Zheng Gong

On the security of 4-bit involutive S-boxes for lightweight designs

In this work we investigate all the 4-bit involutive S-boxes with linear, differential and almost resilient analysis. The results show that involutive S-boxes can be optimal against linear attack. We prove that for a 4-bit involutive S-box there always exists a pair of input and output differences such that the Hamming distance is 1, which does not satisfy the strict resistance on differential analysis. Moreover, we find that the almost resilient property is not effective to judge the security of 4-bit involutive S-boxes in practise. How to use the almost resilient property to set up a criterion for an optimal secure S-box needs investigations.

Transitive Signature Scheme from LFSR

Linear feedback sequence register (LFSR) is a useful cryptographic primitive which is widely implemented in many cryptosystems to represent finite field elements with the counterparts of minimal polynomials. In this paper, an efficient transitive signature scheme from LFSR (LFSR-TS) is considered. First, two derived LFSR sequence operations are designed for LFSR-TS, which are not proposed prior to the current work. Next, the security of LFSR-TS is proven to be existentially unforgeable against the adaptive chosen-message attack in the standard model, which only requires the assumption of the discrete logarithm problem (DLP). Finally, the comparison of performances is presented amongst LFSR-TS and some related schemes.

Efficient Partially Blind Signature from LFSR

An image segmentation method based on the OTSU and improved genetic algorithm (GA) is presented. The OTSU is taken as evaluation function and the segmentation problem is turned to the optimization problem. That is, GA efficiently searches the segmentation parameter space in order to obtain the optimal threshold. On the other hand, to overcome some limitation of GA, elite reinsertion is applied. The experimental results indicate that the method can not only obtain a better result, but also shorten the processing time.In this paper, we provide a new partially blind signature scheme which is based on n-th order characteristic sequences generated by LFSR, and then prove its security in the random oracle model (ROM). Compares with the finite field based schemes, our scheme shows advantages on the computation and storage since the reduced representation of finite field elements by LFSR. It will make those applications more efficient in hardware-limited environments, such as cellular networks, tactical networks and sensor nets.

Biclique cryptanalysis using balanced complete bipartite subgraphs

1School of Computer Science, South China Normal University, Guangzhou 510631, China; 2State Key Laboratory of Information Security, Institute of Information Engineering, Chinese Academy of Sciences, Beijing 100093, China; 3School of Mathematics and Statistics, Guangdong University of Finance and Economics, Guangzhou 510320, China; 4School of Electronics and Information, Shanghai Dian Ji University, Shanghai 200240, China; 5School of Information Security Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

Restrictive partially blind signature for resource-constrained information systems

Restrictive partially blind signature, which is designed for privacy-oriented information systems, allows a user to obtain a blind signature from a signer while the blind message must obey some certain rules. In order to reduce storage and communication costs, several public-key cryptosystems are constructed using characteristic sequences generated by linear feedback shift register (LFSR). In this paper, we present a new partially blind signature scheme with the restrictive property, which is based on nth order characteristic sequences generated by LFSR. By assuming the intractability of the discrete logarithm problem, our sequence-based schemes are provably secure in the random oracle model. We also present a practical e-cash application based on our restrictive partially blind signature. Due to the reduced representation of finite field elements and feasible sequence operations from LFSR, our scheme is time- and storage-efficient on both of signer and user sides. The advantages will make privacy-oriented applications more practical for resource-constrained devices.