Wenfang Zhang

Cryptanalysis and improvement on two efficient remote user authentication scheme using smart cards

In 2002, Chien et al. proposed an efficient remote authentication scheme using smart cards, in which only few hashing operations are required. Later, Ku et al. gave an improved scheme to repair the security pitfalls found in Chien et al.s scheme. Also Yoon et al. presented an enhancement on Ku et al.s scheme. In this paper, we show that both Ku et al.s scheme and Yoon et al.s scheme are still vulnerable to the guessing attack, forgery attack and denial of service (DoS) attack. In addition, their schemes lack efficiency when users input wrong passwords. To remedy these flaws, this paper proposes an efficient improvement over Ku et al.s and Yoon et al.s schemes with more security. The computation cost, security, and efficiency of the improved scheme are embarking for the real application in the resource-limited environment.

Secure chaotic system with application to chaotic ciphers

Chaotic cryptography has been widely investigated in the past few years. However, the undesirable dynamical properties of the underlying chaotic systems degrade the security of chaotic ciphers and thereby discourage their applications. To address this issue, this paper first presents discrimination criteria for secure chaotic systems (SCSs) whose dynamical properties make them useful for the construction of secure ciphers and then discusses a class of chaotic systems, digital dynamical filters (DDFs), that meet the SCS criteria. Then, a DDF-based pseudorandom bit generator (DDF-PRBG) for constructing stream ciphers is proposed. Theoretical analysis and simulation results demonstrate that both the DDF and the DDF-PRBG, which satisfy the SCS criteria, have desirable cryptographic properties. Consequently, the SCS criteria and the DDF reference model can be used to overcome the problems caused by the dynamical properties of the underlying chaotic systems and increase the security of chaotic ciphers.

Cryptanalysis and improvement on a parallel keyed hash function based on chaotic neural network

This paper analyzes the security of a chaotic parallel keyed hash function in detail, and points out that it is susceptible to two kinds of forgery attacks and weak key attack (which results in MAC collision). To remedy such security flaws, an improved scheme is further proposed, and its security and performance are also discussed. The theoretical analysis shows that the improved scheme is more secure than the original one. In the meanwhile, it can also keep the parallel merit and other performance advantages of the original scheme.

A Lightweight Authenticated Encryption Scheme Based on Chaotic SCML for Railway Cloud Service

In recent years, intelligent railway operation and maintenance using cloud technology have received wide consideration for the provision of public transport services. Under the cloud environment, information security is critical to ensure the integrity of data through protection from unauthorized manipulation and the confidentiality through protection against the leakage of sensitive information. This paper proposes a lightweight authenticated encryption scheme with associated data based on a novel discrete chaotic S-box coupled map lattice (SCML), which avoids the dynamic degradation of the digital chaotic system and low efficiency of the chaos-based cryptosystem. Based on the chaotic SCML, an authenticated encryption scheme that protects the confidentiality and integrity in one pass is presented in detail. The security analysis and performance simulations in software and hardware show that the proposed scheme is efficient and provides adequate security through authentication and encryption. Such a scheme could be used for applications in a railway cloud service that requires moderate security and low-cost implementations.

An Efficient and Secure Biometric Remote User Authentication Scheme Using Smart Cards

Remote user authentication schemes are widely investigated recently. This paper points out some existent problems in smartcard based schemes. As a comprehensive solution, a novel authentication scheme using two-variant hashing technique and fingerprint-biometric is presented. Security analysis shows that the proposed scheme provides secure, robust, and trustworthy remote authentication over insecure network. Moreover, computational costs and efficiency of this scheme are encouraging for practical implementation in the resource-constraint environment.

Chaotic keystream generator using coupled NDFs with parameter perturbing

Chaotic cryptology has been widely investigated recently. This paper analyzes the security pitfalls existing in digital chaotic stream ciphers, which work on the well characterized one-dimensional(1-D) chaotic systems. As a practical solution to these problems caused by 1-D chaotic systems, a chaotic keystream generator using nonlinear digital filters with n-D uniform distribution is proposed. To improve system security further and overcome the effects of finite wordlength, the coupling method with parameter perturbing is considered. Detailed theoretical analyses show that it has perfect cryptographic properties, and can be used to construct stream ciphers with higher security than other 1-D chaotic ciphers. Finally, some numeric experiments are made and the experimental results coincide well with the theoretical analyses.

The parallel algorithm of 2-D discrete wavelet transform

We discuss a new parallel algorithm of 2-D discrete wavelet transform (DWT) using MPI/spl I.bar/Scatterv and MPI/spl I.bar/Gatherv (MPI: Message Passing Interface). Here the 2-D sequential Daubechies discrete wavelet transform program is first decomposed into several 1-D transforms, and then the parallel conversion is made on them. This parallel program has already been successfully implemented on the dawning parallel computer system, and experimental results show that high performance and pretty flexibility can be achieved.

Chaotic Pseudorandom Bit Generator Using n-dimensional Nonlinear Digital Filter

A chaotic pseudorandom bit generator (PRBG) using n-dimensional NDF is proposed. To overcome the effects of finite wordlength to NDF and to hide its dynamic behavior, a coupling method followed by a quantization function is adopted. Detailed theoretical analyses show that the proposed PRBG has perfect cryptographic properties, and can be used to construct stream ciphers with higher security than other chaotic ciphers. Moreover, it is much faster than other chaotic pseudo random number generators due to the inherent parallel structure of NDF. Finally, some experiments are made for confirmation.

Chaotic secure communication based on discrete-time chaos noise generator

In view of chaos synchronization systems sensitivity to parameter mismatches, a new class of chaotic secure communication schemes based on the discrete time chaos noise generator is proposed. In this scheme it is easy to adjust the level of systems security by raising its exponent or increasing its mapping iteration times. Studying results show this new scheme can resist the attack of adaptive synchronization and has better security properties, when compared with the formal schemes based on the decomposition of low dimensional chaotic systems, and it can be implemented easily.

A virtual bridge certificate authority-based cross-domain authentication mechanism for distributed collaborative manufacturing systems

The virtual enterprise VE is a new collaborative intelligent manufacturing paradigm that pools the core competencies of its member enterprises through computer networks to exploit transient market opportunities. The successful operation of such an organization is strongly dependent on its information securities, in which cross-domain authentication among entities of different member enterprises is a crucial issue. This problem is particularly difficult in VEs because of their collaborative nature in terms of agility, market dynamics, low cost, and diversity of collaboration modes. In this paper, we put forward a novel virtual bridge certificate authority BCA trust model, based on which an efficient cross-domain authentication scheme is further presented. The proposed scheme is implemented by the distributed verifiable secret sharing protocol and the threshold elliptic curve cryptosystem signature algorithm. It has the same advantages of simple construction and short length of inter-enterprise certification paths as the BCA model but does not need to create and maintain a dedicated physical BCA. In addition, the proposed scheme has the merits of high bit security, high efficiency, low cost, conspiracy attack resistance, and adaptability to diverse collaboration modes of VE. Therefore, the scheme is suitable for cross-domain authentications in VEs, especially for resource-limited applications. Copyright