

  2. Enhancing Information Security and Privacy by Combining Biometrics with Cryptography

    CERN Document Server

    Kanade, Sanjay

    2012-01-01

    This book deals with "crypto-biometrics", a relatively new and multi-disciplinary area of research (started in 1998). Combining biometrics and cryptography provides multiple advantages, such as, revocability, template diversity, better verification accuracy, and generation of cryptographically usable keys that are strongly linked to the user identity. In this text, a thorough review of the subject is provided and then some of the main categories are illustrated with recently proposed systems by the authors. Beginning with the basics, this text deals with various aspects of crypto-biometrics, i

  3. Novel optical scanning cryptography using Fresnel telescope imaging.

    Science.gov (United States)

    Yan, Aimin; Sun, Jianfeng; Hu, Zhijuan; Zhang, Jingtao; Liu, Liren

    2015-07-13

    We propose a new method called modified optical scanning cryptography using Fresnel telescope imaging technique for encryption and decryption of remote objects. An image or object can be optically encrypted on the fly by Fresnel telescope scanning system together with an encryption key. For image decryption, the encrypted signals are received and processed with an optical coherent heterodyne detection system. The proposed method has strong performance through use of secure Fresnel telescope scanning with orthogonal polarized beams and efficient all-optical information processing. The validity of the proposed method is demonstrated by numerical simulations and experimental results.

  4. Quantum Overloading Cryptography Using Single-Photon Nonlocality

    Institute of Scientific and Technical Information of China (English)

    TAN Yong-Gang; CAI Qing-Yu; SHI Ting-Yun

    2007-01-01

    @@ Using the single-photon nonlocality, we propose a quantum novel overloading cryptography scheme, in which a single photon carries two bits information in one-way quantum channel. Two commutative modes of the single photon, the polarization mode and the spatial mode, are used to encode secret information. Strict time windows are set to detect the impersonation attack. The spatial mode which denotes the existence of photons is noncommutative with the phase of the photon, so that our scheme is secure against photon-number-splitting attack. Our protocol may be secure against individual attack.

  5. One-way entangled-photon autocompensating quantum cryptography

    Science.gov (United States)

    Walton, Zachary D.; Abouraddy, Ayman F.; Sergienko, Alexander V.; Saleh, Bahaa E.; Teich, Malvin C.

    2003-06-01

    A quantum cryptography implementation is presented that uses entanglement to combine one-way operation with an autocompensating feature that has hitherto only been available in implementations that require the signal to make a round trip between the users. Using the concept of advanced waves, it is shown that this proposed implementation is related to the round-trip implementation in the same way that Ekert’s two-particle scheme is related to the original one-particle scheme of Bennett and Brassard. The practical advantages and disadvantages of the proposed implementation are discussed in the context of existing schemes.

  6. Detection of Eavesdropping in Quantum Cryptography%量子密码的窃听检测

    Institute of Scientific and Technical Information of China (English)

    李凯; 黄晓英; 滕吉红; 李振华

    2012-01-01

    量子密码是密码学与量子力学相结合的产物.它具有得天独厚的优势并逐渐成为下一代密码技术中的重要研究分支.与经典密码相比,量子密码最大的优势就是它的可证明安全性和可检测性.分析了量子密码协议中的窃听检测过程并给出一个新的量子密码协议方案.%Quantum cryptography is the combination of quantum mechanics and cryptography. It has native advantage in the sense of security and is gradually developing into an important branch of next generation of technologies in cryptography. Compared to the classical cryptography, the greatest advantages of quantum cryptography are provable security and detectability. In this paper, the detection of eavesdropping in quantum cryptography schemes is investigated and a new quantum cryptography protocol is presented.

  7. DESIGN OF A NEW SECURITY PROTOCOL USING HYBRID CRYPTOGRAPHY ALGORITHMS

    Directory of Open Access Journals (Sweden)

    Dr.S.Subasree and Dr.N.K.Sakthivel

    2010-02-01

    Full Text Available A Computer Network is an interconnected group of autonomous computing nodes, which use a well defined, mutually agreed set of rules and conventions known as protocols, interact with one-another meaningfully and allow resource sharing preferably in a predictable and controllable manner. Communication has a major impact on today’s business. It is desired to communicate data with high security. Security Attacks compromises the security and hence various Symmetric and Asymmetric cryptographic algorithms have been proposed to achieve the security services such as Authentication, Confidentiality, Integrity, Non-Repudiation and Availability. At present, various types of cryptographic algorithms provide high security to information on controlled networks. These algorithms are required to provide data security and users authenticity. To improve the strength of these security algorithms, a new security protocol for on line transaction can be designed using combination of both symmetric and asymmetric cryptographic techniques. This protocol provides three cryptographic primitives such as integrity, confidentiality and authentication. These three primitives can be achieved with the help of Elliptic Curve Cryptography, Dual-RSA algorithm and Message Digest MD5. That is it uses Elliptic Curve Cryptography for encryption, Dual-RSA algorithm for authentication and MD-5 for integrity. This new security protocol has been designed for better security with integrity using a combination of both symmetric and asymmetric cryptographic techniques.

  8. Architecture for the Secret-Key BC3 Cryptography Algorithm

    Directory of Open Access Journals (Sweden)

    Arif Sasongko

    2011-08-01

    Full Text Available Cryptography is a very important aspect in data security. The focus of research in this field is shifting from merely security aspect to consider as well the implementation aspect. This paper aims to introduce BC3 algorithm with focus on its hardware implementation. It proposes architecture for the hardware implementation for this algorithm. BC3 algorithm is a secret-key cryptography algorithm developed with two considerations: robustness and implementation efficiency. This algorithm has been implemented on software and has good performance compared to AES algorithm. BC3 is improvement of BC2 and AE cryptographic algorithm and it is expected to have the same level of robustness and to gain competitive advantages in the implementation aspect. The development of the architecture gives much attention on (1 resource sharing and (2 having single clock for each round. It exploits regularity of the algorithm. This architecture is then implemented on an FPGA. This implementation is three times smaller area than AES, but about five times faster. Furthermore, this BC3 hardware implementation has better performance compared to BC3 software both in key expansion stage and randomizing stage. For the future, the security of this implementation must be reviewed especially against side channel attack.

  9. 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.

  10. 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.

  11. A Novel Authenticity of an Image Using Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Prashant Kumar Koshta

    2012-04-01

    Full Text Available A digital signature is an important public-key primitive thatperforms the function of conventional handwritten signatures forentity authentication, data integrity, and non-repudiation,especially within the electronic commerce environment.Currently, most conventional digital signature schemes are basedon mathematical hard problems. These mathematical algorithmsrequire computers to perform the heavy and complexcomputations to generate and verify the keys and signatures. In1995, Naor and Shamir proposed a visual cryptography (VC forbinary images. VC has high security and requires simplecomputations. The purpose of this thesis is to provide analternative to the current digital signature technology. Weintroduce a new digital signature scheme based on the concept ofa non-expansion visual cryptography. A visual digital signaturescheme is a method to enable visual verification of theauthenticity of an image in an insecure environment without theneed to perform any complex computations. We proposedscheme generates visual shares and manipulates them using thesimple Boolean operations OR rather than generating andcomputing large and long random integer values as in theconventional digital signature schemes currently in use.

  12. Cryptography on Android Message Applications – A Review

    Directory of Open Access Journals (Sweden)

    Nishika

    2013-05-01

    Full Text Available Short Message Service (SMS is a text messaging service component of phone, web, or mobile communication systems, using standardized communications protocols that allow the exchange of short text messages between fixed line or mobile phone devices. Security of SMS’s is still an open challenging task. Various Cryptographic algorithms have been applied to secure the mobile SMS. The success of any cryptography technique depends on various factors like complexity, time, memory requirement, cost etc. In this paper we survey the most common and widely used SMS Encryption techniques. Each has its own advantages and disadvantages. Recent trends on Cryptography on android message applications have also been discussed. The latest cryptographic algorithm is based on lookup table and dynamic key which is easy to implement and to use and improve the efficiency. In this paper, an improvement in lookup tableand dynamic algorithm is proposed. Rather than using the Static Lookup Table, Dynamic Lookup Table may be used which will improve the overall efficiency.

  13. Quantum random number generators and their applications in cryptography

    Science.gov (United States)

    Stipcevic, Mario

    2012-06-01

    Random number generators (RNG) are an important resource in many areas: cryptography (both quantum and classical), probabilistic computation (Monte Carlo methods), numerical simulations, industrial testing and labeling, hazard games, scientific research etc. Because today's computers are deterministic, they can not create random numbers unless complemented with a physical RNG. Randomness of a RNG can be defined and scientifically characterized and measured. Especially valuable is the information-theoretic provable RNG which, at state of the art, seem to be possible only by harvest of randomness inherent to certain (simple) quantum systems and such a generator we call Quantum RNG (QRNG). On the other hand, current industry standards dictate use of RNGs based on free running oscillators (FRO) whose randomness is derived from electronics noise present in logic circuits and which, although quantum in nature, cannot be strictly proven. This approach is currently used in FPGA and ASIC chips. We compare weak and strong aspects of the two approaches for use in cryptography and in general. We also give an alternative definition of randomness, discuss usage of single photon detectors in realization of QRNGs and give several examples where QRNG can significantly improve security of a cryptographic system.

  14. Fourier-based automatic alignment for improved Visual Cryptography schemes.

    Science.gov (United States)

    Machizaud, Jacques; Chavel, Pierre; Fournel, Thierry

    2011-11-01

    In Visual Cryptography, several images, called "shadow images", that separately contain no information, are overlapped to reveal a shared secret message. We develop a method to digitally register one printed shadow image acquired by a camera with a purely digital shadow image, stored in memory. Using Fourier techniques derived from Fourier Optics concepts, the idea is to enhance and exploit the quasi periodicity of the shadow images, composed by a random distribution of black and white patterns on a periodic sampling grid. The advantage is to speed up the security control or the access time to the message, in particular in the cases of a small pixel size or of large numbers of pixels. Furthermore, the interest of visual cryptography can be increased by embedding the initial message in two shadow images that do not have identical mathematical supports, making manual registration impractical. Experimental results demonstrate the successful operation of the method, including the possibility to directly project the result onto the printed shadow image.

  15. Number Theory and Applications : Proceedings of the International Conferences on Number Theory and Cryptography

    CERN Document Server

    Ramakrishnan, B

    2009-01-01

    This collection of articles contains the proceedings of the two international conferences (on Number Theory and Cryptography) held at the Harish - Chandra Research Institute. In recent years the interest in number theory has increased due to its applications in areas like error-correcting codes and cryptography. These proceedings contain papers in various areas of number theory, such as combinatorial, algebraic, analytic and transcendental aspects, arithmetic algebraic geometry, as well as graph theory and cryptography. While some papers do contain new results, several of the papers are expository articles that mention open questions, which will be useful to young researchers.

  16. 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.

  17. Three-Stage Quantum Cryptography Protocol under Collective-Rotation Noise

    Directory of Open Access Journals (Sweden)

    Linsen Wu

    2015-05-01

    Full Text Available Information security is increasingly important as society migrates to the information age. Classical cryptography widely used nowadays is based on computational complexity, which means that it assumes that solving some particular mathematical problems is hard on a classical computer. With the development of supercomputers and, potentially, quantum computers, classical cryptography has more and more potential risks. Quantum cryptography provides a solution which is based on the Heisenberg uncertainty principle and no-cloning theorem. While BB84-based quantum protocols are only secure when a single photon is used in communication, the three-stage quantum protocol is multi-photon tolerant. However, existing analyses assume perfect noiseless channels. In this paper, a multi-photon analysis is performed for the three-stage quantum protocol under the collective-rotation noise model. The analysis provides insights into the impact of the noise level on a three-stage quantum cryptography system.

  18. Cryptanalysis and security enhancement of optical cryptography based on computational ghost imaging

    Science.gov (United States)

    Yuan, Sheng; Yao, Jianbin; Liu, Xuemei; Zhou, Xin; Li, Zhongyang

    2016-04-01

    Optical cryptography based on computational ghost imaging (CGI) has attracted much attention of researchers because it encrypts plaintext into a random intensity vector rather than complexed-valued function. This promising feature of the CGI-based cryptography reduces the amount of data to be transmitted and stored and therefore brings convenience in practice. However, we find that this cryptography is vulnerable to chosen-plaintext attack because of the linear relationship between the input and output of the encryption system, and three feasible strategies are proposed to break it in this paper. Even though a large number of plaintexts need to be chosen in these attack methods, it means that this cryptography still exists security risks. To avoid these attacks, a security enhancement method utilizing an invertible matrix modulation is further discussed and the feasibility is verified by numerical simulations.

  19. Device-independence for two-party cryptography and position verification

    DEFF Research Database (Denmark)

    Ribeiro, Jeremy; Thinh, Le Phuc; Kaniewski, Jedrzej;

    Quantum communication has demonstrated its usefulness for quantum cryptography far beyond quantum key distribution. One domain is two-party cryptography, whose goal is to allow two parties who may not trust each other to solve joint tasks. Another interesting application is position......-based cryptography whose goal is to use the geographical location of an entity as its only identifying credential. Unfortunately, security of these protocols is not possible against an all powerful adversary. However, if we impose some realistic physical constraints on the adversary, there exist protocols for which...... security can be proven, but these so far relied on the knowledge of the quantum operations performed during the protocols. In this work we give device-independent security proofs of two-party cryptography and Position Verification for memoryless devices under different physical constraints on the adversary...

  20. 量子密码体系研究%Study on Quantum Cryptography System

    Institute of Scientific and Technical Information of China (English)

    李佳

    2013-01-01

    本文主要介绍了量子密码体系中密码算法、密钥管理、密码技术、安全协议、密钥分配等主要内容。得出了量子密码比传统密码更安全的有效结论,最后总结了量子密码广阔的发展前景。%T his paper introduced som e im portantcontenton quantum cryptography system ,such as encryption algorithm , key m anagem ent, encryption technology, secure protocol, key distribution. It pointed out safer com-pared quantum cryptography w ith traditional cryptography and the broad prospects of developm ent on quantum cryptography system atlast.

  1. Why cryptography should not rely on physical attack complexity

    CERN Document Server

    Krämer, Juliane

    2015-01-01

    This book presents two practical physical attacks. It shows how attackers can reveal the secret key of symmetric as well as asymmetric cryptographic algorithms based on these attacks, and presents countermeasures on the software and the hardware level that can help to prevent them in the future. Though their theory has been known for several years now, since neither attack has yet been successfully implemented in practice, they have generally not been considered a serious threat. In short, their physical attack complexity has been overestimated and the implied security threat has been underestimated. First, the book introduces the photonic side channel, which offers not only temporal resolution, but also the highest possible spatial resolution. Due to the high cost of its initial implementation, it has not been taken seriously. The work shows both simple and differential photonic side channel analyses. Then, it presents a fault attack against pairing-based cryptography. Due to the need for at least two indepe...

  2. Continuous-variable quantum cryptography with untrusted relays

    CERN Document Server

    Pirandola, Stefano; Spedalieri, Gaetana; Weedbrook, Christian; Braunstein, Samuel L

    2013-01-01

    We extend the field of continuous-variable quantum cryptography to a more robust formulation which can be applied to untrusted networks. We consider two remote parties connected to an untrusted relay by insecure quantum links. To generate correlations, they transmit coherent states to the relay where a continuous-variable Bell detection is performed. Despite the possibility that the working mechanism of the relay could be fully corrupted and the links subject to optimal coherent attacks, the parties are still able to extract a secret key. Furthermore, our analysis shows that very long distances and high rates can be reached when the relay is proximal to one of the parties, configuration typical of a mobile device connecting to a public access point. Thus, using the cheapest possible quantum resources, we show the possibility of long-distance high-rate quantum key distribution in network topologies where direct links are missing between two end-users and intermediate relays cannot be trusted.

  3. Malicious cryptography techniques for unreversable (malicious or not) binaries

    CERN Document Server

    Filiol, Eric

    2010-01-01

    Fighting against computer malware require a mandatory step of reverse engineering. As soon as the code has been disassemblied/decompiled (including a dynamic analysis step), there is a hope to understand what the malware actually does and to implement a detection mean. This also applies to protection of software whenever one wishes to analyze them. In this paper, we show how to amour code in such a way that reserse engineering techniques (static and dymanic) are absolutely impossible by combining malicious cryptography techniques developped in our laboratory and new types of programming (k-ary codes). Suitable encryption algorithms combined with new cryptanalytic approaches to ease the protection of (malicious or not) binaries, enable to provide both total code armouring and large scale polymorphic features at the same time. A simple 400 Kb of executable code enables to produce a binary code and around $2^{140}$ mutated forms natively while going far beyond the old concept of decryptor.

  4. SPEED AND SECURITY ENHANCEMENT THROUGH PUBLIC KEY CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    J.SAIGEETHA

    2010-08-01

    Full Text Available It is true that the transfer of data is essential in the fast developing world. It is equally true that the transfer of data tobe taken place with much security by not giving groom to the intruders. This paper presents the analysis of the security of information with enhanced the speed of encryption and decryption process. This process uses public key cryptography via RSA algorithm with some modification. There are two keys used in RSA algorithm foreffectiveness in the aspect of security one being the public key used for all and the other being the secret key. The implementation is done in the JAVA language and crypt analysis is performed to check the level of protection and speed .

  5. State-of-the-Art Visual Cryptography Schemes

    Directory of Open Access Journals (Sweden)

    Mahmoud E. Hodeish

    2014-03-01

    Full Text Available Visual Cryptography (VC is recent technology used to the strengthen security of many applications in various fields. It allows visual information like printed text, handwritten notes, and images to be encrypted by dividing it into shares. The most important characteristic of VCS is that one can visually decrypted the secret image by stacking shares without computation. The current paper aims at introducing a descriptive review for VC, which covering the "state-of-the-art" concept, and classification of schemes. In this paper, we have classified the VC schemes and provide some interpretation on the base of some various measures such as pixel expansion, share generated, format of secret image and number of secret image, which actually deemed as valuable contribution in the field of VC studies

  6. 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.

  7. Entropy in quantum information theory - Communication and cryptography

    DEFF Research Database (Denmark)

    Majenz, Christian

    to density matrices, the von Neumann entropy behaves dierently. The latter does not, for example, have the monotonicity property that the latter possesses: When adding another quantum system, the entropy can decrease. A long-standing open question is, whether there are quantum analogues of unconstrained non......Entropies have been immensely useful in information theory. In this Thesis, several results in quantum information theory are collected, most of which use entropy as the main mathematical tool. The rst one concerns the von Neumann entropy. While a direct generalization of the Shannon entropy...... in quantum Shannon theory. While immensely more entanglement-consuming, the variant of port based teleportation is interesting for applications like instantaneous non-local computation and attacks on quantum position-based cryptography. Port based teleportation cannot be implemented perfectly...

  8. Experimental realization of quantum cryptography communication in free space

    Institute of Scientific and Technical Information of China (English)

    WANG; Chuan; ZHANG; Jingfu; WANG; Pingxiao; DENG; Fuguo; A

    2005-01-01

    Utilizing linear optical devices, the principle of B92 quantum key distribution (QKD) protocol is demonstrated in free space with a distance of transmission of 2.2 meters. The faint laser pulses with 650 nm wavelength are used as the single photon sources. The experimental results show that the eavesdropping behavior in the signal transmission can be detected. We also discuss the problems and solutions in using the quantum cryptography communication practically. It is pointed out that one of the approaches to increasing the distance of the quantum communication is to overcome the attenuation of the single photon in transmission. This could not be solved by the use of single photon source, and new quantum communication protocols are needed to solve these problems.

  9. A Hyper Modern Cryptography Algorithm to Improved Data Security: HMCA

    Directory of Open Access Journals (Sweden)

    Vishwa Gupta

    2011-12-01

    Full Text Available In this paper, we propose an improved block cipher symmetric encryption algorithm that has the same structure of encryption and decryption. So far, conventional cryptography algorithms have difference structure of encryption and decryption. We devise our algorithm by inserting a symmetric layer using random number, encryption number and XOR operations, in which the whole proposed algorithm rounds uses encryption procedure and the same for it decryption procedure. The symmetry layer is put between encryption part and decryption one. The proposed algorithm has the batter speed compared with the comparing encryption algorithm. Nevertheless, the proposed algorithm improves encryption security by inserting the symmetric layer. The proposed algorithm will be useful to the applications which require the same procedure of encryption and decryption

  10. INTEGRATING IDENTITY-BASED CRYPTOGRAPHY IN IMS SERVICE AUTHENTICATION

    Directory of Open Access Journals (Sweden)

    Mohamed Abid

    2009-10-01

    Full Text Available Nowadays, the IP Multimedia Subsystem (IMS is a promising research field. Many ongoing works related to the security and the performances of its employment are presented to the research community. Although, the security and data privacy aspects are very important in the IMS global objectives, they observe little attention so far. Secure access to multimedia services is based on SIP and HTTP digest on top of IMS architecture. The standard deploys AKA-MD5 for the terminal authentication. The third Generation Partnership Project (3GPP provided Generic Bootstrapping Architecture (GBA toauthenticate the subscriber before accessing multimedia services over HTTP. In this paper, we propose a new IMS Service Authentication scheme using Identity Based cryptography (IBC. This new scheme willlead to better performances when there are simultaneous authentication requests using Identity-based Batch Verification. We analyzed the security of our new protocol and we presented a performance evaluation of its cryptographic operations.

  11. Quantum random number generators and their use in cryptography

    CERN Document Server

    Stipcevic, Mario

    2011-01-01

    Random number generators (RNG) are an important resource in many areas: cryptography (both quantum and classical), probabilistic computation (Monte Carlo methods), numerical simulations, industrial testing and labeling, hazard games, scientific research, etc. Because today's computers are deterministic, they can not create random numbers unless complemented with a RNG. Randomness of a RNG can be precisely, scientifically characterized and measured. Especially valuable is the information-theoretic provable RNG (True RNG - TRNG) which, at state of the art, seem to be possible only by use of physical randomness inherent to certain (simple) quantum systems. On the other hand, current industry standard dictates use of RNG's based on free running oscillators (FRO) whose randomness is derived from electronics noise present in logic circuits and which cannot be strictly proven. This approach is currently used in 3-rd and 4-th generation FPGA and ASIC hardware, unsuitable for realization of quantum TRNG. We compare we...

  12. Step to improve neural cryptography against flipping attacks.

    Science.gov (United States)

    Zhou, Jiantao; Xu, Qinzhen; Pei, Wenjiang; He, Zhenya; Szu, Harold

    2004-12-01

    Synchronization of neural networks by mutual learning has been demonstrated to be possible for constructing key exchange protocol over public channel. However, the neural cryptography schemes presented so far are not the securest under regular flipping attack (RFA) and are completely insecure under majority flipping attack (MFA). We propose a scheme by splitting the mutual information and the training process to improve the security of neural cryptosystem against flipping attacks. Both analytical and simulation results show that the success probability of RFA on the proposed scheme can be decreased to the level of brute force attack (BFA) and the success probability of MFA still decays exponentially with the weights' level L. The synchronization time of the parties also remains polynomial with L. Moreover, we analyze the security under an advanced flipping attack.

  13. Tight finite-key analysis for quantum cryptography.

    Science.gov (United States)

    Tomamichel, Marco; Lim, Charles Ci Wen; Gisin, Nicolas; Renner, Renato

    2012-01-17

    Despite enormous theoretical and experimental progress in quantum cryptography, the security of most current implementations of quantum key distribution is still not rigorously established. One significant problem is that the security of the final key strongly depends on the number, M, of signals exchanged between the legitimate parties. Yet, existing security proofs are often only valid asymptotically, for unrealistically large values of M. Another challenge is that most security proofs are very sensitive to small differences between the physical devices used by the protocol and the theoretical model used to describe them. Here we show that these gaps between theory and experiment can be simultaneously overcome by using a recently developed proof technique based on the uncertainty relation for smooth entropies.

  14. Postselection technique for quantum channels with applications to quantum cryptography.

    Science.gov (United States)

    Christandl, Matthias; König, Robert; Renner, Renato

    2009-01-16

    We propose a general method for studying properties of quantum channels acting on an n-partite system, whose action is invariant under permutations of the subsystems. Our main result is that, in order to prove that a certain property holds for an arbitrary input, it is sufficient to consider the case where the input is a particular de Finetti-type state, i.e., a state which consists of n identical and independent copies of an (unknown) state on a single subsystem. Our technique can be applied to the analysis of information-theoretic problems. For example, in quantum cryptography, we get a simple proof for the fact that security of a discrete-variable quantum key distribution protocol against collective attacks implies security of the protocol against the most general attacks. The resulting security bounds are tighter than previously known bounds obtained with help of the exponential de Finetti theorem.

  15. SECURITY SYSTEM FOR DATA USING STEGANOGRAPHY AND CRYPTOGRAPHY (SSDSC

    Directory of Open Access Journals (Sweden)

    Ayman Wazwaz1

    2016-08-01

    Full Text Available Security System for Data using Steganography and Cryptography (SSDSC is a set of hardware and software components that will be used to send secured documents through the internet. Some of the software will be loaded into a microcontrollers in order to increase the complexity and security. The data will be encrypted using the Advanced Encryption Standard (AES algorithm with a key from the Raspberry PI microcontroller and hide it inside an image using Least Significant Bit (LSB algorithm, the data will be invisible. The image will be transmitted and received through the internet, the receivers will extract the hidden data from the image and decrypt it to have the original data with the image. Complicating the steps of hiding and encryption will reduce the possiblity of intrusin of secured documents, and the process will be trasparent to the user to increase security without affecting the normal steps and the behavior in secured documents exchange.

  16. Quantum cryptography in real-life applications: Assumptions and security

    Science.gov (United States)

    Zhao, Yi

    Quantum cryptography, or quantum key distribution (QKD), provides a means of unconditionally secure communication. The security is in principle based on the fundamental laws of physics. Security proofs show that if quantum cryptography is appropriately implemented, even the most powerful eavesdropper cannot decrypt the message from a cipher. The implementations of quantum crypto-systems in real life may not fully comply with the assumptions made in the security proofs. Such discrepancy between the experiment and the theory can be fatal to the security of a QKD system. In this thesis we address a number of these discrepancies. A perfect single-photon source is often assumed in many security proofs. However, a weak coherent source is widely used in a real-life QKD implementation. Decoy state protocols have been proposed as a novel approach to dramatically improve the performance of a weak coherent source based QKD implementation without jeopardizing its security. Here, we present the first experimental demonstrations of decoy state protocols. Our experimental scheme was later adopted by most decoy state QKD implementations. In the security proof of decoy state protocols as well as many other QKD protocols, it is widely assumed that a sender generates a phase-randomized coherent state. This assumption has been enforced in few implementations. We close this gap in two steps: First, we implement and verify the phase randomization experimentally; second, we prove the security of a QKD implementation without the coherent state assumption. In many security proofs of QKD, it is assumed that all the detectors on the receiver's side have identical detection efficiencies. We show experimentally that this assumption may be violated in a commercial QKD implementation due to an eavesdropper's malicious manipulation. Moreover, we show that the eavesdropper can learn part of the final key shared by the legitimate users as a consequence of this violation of the assumptions.

  17. Secure Antnet Routing Algorithm for Scalable Adhoc Networks Using Elliptic Curve Cryptography

    Directory of Open Access Journals (Sweden)

    V. Vijayalakshmi

    2007-01-01

    Full Text Available The secure end-to-end route discovery in the decentralized Mobile Adhoc Networks (MANETs should have to meet the requirements of prevention of DoS attacks on data traffic, should be adaptive and fault tolerant and must have high speed, low energy overhead and scalability for future development. In this research a secure routing using antnet mechanism and mutual authentication using Elliptic Curve Cryptography (ECC has been proposed to meet the above requirements. The common perception of public key cryptography is that it is not well suited for adhoc networks as they are very complex and slow. Against this popular belief, this research implements Elliptic Curve Cryptography -a public key cryptography scheme. ECC provides a similar level of security to conventional integer-based public-key algorithms, but with much shorter keys. Because of the shorter keys ECC algorithms run faster, require less space and consume less energy. These advantages make ECC a better choice of public key cryptography, especially for a resource constrained systems like MANETs. Using the antnet routing algorithm, the highly trustable route will be selected for data transfer and each Mobile Node (MN in MANET maintains the trust value of its one-hop neighbors. The mutual authentication between source and destination is done by master key exchange using Elliptic Curve Cryptography (ECC. v

  18. 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.

  19. Approach to design neural cryptography: a generalized architecture and a heuristic rule.

    Science.gov (United States)

    Mu, Nankun; Liao, Xiaofeng; Huang, Tingwen

    2013-06-01

    Neural cryptography, a type of public key exchange protocol, is widely considered as an effective method for sharing a common secret key between two neural networks on public channels. How to design neural cryptography remains a great challenge. In this paper, in order to provide an approach to solve this challenge, a generalized network architecture and a significant heuristic rule are designed. The proposed generic framework is named as tree state classification machine (TSCM), which extends and unifies the existing structures, i.e., tree parity machine (TPM) and tree committee machine (TCM). Furthermore, we carefully study and find that the heuristic rule can improve the security of TSCM-based neural cryptography. Therefore, TSCM and the heuristic rule can guide us to designing a great deal of effective neural cryptography candidates, in which it is possible to achieve the more secure instances. Significantly, in the light of TSCM and the heuristic rule, we further expound that our designed neural cryptography outperforms TPM (the most secure model at present) on security. Finally, a series of numerical simulation experiments are provided to verify validity and applicability of our results.

  20. Efficient Reversible Montgomery Multiplier and Its Application to Hardware Cryptography

    Directory of Open Access Journals (Sweden)

    Noor M. Nayeem

    2009-01-01

    Full Text Available Problem Statement: Arithmetic Logic Unit (ALU of a crypto-processor and microchips leak information through power consumption. Although the cryptographic protocols are secured against mathematical attacks, the attackers can break the encryption by measuring the energy consumption. Approach: To thwart attacks, this study proposed the use of reversible logic for designing the ALU of a crypto-processor. Ideally, reversible circuits do not dissipate any energy. If reversible circuits are used, then the attacker would not be able to analyze the power consumption. In order to design the reversible ALU of a crypto-processor, reversible Carry Save Adder (CSA using Modified TSG (MTSG gates and architecture of Montgomery multiplier were proposed. For reversible implementation of Montgomery multiplier, efficient reversible multiplexers and sequential circuits such as reversible registers and shift registers were presented. Results: This study showed that modified designs perform better than the existing ones in terms of number of gates, number of garbage outputs and quantum cost. Lower bounds of the proposed designs were established by providing relevant theorems and lemmas. Conclusion: The application of reversible circuit is suitable to the field of hardware cryptography.

  1. Grid authentication from identity-based cryptography without random oracles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As a critical component of grid security, secure and efficient grid authentication needs to be well addressed. However, the most widely accepted and applied grid authentication is based on public key infrastructure (PKI) and X.509 certificates, which make the system have low processing efficiency and poor anti-attack capability. To accommodate the challenge of grid authentication, this article aims at designing a secure and efficient method for grid authentication by employing identity-based cryptography (IBC). Motivated by a recently proposed secure and efficient identity-based encryption (IBE) scheme without random oracles, an identity-based signature (IBS) scheme is first proposed for the generation of private key during grid authentication. Based on the proposed IBS and the former IBE schemes, the structure of a novel grid authentication model is given, followed by a grid authentication protocol described in detail. According to the theoretical analysis of the model and the protocol, it can be argued that the new system has improved both the security and efficiency of the grid authentication when compared with the traditional PKI-based and some current IBC-based models.

  2. FINGERPRINT IDENTIFICATION SYSTEM combined with "CRYPTOGRAPHY" for Authentication.

    Directory of Open Access Journals (Sweden)

    G.Prasanna Lakshmi

    2010-07-01

    Full Text Available Biometrics technology, which uses physical or behavioral characteristics to identify users, has come to attract increased attention as a means of reliable personal authentication that helps the identity of an actual user. Among various modalities of Biometrics, Fingerprints are known to have the longest history of actual use in law enforcement applications with proven performance. This project surveys the state of the art in fingerprint identification technology. In this project, a design schema of a security authentication system combined with fingerprint identification and public key cryptography is explored, and its specific security mechanism is discussed in detail. In our schema, fingerprint is added into user's private key and served a security parameter, such that user’s secret key is separated into secret key parameters and fingerprint, by secret splitting mechanism, which makes the secret key to be bounded with user's information. This will increase the security of secret key ultimately. In such an uthentication system, the diplex authentication technologies --- fingerprint and smart card --- are adopted, and the user fingerprint needn’t to be transmitted during the authentication process, whichcan protect user's privacy effectively.

  3. Application of visual cryptography for learning in optics and photonics

    Science.gov (United States)

    Mandal, Avikarsha; Wozniak, Peter; Vauderwange, Oliver; Curticapean, Dan

    2016-09-01

    In the age data digitalization, important applications of optics and photonics based sensors and technology lie in the field of biometrics and image processing. Protecting user data in a safe and secure way is an essential task in this area. However, traditional cryptographic protocols rely heavily on computer aided computation. Secure protocols which rely only on human interactions are usually simpler to understand. In many scenarios development of such protocols are also important for ease of implementation and deployment. Visual cryptography (VC) is an encryption technique on images (or text) in which decryption is done by human visual system. In this technique, an image is encrypted into number of pieces (known as shares). When the printed shares are physically superimposed together, the image can be decrypted with human vision. Modern digital watermarking technologies can be combined with VC for image copyright protection where the shares can be watermarks (small identification) embedded in the image. Similarly, VC can be used for improving security of biometric authentication. This paper presents about design and implementation of a practical laboratory experiment based on the concept of VC for a course in media engineering. Specifically, our contribution deals with integration of VC in different schemes for applications like digital watermarking and biometric authentication in the field of optics and photonics. We describe theoretical concepts and propose our infrastructure for the experiment. Finally, we will evaluate the learning outcome of the experiment, performed by the students.

  4. A neural-network approach for visual cryptography and authorization.

    Science.gov (United States)

    Yue, Tai-Wen; Chiang, Suchen

    2004-06-01

    In this paper, we propose a neural-network approach for visual authorization, which is an application of visual cryptography (VC). The scheme contains a key-share and a set of user-shares. The administrator owns the key-share, and each user owns a user-share issued by the administrator from the user-share set. The shares in the user-share set are visually indistinguishable, i.e. they have the same pictorial meaning. However, the stacking of the key-share with different user-shares will reveal significantly different images. Therefore, the administrator (in fact, only the administrator) can visually recognize the authority assigned to a particular user by viewing the information appearing in the superposed image of key-share and user-share. This approach is completely different from traditional VC approaches. The salient features include: (i) the access schemes are described using a set of graytone images, and (ii) the codebooks to fulfil them are not required; and (iii) the size of share images is the same as the size of target image.

  5. Virtual microscopy and public-key cryptography for Internet telepathology.

    Science.gov (United States)

    Strauss, J S; Felten, C L; Okada, D H; Marchevsky, A M

    1999-01-01

    The Internet is a potentially inexpensive, widely available medium for telepathology, but there are concerns about its reliability and security. Using a digital camera, 41 photomicrographs of transbronchial biopsies, at x 100 optical magnification, were captured and digitized at 2700 x 3400 pixel, 24 bit/pixel resolution. The image files were saved in JPEG format at medium compression, attached to text files with patient information, encrypted for security in the S/MIME format using a digital signature and digital envelope, and transmitted by email. Received email files were decrypted automatically and the images viewed with standard software. Telepathology diagnoses were compared with original interpretations. The images averaged 810 kByte in size. The encryption and decryption did not cause significant delays in overall transmission time and, together with transmission, did not produce noticeable image degradation. The received image files could be viewed in a manner that simulated light microscopy. There was agreement between telepathology and original diagnoses in 92% of the cases. All the discrepancies were due to inadequate area selection because the pathological features of interest were present in histological levels other than those photographed. The use of high-resolution digital photomicrography, the Internet and public-key cryptography offers an effective and relatively inexpensive method of telepathology consultation. The method is best suited for the diagnosis of small biopsy specimens that require the transmission of only a few digital images that represent the majority of the biopsy materials.

  6. Cryptography Based E-Commerce Security: A Review

    Directory of Open Access Journals (Sweden)

    Shazia Yasin

    2012-03-01

    Full Text Available E-commerce is a powerful tool for business transformation that allows companies to enhance their supply-chain operation, reach new markets, and improve services for customers as well as for providers. Implementing the E-commerce applications that provide these benefits may be impossible without a coherent, consistent approach to E-commerce security. E-commerce has presented a new way of doing transactions all over the world using internet. Organizations have changed their way of doing business from a traditional approach to embrace E-commerce processes. As individuals and businesses increase information sharing, a concern regarding the exchange of money securely and conveniently over the internet increases. Security is a necessity in an E-commerce transaction. The purpose of this paper is to explain the importance of E-commerce security and will discuss pretty good privacy, secure E-commerce protocol, public key infrastructure, digital signature and certificate based cryptography techniques in E-commerce security.

  7. 贵州瓮安陡山沱组球状化石元素地球化学浅析%Preliminary Analysis on the Elemental Geochemistry of Doushantuo Spherical Microfossils from the Weng'an Biota in South China

    Institute of Scientific and Technical Information of China (English)

    唐烽; 高林志; 尹崇玉; 王约

    2011-01-01

    The Ediacaran Doushantuo Formation in Weng'an and Fuquan areas of the Guizhou Provincein southern China hosts high-grade phosphorus ore deposits and exceptionally well-preserved phosphaticmicrofossils that are commonly less than 1 mm in diameter. Earlier studies attributed these fossils to algaeor acritarchs. In the last decade, researchers found that the spherical microfossils, in a large proportion,show metazoan embryonic development features with early cleavage stages. Thus these sphericalmicrofossils have been considered as diploblast or triploblast embryos and resting eggs of early animals.However, reliable fossils similar to blastula, gastrula embryos, fossils of larvae after hatching, andparticularly, the corresponding body fossils of these animal embryos have never been found in the relevantstrata. This phenomenon challenges the interpretation that these globular microfossils are animal embryos.Because the major uncertainty on these fossils is whether they are animals or plants, a detailed geochemicalanalyses across the fossils may help to reveal the differences (between animal and plant) in the compositionof cell membrane / wall and cell inclusions, the pattern of physiological metabolism, and the phosphatizedmechanisms in particular depositional environments. On this basis and in combination with morphologicalcomparison with the Cambrian microfossils and modern metazoan embryos, elemental geochemistry acrossthe spherical microfossils ("embryos") of the Weng' an biota may provide new information for betterunderstanding the genetic affinity of the Doushantuo globular fossils. In this paper, the author analyzesthe microfossils collected from Weng' an and Fuquan areas in Guizhou by electron probe micro-analyzer(EPMA) to obtain trace elemental geochemistry across the globular fossils. For comparison purposes, twotypes of fossils have been analyzed, including fossils with tumor-like outer wall and those with polygonalplate-shaped outer wall. Comparing results

  8. An Efficient Interception Mechanism Against Cheating In Visual Cryptography With Non Pixel Expansion Of Images

    Directory of Open Access Journals (Sweden)

    Linju P.S

    2015-08-01

    Full Text Available Visual cryptography is a technique of cryptography in which secret images are divided into multiple shares and are distributed to different entities. Each secret can be reconstructed by superimposing these shares using different operations. Common traditional drawbacks of all existing methods are pixel expansion and noise at output. Another major issues that can occur in existing visual cryptography systems are Cheating between share holders and Share holders cheating owner. In order to overcome these limitations sealing algorithm is used with two applications of VC such as MIVC and EVC. Here two secret images can be send at the same time by converting them to halftone representations which in turn are partitioned as three shares in total.

  9. Device-independent two-party cryptography secure against sequential attacks

    DEFF Research Database (Denmark)

    Kaniewski, Jedrzej; Wehner, Stephanie

    2016-01-01

    The goal of two-party cryptography is to enable two parties, Alice and Bob, to solve common tasks without the need for mutual trust. Examples of such tasks are private access to a database, and secure identification. Quantum communication enables security for all of these problems in the noisy......-storage model by sending more signals than the adversary can store in a certain time frame. Here, we initiate the study of device-independent (DI) protocols for two-party cryptography in the noisy-storage model. Specifically, we present a relatively easy to implement protocol for a cryptographic building block...... known as weak string erasure and prove its security even if the devices used in the protocol are prepared by the dishonest party. DI two-party cryptography is made challenging by the fact that Alice and Bob do not trust each other, which requires new techniques to establish security. We fully analyse...

  10. AUDIO CRYPTANALYSIS- AN APPLICATION OF SYMMETRIC KEY CRYPTOGRAPHY AND AUDIO STEGANOGRAPHY

    Directory of Open Access Journals (Sweden)

    Smita Paira

    2016-09-01

    Full Text Available In the recent trend of network and technology, “Cryptography” and “Steganography” have emerged out as the essential elements of providing network security. Although Cryptography plays a major role in the fabrication and modification of the secret message into an encrypted version yet it has certain drawbacks. Steganography is the art that meets one of the basic limitations of Cryptography. In this paper, a new algorithm has been proposed based on both Symmetric Key Cryptography and Audio Steganography. The combination of a randomly generated Symmetric Key along with LSB technique of Audio Steganography sends a secret message unrecognizable through an insecure medium. The Stego File generated is almost lossless giving a 100 percent recovery of the original message. This paper also presents a detailed experimental analysis of the algorithm with a brief comparison with other existing algorithms and a future scope. The experimental verification and security issues are promising.

  11. Special Issue on Entropy-Based Applied Cryptography and Enhanced Security for Ubiquitous Computing

    Directory of Open Access Journals (Sweden)

    James (Jong Hyuk Park

    2016-09-01

    Full Text Available Entropy is a basic and important concept in information theory. It is also often used as a measure of the unpredictability of a cryptographic key in cryptography research areas. Ubiquitous computing (Ubi-comp has emerged rapidly as an exciting new paradigm. In this special issue, we mainly selected and discussed papers related with ore theories based on the graph theory to solve computational problems on cryptography and security, practical technologies; applications and services for Ubi-comp including secure encryption techniques, identity and authentication; credential cloning attacks and countermeasures; switching generator with resistance against the algebraic and side channel attacks; entropy-based network anomaly detection; applied cryptography using chaos function, information hiding and watermark, secret sharing, message authentication, detection and modeling of cyber attacks with Petri Nets, and quantum flows for secret key distribution, etc.

  12. Device-independent two-party cryptography secure against sequential attacks

    DEFF Research Database (Denmark)

    Kaniewski, Jedrzej; Wehner, Stephanie

    2016-01-01

    The goal of two-party cryptography is to enable two parties, Alice and Bob, to solve common tasks without the need for mutual trust. Examples of such tasks are private access to a database, and secure identification. Quantum communication enables security for all of these problems in the noisy......-storage model by sending more signals than the adversary can store in a certain time frame. Here, we initiate the study of device-independent (DI) protocols for two-party cryptography in the noisy-storage model. Specifically, we present a relatively easy to implement protocol for a cryptographic building block...... known as weak string erasure and prove its security even if the devices used in the protocol are prepared by the dishonest party. DI two-party cryptography is made challenging by the fact that Alice and Bob do not trust each other, which requires new techniques to establish security. We fully analyse...

  13. Two-out-of-two color matching based visual cryptography schemes.

    Science.gov (United States)

    Machizaud, Jacques; Fournel, Thierry

    2012-09-24

    Visual cryptography which consists in sharing a secret message between transparencies has been extended to color prints. In this paper, we propose a new visual cryptography scheme based on color matching. The stacked printed media reveal a uniformly colored message decoded by the human visual system. In contrast with the previous color visual cryptography schemes, the proposed one enables to share images without pixel expansion and to detect a forgery as the color of the message is kept secret. In order to correctly print the colors on the media and to increase the security of the scheme, we use spectral models developed for color reproduction describing printed colors from an optical point of view.

  14. Security proof of counterfactual quantum cryptography against general intercept-resend attacks and its vulnerability

    Institute of Scientific and Technical Information of China (English)

    Zhang Sheng; Wang Jian; Tang Chao-Jing

    2012-01-01

    Counterfactual quantum cryptography,recently proposed by Noh,is featured with no transmission of signal particles.This exhibits evident security advantages,such as its immunity to the well-known photon-number-splitting attack.In this paper,the theoretical security of counterfactual quantum cryptography protocol against the general interceptresend attacks is proved by bounding the information of an eavesdropper Eve more tightly than in Yin's proposal [Phys.Rev.A 82 042335 (2010)].It is also shown that practical counterfactual quantum cryptography implementations may be vulnerable when equipped with imperfect apparatuses,by proving that a negative key rate can be achieved when Eve launches a time-shift attack based on imperfect detector efficiency.

  15. A new spin on quantum cryptography: Avoiding trapdoors and embracing public keys

    CERN Document Server

    Ioannou, Lawrence M

    2011-01-01

    We give new arguments in support of \\emph{signed quantum key establishment}, where quantum cryptography is used in a public-key infrastructure that provides the required authentication. We also analyze more thoroughly than previous works the benefits that quantum key establishment protocols have over certain classical protocols, motivated in part by the various objections to quantum key establishment that are sometimes raised. Previous knowledge of quantum cryptography on the reader's part is not required for this article, as the definition of "quantum key establishment" that we use is an entirely classical and black-box characterization (one need only trust that protocols satisfying the definition exist).

  16. Color Extended Visual Cryptography Using Error Diffusion for High Visual Quality Shares

    Directory of Open Access Journals (Sweden)

    Lavanya Bandamneni

    2012-06-01

    Full Text Available for providing meaningful shares with high visual quality color visual cryptography is not sufficient. This paper introduces a color visual cryptography encryption method that produces meaningful color shares with high visual quality via visual information pixel (VIP synchronization and error diffusion. VIPs synchronize the positions of pixels that carry visual information of original images across the color channels so as to retain the original pixel values the same before and after encryption. To generate shares pleasant to human eyes Error diffusion is used. This method provides better results compared to the previous techniques.

  17. Research on Applications of Cryptography for Multi-Mobile Agent System

    Institute of Scientific and Technical Information of China (English)

    HUANG Hai-ping; WANG Ru-chuan; XU Xiao-long

    2004-01-01

    With the development of information network and agent technology, Multi-Mobile Agents' Cooperation can not only improve the computing efficiency, but also have a comprehensive applicative value in solving the security issues of mobile agent system. Aiming at the security and flexibility, this paper proposes a kind of basic architecture and the design pattern of Multi-Mobile Agent System (MMAS). Combined with cryptography, it builds the security mechanism on keys' distribution and management and Coalition Signature of MMAS. Through the analysis of security and validity, the introduction and application of cryptography can improve the performance of MMAS.

  18. Error Filtering Schemes for Color Images in Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Shiny Malar F.R

    2011-11-01

    Full Text Available The color visual cryptography methods are free from the limitations of randomness on color images. The two basic ideas used are error diffusion and pixel synchronization. Error diffusion is a simple method, in which the quantization error at each pixel level is filtered and fed as the input to the next pixel. In this way low frequency that is obtained between the input and output image is minimized which in turn give quality images. Degradation of colors are avoided with the help of pixel synchronization. The proposal of this work presents an efficient color image visual cryptic filtering scheme to improve the image quality on restored original image from visual cryptic shares. The proposed color image visual cryptic filtering scheme presents a deblurring effect on the non-uniform distribution of visual cryptic share pixels. After eliminating blurring effects on the pixels, Fourier transformation is applied to normalize the unevenly transformed share pixels on the original restored image. This in turn improves the quality of restored visual cryptographic image to its optimality. In addition the overlapping portions of the two or multiple visual cryptic shares are filtered out with homogeneity of pixel texture property on the restored original image. Experimentation are conducted with standard synthetic and real data set images, which shows better performance of proposed color image visual cryptic filtering scheme measured in terms of PSNR value (improved to 3 times and share pixel error rate (reduced to nearly 11% with existing grey visual cryptic filters. The results showed that the noise effects such as blurring on the restoration of original image are removed completely.

  19. The Design and Evaluation of a Cryptography Teaching Strategy for Software Engineering Students

    Science.gov (United States)

    Dowling, T.

    2006-01-01

    The present paper describes the design, implementation and evaluation of a cryptography module for final-year software engineering students. The emphasis is on implementation architectures and practical cryptanalysis rather than a standard mathematical approach. The competitive continuous assessment process reflects this approach and rewards…

  20. A Secure Key Distribution System of Quantum Cryptography Based on the Coherent State

    Science.gov (United States)

    Guo, Guang-Can; Zhang, Xiao-Yu

    1996-01-01

    The cryptographic communication has a lot of important applications, particularly in the magnificent prospects of private communication. As one knows, the security of cryptographic channel depends crucially on the secrecy of the key. The Vernam cipher is the only cipher system which has guaranteed security. In that system the key must be as long as the message and most be used only once. Quantum cryptography is a method whereby key secrecy can be guaranteed by a physical law. So it is impossible, even in principle, to eavesdrop on such channels. Quantum cryptography has been developed in recent years. Up to now, many schemes of quantum cryptography have been proposed. Now one of the main problems in this field is how to increase transmission distance. In order to use quantum nature of light, up to now proposed schemes all use very dim light pulses. The average photon number is about 0.1. Because of the loss of the optical fiber, it is difficult for the quantum cryptography based on one photon level or on dim light to realize quantum key-distribution over long distance. A quantum key distribution based on coherent state is introduced in this paper. Here we discuss the feasibility and security of this scheme.

  1. Cryptography from quantum uncertainty in the presence of quantum side information

    NARCIS (Netherlands)

    Bouman, Niek Johannes

    2012-01-01

    The thesis starts with a high-level introduction into cryptography and quantum mechanics. Chapter 2 gives a theoretical foundation by introducing probability theory, information theory, functional analysis, quantum mechanics and quantum information theory. Chapter 3, 4 and 5 are editions of work

  2. The Design and Evaluation of a Cryptography Teaching Strategy for Software Engineering Students

    Science.gov (United States)

    Dowling, T.

    2006-01-01

    The present paper describes the design, implementation and evaluation of a cryptography module for final-year software engineering students. The emphasis is on implementation architectures and practical cryptanalysis rather than a standard mathematical approach. The competitive continuous assessment process reflects this approach and rewards…

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

    CSIR Research Space (South Africa)

    Louw, J

    2016-12-01

    Full Text Available Conference on Industrial Informatics (INDIN), 19-21 July 2016, Futuroscope-Poitiers, France A key distribution scheme using elliptic curve cryptography in wireless sensor networks J. Louw ; G. Niezen ; T. D. Ramotsoela ; A. M. Abu-Mahfouz Abstract...

  4. Cryptography from quantum uncertainty in the presence of quantum side information

    NARCIS (Netherlands)

    Bouman, Niek Johannes

    2012-01-01

    The thesis starts with a high-level introduction into cryptography and quantum mechanics. Chapter 2 gives a theoretical foundation by introducing probability theory, information theory, functional analysis, quantum mechanics and quantum information theory. Chapter 3, 4 and 5 are editions of work pub

  5. NumTheoryPy library v.1: for cryptography education and software design

    OpenAIRE

    Benaben, Alejandro; Castro Lechtaler, Antonio; Cipriano, Marcelo; Liporace, Julio

    2009-01-01

    This work develops an open source library in Python with applications in academic settings, for educational purposes. It can also be used for general software development. It allows users to implement Number Theory applications commonly employed in Cryptography and Information System Security. Improvements in teaching quality, user software readability, and time savings at the encoding stage could be expected.

  6. QUANTUM CRYPTOGRAPHY SYSTEM WITH A SINGLE PHOTON SOURCE BASED ON THE SPONTANEOUS PARAMETRIC SCATTERING EFFECT

    Directory of Open Access Journals (Sweden)

    V. I. Egorov

    2012-01-01

    Full Text Available A scheme of a single photon source for quantum informatics applications based on the spontaneous parametric scattering effect is proposed and a quantum cryptography setup using it is presented. The system is compared to the alternative ones that operate with attenuated classic light.

  7. UbiKiMa : Ubiquitous authentication using a smartphone, migrating from passwords to strong cryptography

    NARCIS (Netherlands)

    Everts, M.H.; Hoepman, J.H.; Siljee B.I.J.

    2013-01-01

    Passwords are the only ubiquitous form of authentication currently available on the web. Unfortunately, passwords are insecure. In this paper we therefore propose the use of strong cryptography, using the fact that users increasingly own a smartphone that can perform the required cryptographic

  8. An Application-Independent Cryptography Model That Is Easy to Use for All Level Users

    Science.gov (United States)

    Gabrielson, Anthony J.

    2013-01-01

    Cryptography libraries are inflexible and difficult for developers to integrate with their applications. These difficulties are often encountered by applications, like PGP, which are non-intuitive for end-users and are often used improperly or not at all. This thesis discusses the negative impact of the current prevailing poor usability on…

  9. Cryptographic Research and NSA: Report of the Public Cryptography Study Group.

    Science.gov (United States)

    Davida, George I.

    1981-01-01

    The Public Cryptography Study Group accepted the claim made by the National Security Agency that some information in some publications concerning cryptology could be inimical to national security, and is allowing the establishment of a voluntary mechanism, on an experimental basis, for NSA to review cryptology manuscripts. (MLW)

  10. Characterization of collective Gaussian attacks and security of coherent-state quantum cryptography.

    Science.gov (United States)

    Pirandola, Stefano; Braunstein, Samuel L; Lloyd, Seth

    2008-11-14

    We provide a simple description of the most general collective Gaussian attack in continuous-variable quantum cryptography. In the scenario of such general attacks, we analyze the asymptotic secret-key rates which are achievable with coherent states, joint measurements of the quadratures and one-way classical communication.

  11. Quantum cryptography using coherent states: Randomized encryption and key generation

    Science.gov (United States)

    Corndorf, Eric

    With the advent of the global optical-telecommunications infrastructure, an increasing number of individuals, companies, and agencies communicate information with one another over public networks or physically-insecure private networks. While the majority of the traffic flowing through these networks requires little or no assurance of secrecy, the same cannot be said for certain communications between banks, between government agencies, within the military, and between corporations. In these arenas, the need to specify some level of secrecy in communications is a high priority. While the current approaches to securing sensitive information (namely the public-key-cryptography infrastructure and deterministic private-key ciphers like AES and 3DES) seem to be cryptographically strong based on empirical evidence, there exist no mathematical proofs of secrecy for any widely deployed cryptosystem. As an example, the ubiquitous public-key cryptosystems infer all of their secrecy from the assumption that factoring of the product of two large primes is necessarily time consuming---something which has not, and perhaps cannot, be proven. Since the 1980s, the possibility of using quantum-mechanical features of light as a physical mechanism for satisfying particular cryptographic objectives has been explored. This research has been fueled by the hopes that cryptosystems based on quantum systems may provide provable levels of secrecy which are at least as valid as quantum mechanics itself. Unfortunately, the most widely considered quantum-cryptographic protocols (BB84 and the Ekert protocol) have serious implementation problems. Specifically, they require quantum-mechanical states which are not readily available, and they rely on unproven relations between intrusion-level detection and the information available to an attacker. As a result, the secrecy level provided by these experimental implementations is entirely unspecified. In an effort to provably satisfy the cryptographic

  12. Elliptic Curve Cryptography with Security System in Wireless Sensor Networks

    Science.gov (United States)

    Huang, Xu; Sharma, Dharmendra

    2010-10-01

    The rapid progress of wireless communications and embedded micro-electro-system technologies has made wireless sensor networks (WSN) very popular and even become part of our daily life. WSNs design are generally application driven, namely a particular application's requirements will determine how the network behaves. However, the natures of WSN have attracted increasing attention in recent years due to its linear scalability, a small software footprint, low hardware implementation cost, low bandwidth requirement, and high device performance. It is noted that today's software applications are mainly characterized by their component-based structures which are usually heterogeneous and distributed, including the WSNs. But WSNs typically need to configure themselves automatically and support as hoc routing. Agent technology provides a method for handling increasing software complexity and supporting rapid and accurate decision making. This paper based on our previous works [1, 2], three contributions have made, namely (a) fuzzy controller for dynamic slide window size to improve the performance of running ECC (b) first presented a hidden generation point for protection from man-in-the middle attack and (c) we first investigates multi-agent applying for key exchange together. Security systems have been drawing great attentions as cryptographic algorithms have gained popularity due to the natures that make them suitable for use in constrained environment such as mobile sensor information applications, where computing resources and power availability are limited. Elliptic curve cryptography (ECC) is one of high potential candidates for WSNs, which requires less computational power, communication bandwidth, and memory in comparison with other cryptosystem. For saving pre-computing storages recently there is a trend for the sensor networks that the sensor group leaders rather than sensors communicate to the end database, which highlighted the needs to prevent from the man

  13. Color image zero-watermarking based on SVD and visual cryptography in DWT domain

    Science.gov (United States)

    Liu, Xilin; Chen, Beijing; Coatrieux, Gouenou; Shu, Huazhong

    2017-02-01

    This paper presents a novel robust color image zero-watermarking scheme based on SVD and visual cryptography. We firstly generate the image feature from the SVD of the image blocks, and then employ the visual secret sharing scheme to construct ownership share from the watermark and the image feature. The low frequency component of one level discrete wavelet transform of the color image is partitioned into blocks. Then we propose to use the feature generated from the first singular value of the blocks to construct the master share. When ownership debate occurs, the ownership share is used to extract the watermark. Experimental results show the better performance of the proposed watermarking system in terms of robustness to various attacks, including noise, filtering, JPEG compression and so on, than other visual cryptography based color image watermarking algorithm.

  14. 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.

  15. A Fair E-Cash Scheme Based on Elliptic Curve Cryptography

    Institute of Scientific and Technical Information of China (English)

    WANG Changji; WU Jianping; DUAN Haixin

    2004-01-01

    A new fair off-line electronic cash scheme on elliptic curve cryptography was presented. The new scheme is more efficient than those by extending fair off-line electronic cash scheme from finite field into elliptic curve cryptography and introducing a new elliptic curve discrete logarithm assumption. The expiry date and denomination are embedded into the blindly signed coin by integrating partially blind signature with restrictive blind signature. A bank need not use different public keys for different coin values, shops and users need not carry a list of bank's public keys to verify in their electronic wallet. At the same time, the bank just needs to keep undue electronic coins for double spending check in his database, thus bank's database can be dramatically reduced.

  16. A novel mutual authentication and key agreement protocol based on NTRU cryptography for wireless communications

    Institute of Scientific and Technical Information of China (English)

    JIANG Jun; HE Chen

    2005-01-01

    In this paper, the authors present a novel mutual authentication and key agreement protocol based on the Number Theory Research Unit (NTRU) public key cryptography. The symmetric encryption, hash and "challenge-response" techniques were adopted to build their protocol. To implement the mutual authentication and session key agreement, the proposed protocol contains two stages: namely initial procedure and real execution stage. Since the lightweight NTRU public key cryptography is employed, their protocol can not only overcome the security flaws of secret-key based authentication protocols such as those used in Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS), but also provide greater security and lower computational complexity in comparison with currently well-known public key based wireless authentication schemes such as Beller-Yacobi and M.Aydos protocols.

  17. Modern Method for Detecting Web Phishing Using Visual Cryptography (VC and Quick Response Code (QR code

    Directory of Open Access Journals (Sweden)

    Ms. Ashvini Kute

    2015-01-01

    Full Text Available Phishing is an attempt by an individual or a group to thieve personal confidential information such as passwords, credit card information etc from unsuspecting victims for identity theft, financial gain and other fraudulent activities. Here an image based (QR codes authentication using Visual Cryptography (VC is used. The use of Visual cryptography is explored to convert the QR code into two shares and both these shares can then be transmitted separately. One Time Passwords (OTP is passwords which are valid only for a session to validate the user within a specified amount of time. In this paper we are presenting a new authentication scheme for secure OTP distribution in phishing website detection through VC and QR codes.

  18. Modern Method for Detecting Web Phishing Using Visual Cryptography (VC and Quick Response Code (QR code

    Directory of Open Access Journals (Sweden)

    Ms. Ashvini Kute

    2015-05-01

    Full Text Available Phishing is an attempt by an individual or a group to thieve personal confidential information such as passwords, credit card information etc from unsuspecting victims for identity theft, financial gain and other fraudulent activities. Here an image based (QR codes authentication using Visual Cryptography (VC is used. The use of Visual cryptography is explored to convert the QR code into two shares and both these shares can then be transmitted separately. One Time Passwords (OTP is passwords which are valid only for a session to validate the user within a specified amount of time. In this paper we are presenting a new authentication scheme for secure OTP distribution in phishing website detection through VC and QR codes.

  19. DNA-Cryptography-Based Obfuscated Systolic Finite Field Multiplier for Secure Cryptosystem in Smart Grid

    Science.gov (United States)

    Chen, Shaobo; Chen, Pingxiuqi; Shao, Qiliang; Basha Shaik, Nazeem; Xie, Jiafeng

    2017-05-01

    The elliptic curve cryptography (ECC) provides much stronger security per bits compared to the traditional cryptosystem, and hence it is an ideal role in secure communication in smart grid. On the other side, secure implementation of finite field multiplication over GF(2 m ) is considered as the bottle neck of ECC. In this paper, we present a novel obfuscation strategy for secure implementation of systolic field multiplier for ECC in smart grid. First, for the first time, we propose a novel obfuscation technique to derive a novel obfuscated systolic finite field multiplier for ECC implementation. Then, we employ the DNA cryptography coding strategy to obfuscate the field multiplier further. Finally, we obtain the area-time-power complexity of the proposed field multiplier to confirm the efficiency of the proposed design. The proposed design is highly obfuscated with low overhead, suitable for secure cryptosystem in smart grid.

  20. AUTHENTICATION ARCHITECTURE USING THRESHOLD CRYPTOGRAPHY IN KERBEROS FOR MOBILE AD HOC NETWORKS

    Directory of Open Access Journals (Sweden)

    Hadj Gharib

    2014-06-01

    Full Text Available The use of wireless technologies is gradually increasing and risks related to the use of these technologies are considerable. Due to their dynamically changing topology and open environment without a centralized policy control of a traditional network, a mobile ad hoc network (MANET is vulnerable to the presence of malicious nodes and attacks. The ideal solution to overcome a myriad of security concerns in MANET’s is the use of reliable authentication architecture. In this paper we propose a new key management scheme based on threshold cryptography in kerberos for MANET’s, the proposed scheme uses the elliptic curve cryptography method that consumes fewer resources well adapted to the wireless environment. Our approach shows a strength and effectiveness against attacks.

  1. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    Science.gov (United States)

    Chen, Wen; Chen, Xudong

    2011-05-01

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed.

  2. Entropy-as-a-Service: Unlocking the Full Potential of Cryptography

    Science.gov (United States)

    Vassilev, Apostol; Staples, Robert

    2016-01-01

    Securing the Internet requires strong cryptography, which depends on the availability of good entropy for generating unpredictable keys and accurate clocks. Attacks abusing weak keys or old inputs portend challenges for the Internet. EaaS is a novel architecture providing entropy and timestamps from a decentralized root of trust, scaling gracefully across diverse geopolitical locales and remaining trustworthy unless much of the collective is compromised. PMID:28003687

  3. 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.

  4. Secure Programming Cookbook for C and C++ Recipes for Cryptography, Authentication, Input Validation & More

    CERN Document Server

    Viega, John

    2009-01-01

    Secure Programming Cookbook for C and C++ is an important new resource for developers serious about writing secure code for Unix® (including Linux®) and Windows® environments. This essential code companion covers a wide range of topics, including safe initialization, access control, input validation, symmetric and public key cryptography, cryptographic hashes and MACs, authentication and key exchange, PKI, random numbers, and anti-tampering.

  5. A new multi-tier adaptive military MANET security protocol using hybrid cryptography and signcryption

    OpenAIRE

    YAVUZ, Attila A.; ALAGÖZ, Fatih; Anarim, Emin

    2014-01-01

    Mobile Ad-hoc NETworks (MANETs) are expected to play an important role in tactical military networks by providing infrastructureless communication. However, maintaining secure and instant information sharing is a difficult task especially for highly dynamic military MANETs. To address this requirement, we propose a new multi-tier adaptive military MANET security protocol using hybrid cryptography and signcryption. In our protocol, we bring novelties to secure military MANET communic...

  6. Advances in cryptography and information security-introduction of 2002-2006 progress of SKLOIS

    Institute of Scientific and Technical Information of China (English)

    FENG Dengguo; WU Chuankun

    2007-01-01

    This paper introduces the research progress of the State Key Laboratory of Information Security(SKLOIS)in China during 2002-2006.This introduction covers four selected areas with each covering some selected research findings.The four selected areas are:the fundamentals of cryptography;the design,analysis and testing of block cipher algorithms;the design and analysis of security protocols based on computational intractability;authentication,authorization and their applications.

  7. Bounds for reference-frame independent protocols in quantum cryptography using generalized uncertainty relations

    CERN Document Server

    Le, Thinh Phuc; Scarani, Valerio

    2011-01-01

    We define a family of reference-frame-independent quantum cryptography protocols for arbitrary dimensional signals. The generalized entropic uncertainty relations [M. Tomamichel and R. Renner, Phys. Rev. Lett. 106, 110506 (2011)] are used for the first time to derive security bounds for protocols which use more than two measurements and combine the statistics in a non-linear parameter. This shows the power and versatility of this technique compared to the heavier, though usually tighter, conventional techniques.

  8. An Elliptic Curve Cryptography-Based RFID Authentication Securing E-Health System

    OpenAIRE

    2015-01-01

    Mobile healthcare (M-health) systems can monitor the patients’ conditions remotely and provide the patients and doctors with access to electronic medical records, and Radio Frequency Identification (RFID) technology plays an important role in M-health services. It is important to securely access RFID data in M-health systems: here, authentication, privacy, anonymity, and tracking resistance are desirable security properties. In 2014, He et al. proposed an elliptic curve cryptography- (ECC-) b...

  9. Hardware-Software Codesign of a Vector Co-processor for Public Key Cryptography

    OpenAIRE

    Fournier, Jacques Jean-Alain; Moore, Simon

    2006-01-01

    International audience; Until now, most cryptography implementations on parallel architectures have focused on adapting the software to SIMD architectures initially meant for media applications. In this paper, we review some of the most significant contributions in this area. We then propose a vector architecture to efficiently implement long precision modular multiplications. Having such a data level parallel hardware provides a circuit whose decode and schedule units are at least of the sam...

  10. Reduced randomness in quantum cryptography with sequences of qubits encoded in the same basis

    CERN Document Server

    Lamoureux, L P; Cerf, N J; Gisin, Nicolas; Macchiavello, C

    2005-01-01

    We consider the cloning of sequences of qubits prepared in the states used in the BB84 or 6-state quantum cryptography protocol, and show that the single-qubit fidelity is unaffected even if entire sequences of qubits are prepared in the same basis. This result is of great importance for practical quantum cryptosystems because it reduces the need for high-speed random number generation without impairing on the security against finite-size attacks.

  11. MULTI-WATERMARKING SCHEME FOR GROUP USERS BASED ON VISUAL CRYPTOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    Yuan Zhonglan; Xia Guangsheng; Wen Qiaoyan; Yang Yixian

    2005-01-01

    All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in each group as a key. In the watermarking extraction procedure, users in different group can obtain different watermark by combining their shadows with the extracted one from the watermarked signal. Analysis and experimental results show that the new watermarking method is novel, secure and robust.

  12. Active stabilization of the optical part in fiber optic quantum cryptography

    Science.gov (United States)

    Balygin, K. A.; Klimov, A. N.; Kulik, S. P.; Molotkov, S. N.

    2016-03-01

    The method of active stabilization of the polarization and other parameters of the optical part of a two-pass fiber optic quantum cryptography has been proposed and implemented. The method allows the completely automated maintenance of the visibility of interference close to an ideal value ( V ≥ 0.99) and the reduction of the instrumental contribution to the error in primary keys (QBER) to 0.5%.

  13. Compact transmission system using single-sideband modulation of light for quantum cryptography.

    Science.gov (United States)

    Duraffourg, L; Merolla, J M; Goedgebuer, J P; Mazurenko, Y; Rhodes, W T

    2001-09-15

    We report a new transmission that can be used for quantum key distribution. The system uses single-sideband-modulated light in an implementation of the BB84 quantum cryptography protocol. The system is formed by two integrated unbalanced Mach-Zehnder interferometers and is based on interference between phase-modulated sidebands in the spectral domain. Experiments show that high interference visibility can be obtained.

  14. Public channel cryptography by synchronization of neural networks and chaotic maps.

    Science.gov (United States)

    Mislovaty, Rachel; Klein, Einat; Kanter, Ido; Kinzel, Wolfgang

    2003-09-12

    Two different kinds of synchronization have been applied to cryptography: synchronization of chaotic maps by one common external signal and synchronization of neural networks by mutual learning. By combining these two mechanisms, where the external signal to the chaotic maps is synchronized by the nets, we construct a hybrid network which allows a secure generation of secret encryption keys over a public channel. The security with respect to attacks, recently proposed by Shamir et al., is increased by chaotic synchronization.

  15. Device-independent two-party cryptography secure against sequential attacks

    Science.gov (United States)

    Kaniewski, Jędrzej; Wehner, Stephanie

    2016-05-01

    The goal of two-party cryptography is to enable two parties, Alice and Bob, to solve common tasks without the need for mutual trust. Examples of such tasks are private access to a database, and secure identification. Quantum communication enables security for all of these problems in the noisy-storage model by sending more signals than the adversary can store in a certain time frame. Here, we initiate the study of device-independent (DI) protocols for two-party cryptography in the noisy-storage model. Specifically, we present a relatively easy to implement protocol for a cryptographic building block known as weak string erasure and prove its security even if the devices used in the protocol are prepared by the dishonest party. DI two-party cryptography is made challenging by the fact that Alice and Bob do not trust each other, which requires new techniques to establish security. We fully analyse the case of memoryless devices (for which sequential attacks are optimal) and the case of sequential attacks for arbitrary devices. The key ingredient of the proof, which might be of independent interest, is an explicit (and tight) relation between the violation of the Clauser-Horne-Shimony-Holt inequality observed by Alice and Bob and uncertainty generated by Alice against Bob who is forced to measure his system before finding out Alice’s setting (guessing with postmeasurement information). In particular, we show that security is possible for arbitrarily small violation.

  16. Secured Wireless Communication using Fuzzy Logic based High Speed Public-Key Cryptography (FLHSPKC

    Directory of Open Access Journals (Sweden)

    Arindam Sarkar

    2012-10-01

    Full Text Available In this paper secured wireless communication using fuzzy logic based high speed public-key cryptography (FLHSPKC has been proposed by satisfying the major issues likes computational safety, power management and restricted usage of memory in wireless communication. Wireless Sensor Network (WSN has several major constraints likes’ inadequate source of energy, restricted computational potentiality and limited memory. Though conventional Elliptic Curve Cryptography (ECC which is a sort of public-key cryptography used in wireless communication provides equivalent level of security like other existing public–key algorithm using smaller parameters than other but this traditional ECC does not take care of all these major limitations in WSN. In conventional ECC consider Elliptic curve point p, an arbitrary integer k and modulus m, ECC carry out scalar multiplication kP mod m, which takes about 80% of key computation time on WSN. In this paper proposed FLHSPKC scheme provides some novel strategy including novel soft computing based strategy to speed up scalar multiplication in conventional ECC and which in turn takes shorter computational time and also satisfies power consumption restraint, limited usage of memory without hampering the security level. Performance analysis of the different strategies under FLHSPKC scheme and comparison study with existing conventional ECC methods has been done.

  17. Adaptive pixel-selection using chaotic map lattices for image cryptography

    Science.gov (United States)

    Sittigorn, Jirasak; Paithoonwattanakij, Kitti; Surawatpunya, Charray

    2014-01-01

    Chaotic theory has been used in cryptography application for generating a sequence of data that is close to pseudorandom number based on an adjusted initial condition and a parameter. However, data recovery becomes a crucial problem due to the precision of the parameters. This difficulty leads to limited usage of Chaotic-based cryptography especially for error sensitive applications such as voice cryptography. In order to enhance the encryption security and overcome this limitation, an Adaptive Pixel-Selection using Chaotic Map Lattices (APCML) is proposed. In APCML, the encryption sequence has been adaptively selected based on chaos generator. Moreover, the chaotic transformation and normalization boundary have been revised to alleviate the rounding error and inappropriate normalization boundary problems. In the experiments, the measurement indices of originality preservation, visual inspection, and statistical analysis are used to evaluate the performance of the proposed APCML compared to that of the original CML. Consequently, the APCML algorithm offers greater performance with full recovery of the original message.

  18. Design of an Elliptic Curve Cryptography Processor for RFID Tag Chips

    Directory of Open Access Journals (Sweden)

    Zilong Liu

    2014-09-01

    Full Text Available Radio Frequency Identification (RFID is an important technique for wireless sensor networks and the Internet of Things. Recently, considerable research has been performed in the combination of public key cryptography and RFID. In this paper, an efficient architecture of Elliptic Curve Cryptography (ECC Processor for RFID tag chip is presented. We adopt a new inversion algorithm which requires fewer registers to store variables than the traditional schemes. A new method for coordinate swapping is proposed, which can reduce the complexity of the controller and shorten the time of iterative calculation effectively. A modified circular shift register architecture is presented in this paper, which is an effective way to reduce the area of register files. Clock gating and asynchronous counter are exploited to reduce the power consumption. The simulation and synthesis results show that the time needed for one elliptic curve scalar point multiplication over GF(2163 is 176.7 K clock cycles and the gate area is 13.8 K with UMC 0.13 μm Complementary Metal Oxide Semiconductor (CMOS technology. Moreover, the low power and low cost consumption make the Elliptic Curve Cryptography Processor (ECP a prospective candidate for application in the RFID tag chip.

  19. Design of an Elliptic Curve Cryptography processor for RFID tag chips.

    Science.gov (United States)

    Liu, Zilong; Liu, Dongsheng; Zou, Xuecheng; Lin, Hui; Cheng, Jian

    2014-09-26

    Radio Frequency Identification (RFID) is an important technique for wireless sensor networks and the Internet of Things. Recently, considerable research has been performed in the combination of public key cryptography and RFID. In this paper, an efficient architecture of Elliptic Curve Cryptography (ECC) Processor for RFID tag chip is presented. We adopt a new inversion algorithm which requires fewer registers to store variables than the traditional schemes. A new method for coordinate swapping is proposed, which can reduce the complexity of the controller and shorten the time of iterative calculation effectively. A modified circular shift register architecture is presented in this paper, which is an effective way to reduce the area of register files. Clock gating and asynchronous counter are exploited to reduce the power consumption. The simulation and synthesis results show that the time needed for one elliptic curve scalar point multiplication over GF(2163) is 176.7 K clock cycles and the gate area is 13.8 K with UMC 0.13 μm Complementary Metal Oxide Semiconductor (CMOS) technology. Moreover, the low power and low cost consumption make the Elliptic Curve Cryptography Processor (ECP) a prospective candidate for application in the RFID tag chip.

  20. A copyright protection scheme for digital images based on shuffled singular value decomposition and visual cryptography.

    Science.gov (United States)

    Devi, B Pushpa; Singh, Kh Manglem; Roy, Sudipta

    2016-01-01

    This paper proposes a new watermarking algorithm based on the shuffled singular value decomposition and the visual cryptography for copyright protection of digital images. It generates the ownership and identification shares of the image based on visual cryptography. It decomposes the image into low and high frequency sub-bands. The low frequency sub-band is further divided into blocks of same size after shuffling it and then the singular value decomposition is applied to each randomly selected block. Shares are generated by comparing one of the elements in the first column of the left orthogonal matrix with its corresponding element in the right orthogonal matrix of the singular value decomposition of the block of the low frequency sub-band. The experimental results show that the proposed scheme clearly verifies the copyright of the digital images, and is robust to withstand several image processing attacks. Comparison with the other related visual cryptography-based algorithms reveals that the proposed method gives better performance. The proposed method is especially resilient against the rotation attack.

  1. A New Approach to Generate the Recursive Sequence in Image Cryptography Using Genetic AlgorithmA New Approach to Generate the Recursive Sequence in Image Cryptography Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    z. talebi

    2014-07-01

    Full Text Available Digital image has special cryptography algorithms for its specific properties. A mathematics sequence in most image cryptography has been used for image scrambling. The used mathematics sequence has a recursive equation which it has some coefficients that changes of these coefficients can generate different sequences. Performance of this sequence in image cryptography is evaluated with different standard criteria. Due to complexity of system and no direct relation between the coefficient and evaluation criteria, selection of the suitable coefficient is not easily possible. In this article, by considering a general form of recursive equation and define a fitness function, the proper coefficients are calculated by genetic algorithm that satisfies the evaluation criteria. The experimental results show that recursive equation that is computed by the genetic algorithm has satisfactory performance from some schemes.

  2. 密码学实验课程的建设%Construction of Experimental Course on Cryptography

    Institute of Scientific and Technical Information of China (English)

    陈逢林

    2012-01-01

    在分析密码学教学特点和面临的问题的基础上,提出了设立实验课的必要性,从实验内容和类型上提出了密码学实验教学内容安排,为密码学教学提出了可行的方案。%This thesis indicates the characteristics and problems about cryptography teaching,and points out the necessity establishing experimental courses.Moreover,it gives the cryptography experimental arrangements content according to its content and type.Then,it takes a feasible proposal for the cryptography teaching reform.

  3. Conjugacy Systems Based on Nonabelian Factorization Problems and Their Applications in Cryptography

    Directory of Open Access Journals (Sweden)

    Lize Gu

    2014-01-01

    Full Text Available To resist known quantum algorithm attacks, several nonabelian algebraic structures mounted upon the stage of modern cryptography. Recently, Baba et al. proposed an important analogy from the integer factorization problem to the factorization problem over nonabelian groups. In this paper, we propose several conjugated problems related to the factorization problem over nonabelian groups and then present three constructions of cryptographic primitives based on these newly introduced conjugacy systems: encryption, signature, and signcryption. Sample implementations of our proposal as well as the related performance analysis are also presented.

  4. Perspectives on Entangled Nuclear Particle Pairs Generation and Manipulation in Quantum Communication and Cryptography Systems

    Directory of Open Access Journals (Sweden)

    Octavian Dănilă

    2012-01-01

    Full Text Available Entanglement between two quantum elements is a phenomenon which presents a broad application spectrum, being used largely in quantum cryptography schemes and in physical characterisation of the universe. Commonly known entangled states have been obtained with photons and electrons, but other quantum elements such as quarks, leptons, and neutrinos have shown their informational potential. In this paper, we present the perspective of exploiting the phenomenon of entanglement that appears in nuclear particle interactions as a resource for quantum key distribution protocols.

  5. Field test of a practical secure communication network with decoy-state quantum cryptography.

    Science.gov (United States)

    Chen, Teng-Yun; Liang, Hao; Liu, Yang; Cai, Wen-Qi; Ju, Lei; Liu, Wei-Yue; Wang, Jian; Yin, Hao; Chen, Kai; Chen, Zeng-Bing; Peng, Cheng-Zhi; Pan, Jian-Wei

    2009-04-13

    We present a secure network communication system that operated with decoy-state quantum cryptography in a real-world application scenario. The full key exchange and application protocols were performed in real time among three nodes, in which two adjacent nodes were connected by approximate 20 km of commercial telecom optical fiber. The generated quantum keys were immediately employed and demonstrated for communication applications, including unbreakable real-time voice telephone between any two of the three communication nodes, or a broadcast from one node to the other two nodes by using one-time pad encryption.

  6. USING MODIFIED STERN SERIES FOR DIGITAL SIGNATURE AUTHENTICATION IN ELLIPTIC CURVE CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Latha Parthiban

    2011-12-01

    Full Text Available This paper presents the generation of digital signature along with message recovery based on Elliptic Curve Cryptography (ECC and knapsack algorithm. In digital signature along with message recovery scheme, signature alone is sent and message is recovered from the signature (r, s. ECC provides greater security with less key size, when compared to integer factorization and discrete logarithm system. As the strength of knapsack algorithm depends on the selection of the series, the proposed algorithm uses modified Stern series which not only reduces the time complexity but also provides better security.

  7. Invisible transmission in quantum cryptography using continuous variables: A proof of Eve's vulnerability

    Science.gov (United States)

    Navez, Patrick; Gatti, Alessandra; Lugiato, Luigi A.

    2002-03-01

    By analogy to classical cryptography, we develop a quantum cryptographic scheme in which the two public and private keys consist in each of two entangled beams of squeezed light. An analog secret information is encrypted by modulating the phase of the beam sent in public. The knowledge of the degree of nonclassical correlation between the beam quadratures measured in private and in public allows only the receiver to decrypt the secret information. Finally, in a view towards absolute security, we formally prove that any external intervention of an eavesdropper makes him vulnerable to any subsequent detection.

  8. A secure RFID mutual authentication protocol for healthcare environments using elliptic curve cryptography.

    Science.gov (United States)

    Jin, Chunhua; Xu, Chunxiang; Zhang, Xiaojun; Zhao, Jining

    2015-03-01

    Radio Frequency Identification(RFID) is an automatic identification technology, which can be widely used in healthcare environments to locate and track staff, equipment and patients. However, potential security and privacy problems in RFID system remain a challenge. In this paper, we design a mutual authentication protocol for RFID based on elliptic curve cryptography(ECC). We use pre-computing method within tag's communication, so that our protocol can get better efficiency. In terms of security, our protocol can achieve confidentiality, unforgeability, mutual authentication, tag's anonymity, availability and forward security. Our protocol also can overcome the weakness in the existing protocols. Therefore, our protocol is suitable for healthcare environments.

  9. Authentication in insecure environments using visual cryptography and non-transferable credentials in practise

    CERN Document Server

    Pape, Sebastian

    2014-01-01

    Sebastian Pape discusses two different scenarios for authentication. On the one hand, users cannot trust their devices and nevertheless want to be able to do secure authentication. On the other hand, users may not want to be tracked while their service provider does not want them to share their credentials. Many users may not be able to determine whether their device is trustworthy, i.e. it might contain malware. One solution is to use visual cryptography for authentication. The author generalizes this concept to human decipherable encryption schemes and establishes a relationship to CAPTCHAS.

  10. Quantum Cryptography using entangled photons in energy-time Bell states

    OpenAIRE

    Tittel, Wolfgang; Brendel, Jurgen; Zbinden, Hugo; Gisin, Nicolas

    1999-01-01

    We present a setup for quantum cryptography based on photon pairs in energy-time Bell states and show its feasibility in a laboratory experiment. Our scheme combines the advantages of using photon pairs instead of faint laser pulses and the possibility to preserve energy-time entanglement over long distances. Moreover, using four-dimensional energy-time states, no fast random change of bases is required in our setup: Nature itself decides whether to measure in the energy or in the time base, ...

  11. Optical double-image cryptography based on diffractive imaging with a laterally-translated phase grating.

    Science.gov (United States)

    Chen, Wen; Chen, Xudong; Sheppard, Colin J R

    2011-10-10

    In this paper, we propose a method using structured-illumination-based diffractive imaging with a laterally-translated phase grating for optical double-image cryptography. An optical cryptosystem is designed, and multiple random phase-only masks are placed in the optical path. When a phase grating is laterally translated just before the plaintexts, several diffraction intensity patterns (i.e., ciphertexts) can be correspondingly obtained. During image decryption, an iterative retrieval algorithm is developed to extract plaintexts from the ciphertexts. In addition, security and advantages of the proposed method are analyzed. Feasibility and effectiveness of the proposed method are demonstrated by numerical simulation results.

  12. Secure information display with limited viewing zone by use of multi-color visual cryptography.

    Science.gov (United States)

    Yamamoto, Hirotsugu; Hayasaki, Yoshio; Nishida, Nobuo

    2004-04-01

    We propose a display technique that ensures security of visual information by use of visual cryptography. A displayed image appears as a completely random pattern unless viewed through a decoding mask. The display has a limited viewing zone with the decoding mask. We have developed a multi-color encryption code set. Eight colors are represented in combinations of a displayed image composed of red, green, blue, and black subpixels and a decoding mask composed of transparent and opaque subpixels. Furthermore, we have demonstrated secure information display by use of an LCD panel.

  13. Practical limitation for continuous-variable quantum cryptography using coherent States.

    Science.gov (United States)

    Namiki, Ryo; Hirano, Takuya

    2004-03-19

    In this Letter, first, we investigate the security of a continuous-variable quantum cryptographic scheme with a postselection process against individual beam splitting attack. It is shown that the scheme can be secure in the presence of the transmission loss owing to the postselection. Second, we provide a loss limit for continuous-variable quantum cryptography using coherent states taking into account excess Gaussian noise on quadrature distribution. Since the excess noise is reduced by the loss mechanism, a realistic intercept-resend attack which makes a Gaussian mixture of coherent states gives a loss limit in the presence of any excess Gaussian noise.

  14. Information hiding based on double random-phase encoding and public-key cryptography.

    Science.gov (United States)

    Sheng, Yuan; Xin, Zhou; Alam, Mohammed S; Xi, Lu; Xiao-Feng, Li

    2009-03-01

    A novel information hiding method based on double random-phase encoding (DRPE) and Rivest-Shamir-Adleman (RSA) public-key cryptosystem is proposed. In the proposed technique, the inherent diffusion property of DRPE is cleverly utilized to make up the diffusion insufficiency of RSA public-key cryptography, while the RSA cryptosystem is utilized for simultaneous transmission of the cipher text and the two phase-masks, which is not possible under the DRPE technique. This technique combines the complementary advantages of the DPRE and RSA encryption techniques and brings security and convenience for efficient information transmission. Extensive numerical simulation results are presented to verify the performance of the proposed technique.

  15. General Theory of Decoy-State Quantum Cryptography with Dark Count Rate Fluctuation

    Institute of Scientific and Technical Information of China (English)

    GAO Xiang; SUN Shi-Hai; LIANG Lin-Mei

    2009-01-01

    The existing theory of decoy-state quantum cryptography assumes that the dark count rate is a constant, but in practice there exists fluctuation. We develop a new scheme of the decoy state, achieve a more practical key generation rate in the presence of fluctuation of the dark count rate, and compare the result with the result of the decoy-state without fluctuation.It is found that the key generation rate and maximal secure distance will be decreased under the influence of the fluctuation of the dark count rate.

  16. The Modeling Library of Eavesdropping Methods in Quantum Cryptography Protocols by Model Checking

    Science.gov (United States)

    Yang, Fan; Yang, Guowu; Hao, Yujie

    2016-07-01

    The most crucial issue of quantum cryptography protocols is its security. There exists many ways to attack the quantum communication process. In this paper, we present a model checking method for modeling the eavesdropping in quantum information protocols. So when the security properties of a certain protocol are needed to be verified, we can directly use the models which are already built. Here we adopt the probabilistic model checking tool—PRISM to model these attack methods. The verification results show that the detection rate of eavesdropping is approximately close to 1 when enough photons are transmitted.

  17. Quantum cryptography using entangled photons in energy-time bell states

    Science.gov (United States)

    Tittel; Brendel; Zbinden; Gisin

    2000-05-15

    We present a setup for quantum cryptography based on photon pairs in energy-time Bell states and show its feasibility in a laboratory experiment. Our scheme combines the advantages of using photon pairs instead of faint laser pulses and the possibility to preserve energy-time entanglement over long distances. Moreover, using four-dimensional energy-time states, no fast random change of bases is required in our setup: Nature itself decides whether to measure in the energy or in the time base, thus rendering eavesdropper attacks based on "photon number splitting" less efficient.

  18. Disorder generated by interacting neural networks: application to econophysics and cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Kinzel, Wolfgang [Institut fuer Theoretische Physik, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Kanter, Ido [Department of Physics, Bar Ilan University, Ramat Gan (Israel)

    2003-10-31

    When neural networks are trained on their own output signals they generate disordered time series. In particular, when two neural networks are trained on their mutual output they can synchronize; they relax to a time-dependent state with identical synaptic weights. Two applications of this phenomenon are discussed for (a) econophysics and (b) cryptography. (a) When agents competing in a closed market (minority game) are using neural networks to make their decisions, the total system relaxes to a state of good performance. (b) Two partners communicating over a public channel can find a common secret key.

  19. Implementation and Analysis Audio Steganography Used Parity Coding for Symmetric Cryptography Key Delivery

    Directory of Open Access Journals (Sweden)

    Afany Zeinata Firdaus

    2013-12-01

    Full Text Available In today's era of communication, online data transactions is increasing. Various information even more accessible, both upload and download. Because it takes a capable security system. Blowfish cryptographic equipped with Audio Steganography is one way to secure the data so that the data can not be accessed by unauthorized parties. In this study Audio Steganography technique is implemented using parity coding method that is used to send the key cryptography blowfish in e-commerce applications based on Android. The results obtained for the average computation time on stage insertion (embedding the secret message is shorter than the average computation time making phase (extracting the secret message. From the test results can also be seen that the more the number of characters pasted the greater the noise received, where the highest SNR is obtained when a character is inserted as many as 506 characters is equal to 11.9905 dB, while the lowest SNR obtained when a character is inserted as many as 2006 characters at 5,6897 dB . Keywords: audio steganograph, parity coding, embedding, extractin, cryptography blowfih.

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

    Directory of Open Access Journals (Sweden)

    B. SENTHILKUMAR

    2015-05-01

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

  1. On the improvement of neural cryptography using erroneous transmitted information with error prediction.

    Science.gov (United States)

    Allam, Ahmed M; Abbas, Hazem M

    2010-12-01

    Neural cryptography deals with the problem of "key exchange" between two neural networks using the mutual learning concept. The two networks exchange their outputs (in bits) and the key between the two communicating parties is eventually represented in the final learned weights, when the two networks are said to be synchronized. Security of neural synchronization is put at risk if an attacker is capable of synchronizing with any of the two parties during the training process. Therefore, diminishing the probability of such a threat improves the reliability of exchanging the output bits through a public channel. The synchronization with feedback algorithm is one of the existing algorithms that enhances the security of neural cryptography. This paper proposes three new algorithms to enhance the mutual learning process. They mainly depend on disrupting the attacker confidence in the exchanged outputs and input patterns during training. The first algorithm is called "Do not Trust My Partner" (DTMP), which relies on one party sending erroneous output bits, with the other party being capable of predicting and correcting this error. The second algorithm is called "Synchronization with Common Secret Feedback" (SCSFB), where inputs are kept partially secret and the attacker has to train its network on input patterns that are different from the training sets used by the communicating parties. The third algorithm is a hybrid technique combining the features of the DTMP and SCSFB. The proposed approaches are shown to outperform the synchronization with feedback algorithm in the time needed for the parties to synchronize.

  2. Trichocyanines: a Red-Hair-Inspired Modular Platform for Dye-Based One-Time-Pad Molecular Cryptography.

    Science.gov (United States)

    Leone, Loredana; Pezzella, Alessandro; Crescenzi, Orlando; Napolitano, Alessandra; Barone, Vincenzo; d'Ischia, Marco

    2015-06-01

    Current molecular cryptography (MoCryp) systems are almost exclusively based on DNA chemistry and reports of cryptography technologies based on other less complex chemical systems are lacking. We describe herein, as proof of concept, the prototype of the first asymmetric MoCryp system, based on an 8-compound set of a novel bioinspired class of cyanine-type dyes called trichocyanines. These novel acidichromic cyanine-type dyes inspired by red hair pigments were synthesized and characterized with the aid of density functional theory (DFT) calculations. Trichocyanines consist of a modular scaffold easily accessible via an expedient condensation of 3-phenyl- or 3-methyl-2H-1,4-benzothiazines with N-dimethyl- or o-methoxyhydroxy-substituted benzaldehyde or cinnamaldehyde derivatives. The eight representative members synthesized herein can be classified as belonging to two three-state systems tunable through four different control points. This versatile dye platform can generate an expandable palette of colors and appears to be specifically suited to implement an unprecedented single-use asymmetric molecular cryptography system. With this system, we intend to pioneer the translation of digital public-key cryptography into a chemical-coding one-time-pad-like system.

  3. Encrypted Objects and Decryption Processes: Problem-Solving with Functions in a Learning Environment Based on Cryptography

    Science.gov (United States)

    White, Tobin

    2009-01-01

    This paper introduces an applied problem-solving task, set in the context of cryptography and embedded in a network of computer-based tools. This designed learning environment engaged students in a series of collaborative problem-solving activities intended to introduce the topic of functions through a set of linked representations. In a…

  4. 量子密码通信及其研究进展%Quantum Cryptography and Its Research Progress

    Institute of Scientific and Technical Information of China (English)

    林帅; 林雄

    2012-01-01

    2007年4月2日,国际上首个量子密码通信网络由中国科学家在北京测试运行成功。这是迄今为止国际公开报道的唯一无中转,可同时、任意互通的量子密码通信网络,标志着量子保密通信技术从点对点方式向网络化迈出了关键一步。这次实验的成功,为量子因特网的发展奠定了基础。文章阐述量子密码的产生、量子密码学的基本原理、该领域的实验研究及研究成果,最后指出量子密码通信将是保障未来网络通信安全的一种重要技术。%China's first quantum cryptography network has been successfully tested in Beijing, the Chinese Academy of Sciences announced on April 2, 2007. It is the only fully-connected quantum network that could make simultaneous communications without any relay ever reported in the world, according to experts. The feat is a crucial step towards the practical usage of quantum cryptography from the point-to-point network. The success of this experiment, laid the foundation for the development of quantum Internet. This paper describes the generation of quantum cryptography, the basic principle of quantum cryptography in the field of experimental research and research results, and finally pointed out that quantum cryptography will be an important technology to protect the security of network communication.

  5. NEW MATERIALS OF PHOSPHATIZED CYLINDRICAL AND TABULATE MICROFOSSILS FROM THE NEOPROTEROZOIC DOUSHANTUO FORMATION AT WENG'AN, GUIZHOU, SOUTH CHINA%贵州瓮安新元古代陡山沱组磷酸盐化管柱状微体化石新材料

    Institute of Scientific and Technical Information of China (English)

    李勇; 张兴亮; 郭俊峰; 丁莲芳; 韩健; 舒德干

    2003-01-01

    在用醋酸浸泡处理采自贵州瓮安新元古代陡山沱组磷酸质岩石样品时,获得大量微体动物骨骼化石.文中重点报道部分管柱状微体化石,即:Sinoquadraticus poratus gen. et sp. nov.和 Sinoquadraticus wenganensis gen. et sp. nov..并对Sinocyclocylicus的部分特征进行补充.%In 1992 Xue et al. reported some skeletal fossils, including one genus and two species, from the Neoprotorozoic Doushantuo Formation at Weng'an, Guizhou, and assigned them to Echinodermata. In this paper, new materials of phosphatized cylindrical and tabulate microfossils, including a new genus and two new species, are described from the same layer and locality. It provides us much more evidence not only to display the Neoproterozoic biodiversity, but also to explore the origin and the early evolution of biomineralization.

  6. Aspects of Nonabelian Group Based Cryptography: A Survey and Open Problems

    CERN Document Server

    Fine, Benjamin; Kahrobaei, Delaram; Rosenberger, Gerhard

    2011-01-01

    Most common public key cryptosystems and public key exchange protocols presently in use, such as the RSA algorithm, Diffie-Hellman, and elliptic curve methods are number theory based and hence depend on the structure of abelian groups. The strength of computing machinery has made these techniques theoretically susceptible to attack and hence recently there has been an active line of research to develop cryptosystems and key exchange protocols using noncommutative cryptographic platforms. This line of investigation has been given the broad title of noncommutative algebraic cryptography. This was initiated by two public key protocols that used the braid groups, one by Ko, Lee et.al.and one by Anshel, Anshel and Goldfeld. The study of these protocols and the group theory surrounding them has had a large effect on research in infinite group theory. In this paper we survey these noncommutative group based methods and discuss several ideas in abstract infinite group theory that have arisen from them. We then presen...

  7. Threshold Cryptography-based Group Authentication (TCGA) Scheme for the Internet of Things (IoT)

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Prasad, Neeli R.; Prasad, Ramjee

    2014-01-01

    , and receipt of their authentication request at the same time. Therefore, secure, and efficient group authentication, and authorization scheme is required that authenticates a group of devices at once in the context of resource constrained IoT. This paper presents novel Threshold Cryptography-based Group...... Authentication (TCGA) scheme for the IoT which verifies authenticity of all the devices taking part in the group communication. This paper also presents TCGA framework which is flexible and secure. The proposed TCGA scheme is implemented for WI-FI environment, and the result shows that TCGA scheme is lightweight......Internet of things (IoT) is an emerging paradigm where the devices around us (persistent and non-persistent) are connected to each other to provide seamless communication, and contextual services. In the IoT, each device cannot be authenticated in the short time due to unbounded number of devices...

  8. Role of causality in ensuring unconditional security of relativistic quantum cryptography

    CERN Document Server

    Molotkov, S N

    2001-01-01

    The problem of unconditional security of quantum cryptography (i.e. the security which is guaranteed by the fundamental laws of nature rather than by technical limitations) is one of the central points in quantum information theory. We propose a relativistic quantum cryptosystem and prove its unconditional security against any eavesdropping attempts. Relativistic causality arguments allow to demonstrate the security of the system in a simple way. Since the proposed protocol does not employ collective measurements and quantum codes, the cryptosystem can be experimentally realized with the present state-of-art in fiber optics technologies. The proposed cryptosystem employs only the individual measurements and classical codes and, in addition, the key distribution problem allows to postpone the choice of the state encoding scheme until after the states are already received instead of choosing it before sending the states into the communication channel (i.e. to employ a sort of ``antedate'' coding).

  9. A novel chaotic system for Video Cryptography using 2D logistics Sine-Cosine maps

    Directory of Open Access Journals (Sweden)

    Manjunatha V G,

    2015-11-01

    Full Text Available The astonishing developments have been occurring in the field of network communications for a long time and these advancement lead to a genuine and conspicuous need of image transfer and getting safely through the web. The web is not secure for the exchange of dependable data, for example, content, picture and video. Cryptographic procedures are vital to be improved to exchange data through web safely. Routine cryptography, for example, AES, DES, IDEA and RSA includes simply rearranging of pixels and henceforth will prompt decreased security for information protection. With a specific end goal to enhance the security, it is important to expand the intricacy in encryption. As an answer for this it is proposed to utilize confused maps in encryption methods which expand the multifaceted nature. As intricacy builds, data security increments. Thus, chaos-based encryption has its own significance in providing security for secret information i.e. data confidentiality than conventional.

  10. Digital Signature and Watermark Methods For Image Authentication using Cryptography Analysis

    Directory of Open Access Journals (Sweden)

    M.Sreerama Murty

    2011-06-01

    Full Text Available The digital signature and watermarking methods are used for image authentication. Digital signature encodes the signature in a file separate from the original image. Cryptographic algorithms have suggested several advantages over the traditional encryption algorithms such as high security, speed, reasonablecomputational overheads and computational power. A digital watermark and signature method for image authentication using cryptography analysis is proposed. The digital signature created for the originalimage and apply watermark. Images are resized before transmission in the network. After digital signature and water marking an image, apply the encryption and decryption process to an image for the authentication. The encryption is used to securely transmit data in open networks for the encryption of an image using public key and decrypt that image using private key.

  11. Real Time MODBUS Transmissions and Cryptography Security Designs and Enhancements of Protocol Sensitive Information

    Directory of Open Access Journals (Sweden)

    Aamir Shahzad

    2015-07-01

    Full Text Available Information technology (IT security has become a major concern due to the growing demand for information and massive development of client/server applications for various types of applications running on modern IT infrastructure. How has security been taken into account and which paradigms are necessary to minimize security issues while increasing efficiency, reducing the influence on transmissions, ensuring protocol independency and achieving substantial performance? We have found cryptography to be an absolute security mechanism for client/server architectures, and in this study, a new security design was developed with the MODBUS protocol, which is considered to offer phenomenal performance for future development and enhancement of real IT infrastructure. This study is also considered to be a complete development because security is tested in almost all ways of MODBUS communication. The computed measurements are evaluated to validate the overall development, and the results indicate a substantial improvement in security that is differentiated from conventional methods.

  12. Digital Signature and Watermark Methods For Image Authentication using Cryptography Analysis

    Directory of Open Access Journals (Sweden)

    M.Sreerama Murty

    2011-09-01

    Full Text Available The digital signature and watermarking methods are used for image authentication. Digital signature encodes the signature in a file separate from the original image. Cryptographic algorithms have suggested several advantages over the traditional encryption algorithms such as high security, speed, reasonablecomputational overheads and computational power. A digital watermark and signature method for image authentication using cryptography analysis is proposed. The digital signature created for the originalimage and apply watermark. Images are resized before transmission in the network. After digital signature and water marking an image, apply the encryption and decryption process to an image for the authentication. The encryption is used to securely transmit data in open networks for the encryption of an image using public key and decrypt that image using private key.

  13. A Novel Elliptic curve cryptography Processor using NoC design

    CERN Document Server

    Javashi, Hamid

    2011-01-01

    In this paper, we propose an elliptic curve key generation processor over GF(2m) and GF(P) with Network-on-Chip (NoC) design scheme based on binary scalar multiplication algorithm. Over the Two last decades, Elliptic Curve Cryptography (ECC) has gained increasing acceptance in the industry and the academic community. This interest is mainly caused by the same level of security with relatively small keys provided by ECC comparing to large key size in Rivest Shamir Adleman (RSA). Parallelism can be utilized in different hierarchy levels as shown in many publications. By using NoC, a new method with the reduced latency of point multiplication (with parallel field arithmetic) is introduced in this paper.

  14. A LIGHT-WEIGHT CRYPTOGRAPHY ANALYSIS FOR WIRELESS BASED HEALTHCARE APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Sivasangari

    2014-01-01

    Full Text Available Patient health monitoring devices are flexible. Powerful ECG acquisition system is used at anytime and anywhere in the patient monitoring system. The increasing feasibility and convenience of mobile healthcare has already introduced several significant challenges in hospitals, healthcare providers, policy makers and patients. This study provides adaptive humming bird algorithm of light weight cryptography. This method has higher level of security over health care application with adaptive Humming Bird Algorithm for ECG acquisition systems which enables Intensive Care Monitoring. This study provides a key agreement scheme that allows neighboring nodes in BAN to share the common keys generated by electrocardiogram signal. The proposed ECG-humming bird key agreement scheme enables the secure communication over the WBAN. The experimental results are presented, which show that the proposed scheme provide better security performance in terms of false acceptance rate and false rejection rate than other approaches.

  15. An efficient RFID authentication protocol to enhance patient medication safety using elliptic curve cryptography.

    Science.gov (United States)

    Zhang, Zezhong; Qi, Qingqing

    2014-05-01

    Medication errors are very dangerous even fatal since it could cause serious even fatal harm to patients. In order to reduce medication errors, automated patient medication systems using the Radio Frequency Identification (RFID) technology have been used in many hospitals. The data transmitted in those medication systems is very important and sensitive. In the past decade, many security protocols have been proposed to ensure its secure transition attracted wide attention. Due to providing mutual authentication between the medication server and the tag, the RFID authentication protocol is considered as the most important security protocols in those systems. In this paper, we propose a RFID authentication protocol to enhance patient medication safety using elliptic curve cryptography (ECC). The analysis shows the proposed protocol could overcome security weaknesses in previous protocols and has better performance. Therefore, the proposed protocol is very suitable for automated patient medication systems.

  16. Protection and Retrieval of Encrypted Multimedia Content: When Cryptography Meets Signal Processing

    Directory of Open Access Journals (Sweden)

    Mauro Barni

    2008-03-01

    Full Text Available The processing and encryption of multimedia content are generally considered sequential and independent operations. In certain multimedia content processing scenarios, it is, however, desirable to carry out processing directly on encrypted signals. The field of secure signal processing poses significant challenges for both signal processing and cryptography research; only few ready-to-go fully integrated solutions are available. This study first concisely summarizes cryptographic primitives used in existing solutions to processing of encrypted signals, and discusses implications of the security requirements on these solutions. The study then continues to describe two domains in which secure signal processing has been taken up as a challenge, namely, analysis and retrieval of multimedia content, as well as multimedia content protection. In each domain, state-of-the-art algorithms are described. Finally, the study discusses the challenges and open issues in the field of secure signal processing.

  17. Safety Evalution of Cryptography Modules within Safety Related Control Systems for Railway Applications

    Directory of Open Access Journals (Sweden)

    Maria Franekova

    2011-01-01

    Full Text Available The paper deals with the problem of safety evaluation of cryptographic modules used within safety-related control system for applications with increasing safety integrity level. The requirements to cryptographic techniques in safety-related communication for railway application are describe. The mainly part is oriented to description of mathematical apparatus for an error probability of cryptography code with a safety code, used in an additional safety communication layer. The practical results are related with the quantitative evaluation of an average error probability of code word for Euroradio protocol recommended for communication in European Train Control System.

  18. 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.

  19. A Novel Image Steganography Technique for Secured Online Transaction Using DWT and Visual Cryptography

    Science.gov (United States)

    Anitha Devi, M. D.; ShivaKumar, K. B.

    2017-08-01

    Online payment eco system is the main target especially for cyber frauds. Therefore end to end encryption is very much needed in order to maintain the integrity of secret information related to transactions carried online. With access to payment related sensitive information, which enables lot of money transactions every day, the payment infrastructure is a major target for hackers. The proposed system highlights, an ideal approach for secure online transaction for fund transfer with a unique combination of visual cryptography and Haar based discrete wavelet transform steganography technique. This combination of data hiding technique reduces the amount of information shared between consumer and online merchant needed for successful online transaction along with providing enhanced security to customer’s account details and thereby increasing customer’s confidence preventing “Identity theft” and “Phishing”. To evaluate the effectiveness of proposed algorithm Root mean square error, Peak signal to noise ratio have been used as evaluation parameters

  20. DWT-SVD BASED SECURED IMAGE WATERMARKING FOR COPYRIGHT PROTECTION USING VISUAL CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Sushila Kamble

    2012-01-01

    Full Text Available In this paper, a new robust watermarking technique for copyright protection based on Discrete Wavelet Transform and Singular Value Decomposition is proposed. The high frequency subband of the wavelet decomposed cover image is modified by modifying its singular values. A secret key is generated from the original watermark with the help of visual cryptography to claim the ownership of the image. The ownership of the image can be claimed by superimposing this secret key on the extracted watermark from the watermarked image. The robustness of the technique is tested by applying different attacks and the visual quality of the extracted watermark after applying these attacks is good. Also, the visual quality of the watermarked image is undistinguishable from the original image.

  1. Which optical processes are suitable to make probabilistic single photon sources for quantum cryptography?

    CERN Document Server

    Verma, Amit

    2009-01-01

    Single photon sources to be used in quantum cryptography must show higher order antibunching (HOA). HOA is reported by us in several many wave mixing processes. In the present work we have investigated the possibility of observing HOA in multiwave mixing processes in general. The generalized Hamiltonian is solved for several particular cases in Heisenberg picture and possibility of observing HOA is investigated with the help of criterion of Pathak and Garcia. Several particular cases of the generalized Hamiltonian are solved with the help of short time approximation technique and HOA is reported for pump modes of different multiwave mixing processes. It is also found that HOA can not be observed for the signal and stokes modes in of the cases studied here.

  2. Image size invariant visual cryptography for general access structures subject to display quality constraints.

    Science.gov (United States)

    Lee, Kai-Hui; Chiu, Pei-Ling

    2013-10-01

    Conventional visual cryptography (VC) suffers from a pixel-expansion problem, or an uncontrollable display quality problem for recovered images, and lacks a general approach to construct visual secret sharing schemes for general access structures. We propose a general and systematic approach to address these issues without sophisticated codebook design. This approach can be used for binary secret images in non-computer-aided decryption environments. To avoid pixel expansion, we design a set of column vectors to encrypt secret pixels rather than using the conventional VC-based approach. We begin by formulating a mathematic model for the VC construction problem to find the column vectors for the optimal VC construction, after which we develop a simulated-annealing-based algorithm to solve the problem. The experimental results show that the display quality of the recovered image is superior to that of previous papers.

  3. Synchronization of random bit generators based on coupled chaotic lasers and application to cryptography.

    Science.gov (United States)

    Kanter, Ido; Butkovski, Maria; Peleg, Yitzhak; Zigzag, Meital; Aviad, Yaara; Reidler, Igor; Rosenbluh, Michael; Kinzel, Wolfgang

    2010-08-16

    Random bit generators (RBGs) constitute an important tool in cryptography, stochastic simulations and secure communications. The later in particular has some difficult requirements: high generation rate of unpredictable bit strings and secure key-exchange protocols over public channels. Deterministic algorithms generate pseudo-random number sequences at high rates, however, their unpredictability is limited by the very nature of their deterministic origin. Recently, physical RBGs based on chaotic semiconductor lasers were shown to exceed Gbit/s rates. Whether secure synchronization of two high rate physical RBGs is possible remains an open question. Here we propose a method, whereby two fast RBGs based on mutually coupled chaotic lasers, are synchronized. Using information theoretic analysis we demonstrate security against a powerful computational eavesdropper, capable of noiseless amplification, where all parameters are publicly known. The method is also extended to secure synchronization of a small network of three RBGs.

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

    Science.gov (United States)

    Chen, Huifang; Ge, Linlin; Xie, Lei

    2015-07-14

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

  5. 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.

  6. Optical asymmetric cryptography based on elliptical polarized light linear truncation and a numerical reconstruction technique.

    Science.gov (United States)

    Lin, Chao; Shen, Xueju; Wang, Zhisong; Zhao, Cheng

    2014-06-20

    We demonstrate a novel optical asymmetric cryptosystem based on the principle of elliptical polarized light linear truncation and a numerical reconstruction technique. The device of an array of linear polarizers is introduced to achieve linear truncation on the spatially resolved elliptical polarization distribution during image encryption. This encoding process can be characterized as confusion-based optical cryptography that involves no Fourier lens and diffusion operation. Based on the Jones matrix formalism, the intensity transmittance for this truncation is deduced to perform elliptical polarized light reconstruction based on two intensity measurements. Use of a quick response code makes the proposed cryptosystem practical, with versatile key sensitivity and fault tolerance. Both simulation and preliminary experimental results that support theoretical analysis are presented. An analysis of the resistance of the proposed method on a known public key attack is also provided.

  7. On protection against a bright-pulse attack in the two-pass quantum cryptography system

    Science.gov (United States)

    Balygin, K. A.; Klimov, A. N.; Korol'kov, A. V.; Kulik, S. P.; Molotkov, S. N.

    2016-06-01

    The security of keys in quantum cryptography systems, in contrast to mathematical cryptographic algorithms, is guaranteed by fundamental quantum-mechanical laws. However, the cryptographic resistance of such systems, which are distributed physical devices, fundamentally depends on the method of their implementation and particularly on the calibration and control of critical parameters. The most important parameter is the number of photons in quasi-single-photon information states in a communication channel. The sensitivity to a bright-pulse attack has been demonstrated in an explicit form for a number of systems. A method guaranteeing the resistance to such attacks has been proposed and implemented. Furthermore, the relation of physical observables used and obtained at the control of quantum states to the length of final secret keys has been obtained for the first time.

  8. Coherent pulse implementations of quantum cryptography protocols resistant to photon number splitting attacks

    CERN Document Server

    Acin, A; Scarani, V; Acin, Antonio; Gisin, Nicolas; Scarani, Valerio

    2004-01-01

    A new class of quantum cryptography (QC) protocols that are robust against the most general photon number splitting attacks in a weak coherent pulse implementation has been recently proposed. In this article we give a quite exhaustive analysis of several eavesdropping attacks on these schemes. The eavesdropper (Eve) is supposed to have unlimited technological power while the honest parties (Alice and Bob) use present day technology, in particular an attenuated laser as an approximation of a single-photon source. They exploit the nonorthogonality of quantum states for decreasing the information accessible to Eve in the multi-photon pulses accidentally produced by the imperfect source. An implementation of some of these protocols using present day technology allow for a secure key distribution up to distances of $\\sim$ 150 km. We also show that strong-pulse implementations, where a strong pulse is included as a reference, allow for key distribution robust against photon number splitting attacks.

  9. Elementary mathematics and cryptography%初等数学与密码学

    Institute of Scientific and Technical Information of China (English)

    杨万鑫

    2015-01-01

    在中学里,新学科永远是中学学生感兴趣的一点,特别是现在网络时代,密码学更是中学时代学生想去探究的学科。本文将从中学基础的因子、模、同余、最大最因数介绍起,到深层次的逆元、群、多项式逐一讨论,且立足于中学数学与信息技术两门学科,通过一个个例子把中学数学中所蕴含的密码学基础知识传输给学生,以提高了学生兴趣,并为其它学科的学习打下基础。%In middle school, a new subject is always secondary school students interested in a bit, especially now that the Internet age, cryptography but also the subject of middle school students want to go to explore. In this article, we will learn from the basis of factor, mold, congruence, the biggest factor is introduced, the deep inverse and discuss each group, polynomials, and based on two secondary school mathematics and information technology subject, through one example contained in the middle school mathematics of cryptography based knowledge transfer to students, to improve the students' interest, and other disciplines of study to lay the foundation.

  10. Secure Cluster Based Routing Using SAT/ILP Techniques and ECC EL-Gamal Threshold Cryptography in MANET

    Directory of Open Access Journals (Sweden)

    Mr. P. Kanagaraju. Me, (Ph. D

    2014-03-01

    Full Text Available The Elliptic curve cryptography ( ECC a promising and important because it requires less computing power, bandwidth, and also the memory when comparing to other cryptosystems The clustering algorithm using the Integer Linear Programming (ILP and Boolean Satisfiability (SAT solvers. These improvements will secure the application of SAT and ILP techniques in modeling composite engineering problem that is the Clustering Problem in Mobile Ad-Hoc Networks (MANETs. The Clustering Problem in MANETs consists of selecting the most appropriate nodes of a given MANET topology as clusterheads, and ensuring that regular nodes are related to clusterheads such that the lifetime of the network is maximized. In which, discussing SAT/ILP techniques for clustering techniques and ECC El Gamal Threshold Cryptography for the security. Through our implementation, explored the possibility of using ECCEG-TC in MANETs.

  11. All-optical cryptography of M-QAM formats by using two-dimensional spectrally sliced keys.

    Science.gov (United States)

    Abbade, Marcelo L F; Cvijetic, Milorad; Messani, Carlos A; Alves, Cleiton J; Tenenbaum, Stefan

    2015-05-10

    There has been an increased interest in enhancing the security of optical communications systems and networks. All-optical cryptography methods have been considered as an alternative to electronic data encryption. In this paper we propose and verify the use of a novel all-optical scheme based on cryptographic keys applied on the spectral signal for encryption of the M-QAM modulated data with bit rates of up to 200 gigabits per second.

  12. Wigner representation for experiments on quantum cryptography using two-photon polarization entanglement produced in parametric down-conversion

    Energy Technology Data Exchange (ETDEWEB)

    Casado, A [Departamento de Fisica Aplicada III, Escuela Superior de Ingenieros, Universidad de Sevilla, 41092 Sevilla (Spain); Guerra, S [Centro Asociado de la Universidad Nacional de Educacion a Distancia de Las Palmas de Gran Canaria (Spain); Placido, J [Departamento de Fisica, Universidad de Las Palmas de Gran Canaria (Spain)], E-mail: acasado@us.es

    2008-02-28

    In this paper, the theory of parametric down-conversion in the Wigner representation is applied to Ekert's quantum cryptography protocol. We analyse the relation between two-photon entanglement and (non-secure) quantum key distribution within the Wigner framework in the Heisenberg picture. Experiments using two-qubit polarization entanglement generated in nonlinear crystals are analysed in this formalism, along with the effects of eavesdropping attacks in the case of projective measurements.

  13. Dynamic DNS update security, based on cryptographically generated addresses and ID-based cryptography, in an IPv6 autoconfiguration context

    OpenAIRE

    Combes, Jean-Michel; Arfaoui, Ghada; LAURENT, Maryline

    2012-01-01

    International audience; This paper proposes a new security method for protecting signalling for Domain Name System (DNS) architecture. That is, it makes secure DNS update messages for binding a Fully Qualified Domain Name (FQDN) of an IPv6 node and the IPv6 address of the node owning this FQDN. This method is based on the use of Cryptographically Generated Addresses (CGA) and IDBased Cryptography (IBC). Combination of these two techniques allows DNS server to check the ownership of the IPv6 a...

  14. Deciphering the language of nature: cryptography, secrecy, and alterity in Francis Bacon.

    Science.gov (United States)

    Clody, Michael C

    2011-01-01

    The essay argues that Francis Bacon's considerations of parables and cryptography reflect larger interpretative concerns of his natural philosophic project. Bacon describes nature as having a language distinct from those of God and man, and, in so doing, establishes a central problem of his natural philosophy—namely, how can the language of nature be accessed through scientific representation? Ultimately, Bacon's solution relies on a theory of differential and duplicitous signs that conceal within them the hidden voice of nature, which is best recognized in the natural forms of efficient causality. The "alphabet of nature"—those tables of natural occurrences—consequently plays a central role in his program, as it renders nature's language susceptible to a process and decryption that mirrors the model of the bilateral cipher. It is argued that while the writing of Bacon's natural philosophy strives for literality, its investigative process preserves a space for alterity within scientific representation, that is made accessible to those with the interpretative key.

  15. Scalable Symmetric Key Cryptography Using Asynchronous Data Exchange in Enterprise Grid

    Directory of Open Access Journals (Sweden)

    Medhat Awadallah

    2011-11-01

    Full Text Available Symmetric key cryptography is one of the most critical computing problems that need high performance computing power resources. The use of large key sizes and complex encryption/decryption algorithms to achieve unbreakable state has led to an increased time computational complexity. Traditionally, this problem is solved in the grid environment by partitioning data streams into several blocks of a predefined size. This is done while sequentially reading the data from the raw data file. The grid manager node then takes the responsibility of passing these blocks to the executer nodes where different blocks are processed separately and simultaneously. Although this technique allows parallel processing to speed up the encryption/decryption process, creating blocks by sequentially reading the data file and distributing these blocks on executers synchronously by the central manager node is a poor technique and a source of delay. In this paper, we present a novel approach that tackles this problem by allowing executers to access data file at random and asynchronously exchange the blocks among them, thereby, delay is significantly reduced and data size can be scaled up. In order to show the merit of our approach experiments have been conducted through a system-level middleware for grid computing called Alchemi. The results show a remarkable performance enhancement in our approach over traditional approaches in terms of speed.

  16. Composite Field Multiplier based on Look-Up Table for Elliptic Curve Cryptography Implementation

    Directory of Open Access Journals (Sweden)

    Marisa W. Paryasto

    2013-09-01

    Full Text Available Implementing a secure cryptosystem requires operations involving hundreds of bits. One of the most recommended algorithm is Elliptic Curve Cryptography (ECC. The complexity of elliptic curve algorithms and parameters with hundreds of bits requires specific design and implementation strategy. The design architecture must be customized according to security requirement, available resources and parameter choices. In this work we propose the use of composite field to implement finite field multiplication for ECC implementation. We use 299-bit keylength represented in GF((21323 instead of in GF(2299. Composite field multiplier can be implemented using different multiplier for ground-field and for extension field. In this paper, LUT is used for multiplication in the ground-field and classic multiplieris used for the extension field multiplication. A generic architecture for the multiplier is presented. Implementation is done with VHDL with the target device Altera DE2. The work in this paper uses the simplest algorithm to confirm the idea that by dividing field into composite, use different multiplier for base and extension field would give better trade-off for time and area. This work will be the beginning of our more advanced further research that implements composite-field using Mastrovito Hybrid, KOA and LUT.

  17. Compilation Techniques Specific for a Hardware Cryptography-Embedded Multimedia Mobile Processor

    Directory of Open Access Journals (Sweden)

    Masa-aki FUKASE

    2007-12-01

    Full Text Available The development of single chip VLSI processors is the key technology of ever growing pervasive computing to answer overall demands for usability, mobility, speed, security, etc. We have so far developed a hardware cryptography-embedded multimedia mobile processor architecture, HCgorilla. Since HCgorilla integrates a wide range of techniques from architectures to applications and languages, one-sided design approach is not always useful. HCgorilla needs more complicated strategy, that is, hardware/software (H/S codesign. Thus, we exploit the software support of HCgorilla composed of a Java interface and parallelizing compilers. They are assumed to be installed in servers in order to reduce the load and increase the performance of HCgorilla-embedded clients. Since compilers are the essence of software's responsibility, we focus in this article on our recent results about the design, specifications, and prototyping of parallelizing compilers for HCgorilla. The parallelizing compilers are composed of a multicore compiler and a LIW compiler. They are specified to abstract parallelism from executable serial codes or the Java interface output and output the codes executable in parallel by HCgorilla. The prototyping compilers are written in Java. The evaluation by using an arithmetic test program shows the reasonability of the prototyping compilers compared with hand compilers.

  18. Post-selection technique for quantum channels with applications to quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Christandl, Matthias [University of Munich (Germany); Koenig, Robert [California Institute of Technology, Pasadena, CA (United States); Renner, Renato [ETH Zurich (Switzerland)

    2009-07-01

    We propose a general method for studying properties of quantum channels acting on an n-partite system, whose action is invariant under permutations of the subsystems. Our main result is that, in order to prove that a certain property holds for any arbitrary input, it is sufficient to consider the special case where the input is a particular de Finetti-type state, i.e., a state which consists of n identical and independent copies of an (unknown) state on a single subsystem. A similar statement holds for more general channels which are covariant with respect to the action of an arbitrary finite or locally compact group. Our technique can be applied to the analysis of information-theoretic problems. For example, in quantum cryptography, we get a simple proof for the fact that security of a discrete-variable quantum key distribution protocol against collective attacks implies security of the protocol against the most general attacks. The resulting security bounds are tighter than previously known bounds obtained by proofs relying on the exponential de Finetti theorem.

  19. Resource efficiency of hardware extensions of a 4-issue VLIW processor for elliptic curve cryptography

    Science.gov (United States)

    Jungeblut, T.; Puttmann, C.; Dreesen, R.; Porrmann, M.; Thies, M.; Rückert, U.; Kastens, U.

    2010-12-01

    The secure transmission of data plays a significant role in today's information era. Especially in the area of public-key-cryptography methods, which are based on elliptic curves (ECC), gain more and more importance. Compared to asymmetric algorithms, like RSA, ECC can be used with shorter key lengths, while achieving an equal level of security. The performance of ECC-algorithms can be increased significantly by adding application specific hardware extensions. Due to their fine grained parallelism, VLIW-processors are well suited for the execution of ECC algorithms. In this work, we extended the fourfold parallel CoreVA-VLIW-architecture by several hardware accelerators to increase the resource efficiency of the overall system. For the design-space exploration we use a dual design flow, which is based on the automatic generation of a complete C-compiler based tool chain from a central processor specification. Using the hardware accelerators the performance of the scalar multiplication on binary fields can be increased by the factor of 29. The energy consumption can be reduced by up to 90%. The extended processor hardware was mapped on a current 65 nm low-power standard-cell-technology. The chip area of the CoreVA-VLIW-architecture is 0.24 mm2 at a power consumption of 29 mW/MHz. The performance gain is analyzed in respect to the increased hardware costs, as chip area or power consumption.

  20. System Level Design of Reconfigurable Server Farms Using Elliptic Curve Cryptography Processor Engines

    Directory of Open Access Journals (Sweden)

    Sangook Moon

    2014-01-01

    Full Text Available As today’s hardware architecture becomes more and more complicated, it is getting harder to modify or improve the microarchitecture of a design in register transfer level (RTL. Consequently, traditional methods we have used to develop a design are not capable of coping with complex designs. In this paper, we suggest a way of designing complex digital logic circuits with a soft and advanced type of SystemVerilog at an electronic system level. We apply the concept of design-and-reuse with a high level of abstraction to implement elliptic curve crypto-processor server farms. With the concept of the superior level of abstraction to the RTL used with the traditional HDL design, we successfully achieved the soft implementation of the crypto-processor server farms as well as robust test bench code with trivial effort in the same simulation environment. Otherwise, it could have required error-prone Verilog simulations for the hardware IPs and other time-consuming jobs such as C/SystemC verification for the software, sacrificing more time and effort. In the design of the elliptic curve cryptography processor engine, we propose a 3X faster GF(2m serial multiplication architecture.

  1. Lightweight Data Aggregation Scheme against Internal Attackers in Smart Grid Using Elliptic Curve Cryptography

    Directory of Open Access Journals (Sweden)

    Debiao He

    2017-01-01

    Full Text Available Recent advances of Internet and microelectronics technologies have led to the concept of smart grid which has been a widespread concern for industry, governments, and academia. The openness of communications in the smart grid environment makes the system vulnerable to different types of attacks. The implementation of secure communication and the protection of consumers’ privacy have become challenging issues. The data aggregation scheme is an important technique for preserving consumers’ privacy because it can stop the leakage of a specific consumer’s data. To satisfy the security requirements of practical applications, a lot of data aggregation schemes were presented over the last several years. However, most of them suffer from security weaknesses or have poor performances. To reduce computation cost and achieve better security, we construct a lightweight data aggregation scheme against internal attackers in the smart grid environment using Elliptic Curve Cryptography (ECC. Security analysis of our proposed approach shows that it is provably secure and can provide confidentiality, authentication, and integrity. Performance analysis of the proposed scheme demonstrates that both computation and communication costs of the proposed scheme are much lower than the three previous schemes. As a result of these aforementioned benefits, the proposed lightweight data aggregation scheme is more practical for deployment in the smart grid environment.

  2. SD-EQR: A New Technique To Use QR CodesTM in Cryptography

    CERN Document Server

    Dey, Somdip

    2012-01-01

    In this paper the author present a new technique of using QR Codes (commonly known as 'Quick Respond Codes') in the field of Cryptography. QR Codes are mainly used to convey or store messages because they have higher or large storage capacity than any other normal conventional 'barcodes'. In this paper the primary focus will be on storing messages in encrypted format with a password and send it to the required destination hiding in a QR Code, without being tracked or decrypted properly by any hacker or spyware. Since QR Codes have fast response time and have large storage capacity, QR Codes can be used perfectly to send encrypted data (messages) to the receiver. This method will be suitable in any business house, government sectors, communication network to send their encrypted messages faster to the destination. Or a person can even use this method to keep his important documents, like passport number, pan-card id, social security number, perfectly secured with him all the time, without the information getti...

  3. Multiple Schemes for Mobile Payment Authentication Using QR Code and Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Jianfeng Lu

    2017-01-01

    Full Text Available QR code (quick response code is used due to its beneficial properties, especially in the mobile payment field. However, there exists an inevitable risk in the transaction process. It is not easily perceived that the attacker tampers with or replaces the QR code that contains merchant’s beneficiary account. Thus, it is of great urgency to conduct authentication of QR code. In this study, we propose a novel mechanism based on visual cryptography scheme (VCS and aesthetic QR code, which contains three primary schemes for different concealment levels. The main steps of these schemes are as follows. Firstly, one original QR code is split into two shadows using VC multiple rules; secondly, the two shadows are embedded into the same background image, respectively, and the embedded results are fused with the same carrier QR code, respectively, using XOR mechanism of RS and QR code error correction mechanism. Finally, the two aesthetic QR codes can be stacked precisely and the original QR code is restored according to the defined VCS. Experiments corresponding to three proposed schemes are conducted and demonstrate the feasibility and security of the mobile payment authentication, the significant improvement of the concealment for the shadows in QR code, and the diversity of mobile payment authentication.

  4. Efficient Implementation of Elliptic Curve Cryptography Using Low-power Digital Signal Processor

    CERN Document Server

    Malik, Muhammad Yasir

    2011-01-01

    RSA(Rivest, Shamir and Adleman)is being used as a public key exchange and key agreement tool for many years. Due to large numbers involved in RSA, there is need for more efficient methods in implementation for public key cryptosystems. Elliptic Curve Cryptography(ECC) is based on elliptic curves defined over a finite field. Elliptic curve cryptosystems(ECC) were discovered by Victor Miller and Neal Koblitz in 1985.This paper comprises of five sections. Section I is introduction to ECC and its components. Section II describes advantages of ECC schemes and its comparison with RSA. Section III is about some of the applications of ECC. Section IV gives some embedded implementations of ECC. Section V contains ECC implementation on fixed point Digital Signal Processor(TMS320VC5416). ECC was implemented using general purpose microcontrollers and Field Programmable Gate Arrays (FPGA) before this work. DSP is more powerful than microcontrollers and much economical than FPGA. So this implementation can be efficiently u...

  5. Elliptic Curve Cryptography-Based Authentication with Identity Protection for Smart Grids.

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    Full Text Available In a smart grid, the power service provider enables the expected power generation amount to be measured according to current power consumption, thus stabilizing the power system. However, the data transmitted over smart grids are not protected, and then suffer from several types of security threats and attacks. Thus, a robust and efficient authentication protocol should be provided to strength the security of smart grid networks. As the Supervisory Control and Data Acquisition system provides the security protection between the control center and substations in most smart grid environments, we focus on how to secure the communications between the substations and smart appliances. Existing security approaches fail to address the performance-security balance. In this study, we suggest a mitigation authentication protocol based on Elliptic Curve Cryptography with privacy protection by using a tamper-resistant device at the smart appliance side to achieve a delicate balance between performance and security of smart grids. The proposed protocol provides some attractive features such as identity protection, mutual authentication and key agreement. Finally, we demonstrate the completeness of the proposed protocol using the Gong-Needham-Yahalom logic.

  6. Elliptic Curve Cryptography-Based Authentication with Identity Protection for Smart Grids.

    Science.gov (United States)

    Zhang, Liping; Tang, Shanyu; Luo, He

    2016-01-01

    In a smart grid, the power service provider enables the expected power generation amount to be measured according to current power consumption, thus stabilizing the power system. However, the data transmitted over smart grids are not protected, and then suffer from several types of security threats and attacks. Thus, a robust and efficient authentication protocol should be provided to strength the security of smart grid networks. As the Supervisory Control and Data Acquisition system provides the security protection between the control center and substations in most smart grid environments, we focus on how to secure the communications between the substations and smart appliances. Existing security approaches fail to address the performance-security balance. In this study, we suggest a mitigation authentication protocol based on Elliptic Curve Cryptography with privacy protection by using a tamper-resistant device at the smart appliance side to achieve a delicate balance between performance and security of smart grids. The proposed protocol provides some attractive features such as identity protection, mutual authentication and key agreement. Finally, we demonstrate the completeness of the proposed protocol using the Gong-Needham-Yahalom logic.

  7. 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...

  8. Quantum Information, computation and cryptography. An introductory survey of theory, technology and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Benatti, Fabio [Trieste Univ., Miramare (Italy). Dipt. Fisica Teorica; Fannes, Mark [Leuven Univ. (Belgium). Inst. voor Theoretische Fysica; Floreanini, Roberto [INFN, Trieste (Italy). Dipt. di Fisica Teorica; Petritis, Dimitri (eds.) [Rennes 1 Univ., 35 (France). Inst. de Recherche Mathematique de Rennes

    2010-07-01

    This multi-authored textbook addresses graduate students with a background in physics, mathematics or computer science. No research experience is necessary. Consequently, rather than comprehensively reviewing the vast body of knowledge and literature gathered in the past twenty years, this book concentrates on a number of carefully selected aspects of quantum information theory and technology. Given the highly interdisciplinary nature of the subject, the multi-authored approach brings together different points of view from various renowned experts, providing a coherent picture of the subject matter. The book consists of ten chapters and includes examples, problems, and exercises. The first five present the mathematical tools required for a full comprehension of various aspects of quantum mechanics, classical information, and coding theory. Chapter 6 deals with the manipulation and transmission of information in the quantum realm. Chapters 7 and 8 discuss experimental implementations of quantum information ideas using photons and atoms. Finally, chapters 9 and 10 address ground-breaking applications in cryptography and computation. (orig.)

  9. Security Enhanced User Authentication Protocol for Wireless Sensor Networks Using Elliptic Curves Cryptography

    Directory of Open Access Journals (Sweden)

    Younsung Choi

    2014-06-01

    Full Text Available Wireless sensor networks (WSNs consist of sensors, gateways and users. Sensors are widely distributed to monitor various conditions, such as temperature, sound, speed and pressure but they have limited computational ability and energy. To reduce the resource use of sensors and enhance the security of WSNs, various user authentication protocols have been proposed. In 2011, Yeh et al. first proposed a user authentication protocol based on elliptic curve cryptography (ECC for WSNs. However, it turned out that Yeh et al.’s protocol does not provide mutual authentication, perfect forward secrecy, and key agreement between the user and sensor. Later in 2013, Shi et al. proposed a new user authentication protocol that improves both security and efficiency of Yeh et al.’s protocol. However, Shi et al.’s improvement introduces other security weaknesses. In this paper, we show that Shi et al.’s improved protocol is vulnerable to session key attack, stolen smart card attack, and sensor energy exhausting attack. In addition, we propose a new, security-enhanced user authentication protocol using ECC for WSNs.

  10. Achieving Identity-Based Cryptography in a Personal Digital Assistant Device

    Directory of Open Access Journals (Sweden)

    L. Martínez-Ramos

    2011-12-01

    Full Text Available Continuous technological advances have allowed that mobile devices, such as Personal Digital Assistants (PDAs, can execute sophisticated applications that more often than not must be equipped with a layer of security that should include the confidentiality and the authentication services within its repertory. Nevertheless, when compared against front-end computing devices, most PDAs are still seen as constrained devices with limited processing and storage capabilities.In order to achieve Identity-Based Cryptography (IBC, which was an open problem proposed by Adi Shamir in 1984, Bonehand Franklin presented in Crypto 2001, a solution that uses bilinear pairings as its main building block. Since then, IBC hasbecome an active area of investigation where many efficient IBC security protocols are proposed year after year. In this paper,we present a cryptographic application that allows the secure exchange of documents from a Personal Digital Assistant (PDAthat is wirelessly connected to other nodes. The architecture of our application is inspired by the traditional PGP (Pretty GoodPrivacy email security protocol. Our application achieves identity-based authentication and confidentiality functionalities at the 80-bit security level through the usage of a cryptographic library that was coded in C++. Our library can perform basic primitives such as bilinear pairings defined over the binary field and the ternary field , as well as other required primitivesknown as map-to-point hash functions. We report the timings achieved by our application and we show that they compare wellagainst other similar works published in the open literature.

  11. Clipper Meets Apple vs. FBI—A Comparison of the Cryptography Discourses from 1993 and 2016

    Directory of Open Access Journals (Sweden)

    Matthias Schulze

    2017-03-01

    Full Text Available This article analyzes two cryptography discourses dealing with the question of whether governments should be able to monitor secure and encrypted communication, for example via security vulnerabilities in cryptographic systems. The Clipper chip debate of 1993 and the FBI vs. Apple case of 2016 are analyzed to infer whether these discourses show similarities in their arguments and to draw lessons from them. The study is based on the securitization framework and analyzes the social construction of security threats in political discourses. The findings are that the arguments made by the proponents of exceptional access show major continuities between the two cases. In contrast, the arguments of the critics are more diverse. The critical arguments for stronger encryption remain highly relevant, especially in the context of the Snowden revelations. The article concludes that we need to adopt a more general cyber security perspective, considering the threat of cyber crime and state hacking, when debating whether the government should be able to weaken encryption.

  12. Policy for cryptography in healthcare--a view from the NHS.

    Science.gov (United States)

    Donaldson, A

    2000-11-01

    Effective security arrangements, which both protect and assure those information assets of healthcare providers, doctors and patients, are fundamental requirements in a modern electronic healthcare culture. At the heart of healthcare information systems in future will be those infrastructure components and services, which underpin the principles of confidentiality, integrity and availability. Before embarking upon any major implementation of cryptographic support services, there are a number of critical policy issues, which must first be considered and addressed. To address these successfully will maximise the potential values of these services and facilities to their users on a broad front. A primary consideration for all information security projects, is the need to establish clear scope and objectives for the security services to be implemented. When considering the policy, scope and design implications of a large scale cryptography programme, a number of external issues also need to be considered not least of which are the legal liabilities, implications and obligations of the country or countries where the system(s) will operate. Where such legislation exists, regulatory arrangements may potentially influence how secure information sharing across international healthcare boundaries can be achieved.

  13. An Interoperability Consideration in Selecting Domain Parameters for Elliptic Curve Cryptography

    Science.gov (United States)

    Ivancic, Will (Technical Monitor); Eddy, Wesley M.

    2005-01-01

    Elliptic curve cryptography (ECC) will be an important technology for electronic privacy and authentication in the near future. There are many published specifications for elliptic curve cryptosystems, most of which contain detailed descriptions of the process for the selection of domain parameters. Selecting strong domain parameters ensures that the cryptosystem is robust to attacks. Due to a limitation in several published algorithms for doubling points on elliptic curves, some ECC implementations may produce incorrect, inconsistent, and incompatible results if domain parameters are not carefully chosen under a criterion that we describe. Few documents specify the addition or doubling of points in such a manner as to avoid this problematic situation. The safety criterion we present is not listed in any ECC specification we are aware of, although several other guidelines for domain selection are discussed in the literature. We provide a simple example of how a set of domain parameters not meeting this criterion can produce catastrophic results, and outline a simple means of testing curve parameters for interoperable safety over doubling.

  14. Security enhanced user authentication protocol for wireless sensor networks using elliptic curves cryptography.

    Science.gov (United States)

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

    2014-06-10

    Wireless sensor networks (WSNs) consist of sensors, gateways and users. Sensors are widely distributed to monitor various conditions, such as temperature, sound, speed and pressure but they have limited computational ability and energy. To reduce the resource use of sensors and enhance the security of WSNs, various user authentication protocols have been proposed. In 2011, Yeh et al. first proposed a user authentication protocol based on elliptic curve cryptography (ECC) for WSNs. However, it turned out that Yeh et al.'s protocol does not provide mutual authentication, perfect forward secrecy, and key agreement between the user and sensor. Later in 2013, Shi et al. proposed a new user authentication protocol that improves both security and efficiency of Yeh et al.'s protocol. However, Shi et al.'s improvement introduces other security weaknesses. In this paper, we show that Shi et al.'s improved protocol is vulnerable to session key attack, stolen smart card attack, and sensor energy exhausting attack. In addition, we propose a new, security-enhanced user authentication protocol using ECC for WSNs.

  15. Compilation Techniques Specific for a Hardware Cryptography-Embedded Multimedia Mobile Processor

    Directory of Open Access Journals (Sweden)

    Masa-aki FUKASE

    2007-12-01

    Full Text Available The development of single chip VLSI processors is the key technology of ever growing pervasive computing to answer overall demands for usability, mobility, speed, security, etc. We have so far developed a hardware cryptography-embedded multimedia mobile processor architecture, HCgorilla. Since HCgorilla integrates a wide range of techniques from architectures to applications and languages, one-sided design approach is not always useful. HCgorilla needs more complicated strategy, that is, hardware/software (H/S codesign. Thus, we exploit the software support of HCgorilla composed of a Java interface and parallelizing compilers. They are assumed to be installed in servers in order to reduce the load and increase the performance of HCgorilla-embedded clients. Since compilers are the essence of software's responsibility, we focus in this article on our recent results about the design, specifications, and prototyping of parallelizing compilers for HCgorilla. The parallelizing compilers are composed of a multicore compiler and a LIW compiler. They are specified to abstract parallelism from executable serial codes or the Java interface output and output the codes executable in parallel by HCgorilla. The prototyping compilers are written in Java. The evaluation by using an arithmetic test program shows the reasonability of the prototyping compilers compared with hand compilers.

  16. Quantum cryptography: Theoretical protocols for quantum key distribution and tests of selected commercial QKD systems in commercial fiber networks

    Science.gov (United States)

    Jacak, Monika; Jacak, Janusz; Jóźwiak, Piotr; Jóźwiak, Ireneusz

    2016-06-01

    The overview of the current status of quantum cryptography is given in regard to quantum key distribution (QKD) protocols, implemented both on nonentangled and entangled flying qubits. Two commercial R&D platforms of QKD systems are described (the Clavis II platform by idQuantique implemented on nonentangled photons and the EPR S405 Quelle platform by AIT based on entangled photons) and tested for feasibility of their usage in commercial TELECOM fiber metropolitan networks. The comparison of systems efficiency, stability and resistivity against noise and hacker attacks is given with some suggestion toward system improvement, along with assessment of two models of QKD.

  17. Foundations of Coding Theory and Applications of Error-Correcting Codes with an Introduction to Cryptography and Information Theory

    CERN Document Server

    Adamek, Jiri

    1991-01-01

    Although devoted to constructions of good codes for error control, secrecy or data compression, the emphasis is on the first direction. Introduces a number of important classes of error-detecting and error-correcting codes as well as their decoding methods. Background material on modern algebra is presented where required. The role of error-correcting codes in modern cryptography is treated as are data compression and other topics related to information theory. The definition-theorem proof style used in mathematics texts is employed through the book but formalism is avoided wherever possible.

  18. 基于《翁同龢日记》天气记录重建的北京1860~1897年的降水量%Reconstructed Precipitation in Beijing during 1860-1897 Based on the Weather Records from “Diary of Weng Tonghe”

    Institute of Scientific and Technical Information of China (English)

    张学珍; 方修琦; 郑景云; 郝志新

    2011-01-01

    Daily weather records from private diaries are important proxy data for reconstructing historical precipi-tation. The authors extracted daily weather records from "Diary of Weng Tonghe" and calculated the monthly rain/ snow days using these records. The annual and summer precipitation in Beijing during 1860 - 1897 was reconstructed using the conversion functions relating precipitation with rain/snow days. Finally, by integrating the reconstruction with the instrumental data and the reconstruction from Sunshine Rainfall Records (SRR) , the precipitation during 1860 - 1897 in Beijing was reestimated. The results show: (1) The reconstruction based on the rain/snow days from "Diary of Weng Tonghe" is generally reliable and the reconstructed annual precipitation was about 611. 5 mm; how-ever, the precipitation in relative flood years was underestimated by the conversion functions) (2) the reestimated annual precipitation was about 701. 3 mm, which might be more than that in the later half of 20th century; (3) the instrumental precipitation record in 1891 may be more than the actual value and the instrumental precipitation record in 1895 may be lower than the actual value; dry-wet grades in 1869, 1863, 1885, 1889, and 1887 may be not con-sistent with actual conditions. This research demonstrates the daily weather records from private diaries have great potential to reconstruct historical precipitation, but it is worthy to note that lower biases existed in the present reconstruction.%私人日记中的天气记录是重建历史时期高分辨率降水量序列的重要资料.通过摘录、整理《翁同龢日记》中晴、雨(雪)记录,统计了逐月降水日数,并利用降水量与降水日数之间的转换方程,重建了北京1860~1897年的夏季和年降水量.将重建的降水量与当时的器测降水量和依据“晴雨录”重建的降水量进行对比,综合这3种资料重新估算了北京1860~1897年的年降水量,并且将估算降水量

  19. 白头翁汤正丁醇提取物对白念珠菌 VVC 临床株体外生物膜形成的抑制作用%The inhibitory effects of Butyl alcohol extract of BaiTouWeng decoction on biofilm formation of Candida albicans

    Institute of Scientific and Technical Information of China (English)

    张梦翔; 陆克乔; 夏丹; 夏雪; 施高翔; 邵菁; 吴大强; 汪天明; 汪长中

    2015-01-01

    Objective To investigate the effects of Butyl alcohol extract of BaiTouWeng decoction (BAEB)on the biofilm formation of Candida albicans clinical strains isolated from vulvovaginal Candidiasis (VVC).Methods Microdilution meth-ods was used to determine the MIC.XTT reduction assay was applied to determine the SMIC80 .Time-kill curve method was applied to detect the effects of BAEB on living cells of Candida albicans .Crystal violet staining method was used to determine the biomass of the biofilm.Scanning electron microscopy (SEM)was applied to observe the morphological changes of the bio-film.Confocal laser scanning microscopy (CLSM)was applied to determine the thickness of the biofilm.The quantification re-al-time PCR (qRT-PCR)was used to detect expression changes of genes (HSP90 ,UME6 and PES1 )of the biofilm treated by BAEB.Results The MICs of BAEB against C .albicans strains are determined as 64~256 μg/mL.The SMIC80 s of BAEB against the biofilm of C .albicans strains are determined as ≥1 024 μg/mL.Time-kill curve results indicate that BAEB has a promise antifungal effect at concentrations of 5 12 and 1 024 μg/mL.Crystal violet staining results show that the biomass of C .albicans is reduced by BAEB at 5 12 and 1 024 μg/mL.SEM results indicate that the formation of C .albicans biofilm carriers is inhibited by BAEB on different adhesion,and the morphol-ogy of biofilm is also affected by BAEB.The thickness of C .albicans biofilm is reduced by BAEB accord-ing to CLSM results.Furthermore,qRT-PCR results indicate that expression of UME6 is significantly down-regulated by BAEB at 256,5 12,1 024 μg/mL,and HSP90 is up-regulated at 5 12 and 1 024 μg/mL of BAEB,and PES1 is not affected by BAEB at any concentration.Conclusion BAEB inhibits effectively the biofilm formation of VVC strains of C . albicans .%目的:探讨白头翁汤正丁醇提取物(Butyl alcohol extract of Bai Tou Weng decoction,BAEB)对分离自外阴阴道念珠菌病(vulvovaginal candidiasis

  20. Number Theory in Science and Communication With Applications in Cryptography, Physics, Digital Information, Computing, and Self-Similarity

    CERN Document Server

    Schroeder, Manfred

    2009-01-01

    "Number Theory in Science and Communication" is a well-known introduction for non-mathematicians to this fascinating and useful branch of applied mathematics . It stresses intuitive understanding rather than abstract theory and highlights important concepts such as continued fractions, the golden ratio, quadratic residues and Chinese remainders, trapdoor functions, pseudoprimes and primitive elements. Their applications to problems in the real world are one of the main themes of the book. This revised fifth edition is augmented by recent advances in coding theory, permutations and derangements and a chapter in quantum cryptography. From reviews of earlier editions – "I continue to find [Schroeder’s] Number Theory a goldmine of valuable information. It is a marvellous book, in touch with the most recent applications of number theory and written with great clarity and humor.’ Philip Morrison (Scientific American) "A light-hearted and readable volume with a wide range of applications to which the author ha...

  1. Information verification cryptosystem using one-time keys based on double random phase encoding and public-key cryptography

    Science.gov (United States)

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

    2016-08-01

    A novel image encryption system based on double random phase encoding (DRPE) and RSA public-key algorithm is proposed. The main characteristic of the system is that each encryption process produces a new decryption key (even for the same plaintext), thus the encryption system conforms to the feature of the one-time pad (OTP) cryptography. The other characteristic of the system is the use of fingerprint key. Only with the rightful authorization will the true decryption be obtained, otherwise the decryption will result in noisy images. So the proposed system can be used to determine whether the ciphertext is falsified by attackers. In addition, the system conforms to the basic agreement of asymmetric cryptosystem (ACS) due to the combination with the RSA public-key algorithm. The simulation results show that the encryption scheme has high robustness against the existing attacks.

  2. Distinct galactofuranose antigens in the cell wall and culture supernatants as a means to differentiate Fusarium from AspergillusspeciesAnnegret

    DEFF Research Database (Denmark)

    Wiedemann, Annegret; Kakoschke, Tamara Katharina; Speth, Cornelia

    2016-01-01

    tDetection of carbohydrate antigens is an important means for diagnosis of invasive fungal infections. Fordiagnosis of systemic Aspergillus infections, galactomannan is commonly used, the core antigenic struc-ture of which consists of chains of several galactofuranose moieties. In this study, we ...

  3. An improved three party authenticated key exchange protocol using hash function and elliptic curve cryptography for mobile-commerce environments

    Directory of Open Access Journals (Sweden)

    S.K. Hafizul Islam

    2017-07-01

    Full Text Available In the literature, many three-party authenticated key exchange (3PAKE protocols are put forwarded to established a secure session key between two users with the help of trusted server. The computed session key will ensure secure message exchange between the users over any insecure communication networks. In this paper, we identified some deficiencies in Tan’s 3PAKE protocol and then devised an improved 3PAKE protocol without symmetric key en/decryption technique for mobile-commerce environments. The proposed protocol is based on the elliptic curve cryptography and one-way cryptographic hash function. In order to prove security validation of the proposed 3PAKE protocol we have used widely accepted AVISPA software whose results confirm that the proposed protocol is secure against active and passive attacks including replay and man-in-the-middle attacks. The proposed protocol is not only secure in the AVISPA software, but it also secure against relevant numerous security attacks such as man-in-the-middle attack, impersonation attack, parallel attack, key-compromise impersonation attack, etc. In addition, our protocol is designed with lower computation cost than other relevant protocols. Therefore, the proposed protocol is more efficient and suitable for practical use than other protocols in mobile-commerce environments.

  4. An Enhanced Biometric Based Authentication with Key-Agreement Protocol for Multi-Server Architecture Based on Elliptic Curve Cryptography.

    Science.gov (United States)

    Reddy, Alavalapati Goutham; Das, Ashok Kumar; Odelu, Vanga; Yoo, Kee-Young

    2016-01-01

    Biometric based authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in wireless technologies and associated constraints. Lu et al. recently proposed a robust biometric based authentication with key agreement protocol for a multi-server environment using smart cards. They claimed that their protocol is efficient and resistant to prominent security attacks. The careful investigation of this paper proves that Lu et al.'s protocol does not provide user anonymity, perfect forward secrecy and is susceptible to server and user impersonation attacks, man-in-middle attacks and clock synchronization problems. In addition, this paper proposes an enhanced biometric based authentication with key-agreement protocol for multi-server architecture based on elliptic curve cryptography using smartcards. We proved that the proposed protocol achieves mutual authentication using Burrows-Abadi-Needham (BAN) logic. The formal security of the proposed protocol is verified using the AVISPA (Automated Validation of Internet Security Protocols and Applications) tool to show that our protocol can withstand active and passive attacks. The formal and informal security analyses and performance analysis demonstrates that the proposed protocol is robust and efficient compared to Lu et al.'s protocol and existing similar protocols.

  5. 密码通信下的动态认知逻辑%An Dynamic Epistemic Logic in Cryptography Communication

    Institute of Scientific and Technical Information of China (English)

    陈广明

    2015-01-01

    动态认知逻辑能够完成多主体信息交互活动中认知状态的刻画,但是它缺乏对密码通信的支持,同时密文处理规则的描述和主体密码全能问题也是迫切需要解决的问题.CDEL(Cryptography Dynamic Epistemic Logic)是支持密码规则的一阶认知逻辑,它为开放环境下主体传送信息提供了一个良好的描述方法.文章讨论了该逻辑中的密码公理的引入和密码全知问题的处理,简要介绍了其动态扩展方法和进一步研究的方向.

  6. An Enhanced Biometric Based Authentication with Key-Agreement Protocol for Multi-Server Architecture Based on Elliptic Curve Cryptography.

    Directory of Open Access Journals (Sweden)

    Alavalapati Goutham Reddy

    Full Text Available Biometric based authentication protocols for multi-server architectures have gained momentum in recent times due to advancements in wireless technologies and associated constraints. Lu et al. recently proposed a robust biometric based authentication with key agreement protocol for a multi-server environment using smart cards. They claimed that their protocol is efficient and resistant to prominent security attacks. The careful investigation of this paper proves that Lu et al.'s protocol does not provide user anonymity, perfect forward secrecy and is susceptible to server and user impersonation attacks, man-in-middle attacks and clock synchronization problems. In addition, this paper proposes an enhanced biometric based authentication with key-agreement protocol for multi-server architecture based on elliptic curve cryptography using smartcards. We proved that the proposed protocol achieves mutual authentication using Burrows-Abadi-Needham (BAN logic. The formal security of the proposed protocol is verified using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool to show that our protocol can withstand active and passive attacks. The formal and informal security analyses and performance analysis demonstrates that the proposed protocol is robust and efficient compared to Lu et al.'s protocol and existing similar protocols.

  7. 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.

  8. Analysis of the width-[Formula: see text] non-adjacent form in conjunction with hyperelliptic curve cryptography and with lattices.

    Science.gov (United States)

    Krenn, Daniel

    2013-06-17

    In this work the number of occurrences of a fixed non-zero digit in the width-[Formula: see text] non-adjacent forms of all elements of a lattice in some region (e.g. a ball) is analysed. As bases, expanding endomorphisms with eigenvalues of the same absolute value are allowed. Applications of the main result are on numeral systems with an algebraic integer as base. Those come from efficient scalar multiplication methods (Frobenius-and-add methods) in hyperelliptic curves cryptography, and the result is needed for analysing the running time of such algorithms. The counting result itself is an asymptotic formula, where its main term coincides with the full block length analysis. In its second order term a periodic fluctuation is exhibited. The proof follows Delange's method.

  9. Cryptography with chaotic mixing

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luiz P.L. de [Programa Interdisciplinar de Pos-Graduacao em Computacao Aplicada - PIPCA, Universidade do Vale do Rio dos Sinos - UNISINOS, Av. Unisinos 950, 93022-000 Sao Leopoldo, RS (Brazil)], E-mail: lpluna@unisinos.br; Sobottka, Marcelo [Centro de Modelamiento Matematico, Universidad de Chile, Blanco Encalada 2120, 7o piso Casilla 170/3, Correo 3, Santiago (Chile)], E-mail: sobottka@dim.uchile.cl

    2008-02-15

    We propose a cryptosystem based on one-dimensional chaotic maps of the form H{sub p}(x)=r{sub p}{sup -1}0G0r{sub p}(x) defined in the interval [0, 10{sup p}) for a positive integer parameter p, where G(x)=10x(mod10) and r{sub p}(x)={sup p}{radical}(x), which is a topological conjugacy between G and the shift map {sigma} on the space {sigma} of the sequences with 10 symbols. There are three advantages in comparison with the recently proposed cryptosystem based on chaotic logistic maps F{sub {mu}}(x)={mu}x(1-x) with 3 < {mu} {<=} 4: (a) H{sub p} is always chaotic for all parameters p, (b) the knowledge of an ergodic measure allows assignments of the alphabetic symbols to equiprobable sites of H{sub p}'s domain and (c) for each p, the security of the cryptosystem is manageable against brute force attacks.

  10. Hybrid cryptography key management.

    Energy Technology Data Exchange (ETDEWEB)

    Draelos, Timothy John; Torgerson, Mark Dolan; Neumann, William Douglas; Gallup, Donald R.; Collins, Michael Joseph; Beaver, Cheryl Lynn

    2003-11-01

    Wireless communication networks are highly resource-constrained; thus many security protocols which work in other settings may not be efficient enough for use in wireless environments. This report considers a variety of cryptographic techniques which enable secure, authenticated communication when resources such as processor speed, battery power, memory, and bandwidth are tightly limited.

  11. Fault Analysis in Cryptography

    CERN Document Server

    Joye, Marc

    2012-01-01

    In the 1970s researchers noticed that radioactive particles produced by elements naturally present in packaging material could cause bits to flip in sensitive areas of electronic chips. Research into the effect of cosmic rays on semiconductors, an area of particular interest in the aerospace industry, led to methods of hardening electronic devices designed for harsh environments. Ultimately various mechanisms for fault creation and propagation were discovered, and in particular it was noted that many cryptographic algorithms succumb to so-called fault attacks. Preventing fault attacks without

  12. 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.

  13. Algebraic curves and cryptography

    CERN Document Server

    Murty, V Kumar

    2010-01-01

    It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on

  14. Cryptography: Cracking Codes.

    Science.gov (United States)

    Myerscough, Don; And Others

    1996-01-01

    Describes an activity whose objectives are to encode and decode messages using linear functions and their inverses; to use modular arithmetic, including use of the reciprocal for simple equation solving; to analyze patterns and make and test conjectures; to communicate procedures and algorithms; and to use problem-solving strategies. (ASK)

  15. Quantum Erasure Cryptography

    Science.gov (United States)

    Salih, Hatim

    2016-05-01

    The phenomenon of quantum erasure has long intrigued physicists, but has surprisingly found limited practical application. Here, we propose a protocol for quantum key distribution (QKD) based on quantum erasure, promising inherent security against detector attacks. We particularly demonstrate its security against a powerful detector-blinding attack.

  16. Hybrid cryptography key management.

    Energy Technology Data Exchange (ETDEWEB)

    Draelos, Timothy John; Torgerson, Mark Dolan; Neumann, William Douglas; Gallup, Donald R.; Collins, Michael Joseph; Beaver, Cheryl Lynn

    2003-11-01

    Wireless communication networks are highly resource-constrained; thus many security protocols which work in other settings may not be efficient enough for use in wireless environments. This report considers a variety of cryptographic techniques which enable secure, authenticated communication when resources such as processor speed, battery power, memory, and bandwidth are tightly limited.

  17. Application of Elliptic Curve Cryptography in CA Mobile Payment%椭圆曲线密码在移动支付CA中的应用

    Institute of Scientific and Technical Information of China (English)

    王艳红; 袁春花

    2014-01-01

    The mobile payment based on mobile phone or some other mobile terminals brings people convenience, but its security is-sues are also increasingly prominent. By exploring the structure of mobile payment system and the elliptic curve cryptography system, in view of the security problems of the mobile payment system, this paper designs a CA trust model in the mobile payment system, after analyzing the model, the ellipse curve algorithm is applied to it, ensuring the security of the mobile payment system.%基于手机等移动终端的移动支付在带给大家快捷方便的同时,移动支付的安全性问题也日益突出。通过探讨移动支付系统结构以及椭圆曲线密码系统,针对移动支付系统存在的安全问题,设计了移动支付系统中一种CA的信任模型,对该模型分析之后,将椭圆曲线算法应用到其中,保证了移动支付系统的安全。

  18. 基于Python语言的3DES算法优化%Optimization of 3DES Cryptography Algorithm Based on Python

    Institute of Scientific and Technical Information of China (English)

    李爱宁; 唐勇; 孙晓辉; 刘昕彤

    2011-01-01

    This paper discusses the theory of 3DES Cryptography algorithm, describes the optimization process of PyDES module, which is a pure python module that implements the DES and Triple-DES algorithms; and analyzes the problems and solutions encountered in the optimization process; Finally, the optimized algorithm was tested by profile which is a tool for python program testing, and the result shows that the optimized algorithm can Enhance the Security and speed of the original algorithm,,%介绍了3DES加密算法的原理,描述了对Python语言自带模块pyDES模块中3DES算法的优化过程,分析了3DES算法编程实现过程中效率优化时所遇到的问题及解决方法;最后使用Python语言中的profile工具对优化后的算法进行了测试,数据表明优化后的3DES算法提高了原算法的加解密速度和安全性.

  19. 基于FPGA的椭圆曲线密码(ECC)算法硬件设计%Hardware Design of Elliptic Curve Cryptography(ECC) Based on FPGA

    Institute of Scientific and Technical Information of China (English)

    赵曼; 徐和根

    2013-01-01

    Elliptic curve cryptosystem ( ECC) is a public key encryption system with the most secure unit key security at present, the application of FPGA and hardware design to implement the ECC cryptography have become a concern in the field of information security. The further study of the elliptic curve encryption and decryption is based on the theory, using the verilog hardware description language and schematic design method to achieve the ECC encryption algorithm, with high-speed and low-power characteristics.%椭圆曲线密码体制(elliptic curve cryptosystem,ECC)是目前已知的单位密钥安全性最高的一种公钥加密体制,使用FPGA等硬件设计方法来实现ECC密码系统已成为信息安全领域引人关注的研究.该文在深入研究椭圆曲线加解密理论基础上,使用Verilog硬件描述语言和原理图输入法共同实现了ECC加密算法,具有高速、低功耗的特点.

  20. New QC-LDPC codes based Niederreiter cryptography scheme by using dual public-key%基于QC-LD PC码的双公钥 Niederreiter密码方案

    Institute of Scientific and Technical Information of China (English)

    李冲; 韩益亮

    2016-01-01

    As an important research ofpost-quantum cryptography,code-based cryptography had excellent characteristics of low complexity and high security.With the code-based cryptosystem as the core knowledge,we constructed a new QC-LDPC codes based Niederreiter cryptography scheme by using dual public-key.And the safety analysis shows that the new scheme not only resists the common method of attack,but also meets the IND-CCA2 security.The analysis of performance of the scheme is also given.We can get the conclusions that public key sizes reduce by 63%and the information rate increase by 47%.%基于编码的公钥密码体制作为抗量子攻击密码理论的重要研究内容,具有加/解密复杂性低和安全性高的优异特性。针对Niederreiter公钥密码体制进行了研究,利用QC-LDPC码和双公钥的相关知识构造了一种新的Niederreiter加密方案。安全性分析表明,加密方案能抵抗常见攻击方法的同时满足随机预言机模型下的IND-CCA2安全。最后对方案的性能进行分析,较原有Niederreiter密码的公钥量减少63%和信息率提高47%的结论。

  1. Weng et al., Afr J Tradit Complement Altern Med. (2016) 13(3):133 ...

    African Journals Online (AJOL)

    (Nelson, 2008). In Asian menopausal women, the physical symptoms were the most menopausal prevalent symptoms compared to ... minimize any restraint stress before TEAS treatment. ... The Collection and Measurement of the Samples.

  2. A Content Monitoring System Based on Watermarking and Cryptography%基于水印和密码的内容监控管理系统

    Institute of Scientific and Technical Information of China (English)

    吴果; 孟强; 房礼国; 易青松

    2011-01-01

    Based on an in-depth study of watermarking and cryptography, a new monitoring and management program is proposed for monitoring the outdoor LED advertisement content. In this program, the watermark of copyright is bind for the advertisement content before frequency-domain encryption. Under the premise of ensuring the authoritativeness, fairness and practicality, the overall system security is improved and the legitimate rights of the advertising company is safeguarded. A content monitoring and management system of the outdoor LED advertisement is constructed based on the program. Through the establishment of a data center and a monitoring center, the system enhances the management of the outdoor advertisement prior to its broadcast, and the management of the actual content of the advertisement. The outdoor LED can only play the audited content, and perform video recording comparisons to prevent vulnerabilities.%在对水印和密码技术进行深入研究的基础上,针对户外LED广告内容监控问题,本文提出一种新的监控管理方案.该方案对视频数据嵌入版权保护的水印信息再进行频域加密,在没有降低权威性、公平性、实用性的前提下,提高了整个方案的安全性,维护了广告商的合法权益.基于该方案构建户外LED广告内容监控管理系统,该系统通过建立数据中心和监控中心,加强对广告公司户外广告播出前期审核管理,播出实际内容的监控管理,监督广告公司户外LED的播放内容只能播出审核过的内容,并对播放电脑和户外监控录像对比记录,防止漏洞.

  3. 基于排列的(2,n)门限彩色视觉密码方案%(2,N)THRESHOLD COLOUR VISUAL CRYPTOGRAPHY SCHEME BASED ON PERMUTATION

    Institute of Scientific and Technical Information of China (English)

    陈勤; 吕晓蓉; 张雯

    2011-01-01

    Based on halftone technology and trichromatic principle, every pixel of halftone colour secret image is encrypted and extended into a block composing of only four kinds of pixels: red, green, blue and black. Every block generated has the same pixel ratio but in different arrangement. In accordance with this characteristic, the (2, n) threshold colour visual cryptography scheme can be constructed. The new scheme keeps the advantage of the black-white visual cryptography,that is,no complex calculation is needed for encoding and decoding. And it can better settle the conflict between pixel extension and contrast and remain the configuration ratio undistorted, especially in the circumstances of more participants.%采用半色调技术与三基色原理,将半色调的彩色秘密图像的每个像素加密扩展为只有红、绿、蓝、黑四种像素组成的方块.每个方块中各个像素的比例值相同,但排列方式不同,依照此特点就可构造出关于(2,n)门限的彩色视觉密码方案.该方案保持了黑白视觉密码方案的优点,即加密与解密时无需复杂的运算,且在参与者较多的情况下,能较好地折衷像素扩展度和对比度,并保持外形比例不失真.

  4. Quantum cryptography with squeezed states

    CERN Document Server

    Hillery, M

    1999-01-01

    A quantum key distribution scheme based on the use of displaced squeezed vacuum states is presented. The states are squeezed in one of two field quadrature components, and the value of the squeezed component is used to encode a character from an alphabet. The uncertainty relation between quadrature components prevents an eavesdropper from determining both with enough precision to determine the character being sent. Losses degrade the performance of this scheme, but it is possible to use phase-sensitive amplifiers to boost the signal and partially compensate for their effect.

  5. Computation, cryptography, and network security

    CERN Document Server

    Rassias, Michael

    2015-01-01

    Analysis, assessment, and data management are core competencies for operation research analysts. This volume addresses a number of issues and developed methods for improving those skills. It is an outgrowth of a conference held in April 2013 at the Hellenic Military Academy, and brings together a broad variety of mathematical methods and theories with several applications. It discusses directions and pursuits of scientists that pertain to engineering sciences. It is also presents the theoretical background required for algorithms and techniques applied to a large variety of concrete problems. A number of open questions as well as new future areas are also highlighted.   This book will appeal to operations research analysts, engineers, community decision makers, academics, the military community, practitioners sharing the current “state-of-the-art,” and analysts from coalition partners. Topics covered include Operations Research, Games and Control Theory, Computational Number Theory and Information Securi...

  6. High Data Rate Quantum Cryptography

    Science.gov (United States)

    Kwiat, Paul; Christensen, Bradley; McCusker, Kevin; Kumor, Daniel; Gauthier, Daniel

    2015-05-01

    While quantum key distribution (QKD) systems are now commercially available, the data rate is a limiting factor for some desired applications (e.g., secure video transmission). Most QKD systems receive at most a single random bit per detection event, causing the data rate to be limited by the saturation of the single-photon detectors. Recent experiments have begun to explore using larger degree of freedoms, i.e., temporal or spatial qubits, to optimize the data rate. Here, we continue this exploration using entanglement in multiple degrees of freedom. That is, we use simultaneous temporal and polarization entanglement to reach up to 8.3 bits of randomness per coincident detection. Due to current technology, we are unable to fully secure the temporal degree of freedom against all possible future attacks; however, by assuming a technologically-limited eavesdropper, we are able to obtain 23.4 MB/s secure key rate across an optical table, after error reconciliation and privacy amplification. In this talk, we will describe our high-rate QKD experiment, with a short discussion on our work towards extending this system to ship-to-ship and ship-to-shore communication, aiming to secure the temporal degree of freedom and to implement a 30-km free-space link over a marine environment.

  7. Direction Cryptography in Quantum Communications

    CERN Document Server

    Simmons, W; Simmons, Walter; Pakvasa, Sandip

    2003-01-01

    We examine a situation in which an information-carrying signal is sent from two sources to a common receiver. The radiation travels through free space in the presence of noise. The information resides in a relationship between the two beams. We inquire into whether itis possible, in principle, that the locations of the transmitters can be concealed from a party who receives the radiation and decodes the information. Direction finding entails making a set of measurements on asignal and constructing an analytic continuation of the time dependent fields from the results. The fact that this process is generally different in quantum mechanics and in classical electrodynamics is the basis in this investigation. We develop a model based upon encoding information into a microscopic, transverse, non-local quantum image (whose dimensions are of the order of a few wavelengths) and using a detector of a type recently proposed by Strekalov et al. The optical system, which uses SPDC (Spontaneous Parametric Down Conversion)...

  8. Secure Distributed Databases Using Cryptography

    Directory of Open Access Journals (Sweden)

    Ion IVAN

    2006-01-01

    Full Text Available The computational encryption is used intensively by different databases management systems for ensuring privacy and integrity of information that are physically stored in files. Also, the information is sent over network and is replicated on different distributed systems. It is proved that a satisfying level of security is achieved if the rows and columns of tables are encrypted independently of table or computer that sustains the data. Also, it is very important that the SQL - Structured Query Language query requests and responses to be encrypted over the network connection between the client and databases server. All this techniques and methods must be implemented by the databases administrators, designer and developers in a consistent security policy.

  9. BIOMETRIC CRYPTOGRAPHY AND NETWORK AUTHENTICATION

    Directory of Open Access Journals (Sweden)

    Tonimir Kišasondi

    2007-06-01

    Full Text Available In this paper we will present some schemes for strengthening network authentification over insecure channels with biometric concepts or how to securely transfer or use biometric characteristics as cryptographic keys. We will show why some current authentification schemes are insufficient and we will present our concepts of biometric hashes and authentification that rely on unimodal and multimodal biometrics. Our concept can be applied on any biometric authentification scheme and is universal for all systems.

  10. Dialable Cryptography for Wireless Networks

    Science.gov (United States)

    2008-03-01

    www.ansi.org/. 3. Bandera , C., et al., Wireless Just-in-Time Training of Mobile Skilled Support Personnel. Proc. of SPIE, 2006. (62500R-1). 4. Basagni, S...where she stood up the Information Assurance Office for JSTARS. She later transferred to Kirtland Air Force Base, New Mexico to work with AFOTEC in

  11. Securing Mobile Data using Cryptography

    Directory of Open Access Journals (Sweden)

    Shikhar Bhagoliwal

    2016-05-01

    Full Text Available Portability increases the probability for a wireless device to be stolen or lost. These devices usually carry sensitive business or private information. Government Employees store classified documents on their mobile devices. Corporate users save confidential files, PINs, Passwords on their devices. So the content of such devices should be protected from unauthorized access. However, the protection provided should not be heavy for a mobile phone because it would minimize the computing power, storage space, battery lifetime. To prevent this from happening, we are providing an algorithm which would ensure data privacy for the end users. ASCII values of plain text will be used to generate a secret key and same key would be used for decryption. It can be said to be a symmetric encryption algorithm because same key is used to encrypt and decrypt the data. A Secret key will be randomly generated from the ASCII values of plain text which when encrypted with the plain text will provide a cipher text which will be sent back to the Application with the key. For Decryption, cipher text and key will be fetched from Application and decryption process will occur at server. By this method this application will not be heavy for a mobile phone and this would be an efficient method for data security.

  12. Software Obfuscation With Symmetric Cryptography

    Science.gov (United States)

    2008-03-01

    functions are proposed. Simple equations, such as y = a * b + c, trigonometric functions, such as y = cos(x), and the Fibonacci sequence are considered...o f 1 ’s p e r o u tp u t b it Frequency ( Sequence ) bit11 bit10 bit9 bit8 bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0 Fibonacci 0.00 0.00 1.00 1.00...of y = a * b + c Against Random Functions ...............84 Appendix C: Black-box Analysis of Fibonacci Against Random Functions

  13. Elliptic Curve Cryptography with Java

    Science.gov (United States)

    Klima, Richard E.; Sigmon, Neil P.

    2005-01-01

    The use of the computer, and specifically the mathematics software package Maple, has played a central role in the authors' abstract algebra course because it provides their students with a way to see realistic examples of the topics they discuss without having to struggle with extensive computations. However, Maple does not provide the computer…

  14. Practical Computer Security through Cryptography

    Science.gov (United States)

    McNab, David; Twetev, David (Technical Monitor)

    1998-01-01

    The core protocols upon which the Internet was built are insecure. Weak authentication and the lack of low level encryption services introduce vulnerabilities that propagate upwards in the network stack. Using statistics based on CERT/CC Internet security incident reports, the relative likelihood of attacks via these vulnerabilities is analyzed. The primary conclusion is that the standard UNIX BSD-based authentication system is by far the most commonly exploited weakness. Encryption of Sensitive password data and the adoption of cryptographically-based authentication protocols can greatly reduce these vulnerabilities. Basic cryptographic terminology and techniques are presented, with attention focused on the ways in which technology such as encryption and digital signatures can be used to protect against the most commonly exploited vulnerabilities. A survey of contemporary security software demonstrates that tools based on cryptographic techniques, such as Kerberos, ssh, and PGP, are readily available and effectively close many of the most serious security holes. Nine practical recommendations for improving security are described.

  15. Free-space quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

    An experimental free-space quantum key distribution (QKD) system has been tested over an outdoor optical path of {approximately}1 km under nighttime conditions at Los Alamos National Laboratory. This system employs the Bennett 92 protocol; here the authors give a brief overview of this protocol, and describe the experimental implementation of it. An analysis of the system efficiency is presented, as well as a description of the error detection protocol, which employs a two-dimensional parity check scheme. Finally, the susceptibility of this system to eavesdropping by various techniques is determined. Possible applications include the rekeying of satellites in low earth orbit.

  16. 基于多变量公钥密码体制的代理重签名方案%Proxy Re-signature Scheme Based on Multivariate Public Key Cryptography

    Institute of Scientific and Technical Information of China (English)

    孙昌毅; 李益发; 斯雪明

    2012-01-01

    Almost proxy re-signature schemes are hardness of big integer factoring problem and Discrete Logarithm(DL) problem. But the quantum computer can solve this question in polynomial time, which may cause potential security risks to the schemes. This paper uses the characteristics that multivariate public key cryptography can resist quantum computer attack, to design a new proxy re-signature scheme. Theoretical analysis shows that the scheme fits internal and external security, and it is efficient.%代理重签名方案大多是基于大数分解和离散对数难题设计的,而量子计算机能在多项式时间内求解这些难题,从而给方案造成安全隐患.为此,利用多变量公钥密码体制可以抵抗量子攻击的特性,设计一个新的代理重签名方案.理论分析结果表明,该方案满足内部安全性和外部安全性,且运算效率高.

  17. Symmetrical Key Automatic Changing Cryptography Based on Simple Hybrid Selection Coding%基于简易混合选择编码的对称密钥自变动加密

    Institute of Scientific and Technical Information of China (English)

    罗俊; 张国平

    2012-01-01

    Aiming at the encryption system with lower security requirements, this paper puts forward a symmetrical key automatic changing cryptography scheme based on simple hybrid selection coding, with the combination of unilateral canonical Huffman coding and fixed-length coding. The statistical results of plaintext are used as their own encrypted key and coding basis, which makes the scheme to be easy to implement and calculate and of cost low. It is proved that when the keys are completely unknown, the cracking of the encryption system has great difficulty.%针对安全性要求不太高的加密系统,将单边范式Huffman编码与等长编码相结合,提出一种基于混合选择编码的对称密钥自变动加密方案.通过将明文的统计结果作为自身加密的密钥和编码依据,使方案易于实现,且计算存储成本低.理论分析结果证明,在密钥完全未知的情况下破解该加密体制难度较大.

  18. Two-level information management scheme based on visual cryptography and QR code%基于视觉密码和QR码的两级信息管理方案

    Institute of Scientific and Technical Information of China (English)

    刘莺迎; 付正欣; 王益伟

    2016-01-01

    设计了一种新的扩展多秘密视觉密码,能够分享n个公开信息和n-1个隐私信息,其像素扩展度为4且相对差为1/4。在此基础上,结合QR码提出了一种两级信息管理方案,其中一般参与者的共享份可以呈现参与者公开信息的QR码,而且管理者的共享份与一般共享份叠加后,可以呈现参与者隐私信息的QR码。实验结果表明,公开信息和隐私信息的QR码尽管存在失真,仍可以被正确识别。%This paper designed a new extended multi-secret visual cryptography scheme (EMVCS),which could share n pub-lic information and n-1 private information.The pixel expansion of EMVCS was 4,and the relative difference was 1/4.Fur-thermore,it proposed a new two-level information management scheme based on EMVCS and QR code,in which the common participants’shares could display public information QR code.Meanwhile,the private information QR code of common partici-pants would be shown by stacking the share of manager and common participant.The experimental results demonstrate that the distorted QR codes of public and private information can be recognized correctly.

  19. Certificateless Multi-receiver Signcryption Scheme Based on Multivariate Public Key Cryptography%基于多变量公钥密码体制的无证书多接收者签密体制

    Institute of Scientific and Technical Information of China (English)

    李慧贤; 陈绪宝; 庞辽军; 王育民

    2012-01-01

    针对基于身份的多接收者签密方案不能抵抗量子攻击以及存在的密钥托管问题,基于多变量公钥密码体制,提出一个多接收者模型下的无证书签密方案.新方案不仅避免了基于身份密码体制的密钥托管问题,而且继承了多变量公钥密码体制的优势,实现了“抗量子攻击”的高安全性.与现有方案相比,新方案无需双线性对操作,具有更少的计算量,更高的计算效率,适用于智能卡等计算能力较小的终端设备.最后,在随机预言模型下,给出了该文方案基于MQ困难问题假设和IP困难问题假设的安全性证明.分析表明,该文方案具有不可否认性、前向安全性、后向安全性、保护接收者隐私等安全属性.%Aiming at the vulnerability under quantum attacks and the inherent key escrow problem of the existing ID-based multi-receiver signcryption schemes, we propose an efficient certificateless multi-receiver signcryption scheme (CLMSC), which is based on the multivariate public key cryptography (MPKC). The new scheme can not only avoid the inherent key escrow problem in the identity-based cryptographic system,but also have the advantage of MPKC, that is, it can withstand the quantum attack. The proposed scheme does not require any pairing operations in signcrypting a message for any number of receivers. Therefore, compared with the existing signcryption schemes, the proposed scheme is more efficient, and thus it is suitable for terminals which have lower computation capacity like smart card. Finally, we prove its semantic security under the hardness of Multivariate Quadratic (MQ) problem and its unforgeability under the Isomorphism of Polynomials (IP) assumption in the random oracle model respectively. The proposed scheme also has the security properties of non-repudiation, forward security, backward security and the recipient privacy protection.

  20. Trust-Distributed-Based Authentication Mechanism Using Hierarchical Identity-Based Cryptography%基于 HIBC 的云信任分散统一认证机制

    Institute of Scientific and Technical Information of China (English)

    田俊峰; 孙可辉

    2015-01-01

    开放式云环境中,整合在同一云基础设施平台上的服务提供商之间既相互依存,又相互独立,相互合作的同时又相互竞争,不能接受同一个公用中央机构的完全控制。适用于大规模云环境下的统一认证机制面临中央机构安全瓶颈、密钥托管等问题。为解决此类问题,基于 HIBC(hierarchical identity‐based cryptography)算法,依据信任分散理论,提出了一种将中央机构的秘密值秘密共享给参与主体的思想,构建了一套完整的混合云统一认证机制,既实现了统一认证的需求又提高了参与主体对自身的控制能力,中央机构核心工作改由参与主体合作完成。运用伪公钥和滑动窗口机制有效防止了内部合谋攻击和外部截获攻击,加大了敌手攻击的难度。同时给出了跨域认证方案和会话密钥协商方案。最后,比较分析了所提出的方案在不依赖可信中心、无需证书维护、无密钥托管、跨域认证、监督机制、可规模使用等方面具有的优越性。%The relationship among cloud service providers is becoming more and more complex ,while these service providers are integrated on a public large‐scale cloud computing platform .Cooperative relation and competitive relation coexist . Although a unified authentication is necessary for integrating , providers aren’t able to totally trust in a unique central authority . Single sign‐on architecture could be confronted with the problems (such as security bottleneck , mandatory dependencies ,key escrow ,etc .) brought by the central authority .In order to solve these problems , an authentication mechanism based on trust dispersion theory using hierarchical identity ‐based cryptography is proposed in this paper .The secret value of central authority will be shared by service providers ,as a result ,not only the unified authentication is achieved ,but also providers’ ability of self control

  1. Tamper Resilient Cryptography Without Self-Destruct

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Faust, Sebastian; Mukherjee, Pratyay;

    2013-01-01

    a general construction showing that any cryptographic primitive where the secret key can be chosen as a uniformly random string can be made s ecure against bounded tampering and leakage. This holds in a restricted model where the ta mpering functions must be chosen from a set of bounded size after...... arbitrarily tamper with the prover’s state a bounded number of times and/or obtain some bounded amount of leakage. Interestingly, for the Okamoto scheme we can allow also independent tampering with the public parameters. 3. We show a bounded tamper and leakage resilient CCA secure public key cryptosystem...

  2. Encrypting Binary Bits via Quantum Cryptography

    Institute of Scientific and Technical Information of China (English)

    ZENGGuihua

    2004-01-01

    A quantum cryptographic algorithm, which may be exploited to encrypt classic information is investigated theoretically in this paper. The proposed algorithm can prevent quantum attack strategy as well as classic attack strategy. A proof-in-principle of experimental demonstration, which exploits optical fibre communication technology and photon technology, is suggested.

  3. The influence of omniscient technology on cryptography

    Science.gov (United States)

    Huang, Weihong; Li, Jian

    2009-07-01

    Scholars agree that concurrent algorithms are an interesting new topic in the field of cyberinformatics, and hackers worldwide concur. In fact, few end-users would disagree with the evaluation of architecture. We propose a Bayesian tool for harnessing massive multiplayer online role-playing games (FIRER), which we use to prove that the well-known ubiquitous algorithm for the improvement of wide-area networks by Karthik Lakshminarayanan is in Co-NP.

  4. Continuous variable quantum cryptography using coherent states.

    Science.gov (United States)

    Grosshans, Frédéric; Grangier, Philippe

    2002-02-04

    We propose several methods for quantum key distribution (QKD) based on the generation and transmission of random distributions of coherent or squeezed states, and we show that they are secure against individual eavesdropping attacks. These protocols require that the transmission of the optical line between Alice and Bob is larger than 50%, but they do not rely on "sub-shot-noise" features such as squeezing. Their security is a direct consequence of the no-cloning theorem, which limits the signal-to-noise ratio of possible quantum measurements on the transmission line. Our approach can also be used for evaluating various QKD protocols using light with Gaussian statistics.

  5. Continuous variable quantum cryptography using coherent states

    CERN Document Server

    Grosshans, F; Grosshans, Fr\\'ed\\'eric; Grangier, Philippe

    2002-01-01

    We propose several methods for quantum key distribution (QKD), based upon the generation and transmission of random distributions of coherent or squeezed states. We show that these protocols are secure against individual eavesdropping attacks, provided that the transmission of the optical line between Alice and Bob is larger than 50 %. The security of the protocol is related to the no-cloning theorem, that limits the signal to noise ratio of possible quantum measurements on the transmission line, even though the transmitted light has no "non-classical" feature such as squeezing. We show also that our approach can be used for evaluating any QKD protocol using light with gaussian statistics.

  6. Cryptography based on spatial chaotic system

    Science.gov (United States)

    Sun, Fuyan; Lü, Zongwang

    2010-08-01

    Encryption of images is different from that of texts due to some intrinsic features of images such as bulk data capacity and high redundancy, which is generally difficult to handle by traditional methods. This paper proposes a new spatial chaos system(SCS), which is investigated by conducting FIPS 140-1 statistic test, and is especially useful for encryption of digital images. It is shown how to adapt a two dimensional(2D) ergodic matrix obtained from SCS to permute the positions of image pixels and confuse the relationship between the cipher image and plain image simultaneously. Experimental results show that the performance and security of the proposed cryptographic system are better than those of existing lower dimensional chaotic cryptographic systems.

  7. Practical Leakage-Resilient Symmetric Cryptography

    DEFF Research Database (Denmark)

    Faust, Sebastian; Pietrzak, Krzysztof; Schipper, Joachim

    2012-01-01

    -adaptively. For example, we show that a three round Feistel network instantiated with a leakage resilient PRF yields a leakage resilient PRP if the inputs are chosen non-adaptively (This complements the result of Dodis and Pietrzak [CRYPTO’10] who show that if a adaptive queries are allowed, a superlogarithmic number...... of rounds is necessary.) We also show that a minor variation of the classical GGM construction gives a leakage resilient PRF if both, the leakage-function and the inputs, are chosen non-adaptively...

  8. Applications of Maple To Algebraic Cryptography.

    Science.gov (United States)

    Sigmon, Neil P.

    1997-01-01

    Demonstrates the use of technology to enhance the appreciation of applications involving abstract algebra. The symbolic manipulator Maple can perform computations required for a linear cryptosystem. One major benefit of this process is that students can encipher and decipher messages using a linear cryptosystem without becoming confused and…

  9. Motivating the Concept of Eigenvectors via Cryptography

    Science.gov (United States)

    Siap, Irfan

    2008-01-01

    New methods of teaching linear algebra in the undergraduate curriculum have attracted much interest lately. Most of this work is focused on evaluating and discussing the integration of special computer software into the Linear Algebra curriculum. In this article, I discuss my approach on introducing the concept of eigenvectors and eigenvalues,…

  10. Hardware Random number Generator for cryptography

    CERN Document Server

    Soorat, Ram; Vudayagiri, Ashok

    2015-01-01

    One of the key requirement of many schemes is that of random numbers. Sequence of random numbers are used at several stages of a standard cryptographic protocol. A simple example is of a Vernam cipher, where a string of random numbers is added to massage string to generate the encrypted code. It is represented as $C=M \\oplus K $ where $M$ is the message, $K$ is the key and $C$ is the ciphertext. It has been mathematically shown that this simple scheme is unbreakable is key K as long as M and is used only once. For a good cryptosystem, the security of the cryptosystem is not be based on keeping the algorithm secret but solely on keeping the key secret. The quality and unpredictability of secret data is critical to securing communication by modern cryptographic techniques. Generation of such data for cryptographic purposes typically requires an unpredictable physical source of random data. In this manuscript, we present studies of three different methods for producing random number. We have tested them by study...

  11. Staging quantum cryptography with chocolate ballsa)

    Science.gov (United States)

    Svozil, Karl

    2006-09-01

    Moderated by a director, laypeople and students assume the role of quanta and enact a quantum cryptographic protocol. The performance is based on a generalized urn model capable of reproducing complementarity even for classical chocolate balls.

  12. Low-Power Public Key Cryptography

    Energy Technology Data Exchange (ETDEWEB)

    BEAVER,CHERYL L.; DRAELOS,TIMOTHY J.; HAMILTON,VICTORIA A.; SCHROEPPEL,RICHARD C.; GONZALES,RITA A.; MILLER,RUSSELL D.; THOMAS,EDWARD V.

    2000-11-01

    This report presents research on public key, digital signature algorithms for cryptographic authentication in low-powered, low-computation environments. We assessed algorithms for suitability based on their signature size, and computation and storage requirements. We evaluated a variety of general purpose and special purpose computing platforms to address issues such as memory, voltage requirements, and special functionality for low-powered applications. In addition, we examined custom design platforms. We found that a custom design offers the most flexibility and can be optimized for specific algorithms. Furthermore, the entire platform can exist on a single Application Specific Integrated Circuit (ASIC) or can be integrated with commercially available components to produce the desired computing platform.

  13. Motivating the Concept of Eigenvectors via Cryptography

    Science.gov (United States)

    Siap, Irfan

    2008-01-01

    New methods of teaching linear algebra in the undergraduate curriculum have attracted much interest lately. Most of this work is focused on evaluating and discussing the integration of special computer software into the Linear Algebra curriculum. In this article, I discuss my approach on introducing the concept of eigenvectors and eigenvalues,…

  14. Quantum cryptography with an ideal local relay

    DEFF Research Database (Denmark)

    Spedalieri, Gaetana; Ottaviani, Carlo; Braunstein, Samuel L.

    2015-01-01

    We consider two remote parties connected to a relay by two quantum channels. To generate a secret key, they transmit coherent states to the relay, where the states are subject to a continuous-variable (CV) Bell detection. We study the ideal case where Alice's channel is lossless, i.e., the relay...

  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. Quantum Cryptography with Entangled QuNits

    Institute of Scientific and Technical Information of China (English)

    DENG Hong-Liang; FANG Xi-Ming

    2005-01-01

    @@ We propose an extension of quantum key distribution based on encoding the key into quNits, i.e. quantum states in an N-dimensional Hilbert space. In our protocol, we adopt asymmetric measurement scheme resulting in an efficiency higher than previous protocols and a generalized Bell inequality [Phys. Rev. Lett. 92 (2004) 130404] is employed to detect the presence of an eavesdropper Eve. We also derive the information gained by a potential eavesdropper Eve applying a cloning-based attack and the maximal error rate which measures the robustness of the protocol. The result shows that the security of our scheme increases with the dimension N.

  17. Applications of Fast Truncated Multiplication in Cryptography

    Directory of Open Access Journals (Sweden)

    Laszlo Hars

    2006-12-01

    Full Text Available Truncated multiplications compute truncated products, contiguous subsequences of the digits of integer products. For an n-digit multiplication algorithm of time complexity O(nα, with 1<α≤2, there is a truncated multiplication algorithm, which is constant times faster when computing a short enough truncated product. Applying these fast truncated multiplications, several cryptographic long integer arithmetic algorithms are improved, including integer reciprocals, divisions, Barrett and Montgomery multiplications, 2n-digit modular multiplication on hardware for n-digit half products. For example, Montgomery multiplication is performed in 2.6 Karatsuba multiplication time.

  18. Public key cryptography from weaker assumptions

    DEFF Research Database (Denmark)

    Zottarel, Angela

    This dissertation is focused on the construction of public key cryptographic primitives and on the relative security analysis in a meaningful theoretic model. This work takes two orthogonal directions. In the first part, we study cryptographic constructions preserving their security properties also...

  19. Applications of Fast Truncated Multiplication in Cryptography

    Directory of Open Access Journals (Sweden)

    Hars Laszlo

    2007-01-01

    Full Text Available Truncated multiplications compute truncated products, contiguous subsequences of the digits of integer products. For an n-digit multiplication algorithm of time complexity O(nα, with 1<α≤2, there is a truncated multiplication algorithm, which is constant times faster when computing a short enough truncated product. Applying these fast truncated multiplications, several cryptographic long integer arithmetic algorithms are improved, including integer reciprocals, divisions, Barrett and Montgomery multiplications, 2n-digit modular multiplication on hardware for n-digit half products. For example, Montgomery multiplication is performed in 2.6 Karatsuba multiplication time.

  20. DNA Technique, cryptography, bit exchange, Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Meenakshi Moza

    2016-07-01

    Full Text Available Internet reliability and performance is based mostly on the underlying routing protocols. The current traffic load has to be taken into account for computation of paths in routing protocols. Addressing the selection of path, from a known source to destination is the basic aim of this paper. Making use of multipoint crossover and mutation is done for optimum and when required alternate path determination. Network scenario which consists of nodes that are fixed and limited to the known size of topology, comprises the population size. This paper proposes a simple method of calculating the shortest path for a network using Genetic Algorithm (GA, which is capable of giving an efficient, dynamic and consistent solution in spite of, what topology, changes in link and node happen and volume of the network. GA is used in this paper for optimization of routing. It helps us in enhancing the performance of the routers.

  1. Chaos-based Cryptography for Cloud Computing

    OpenAIRE

    Tobin, Paul; Tobin, Lee; McKeever, Michael; Blackledge, Jonathan

    2017-01-01

    Cloud computing and poor security issues have quadrupled over the last six years and with the alleged presence of backdoors in common encryption ciphers, has created a need for personalising the encryption process by the client. In 2007, two Microsoft employees gave a presentation ``On the Possibility of a backdoor in the NIST SP800-90 Dual Elliptic Curve Pseudo Random Number Generators'' and was linked in 2013 by the New York Times with notes leaked by Edward Snowden. This confirmed backdoor...

  2. Applications of tripled chaotic maps in cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Behnia, S. [Department of Physics, IAU, Urmia (Iran, Islamic Republic of)], E-mail: s.behnia@iaurmia.ac.ir; Akhshani, A. [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Akhavan, A. [School of Computer Science, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Mahmodi, H. [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia)

    2009-04-15

    Security of information has become a major issue during the last decades. New algorithms based on chaotic maps were suggested for protection of different types of multimedia data, especially digital images and videos in this period. However, many of them fundamentally were flawed by a lack of robustness and security. For getting higher security and higher complexity, in the current paper, we introduce a new kind of symmetric key block cipher algorithm that is based on tripled chaotic maps. In this algorithm, the utilization of two coupling parameters, as well as the increased complexity of the cryptosystem, make a contribution to the development of cryptosystem with higher security. In order to increase the security of the proposed algorithm, the size of key space and the computational complexity of the coupling parameters should be increased as well. Both the theoretical and experimental results state that the proposed algorithm has many capabilities such as acceptable speed and complexity in the algorithm due to the existence of two coupling parameters and high security. Note that the ciphertext has a flat distribution and has the same size as the plaintext. Therefore, it is suitable for practical use in secure communications.

  3. Quantum cryptography: Round-robin with photons

    Science.gov (United States)

    Fröhlich, Bernd; Yuan, Zhiliang

    2015-12-01

    Last year the common notion that signal disturbance has to be monitored in a quantum cryptographic link to guarantee secrecy was challenged by a new protocol. The formidable task of demonstrating it experimentally has now been achieved.

  4. MOBILE PAYMENTMETHODBASED ON PUBLIC-KEY CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Adnan A. Hnaif

    2015-03-01

    Full Text Available Mobile payment is defined as mobile money, which is considered as an attractive alternative for cash, cheque, or credit. In this paper we propose a new secure mobile paymentmethod. This method is summarized in three processes: firstly, the authentication process, which involves the authentication phases for the applied customers. Secondly, the member recognition process which tests and ensures the customer membership by the market server. Finally, payment processwhich will be done by ciphering the customer information using public-key encryption cryptosystem (RSA, to be submitted over an insecure network to the market server. Actually, this mobile payment methodis more efficient than otherpayment methods since the customer can pay from his/her own mobilephone without any extra cost and effort. The RSA public-key encryption system ensures the security of the proposed method. However, to prevent a brute force attack, the choice of the key size becomes crucial.

  5. Leakage-resilient cryptography from minimal assumptions

    DEFF Research Database (Denmark)

    Hazay, Carmit; López-Alt, Adriana; Wee, Hoeteck;

    2013-01-01

    We present new constructions of leakage-resilient cryptosystems, which remain provably secure even if the attacker learns some arbitrary partial information about their internal secret key. For any polynomial ℓ, we can instantiate these schemes so as to tolerate up to ℓ bits of leakage. While the...

  6. Permutation parity machines for neural cryptography.

    Science.gov (United States)

    Reyes, Oscar Mauricio; Zimmermann, Karl-Heinz

    2010-06-01

    Recently, synchronization was proved for permutation parity machines, multilayer feed-forward neural networks proposed as a binary variant of the tree parity machines. This ability was already used in the case of tree parity machines to introduce a key-exchange protocol. In this paper, a protocol based on permutation parity machines is proposed and its performance against common attacks (simple, geometric, majority and genetic) is studied.

  7. Introducing Summer Camp Students to Modern Cryptography

    Science.gov (United States)

    Griffiths, Barry J.

    2015-01-01

    For countries to remain competitive in the global economy, it is important to cultivate the next generation of native mathematicians. However, this goal has been increasingly challenging in the United States where, despite the tremendous increase in university enrollment during recent decades, the number of students studying mathematics has…

  8. Applications of Maple To Algebraic Cryptography.

    Science.gov (United States)

    Sigmon, Neil P.

    1997-01-01

    Demonstrates the use of technology to enhance the appreciation of applications involving abstract algebra. The symbolic manipulator Maple can perform computations required for a linear cryptosystem. One major benefit of this process is that students can encipher and decipher messages using a linear cryptosystem without becoming confused and…

  9. Cryptography Would Reveal Alterations In Photographs

    Science.gov (United States)

    Friedman, Gary L.

    1995-01-01

    Public-key decryption method proposed to guarantee authenticity of photographic images represented in form of digital files. In method, digital camera generates original data from image in standard public format; also produces coded signature to verify standard-format image data. Scheme also helps protect against other forms of lying, such as attaching false captions.

  10. 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...

  11. Practical free-space quantum cryptography

    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.; Simmons, C.M.

    1998-12-01

    An experimental free-space quantum key distribution (QKD) system has been tested over an outdoor optical path of {approx} 1 km under nighttime conditions at Los Alamos National Laboratory. This system employs the Bennett 92 protocol; here the authors give a brief overview of this protocol, and describe the experimental implementation of it. An analysis of the system efficiency is presented, as well as a description of the error detection protocol, which employs a two-dimensional parity check scheme. Finally, the susceptibility of this system to eavesdropping by various techniques is determined, and the effectiveness of privacy amplification procedures is discussed. The conclusions are that free-space QKD is both effective and secure; possible applications include the rekeying of satellites in low earth orbit.

  12. Finite key analysis in quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, T.

    2007-10-31

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

  13. Logic Functions for Cryptography - A Tutorial

    Science.gov (United States)

    2009-05-01

    Lemma 2.1. That is, if f is a bent function, from Lemma 2.4, then so is f ⊕ 1 = f . This proves Lemma 2.1. Definition 2.8 The PPRM (positive polarity Reed...binary decision diagram ( BDD ). The disjoint quadratic function was among the first forms known to be bent [16]. It is interesting that all bent

  14. A Computational Game Theoretic Framework for Cryptography

    Science.gov (United States)

    2009-12-31

    immediately from our result that known protocols, such as those in [Ben-Or, Goldwasser, and Wigderson 1988; Canetti 2001; Goldreich, Micali, and Wigderson 1987...In Proc. CRYPTO 2000, Lecture Notes in Computer Science, Volume 1880, pp. 236–254. Springer-Verlag. Canetti , R. (2001). Universally composable

  15. A Foundational Proof Framework for Cryptography

    Science.gov (United States)

    2015-05-01

    HMAC: Security without collision- resistance. InAdvanc in Cryptolo (CRYPTO) 2006 (pp. 602–619). Springer. [14] Bellare, M., Canetti , R., & Krawczyk, H...symmetric encryption with support for boolean queries. In R. Canetti & J. Garay (Eds.),Advanc in Cryptolo (CRYPTO) 2013, volume 8042 of Lecture Not in

  16. Discussions on Students’ Innovative Practice in Universities---Taking Study on Quantum Cryptography as an Example%高校中开展大学生创新实践活动的探讨--以北京邮电大学的量子密码研究为例

    Institute of Scientific and Technical Information of China (English)

    郭奋卓; 李慧娟; 高飞

    2016-01-01

    Based on the authors’ experience of guiding undergraduates’ innovative practice and observation of research activities of undergraduates in Princeton University, the roles of teachers and university in the innovative practice of undergraduate are analyzed, and some experience are given. Finally, three guidance suggestions are provided for the quantum cryptography research field. The above analysis, summary and suggestions are also helpful to the innovational education in other research fields.%结合作者指导本科生创新实践的经验和在美国普林斯顿大学访学期间对该校本科生科研活动的考察,分析了本科生创新实践过程中指导教师和学校的角色定位,并给出若干经验总结。以量子密码研究方向为例,对从事理论研究的创新实践给出了三点具体的指导性建议。上述分析总结以及相关的建议对于其他研究方向的创新实践也具有一定的指导意义。

  17. 林律师捐地产翁所长建台站%Lawyer Mr. Lin Contributed Landed Property, Director Weng Founded the Station

    Institute of Scientific and Technical Information of China (English)

    高继宗

    2004-01-01

    @@ 在地震工作者中,无人不知我国的第一个地震观测台是鹫峰地震台;无人不晓主持鹫峰地震台工作的是李善邦先生.对于鹫峰地震台的筹建人,我国现代地震科学的开拓者翁文灏先生则知者不多,对于捐献鹫峰台址地产的林行规律师,知者更是寥寥无几.

  18. Analysis and prediction of area- and energy-consumption of optimized polynomial multipliers in hardware for arbitrary GF(2{sup n}) for elliptic curve cryptography; Analyse und Vorhersage des Flaechen- und Energieverbrauches-optimaler Hardware Polynom-Multiplizierer fuer GF(2{sup n}) fuer elliptische Kurven Kryptographie

    Energy Technology Data Exchange (ETDEWEB)

    Dyka, Zoya

    2012-04-13

    During recent years elliptic curve cryptography (ECC) has gained significant attention especially for devices with scarce resources such as wireless sensor nodes. Hardware implementations are considered to be the key enabler for using ECC on this class of devices. Out of the operations needed to execute ECC the polynomial multiplication is the one which is investigated most since it is one of the most complex field operations and executed very often. The majority of research papers focuses on reducing the number of partial- multiplications while neglecting the increased effort for additions of the partial products. This thesis investigates how the latter can be optimized. A reduction of additions can be achieved by using pre-defined processing sequences for summing up partial products. In this work a method to find the optimized processing sequence is presented. It is applied to 10 multiplication methods of polynomials over GF(2{sup n}). For example when applied to the generalized Karatsuba multiplication [18] the optimized processing sequence saves up to 39 per cent of XOR-gates in average for polynomials with a length up to 600 bits. In addition it is known that combining different multiplication methods reduced the total complexity of the multiplier. For example using the classical MM for calculation of small partial products in combination with other MMs can improve chip-parameters of the resulting multipliers. An optimal combination of several multiplication approaches for which the optimized processing sequence of XOR-operations is used reduces the area and energy consumption of the resulting multiplier significantly. This work presents an algorithm to determine the optimal combination of multiplication methods with pre-defined processing sequences for hardware implementation of an highly efficient polynomial multiplier in GF(2{sup n}). The combinations determined by this algorithm save in average 12 % of the chip-area for polynomials with a length up to 600

  19. Secure Level Transmission in Wi-Fi Using Cryptography

    Directory of Open Access Journals (Sweden)

    K. Prasuna

    2013-11-01

    Full Text Available Wi-Fi, is a mechanism that allows electronic devices to exchange data wirelessly over a computer network Wi-Fi suggests Wireless Fidelity, resembling the long-established audio-equipment classification term Hi-Fi or High Fidelity.This paper first gives some background information about WiFi system and security issues in ad hoc networks, then it concentrates on the specific security measures like hybrid encryption techniques using both AES and RSA algorithms and also the different standards. To provide the security for the data transmitted through WiFi ,it uses WEP algorithm,WEP64 and WEP128 and then it moves to WPA (Wi-Fi Protected Access as the key is short in WEP.WPA use the TKIP and depends on RC4,which consist of 128 bit and 48 bit. The security comparisons show that WPA and TPIK is more advantageous than WEP and hence it is more preferable.

  20. Security Notions for Quantum Public-Key Cryptography

    OpenAIRE

    Koshiba, Takeshi

    2007-01-01

    It is well known that Shor's quantum algorithm for integer factorization can break down the RSA public-key cryptosystem, which is widely used in many cryptographic applications. Thus, public-key cryptosystems in the quantum computational setting are longed for cryptology. In order to define the security notions of public-key cryptosystems, we have to model the power of the sender, receiver, adversary and channel. While we may consider a setting where quantum computers are available only to ad...

  1. Security Notions for Quantum Public-Key Cryptography

    CERN Document Server

    Koshiba, T

    2007-01-01

    It is well known that Shor's quantum algorithm for integer factorization can break down the RSA public-key cryptosystem, which is widely used in many cryptographic applications. Thus, public-key cryptosystems in the quantum computational setting are longed for cryptology. In order to define the security notions of public-key cryptosystems, we have to model the power of the sender, receiver, adversary and channel. While we may consider a setting where quantum computers are available only to adversaries, we generally discuss what are the right security notions for (quantum) public-key cryptosystems in the quantum computational setting. Moreover, we consider the security of quantum public-key cryptosystems known so far.

  2. Public-key cryptography based on bounded quantum reference frames

    OpenAIRE

    Ioannou, Lawrence M.; Mosca, Michele

    2009-01-01

    We demonstrate that the framework of bounded quantum reference frames has application to building quantum-public-key cryptographic protocols and proving their security. Thus, the framework we introduce can be seen as a public-key analogue of the framework of Bartlett et al. (Phys. Rev. A 70, 032307), where a private shared reference frame is shown to have cryptographic application. The protocol we present in this paper is an identification scheme, which, like a digital signature scheme, is a ...

  3. A Study of Quantum Algorithms and Quantum Cryptography

    OpenAIRE

    小柴, 健史

    2007-01-01

    This report describes properties of basic cryptographic primitives (quantum public-key cryptosystmes and quantum one-way functions) in the quantum world where quantum computers are available. Some quantum public-key cryptosystems have already proposed. However, the security requirements for quantum public-key cryptosystems are not studied well. We propose several security notions for quantum public-key cryptosystems and discuss relation among them. In the classical setting, the notion of one-...

  4. Attacks to Cryptography Protocols of Wireless Industrial Communication Systems

    Directory of Open Access Journals (Sweden)

    Maria Franekova

    2010-01-01

    Full Text Available The paper deals with problems of safety and security principles within wireless industrial communication systems. First safety requirements to wireless industrial communication system, summarisation of attack methods and the available measures for risks elimination are described with orientation to safety critical applications. The mainly part is oriented to identification of risks and summarisation of defensive methods of wireless communication based on cryptographic techniques. Practical part the cryptoanalytic’s attacks to COTS (Commercial Off-The-Shelf wireless communications are mentioned based on the IEEE 802.11 standards.

  5. Lattice Based Tools in Cryptanalysis for Public Key Cryptography

    Directory of Open Access Journals (Sweden)

    R.Santosh Kumar

    2012-03-01

    Full Text Available Lattice reduction is a powerful concept for solving diverse problems involving point lattices. Latticereduction has been successfully utilizing in Number Theory, Linear algebra and Cryptology. Not only the existence of lattice based cryptosystems of hard in nature, but also has vulnerabilities by lattice reduction techniques. In this survey paper, we are focusing on point lattices and then describing an introduction to the theoretical and practical aspects of lattice reduction. Finally, we describe the applications of lattice reduction in Number theory, Linear algebra

  6. Cryptography Using Multiple Two-Dimensional Chaotic Maps

    Directory of Open Access Journals (Sweden)

    Ibrahim S. I. Abuhaiba

    2012-08-01

    Full Text Available In this paper, a symmetric key block cipher cryptosystem is proposed, involving multiple two-dimensional chaotic maps and using 128-bits external secret key. Computer simulations indicate that the cipher has good diffusion and confusion properties with respect to the plaintext and the key. Moreover, it produces ciphertext with random distribution. The computation time is much less than previous related works. Theoretic analysis verifies its superiority to previous cryptosystems against different types of attacks.

  7. Leakage-Resilient Cryptography from the Inner-Product Extractor

    DEFF Research Database (Denmark)

    Dziembowski, Stefan; Faust, Sebastian

    2011-01-01

    , the randomness that is used for certain operations comes from a simple (non-uniform) distribution. As a fundamental building block, we construct a scheme to store a cryptographic secret such that it remains information theoretically hidden, even given arbitrary continuous leakage from the storage. To this end...

  8. A Secured Authentication Protocol for SIP Using Elliptic Curves Cryptography

    Science.gov (United States)

    Chen, Tien-Ho; Yeh, Hsiu-Lien; Liu, Pin-Chuan; Hsiang, Han-Chen; Shih, Wei-Kuan

    Session initiation protocol (SIP) is a technology regularly performed in Internet Telephony, and Hyper Text Transport Protocol (HTTP) as digest authentication is one of the major methods for SIP authentication mechanism. In 2005, Yang et al. pointed out that HTTP could not resist server spoofing attack and off-line guessing attack and proposed a secret authentication with Diffie-Hellman concept. In 2009, Tsai proposed a nonce based authentication protocol for SIP. In this paper, we demonstrate that their protocol could not resist the password guessing attack and insider attack. Furthermore, we propose an ECC-based authentication mechanism to solve their issues and present security analysis of our protocol to show that ours is suitable for applications with higher security requirement.

  9. Computer Security: Cryptography and authentication (2/4)

    CERN Document Server

    CERN. Geneva

    2012-01-01

    Remi Mollon studied computer security at University and he first worked on Grids, with the EGEE project, for a French Bioinformatics institute. Information security being crucial in that field, he developed an encrypted file management system on top of Grid middleware, and he contributed in integrating legacy applications with Grids. Then, he was hired by CERN as a Grid Data Management developer, and he joined the Grid Operational Security Coordination Team. Remi has now moved to CERN Computer Security Team. Remi is involved in the daily security operations, in addition to be responsible to design Team's computer infrastructure, and to participate to several projects, like multi-factor authentication at CERN. With the prevalence of modern information technologies and its increasing integration into our daily live, digital systems become more and more playground for evil people. While in the past, attacks were driven by fame& kudos, nowadays money is the motivating factor. Just the recent months have s...

  10. Cryptography on elliptic curves over p-adic number fields

    Institute of Scientific and Technical Information of China (English)

    XU MaoZhi; ZHAO ChunLai; FENG Min; REN ZhaoRong; YE JiQing

    2008-01-01

    In this paper we introduce a cryptosystem based on the quotient groups of the group of rational points of an elliptic curve defined over p-adic number field. Some addi-tional parameters are taken in this system, which have an advantage in performing point multiplication while keeping the security of ECC over finite fields. We give a method to select generators of the cryptographic groups, and give a way to represent the elements of the quotient groups with finitely bounded storage by establishing a bijection between these elements and their approximate coordinates. The addition formula under this representation is also presented.

  11. Gaps between equations and experiments in quantum cryptography

    Energy Technology Data Exchange (ETDEWEB)

    Myers, John M [Gordon McKay Laboratory, Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Madjid, F Hadi [82 Powers Road, Concord, MA 01742 (United States)

    2002-06-01

    Traditional methods of cryptographic key distribution rest on judgments about an attacker. With the advent of quantum key distribution (QKD) came proofs of security for the mathematical models that define the protocols BB84 and B92; however, applying such proofs to actual transmitting and receiving devices has been questioned. Proofs of QKD security are propositions about models written in the mathematical language of quantum mechanics, and the issue is the linking of such models to actual devices in an experiment on security. To explore this issue, we adapt Wittgenstein's method of language games to view quantum language in its application to experimental activity involving transmitting and receiving devices. We sketch concepts with which to think about models in relation to experiments, without assuming the experiments accord with any model; included is a concept of one quantum mechanical model enveloping another. For any model that agrees with given experimental results and implies the security of a key, there is an enveloping model that agrees with the same results while denying that security. As a result there is a gap between equations and the behaviour recorded from devices in an experiment, a gap bridged only by resort to something beyond the reach of logic and measured data, well named by the word guesswork. While this recognition of guesswork encourages eavesdropping, a related recognition of guesswork in the design of feedback loops can help a transmitter and receiver to reduce their vulnerability to eavesdropping.

  12. Timing channels in cryptography a micro-architectural perspective

    CERN Document Server

    Rebeiro, Chester; Bhattacharya, Sarani

    2015-01-01

    This book deals with timing attacks on software implementations of encryption algorithms. It describes and analyzes various unintended covert timing channels that are formed when ciphers are executed in microprocessors. Modern superscalar microprocessors are considered, which are enabled with features such as multi-threaded, pipelined, parallel, speculative, and out-of-order execution. Various timing attack algorithms are described and analyzed for  block ciphers as well as public-key ciphers. The interplay between the cipher implementation, system architecture, and the attack's success is analyzed. Further hardware and software countermeasures are discussed with the aim of illustrating methods to build systems that can protect against these attacks. Discusses various timing attack algorithms in detail allowing readers to reconstruct the attack. Provides several experimental results to support the theoretical analysis provided in the book. Analyzes information leakage from cache memories and branch predictio...

  13. 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 simulation with quantum side information at the receiver. Our main theorem has two important corollaries: rate-distortion theory with quantum side information and common randomness distillation. Simple proofs of achievability of classical multi-terminal source coding problems can be made via a unified approach using the channel simulation theorem as building blocks. The fully quantum generalization of the problem is also conjectured with outer and inner bounds on the achievable rate pairs.

  14. Reverse reconciliation protocols for quantum cryptography with continuous variables

    CERN Document Server

    Grosshans, F; Grosshans, Fr\\'ed\\'eric; Grangier, Philippe

    2002-01-01

    We introduce new quantum key distribution protocols using quantum continuous variables, that are secure against individual attacks for any transmission of the optical line between Alice and Bob. In particular, it is not required that this transmission is larger than 50 %. Though squeezing or entanglement may be helpful, they are not required, and there is no need for quantum memories or entanglement purification. These protocols can thus be implemented using coherent states and homodyne detection, and they may be more efficient than usual protocols using quantum discrete variables.

  15. Secured Data Transmission Using Wavelet Based Steganography and cryptography

    Directory of Open Access Journals (Sweden)

    K.Ravindra Reddy

    2014-02-01

    Full Text Available Steganography and cryptographic methods are used together with wavelets to increase the security of the data while transmitting through networks. Another technology, the digital watermarking is the process of embedding information into a digital (image signal. Before embedding the plain text into the image, the plain text is encrypted by using Data Encryption Standard (DES algorithm. The encrypted text is embedded into the LL sub band of the wavelet decomposed image using Least Significant Bit (LSB method. Then the inverse wavelet transform is applied and the resultant image is transmitted to the receiver. The receiver will perform the same operations in reverse order

  16. Embedding adaptive arithmetic coder in chaos-based cryptography

    Science.gov (United States)

    Li, Heng-Jian; Zhang, Jia-Shu

    2010-05-01

    In this study an adaptive arithmetic coder is embedded in the Baptista-type chaotic cryptosystem for implementing secure data compression. To build the multiple lookup tables of secure data compression, the phase space of chaos map with a uniform distribution in the search mode is divided non-uniformly according to the dynamic probability estimation of plaintext symbols. As a result, more probable symbols are selected according to the local statistical characters of plaintext and the required number of iterations is small since the more probable symbols have a higher chance to be visited by the chaotic search trajectory. By exploiting non-uniformity in the probabilities under which a number of iteration to be coded takes on its possible values, the compression capability is achieved by adaptive arithmetic code. Therefore, the system offers both compression and security. Compared with original arithmetic coding, simulation results on Calgary Corpus files show that the proposed scheme suffers from a reduction in compression performance less than 12% and is not susceptible to previously carried out attacks on arithmetic coding algorithms.

  17. Communications with chaotic optoelectronic systems cryptography and multiplexing

    Science.gov (United States)

    Rontani, Damien

    With the rapid development of optical communications and the increasing amount of data exchanged, it has become utterly important to provide effective architectures to protect sensitive data. The use of chaotic optoelectronic devices has already demonstrated great potential in terms of additional computational security at the physical layer of the optical network. However, the determination of the security level and the lack of a multi-user framework are two hurdles which have prevented their deployment on a large scale. In this thesis, we propose to address these two issues. First, we investigate the security of a widely used chaotic generator, the external cavity semiconductor laser (ECSL). This is a time-delay system known for providing complex and high-dimensional chaos, but with a low level of security regarding the identification of its most critical parameter, the time delay. We perform a detailed analysis of the in uence of the ECSL parameters to devise how higher levels of security can be achieved and provide a physical interpretation of their origin. Second, we devise new architectures to multiplex optical chaotic signals and realize multi-user communications at high bit rates. We propose two different approaches exploiting known chaotic optoelectronic devices. The first one uses mutually coupled ECSL and extends typical chaos-based encryption strategies, such as chaos-shift keying (CSK) and chaos modulation (CMo). The second one uses an electro-optical oscillator (EOO) with multiple delayed feedback loops and aims first at transposing coded-division multiple access (CDMA) and then at developing novel strategies of encryption and decryption, when the time-delays of each feedback loop are time-dependent.

  18. Field experiment on a robust hierarchical metropolitan quantum cryptography network

    Institute of Scientific and Technical Information of China (English)

    XU FangXing; CHEN Wei; WANG Shuang; YIN ZhenQiang; ZHANG Yang; LIU Yun; ZHOU Zheng; ZHAO YiBo; LI HongWei; LIU Dong; HAN ZhengFu; GUO GuangCan

    2009-01-01

    these bureaus.The whole implementation including the hierarchical quantum cryptographic communication network links and the corresponding application software shows a big step toward the practical user-oriented network with a high security level.

  19. Reversible Anonymization of DICOM Images using Cryptography and Digital Watermarking

    Directory of Open Access Journals (Sweden)

    Lhoussain ELFADIL

    2012-04-01

    Full Text Available Digital Imaging and Communications in Medicine (DICOM is a standard for handling, storing, printing, and transmitting information in medical images. The DICOM file contains the image data and a number of attributes such as identified patient data (name, age, insurance ID card,…, and non-identified patient data (doctor’s interpretation, image type,…. Medical images serve not only for examination, but can also be used for research and education purposes. For research they are used to prevent illegal use of information; before authorizing researchers to use these images, the medical staff deletes all the data which would reveal the patient identity to prevent patient privacy. This manipulation is called anonymization. In this paper, we propose a reversible anonymization of DICOM images. Identifying patient data with image digest, computed by the well-known SHA-256 hash function, are encrypted using the proposed probabilistic public key crypto-system. After compressing the Least Significant Bit (LSB bitplan of the image using Hofmann coding algorithm, the encrypted data is inserted into a liberated zone of the LSB bitplan of the image. The proposed method allows researchers to use anonymous DICOM images and keep to authorized staff -if necessary- the possibility to return to the original image with all related patient data.

  20. Modelling and Simulation of a Biometric Identity-Based Cryptography

    Directory of Open Access Journals (Sweden)

    Dania Aljeaid

    2014-10-01

    Full Text Available Government information is a vital asset that must be kept in a trusted environment and efficiently managed by authorised parties. Even though e-Government provides a number of advantages, it also introduces a range of new security risks. Sharing confidential and top-secret information in a secure manner among government sectors tends to be the main element that government agencies look for. Thus, developing an effective methodology is essential and it is a key factor for e-Government success. The proposed e-Government scheme in this paper is a combination of identity-based encryption and biometric technology. This new scheme can effectively improve the security in authentication systems, which provides a reliable identity with a high degree of assurance. This paper also demonstrates the feasibility of using finite-state machines as a formal method to analyse the proposed protocols. Finally we showed how Petri Nets could be used to simulate the communication patterns between the server and client as well as to validate the protocol functionality.

  1. Hacking commercial quantum cryptography systems by tailored bright illumination

    Science.gov (United States)

    Lydersen, Lars; Wiechers, Carlos; Wittmann, Christoffer; Elser, Dominique; Skaar, Johannes; Makarov, Vadim

    2010-10-01

    The peculiar properties of quantum mechanics allow two remote parties to communicate a private, secret key, which is protected from eavesdropping by the laws of physics. So-called quantum key distribution (QKD) implementations always rely on detectors to measure the relevant quantum property of single photons. Here we demonstrate experimentally that the detectors in two commercially available QKD systems can be fully remote-controlled using specially tailored bright illumination. This makes it possible to tracelessly acquire the full secret key; we propose an eavesdropping apparatus built from off-the-shelf components. The loophole is likely to be present in most QKD systems using avalanche photodiodes to detect single photons. We believe that our findings are crucial for strengthening the security of practical QKD, by identifying and patching technological deficiencies.

  2. Entropy in quantum information theory - Communication and cryptography

    DEFF Research Database (Denmark)

    Majenz, Christian

    Entropies have been immensely useful in information theory. In this Thesis, several results in quantum information theory are collected, most of which use entropy as the main mathematical tool. The rst one concerns the von Neumann entropy. While a direct generalization of the Shannon entropy......-Shannon type inequalities. Here, a new constrained non-von-Neumann type inequality is proven, a step towards a conjectured unconstrained inequality by Linden and Winter. Like many other information-theoretic tasks, quantum source coding problems such as coherent state merging have recently been analyzed...... in the one-shot setting. While the case of many independent, identically distributed quantum states has been treated using the decoupling technique, the essentially optimal one-shot results in terms of the max-mutual information by Berta et al. and Anshu at al. had to bring in additional mathematical...

  3. Checking EABC performance in comparison others cryptography algorithms

    Directory of Open Access Journals (Sweden)

    Hamid Mehdi

    2013-08-01

    Full Text Available Nowadays, selecting algorithm to encryption data is very important considering attacks are varied andaccording to there are many encryption algorithms to protect information. Therefore choosing one algorithmis hard among many algorithms. Data confidentiality is one of the most important functions of encryptionalgorithms, it means when the transferring data between different systems is vague for unauthorized systemsor people. Moreover, Encryption algorithms must maintain data integrity and provide availability forinformation. New encryption methods cause the attackers cannot simply access to the information and do notallow discovering the relationship between information and the encrypted one. Therefore, availability can bedifficult for them. Existing complexities make their longevity and effectiveness increase. In This Article, Ithas been tried to check EABC performance considering execution time, CPU Utilization, Throughput ofencrypting/decrypting database.

  4. Survey paper on different approaches of Threshold Cryptography

    Directory of Open Access Journals (Sweden)

    Neha Gupta

    2012-09-01

    Full Text Available A traditional key management service is based on aCertificate Authority or a Trusted Third party.Security solutions for traditional network are notsuitable for Mobile ad hoc network. Thecharacteristics of MANET presence a number ofchallenges to security such as self-configuring,wireless links, infrastructure less nature. Thresholdcryptography has proved to be an effectivetechnique for key distribution and management. Inthis paper we highlight the different approachesused for certificate generation, discovering andauthentication of public keys.

  5. Network security with openSSL cryptography for secure communications

    CERN Document Server

    Viega, John; Chandra, Pravir

    2002-01-01

    Most applications these days are at least somewhat network aware, but how do you protect those applications against common network security threats? Many developers are turning to OpenSSL, an open source version of SSL/TLS, which is the most widely used protocol for secure network communications.The OpenSSL library is seeing widespread adoption for web sites that require cryptographic functions to protect a broad range of sensitive information, such as credit card numbers and other financial transactions. The library is the only free, full-featured SSL implementation for C and C++, and it can be used programmatically or from the command line to secure most TCP-based network protocols.Network Security with OpenSSL enables developers to use this protocol much more effectively. Traditionally, getting something simple done in OpenSSL could easily take weeks. This concise book gives you the guidance you need to avoid pitfalls, while allowing you to take advantage of the library?s advanced features. And, inst...

  6. Clone-preventive technique that features magnetic microfibers and cryptography

    Science.gov (United States)

    Matsumoto, Hiroyuki; Suzuki, Keiichi; Matsumoto, Tsutomu

    1998-04-01

    We have used the term 'clone' to refer to those things which are produced by methods such as counterfeiting, alteration, duplication or simulation. To satisfy the requirements of secure and low-cost techniques for preventing card fraud, we have recently developed a clone preventive system called 'FibeCrypt (Fiber Cryptosystem)' which utilizes physical characteristics. Each card has a canonical domain (i.e. a distinctive part), similar to fingerprints as the biometric measurement, made up of magnetic micro-fibers scattered randomly inside. We have applied cryptosystems to the system. FibeCrypt examines and authenticates the unique pattern of the canonical domain using pre-stored reference data and a digital signature. In our paper, the schemes and the features of this system are described in detail. The results of our examinations show the accuracy of authentication of the system. We conclude that this authentication technique which utilizes physical characteristics can be very effective for clone prevention in various fields.

  7. Symmetric Encryption Based Privacy using Lightweight Cryptography for RFID Tags

    OpenAIRE

    2015-01-01

    RFID technology emerged as the promising technology for its ease of use and implementation in the ubiquitous computing world. RFID is deployed widely in various applications that use automatic identification and processing for information retrieval. The primary components of an RFID system are the RFID tag (active and passive), the reader and the back-end server (database). Cost is the main factor that drove RFID tags to its immense utilization in which passive tags dominate in...

  8. Cryptographic Path Hardening: Hiding Vulnerabilities in Software through Cryptography

    CERN Document Server

    Ganesh, Vijay; Rinard, Martin

    2012-01-01

    We propose a novel approach to improving software security called Cryptographic Path Hardening, which is aimed at hiding security vulnerabilities in software from attackers through the use of provably secure and obfuscated cryptographic devices to harden paths in programs. By "harden" we mean that certain error-checking if-conditionals in a given program P are replaced by equivalent" we mean that adversaries cannot use semi-automatic program analysis techniques to reason about the hardened program paths and thus cannot discover as-yet-unknown errors along those paths, except perhaps through black-box dictionary attacks or random testing (which we can never prevent). Other than these unpreventable attack methods, we can make program analysis aimed at error-finding "provably hard" for a resource-bounded attacker, in the same sense that cryptographic schemes are hard to break. Unlike security-through-obscurity, in Cryptographic Path Hardening we use provably-secure crypto devices to hide errors and our mathemati...

  9. Quantum Cryptography Based on the Deutsch-Jozsa Algorithm

    Science.gov (United States)

    Nagata, Koji; Nakamura, Tadao; Farouk, Ahmed

    2017-09-01

    Recently, secure quantum key distribution based on Deutsch's algorithm using the Bell state is reported (Nagata and Nakamura, Int. J. Theor. Phys. doi: 10.1007/s10773-017-3352-4, 2017). Our aim is of extending the result to a multipartite system. In this paper, we propose a highly speedy key distribution protocol. We present sequre quantum key distribution based on a special Deutsch-Jozsa algorithm using Greenberger-Horne-Zeilinger states. Bob has promised to use a function f which is of one of two kinds; either the value of f( x) is constant for all values of x, or else the value of f( x) is balanced, that is, equal to 1 for exactly half of the possible x, and 0 for the other half. Here, we introduce an additional condition to the function when it is balanced. Our quantum key distribution overcomes a classical counterpart by a factor O(2 N ).

  10. A weak blind signature scheme based on quantum cryptography

    Science.gov (United States)

    Wen, Xiaojun; Niu, Xiamu; Ji, Liping; Tian, Yuan

    2009-02-01

    In this paper, we present a weak blind signature scheme based on the correlation of EPR (Einstein-Padolsky-Rosen) pairs. Different from classical blind signature schemes and current quantum signature schemes, our quantum blind signature scheme could guarantee not only the unconditionally security but also the anonymity of the message owner. To achieve that, quantum key distribution and one-time pad are adopted in our scheme. Experimental analysis proved that our scheme have the characteristics of non-counterfeit, non-disavowal, blindness and traceability. It has a wide application to E-payment system, E-government, E-business, and etc.

  11. A sessional blind signature based on quantum cryptography

    Science.gov (United States)

    Khodambashi, Siavash; Zakerolhosseini, Ali

    2014-01-01

    In this paper, we present a sessional blind signature protocol whose security is guaranteed by fundamental principles of quantum physics. It allows a message owner to get his message signed by an authorized signatory. However, the signatory is not capable of reading the message contents and everyone can verify authenticity of the message. For this purpose, we took advantage of a sessional signature as well as quantum entangled pairs which are generated with respect to it in our proposed protocol. We describe our proposed blind signature through an example and briefly discuss about its unconditional security. Due to the feasibility of the protocol, it can be widely employed for e-payment, e-government, e-business and etc.

  12. High-dimensional quantum cryptography with twisted light

    CERN Document Server

    Mirhosseini, Mohammad; O'Sullivan, Malcolm N; Rodenburg, Brandon; Malik, Mehul; Gauthier, Daniel J; Boyd, Robert W

    2014-01-01

    Quantum key distribution (QKD) systems have conventionally relied on the polarization of light for encoding. This limits the amount of information that can be sent per photon and puts a tight bound on the error such a system can tolerate. Here we show an experimental realization of a multilevel QKD system that uses the orbital angular momentum (OAM) of photons. Through the use of a 7-dimensional alphabet encoded in OAM, we achieve a channel capacity of 2.1 bits per sifted photon which is more than double the maximum allowed capacity of polarization-based QKD systems. Our experiment uses a digital micro-mirror device for the rapid generation of OAM modes at 4 kHz, and a mode sorter capable of sorting single photons based on OAM with a separation efficiency of 93%. Further, our scheme provides an increased tolerance to errors, leading to a quantum communication channel that is more robust against eavesdropping.

  13. Laser damage helps the eavesdropper in quantum cryptography

    CERN Document Server

    Bugge, Audun N; Ghazali, Aina M M; Skaar, Johannes; Lydersen, Lars; Makarov, Vadim

    2013-01-01

    By destructive laser illumination, an eavesdropper may turn a perfect quantum key distribution (QKD) system into a completely insecure system. We demonstrate this by illuminating avalanche photodiodes with increasingly intense radiation, and monitoring their parameters. After about 1 W illumination, the detectors' dark count rate drops by a factor of 2 to 5, permanently improving their single-photon counting performance. After about 1.5 W, the dark current rises, switching the detectors permanently into the linear photodetection mode and making them completely insecure for QKD applications. Illumination power higher than 2 W destroys all photosensitivity. This shows that an eavesdropper can engineer loopholes in QKD via laser damage.

  14. Elliptic Curve Cryptography on Smart Cards Without Coprocessors

    Science.gov (United States)

    2000-09-20

    Lecture Notes in Computer Science , 1998...implementation for arithmetic operations in GF (2n). In Asiacrypt ’96. Springer-Verlag Lecture Notes in Computer Science , 1996. [9] E. De Win, S. Mister, B...pages 252–266, Berlin, 1998. Springer-Verlag Lecture Notes in Computer Science . [10] P. Gaudry, F. Hess, and N. P. Smart. Constructive and

  15. Bridging the gap between theory and practice in quantum cryptography

    Science.gov (United States)

    Curty, Marcos; Tamaki, Kiyoshi; Xu, Feihu; Mizutani, Akihiro; Lim, Charles C. W.; Qi, Bing; Lo, Hoi-Kwong

    2015-10-01

    Quantum key distribution (QKD) needs to close the big gap between theory and practice to be a suitable technology for achieving information-theoretic secure communications. Indeed, recent studies on side-channel attacks have exposed the vulnerabilities of QKD implementations against an eavesdropper who may try to attack both the source and the measurement device. Here, we review two potential approaches that, combined, could bring this goal closer: measurement-device-independent QKD and the loss-tolerant QKD protocol. The former removes all possible side-channels from the measurement apparatus and guarantees a high performance over long distances. The latter appears as a robust solution against typical source flaws and it offers similar key rates as those of standard QKD systems. Most importantly, the feasibility of both solutions has already been demonstrated in several lab and field-test experiments.

  16. Cryptography in the Bounded Quantum-Storage Model

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Serge, Fehr; Schaffner, Christian;

    2008-01-01

    We initiate the study of two-party cryptographic primitives with unconditional security, assuming that the adversary's quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory...

  17. APPLIED CRYPTOGRAPHY IN PASSWORD ENCRYPTION USING NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Venkata Karthik Gullapalli

    2015-09-01

    Full Text Available Today the world depends on computers and information systems for processing information in various fields. These systems must be developed in such a way that they are less vulnerable to attacks and more reliable and secured. These systems are more vulnerable to technical issues and many cases of data trawling have been reported as a result of password breaches. Encryption and decryption plays a major role in the modern era as the rate of data flow increased tremendously. Social networking sites such as Facebook and Google stores the most important and private data of people electronically in the servers. Artificial intelligence took over many functions of computer systems in different fields including data security. Neural networks process information with care and certainty like human mind does. This paper proposes a methodology to implement encryption and decryption using the feed forward neural networks and to improve the security of information systems.

  18. Number theoretic methods in cryptography complexity lower bounds

    CERN Document Server

    Shparlinski, Igor

    1999-01-01

    The book introduces new techniques which imply rigorous lower bounds on the complexity of some number theoretic and cryptographic problems. These methods and techniques are based on bounds of character sums and numbers of solutions of some polynomial equations over finite fields and residue rings. It also contains a number of open problems and proposals for further research. We obtain several lower bounds, exponential in terms of logp, on the de­ grees and orders of • polynomials; • algebraic functions; • Boolean functions; • linear recurring sequences; coinciding with values of the discrete logarithm modulo a prime p at suf­ ficiently many points (the number of points can be as small as pI/He). These functions are considered over the residue ring modulo p and over the residue ring modulo an arbitrary divisor d of p - 1. The case of d = 2 is of special interest since it corresponds to the representation of the right­ most bit of the discrete logarithm and defines whether the argument is a quadratic...

  19. APE: Authenticated Permutation-Based Encryption for Lightweight Cryptography

    DEFF Research Database (Denmark)

    Andreeva, Elena; Bilgin, Begül; Bogdanov, Andrey

    2015-01-01

    of cryptographic schemes actually require the nonce assumption for their security. In this paper, we propose APE as the first permutation-based authenticated encryption scheme that is resistant against nonce misuse. We formally prove that APE is secure, based on the security of the underlying permutation......, and Spongent. For any of these permutations, an implementation that supports both encryption and decryption requires less than 1.9 kGE and 2.8 kGE for 80-bit and 128-bit security levels, respectively....

  20. SOPC BASED WIRELESS REMOTE PATIENT MONITORING USING ULTRA LIGHTWEIGHT CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    A. Arun

    2014-01-01

    Full Text Available Remote Patient Monitoring (RPM provides flexible and powerful patient surveillance through wearable devices at anytime and anywhere. This can be achieved by using a Body Sensor Network (BSN, which is deployed on a human body for monitoring the healthcare. The mobile healthcare management with increased feasibility and handiness introduced several noteworthy challenges for the provider, policy makers, patient and hospitals. A significant challenge is to provide round-the-clock healthcare services to those patients who require it via wearable medical devices. In addition to this, the sensors collect the personal medical data where the security and privacy are important components in RPM. As a result, one of the most significant and challenging concern to deal with is how to secure the personal information of the patients and to eliminate their privacy issue. This study presents System on Programmable Chip (SoPC implementation of Remote Patient Monitoring System (RPM with Ultra Lightweight algorithms for security issues. Humming Bird 2 (HB-2, PRESENT and HIGHT algorithms were implemented since the wearable medical devices require fewer areas to achieve portability. The comparison results shows that Degree of Confusion of HB-2 is 50.43 which outstand the other, the efficiency of the entire algorithm implemented in SoPC are higher comparing with conventional Field Programmable Gate Array (FPGA implementation. The comparison was extended and in Particular, power and area consumption of HB-2 is less than PRESENT and HIGHT algorithm, which is more suitable for RPM devices.

  1. Practical Quantum Cryptography: the Q-KeyMaker

    CERN Document Server

    Bovino, Fabio A

    2011-01-01

    In the next years the data transmission connections will constitute one of the principal tools of communication among cities, enterprises and public administration. With their enhanced connectivity, the systems and nets of information are now exposed to an increased vulnerability and new safety problems are emerging. Insofar Quantum Key Distribution (QKD) has matured to real world applications and can enhance the safety of the communication nets. In this paper we present the QKD network designed and implemented by Selex-SI and we give an overview of the obtained results.

  2. Hummingbird: Ultra-Lightweight Cryptography for Resource-Constrained Devices

    Science.gov (United States)

    Engels, Daniel; Fan, Xinxin; Gong, Guang; Hu, Honggang; Smith, Eric M.

    Due to the tight cost and constrained resources of high-volume consumer devices such as RFID tags, smart cards and wireless sensor nodes, it is desirable to employ lightweight and specialized cryptographic primitives for many security applications. Motivated by the design of the well-known Enigma machine, we present a novel ultra-lightweight cryptographic algorithm, referred to as Hummingbird, for resource-constrained devices in this paper. Hummingbird can provide the designed security with small block size and is resistant to the most common attacks such as linear and differential cryptanalysis. Furthermore, we also present efficient software implementation of Hummingbird on the 8-bit microcontroller ATmega128L from Atmel and the 16-bit microcontroller MSP430 from Texas Instruments, respectively. Our experimental results show that after a system initialization phase Hummingbird can achieve up to 147 and 4.7 times faster throughput for a size-optimized and a speed-optimized implementations, respectively, when compared to the state-of-the-art ultra-lightweight block cipher PRESENT[10] on the similar platforms.

  3. Free space relativistic quantum cryptography with faint laser pulses

    Science.gov (United States)

    Molotkov, S. N.; Potapova, T. A.

    2013-07-01

    A new protocol for quantum key distribution through empty space is proposed. Apart from the quantum mechanical restrictions on distinguishability of non-orthogonal states, the protocol employs additional restrictions imposed by special relativity. The protocol ensures generation of a secure key even for the source generating non-strictly single-photon quantum states and for arbitrary losses in quantum communication channel.

  4. Bio—Cryptography: A Possible Coding Role for RNA Redundancy

    Science.gov (United States)

    Regoli, M.

    2009-03-01

    The RNA-Crypto System (shortly RCS) is a symmetric key algorithm to cipher data. The idea for this new algorithm starts from the observation of nature. In particular from the observation of RNA behavior and some of its properties. The RNA sequences have some sections called Introns. Introns, derived from the term "intragenic regions," are non-coding sections of precursor mRNA (pre-mRNA) or other RNAs, that are removed (spliced out of the RNA) before the mature RNA is formed. Once the introns have been spliced out of a pre-mRNA, the resulting mRNA sequence is ready to be translated into a protein. The corresponding parts of a gene are known as introns as well. The nature and the role of Introns in the pre-mRNA is not clear and it is under ponderous researches by biologists but, in our case, we will use the presence of Introns in the RNA-Crypto System output as a strong method to add chaotic non coding information and an unnecessary behavior in the access to the secret key to code the messages. In the RNA-Crypto System algorithm the introns are sections of the ciphered message with non-coding information as well as in the precursor mRNA.

  5. Guideline for Implementing Cryptography in the Federal Government

    Science.gov (United States)

    2007-11-02

    Specification of finite state machine model . Required states and optional states. State transition diagram and specification of state transitions... state machine model including state transitions, rules of operation, source code listings. 4. formal model, informal proof FIPS PUB 140-1: Security... machine model . High-level language implementation. Formal model. Pre- and post- conditions. Operating System Security Executable code. Authenticated

  6. Sec.AODV for MANETs using MD5 with Cryptography

    OpenAIRE

    Suketu D. Nayak; Ravindra K. Gupta

    2011-01-01

    Mobile Ad hoc Networks (MANETs) characteristics present major vulnerabilities in security. The threats which thought-out in MANETs are due to maliciousness that intentionally disrupts the network by using variety of attacks and due to insecure routing protocols (e.g. AODV), which were developed without considering security in mind. Due to lack of the infrastructure, open peer-to-peer architecture, shared wireless medium, limited resource constraints and highly dynamic topology, MANETs (Mobile...

  7. ENHANCING SECURITY FOR IPV6 NEIGHBOR DISCOVERY PROTOCOL USING CRYPTOGRAPHY

    Directory of Open Access Journals (Sweden)

    Rosilah Hassan

    2014-01-01

    Full Text Available Internet Protocol version 4 (IPv4 would gradually be replaced by Internet Protocol version 6 (IPv6 as the next generation of Internet protocol. The Neighbor Discovery Protocol (NDP, one of the main protocols in the IPv6 suite, comprises Neighbor Discovery for IPv6. NDP is used by both hosts and routers. Its functions include Neighbor Discovery (ND, Router Discovery (RD, Address Auto configuration, Address Resolution, Neighbor Unreachability Detection (NUD, Duplicate Address Detection (DAD and Redirection. If not secured, NDP is vulnerable to various attacks: Neighbor Solicitation (NS spoofing and Neighbor Advertisement (NS spoofing, redirection, stealing addresses, denial of service are examples of these attacks. Since its early stages of designing and development NDP assumes connections between nodes will be safe but deployment stage prove this assumption is incorrect and highlight the security holes. This fact leads Internet Engineer Task Force (IETF to request solutions in order to overcoming these drawbacks. Secure Neighbor Discovery or SEND is then proposed, SEND solve a part of the threats associated with NDP and request for more researches to find a better solution that manage to forbid all these threats and ignore its limitations. This study presents a new mechanism to avoid security threats for IPv6 NDP based on digital signature procedures. The proposed solution is manage to eliminate the threats because it do mapping and binding between IP address, MAC address and public keys of the nodes in the node’s neighbors cache, intruders will not be able to spoof other nodes’ IP addresses.

  8. Efficient Cryptography for the Next Generation Secure Cloud

    Science.gov (United States)

    Kupcu, Alptekin

    2010-01-01

    Peer-to-peer (P2P) systems, and client-server type storage and computation outsourcing constitute some of the major applications that the next generation cloud schemes will address. Since these applications are just emerging, it is the perfect time to design them with security and privacy in mind. Furthermore, considering the high-churn…

  9. 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.

  10. Laser Damage Helps the Eavesdropper in Quantum Cryptography

    Science.gov (United States)

    Bugge, Audun Nystad; Sauge, Sebastien; Ghazali, Aina Mardhiyah M.; Skaar, Johannes; Lydersen, Lars; Makarov, Vadim

    2014-02-01

    We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After ˜1 W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After ˜1.5 W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.

  11. Cryptography In The Bounded Quantum-Storage Model

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Salvail, Louis; Schaffner, Christian;

    2005-01-01

    We initiate the study of two-party cryptographic primitives with unconditional security, assuming that the adversary's quantum memory is of bounded size. We show that oblivious transfer and bit commitment can be implemented in this model using protocols where honest parties need no quantum memory...

  12. From Greeks to Today: Cipher Trees and Computer Cryptography.

    Science.gov (United States)

    Grady, M. Tim; Brumbaugh, Doug

    1988-01-01

    Explores the use of computers for teaching mathematical models of transposition ciphers. Illustrates the ideas, includes activities and extensions, provides a mathematical model and includes computer programs to implement these topics. (MVL)

  13. 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).

  14. High-Rate Strong-Signal Quantum Cryptography

    Science.gov (United States)

    Yuen, Horace P.

    1996-01-01

    Several quantum cryptosystems utilizing different kinds of nonclassical lights, which can accommodate high intensity fields and high data rate, are described. However, they are all sensitive to loss and both the high rate and the strong-signal character rapidly disappear. A squeezed light homodyne detection scheme is proposed which, with present-day technology, leads to more than two orders of magnitude data rate improvement over other current experimental systems for moderate loss.

  15. Codes, Ciphers, and Cryptography--An Honors Colloquium

    Science.gov (United States)

    Karls, Michael A.

    2010-01-01

    At the suggestion of a colleague, I read "The Code Book", [32], by Simon Singh to get a basic introduction to the RSA encryption scheme. Inspired by Singh's book, I designed a Ball State University Honors Colloquium in Mathematics for both majors and non-majors, with material coming from "The Code Book" and many other sources. This course became…

  16. Thermal blinding of gated detectors in quantum cryptography.

    Science.gov (United States)

    Lydersen, Lars; Wiechers, Carlos; Wittmann, Christoffer; Elser, Dominique; Skaar, Johannes; Makarov, Vadim

    2010-12-20

    It has previously been shown that the gated detectors of two commercially available quantum key distribution (QKD) systems are blindable and controllable by an eavesdropper using continuous-wave illumination and short bright trigger pulses, manipulating voltages in the circuit [Nat. Photonics 4, 686 (2010)]. This allows for an attack eavesdropping the full raw and secret key without increasing the quantum bit error rate (QBER). Here we show how thermal effects in detectors under bright illumination can lead to the same outcome. We demonstrate that the detectors in a commercial QKD system Clavis2 can be blinded by heating the avalanche photo diodes (APDs) using bright illumination, so-called thermal blinding. Further, the detectors can be triggered using short bright pulses once they are blind. For systems with pauses between packet transmission such as the plug-and-play systems, thermal inertia enables Eve to apply the bright blinding illumination before eavesdropping, making her more difficult to catch.

  17. Unconditionally secure commitment in position-based quantum cryptography.

    Science.gov (United States)

    Nadeem, Muhammad

    2014-10-27

    A new commitment scheme based on position-verification and non-local quantum correlations is presented here for the first time in literature. The only credential for unconditional security is the position of committer and non-local correlations generated; neither receiver has any pre-shared data with the committer nor does receiver require trusted and authenticated quantum/classical channels between him and the committer. In the proposed scheme, receiver trusts the commitment only if the scheme itself verifies position of the committer and validates her commitment through non-local quantum correlations in a single round. The position-based commitment scheme bounds committer to reveal valid commitment within allocated time and guarantees that the receiver will not be able to get information about commitment unless committer reveals. The scheme works for the commitment of both bits and qubits and is equally secure against committer/receiver as well as against any third party who may have interests in destroying the commitment. Our proposed scheme is unconditionally secure in general and evades Mayers and Lo-Chau attacks in particular.

  18. Public Key Cryptography Based on Ergodic Matrices over Finite Field

    Institute of Scientific and Technical Information of China (English)

    PEI Shihui; ZHAO Hongwei; ZHAO Yongzhe

    2006-01-01

    A new public key encryption scheme is proposed in this paper, which is based on a hard problem over ergodic matrices. The security of this scheme is equal to the MQ-problem: multivariate quadratic equations over finite fields. This problem has been shown to be NP-complete and can' be solved with polynomial time algorithm.

  19. Successful attack on permutation-parity-machine-based neural cryptography.

    Science.gov (United States)

    Seoane, Luís F; Ruttor, Andreas

    2012-02-01

    An algorithm is presented which implements a probabilistic attack on the key-exchange protocol based on permutation parity machines. Instead of imitating the synchronization of the communicating partners, the strategy consists of a Monte Carlo method to sample the space of possible weights during inner rounds and an analytic approach to convey the extracted information from one outer round to the next one. The results show that the protocol under attack fails to synchronize faster than an eavesdropper using this algorithm.

  20. Laser damage helps the eavesdropper in quantum cryptography.

    Science.gov (United States)

    Bugge, Audun Nystad; Sauge, Sebastien; Ghazali, Aina Mardhiyah M; Skaar, Johannes; Lydersen, Lars; Makarov, Vadim

    2014-02-21

    We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After ∼1  W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After ∼1.5  W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.