The Experts below are selected from a list of 5409 Experts worldwide ranked by ideXlab platform

Liu Nian-sheng - One of the best experts on this subject based on the ideXlab platform.

  • Pseudo-randomness and complexity of binary sequences generated by the chaotic system
    Communications in Nonlinear Science and Numerical Simulation, 2011
    Co-Authors: Liu Nian-sheng
    Abstract:

    Abstract The pseudo-randomness and complexity of binary sequences generated by chaotic systems are investigated in this paper. These chaotic binary sequences can have the same pseudo-randomness and complexity as the chaotic real sequences that are transformed into them by the use of Kohda’s quantification algorithm. The statistical test, correlation function, spectral analysis, Lempel–Ziv complexity and approximate entropy are regarded as quantitative measures to characterize the pseudo-randomness and complexity of these binary sequences. The experimental results show the finite binary sequences generated by the chaotic systems have good properties with the pseudo-randomness and complexity of sequences. However, the pseudo-randomness and complexity of sequence are not added with the increase of sequence length. On the contrary, they steadily decrease with the increase of sequence length in the criterion of approximate entropy and statistical test. The constraint of computational precision is a fundamental reason resulting in the problem. So only the shorter binary sequences generated by the chaotic systems are suitable for Modern Cryptography without other way of adding sequence complexity in the existing computer system.

Chanathip Namprempre - One of the best experts on this subject based on the ideXlab platform.

  • authenticated encryption in ssh provably fixing the ssh binary packet protocol
    Computer and Communications Security, 2002
    Co-Authors: Mihir Bellare, Tadayoshi Kohno, Chanathip Namprempre
    Abstract:

    The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper we propose several fixes to the SSH protocol and, using techniques from Modern Cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol or to SSH implementations. We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

  • provably fixing the ssh binary packet protocol
    2002
    Co-Authors: Mihir Bellare, Tadayoshi Kohno, Chanathip Namprempre
    Abstract:

    The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper we propose several fixes to the SSH protocol and, using techniques from Modern Cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol (or to SSH implementations). We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

  • breaking and provably repairing the ssh authenticated encryption scheme a case study of the encode then encrypt and mac paradigm
    IACR Cryptology ePrint Archive, 2002
    Co-Authors: Mihir Bellare, Tadayoshi Kohno, Chanathip Namprempre
    Abstract:

    The Secure Shell (SSH) protocol is one of the most popular cryptographic protocols on the Internet. Unfortunately, the current SSH authenticated encryption mechanism is insecure. In this paper, we propose several fixes to the SSH protocol and, using techniques from Modern Cryptography, we prove that our modified versions of SSH meet strong new chosen-ciphertext privacy and integrity requirements. Furthermore, our proposed fixes will require relatively little modification to the SSH protocol and to SSH implementations. We believe that our new notions of privacy and integrity for encryption schemes with stateful decryption algorithms will be of independent interest.

Sherali Zeadally - One of the best experts on this subject based on the ideXlab platform.

  • a comprehensive review on collision resistant hash functions on lattices
    Workshop on Information Security Applications, 2021
    Co-Authors: Nimish Mishra, S Hafizul K Islam, Sherali Zeadally
    Abstract:

    Abstract Hash functions have always attracted a lot of attention in Modern Cryptography because of their hard to invert nature. However, all previous constructions of cryptographic primitives face the threat of being broken by the recent advancements in quantum technology. The focus has thus shifted to developing cryptographic primitives on mathematical structures such as lattices that are intractable by quantum algorithms. We review the computational problems defined on lattices and their respective hardness and discuss constructions of hash function families based on both integer and ideal lattices whose security depends on these computational problems on lattices. We provide a comparative analysis of the theoretical security and concrete instantiations claimed by the different hash function families. Finally, we review techniques used in the reductions for the security proofs of constructions of different hash function families.

  • an efficient identity based conditional privacy preserving authentication scheme for vehicular ad hoc networks
    IEEE Transactions on Information Forensics and Security, 2015
    Co-Authors: Sherali Zeadally, Xinyi Huang
    Abstract:

    By broadcasting messages about traffic status to vehicles wirelessly, a vehicular ad hoc network (VANET) can improve traffic safety and efficiency. To guarantee secure communication in VANETs, security and privacy issues must be addressed before their deployment. The conditional privacy-preserving authentication (CPPA) scheme is suitable for solving security and privacy-preserving problems in VANETs, because it supports both mutual authentication and privacy protection simultaneously. Many identity-based CPPA schemes for VANETs using bilinear pairings have been proposed over the last few years to enhance security or to improve performance. However, it is well known that the bilinear pairing operation is one of the most complex operations in Modern Cryptography. To achieve better performance and reduce computational complexity of information processing in VANET, the design of a CPPA scheme for the VANET environment that does not use bilinear paring becomes a challenge. To address this challenge, we propose a CPPA scheme for VANETs that does not use bilinear paring and we demonstrate that it could supports both the mutual authentication and the privacy protection simultaneously. Our proposed CPPA scheme retains most of the benefits obtained with the previously proposed CPPA schemes. Moreover, the proposed CPPA scheme yields a better performance in terms of computation cost and communication cost making it be suitable for use by the VANET safety-related applications.

Michael Waidner - One of the best experts on this subject based on the ideXlab platform.

  • a general composition theorem for secure reactive systems
    Theory of Cryptography Conference, 2004
    Co-Authors: Michael Backes, Birgit Pfitzmann, Michael Waidner
    Abstract:

    We consider compositional properties of reactive systems that are secure in a cryptographic sense. We follow the well-known simulatability approach of Modern Cryptography, i.e., the specification is an ideal system and a real system should in some sense simulate this ideal one. We show that if a system consists of a polynomial number of arbitrary ideal subsystems such that each of them has a secure implementation in the sense of blackbox simulatability, then one can securely replace all ideal subsystems with their respective secure counterparts without destroying the blackbox simulatability relation. We further prove our theorem for universal simulatability by showing that blackbox simulatability implies universal simulatability under reasonable assumptions. We show all our results with concrete security.

  • a model for asynchronous reactive systems and its application to secure message transmission
    IEEE Symposium on Security and Privacy, 2001
    Co-Authors: Birgit Pfitzmann, Michael Waidner
    Abstract:

    We present a rigorous model for secure reactive systems in asynchronous networks with a sound cryptographic semantics, supporting abstract specifications and the composition of secure systems. This enables modular proofs of security, which is essential in bridging the gap between the rigorous proof techniques of Cryptography and tool-supported formal proof techniques. The model follows the general simulatability approach of Modern Cryptography. A variety of network structures and trust models can be described such as static and adaptive adversaries, some examples of this are given. As an example of our specification methodology we provide an abstract and complete specification for Secure Message Transmission, improving on recent results by Lynch (1999), and verify one concrete implementation. Our proof is based on a general theorem on the security of encryption in a reactive multi-user setting, generalizing a recent result by Bellare et. al (2000).

Karn Seth - One of the best experts on this subject based on the ideXlab platform.

  • non black box simulation from one way functions and applications to resettable security
    SIAM Journal on Computing, 2016
    Co-Authors: Kaimin Chung, Rafael Pass, Karn Seth
    Abstract:

    The simulation paradigm, introduced by Goldwasser, Micali, and Rackoff, is of fundamental importance to Modern Cryptography. In a breakthrough work from 2001, Barak [FOCS 2001, IEEE Computer Society, Los Alamitos, CA, 2001, pp. 106--115] introduced a novel non-black-box simulation technique. This technique enabled the construction of new cryptographic primitives, such as resettably sound zero-knowledge arguments, that cannot be proven secure using just black-box simulation techniques. The work of Barak and its follow-ups, however, all require stronger cryptographic hardness assumptions than the minimal assumption of one-way functions: the work of Barak requires the existence of collision-resistant hash functions, and a very recent result by Bitansky and Paneth [FOCS 2012, IEEE, Piscataway, NJ, 2012, pp. 223--232] instead requires the existence of an oblivious transfer protocol. In this work, we show how to perform non-black-box simulation assuming just the existence of one-way functions. In particular, we...

  • non black box simulation from one way functions and applications to resettable security
    Symposium on the Theory of Computing, 2013
    Co-Authors: Kaimin Chung, Rafael Pass, Karn Seth
    Abstract:

    The simulation paradigm, introduced by Goldwasser, Micali and Rackoff, is of fundamental importance to Modern Cryptography. In a breakthrough work from 2001, Barak (FOCS'01) introduced a novel non-black-box simulation technique. This technique enabled the construction of new cryptographic primitives, such as resettably-sound zero-knowledge arguments, that cannot be proven secure using just black-box simulation techniques. The work of Barak and its follow-ups, however, all require stronger cryptographic hardness assumptions than the minimal assumption of one-way functions. In this work, we show how to perform non-black-box simulation assuming just the existence of one-way functions. In particular, we demonstrate the existence of a constant-round resettably-sound zero-knowledge argument based only on the existence of one-way functions. Using this technique, we determine necessary and sufficient assumptions for several other notions of resettable security of zero-knowledge proofs. An additional benefit of our approach is that it seemingly makes practical implementations of non-black-box zero-knowledge viable.