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Weak generalized self-shrinking generators

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Journal of Systems Engineering and Electronics 2007年第2期18卷 407-411页

作者： Dong Lihua Hu Yupu the key lab. of computer networks and information security the Ministry of Education Xidian Univ. Xi'an 710071 P. R. China

The security of certain classes of the generalized self-shrinking sequence （GSS） generators is analyzed. Firstly, it is shown that the security of these GSS generators is equivalent to the security of the GSS generators of the class-1, after which two effective key recovery attacks on the GSS generators of the class-1 are developed to evaluate their security.

关键词： Cryptography Stream cipher, key recovery attacks Generalized self-shrinking sequence.

Cryptanalysis of PRIMATEs

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Science China(information Sciences) 2020年第1期63卷 130-139页

作者： Yanbin LI Meiqin WANG Wenqing LIU Wei WANG key lab.ratory of Cryptologic Technology and information security Ministry of EducationShandong University Shandong Provincial key lab.ratory of computer networks

PRIMATEs is a family of authenticated encryption design submitted to competition for authenticated encryption: security, applicability, and robustness. The three modes of operation in PRIMATEs family are: APE, HANUMAN, GIBBON with security levels: 80, 120 bits. APE is robust despite the nonce misusing. In this study, we revise the algebraic model and find new integral distinguishers for both PRIMATE permutation and its inverse permutation. Moreover, we construct a zero-sum distinguisher for full12-round PRIMATE-80/120 permutation with the 2;/2;complexity, improving over previous work. We also perform an integral attack on 8-round finalization of APE-80/120 with 2;chosen messages. The key recovery process is optimized using the FFT technique presented by Todo and Aoki. Our work is the best attack against APE, demonstrating the practical attack on 8-round finalization of APE-80. The new integral distinguishers apply to create forgeries on 5/6-round finalization of APE and HANUMAN that require2;/2;chosen messages, which is the first forgery attack against APE and HANUMAN.

关键词： PRIMATEs APE HANUMAN integral distinguisher key recovery attack forgery

A resynchronization attack on stream ciphers filtered by Maiorana-McFarland functions

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Frontiers of computer Science 2011年第2期5卷 158-162页

作者： Wenfeng YANG Yupu HU key lab.ratory of computer networks and information security Ministry of Education Xidian University Xi＇an 710071 China

A resynchronization attack is proposed on stream ciphers filtered by Maiorana-McFarland （M-M） functions and equipped with a linear resynchronization mechanism. The proposed attack utilizes the linear weakness of the resynchronization mechanism, the partial linearity of M-M functions, and applies the linear consistency test method to recover the secret key. It is shown that an M-M function should not be implemented by itself but rather in combination with other nonlinear components in stream ciphers using linear mechanisms to prevent the proposed attack. It is also shown that the use of linear resynchronization mechanisms should be avoided despite their high efficiency in stream ciphers filtered by M-M functions.

关键词： stream ciphers Maiorana-McFarland (M-M) functions cryptanalysis resynchronization attack

Efficient quantum secret sharing scheme with two-particle entangled states

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Chinese Physics B 2011年第4期20卷 59-64页

作者：朱珍超张玉清付安民 key lab.of computer networks and information security of Ministry of Education Xidian University National computer Network Intrusion Protection Center Graduate University of the Chinese Academy of Sciences

This paper proposes a protocol for multi-party quantum secret sharing utilizing four non-orthogonal two-particle entangled states following some ideas in the schemes proposed by Liu et al. （2006 Chin. Phys. Lett. 23 3148） and Zhang et al. （2009 Chin. Phys. B 18 2149） respectively. The theoretical efficiency for qubits of the new protocol is improved from 50% to approaching 100%. All the entangled states can be used for generating the private key except those used for the eavesdropping check. The validity of a probable attack called opaque cheat attack to this kind of protocols is considered in the paper for the first time.

关键词： quantum secret sharing quantum entanglement Bell state nonorthogonal base

Short-ciphertext and BDH-based CCA2 secure certificateless encryption

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Science China(information Sciences) 2010年第10期53卷 2005-2015页

作者： SUN YinXia & LI Hui 1 key lab.of computer networks and information security, Ministry of Education, Xidian University, Xi’an 710071, China 1. key lab.of computer networks and information security Ministry of Education Xidian University Xi’an 710071 China

Certificateless public key cryptosystem actually belongs to identity based cryptography, with an attractive characteristic that the private key generator does not have access to any user’s full private key. Most of the existing certificateless encryption schemes employ the FO-technique and/or strong assumptions, for example GBDH, Gap-BDH and BDHI, to achieve adaptive chosen ciphertext security (CCA2 security). However, FO-technique introduces redundancy in ciphertext, and strong assumption reduces our confidence in the security of the underlying scheme. In this paper, we present a short-ciphertext CCA2 secure certificateless encryption scheme under the standard BDH assumption. Due to short ciphertext and convincing security, our scheme has practical value.

关键词： identity based cryptography certificateless encryption bilinear pairing BDH problem twin BDH problem random oracle

Simple Method for Realizing Weil Theorem in Secure ECC Generation

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Tsinghua Science and Technology 2017年第5期22卷 511-519页

作者： Feng Hu Chao Wang Huanguo Zhang Jie Wu the key lab.ratory of Specialty Fiber Optics and Optical Access networks School of Communication and Information EngineeringShanghai University the Department of computer and information Sciences Temple University the key lab.of Aerospace information security and Trusted Computing Wuhan University

How to quickly compute the number of points on an Elliptic Curve （EC） has been a longstanding challenge. The computational complexity of the algorithm usually employed makes it highly inefficient. Unlike the general EC, a simple method called the Weil theorem can be used to compute the order of an EC characterized by a small prime number, such as the Kobltiz EC characterized by two. The fifteen secure ECs recommended by the National Institute of Standards and Technology （NIST） Digital Signature Standard contain five Koblitz ECs whose maximum base domain reaches 571 bits. Experimental results show that the computation speed decreases for base domains exceeding 600 bits. In this paper, we propose a simple method that combines the Weil theorem with Pascals triangle, which greatly reduces the computational complexity. We have validated the performance of this method for base fields ranging from 2l^100 to 2^1000. Furthermore, this new method can be generalized to any ECs characterized by any small prime number.

关键词： Elliptic Curves (ECs) Pascal's triangle Weil theorem

Evolutionary Cryptography Theory-Based Generating Method for Secure ECs

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Tsinghua Science and Technology 2017年第5期22卷 499-510页

作者： Chao Wang Feng Hu Huanguo Zhang Jie Wu the key lab.ratory of Specialty Fiber Optics and Optical Access networks School of Communication and Information EngineeringShanghai University the Department of computer and information Sciences Temple University the key lab.of Aerospace information security and Trusted Computing Wuhan University

Ant Colony Optimization （AGO） has the character of positive feedback, distributed searching, and greedy searching. It is applicable to optimization grouping problems. Traditional cryptographic research is mainly based on pure mathematical methods which have complicated theories and algorithm. It seems that there is no relationship between cryptography and ACO. Actually, some problems in cryptography are due to optimization grouping problems that could be improved using an evolutionary algorithm. Therefore, this paper presents a new method of solving secure curve selection problems using ACO. We improved Complex Multiplication （CM） by combining Evolutionary Cryptography Theory with Weber polynomial solutions. We found that ACO makes full use of valid information generated from factorization and allocates computing resource reasonably. It greatly increases the performance of Weber polynomial solutions. Compared with traditional CM, which can only search one root once time, our new method searches all roots of the polynomial once, and the average time needed to search for one root reduces rapidly. The more roots are searched, the more ECs are obtained.

关键词： ECs Weber polynomial evolutionary algorithm ant algorithm complex multiplication

Secure mediated certificateless signature scheme

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 75-78页

作者： YANG Chen MA Wen-ping WANG Xin-mei Ministry of Education key lab.ratory of computer networks and information security Xidian University Xi'an 710071 China

Ju et al. proposed a certificateless signature scheme with instantaneous revocation by introducing security mediator （SEM） mechanism. This article presents a detailed cryptoanalysis of this scheme and shows that, in their proposed scheme, once a valid signature has been produced, the signer can recover his private key information and the instantaneous revocation property will be damaged. Furthermore, an improved mediated signature scheme, which can eliminate these disadvantages, is proposed, and security proof of the improved scheme under elliptic curve factorization problem （ECFP） assumption and bilinear computational diffie-hellman problem （BCDH） assumption is also proposed.

关键词： certificateless signature scheme bilinear pairing security mediator

Two-step transmission with artificial noise for secure wireless SIMO communications

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Science China(information Sciences) 2015年第4期58卷 115-127页

作者： WANG Bo MU PengCheng YANG PeiZhi YIN QinYe Ministry of Education key lab.for Intelligent networks and Network security School of Electronic and Information Engineering Xi’an Jiaotong University

The issue of physical layer security of the wireless single-input multiple-output(SIMO) system is addressed in this paper. We propose a two-step transmission scheme with artificial noise to improve the security and the scheme does not require the channel state information of the eavesdropper. In the first step, the destination which has multiple antennas generates a random reference symbol and artificial noise and transmits them in the direction of the source and its orthogonal space, respectively. The reference symbol is received by the source without being polluted by the artificial noise, while it is jammed by the artificial noise for the eavesdropper. In the second step, the symbol of the source is multiplied by the received reference symbol and then transmitted. Finally, the destination can directly estimate the symbol of the source using the reference symbol. However, the eavesdropper needs to additionally estimate the reference symbol for demodulating the symbol of the source, which usually obtains an inaccurate result due to the artificial noise. The informationtheoretic security of our scheme is analyzed and a lower bound of the achievable secrecy rate is derived. The performance of the new scheme is compared with that of the traditional approach under different input signals through numerical simulations. The results show that the proposed scheme outperforms the traditional SIMO approach especially in the high SNR region.

关键词： wireless communication physical layer security multi-antenna SIMO artificial noise