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【期刊论文】Cryptanalysis of the Hash Functions MD4 and RIPEMD
王小云, Xiaoyun Wang, Xuejia Lai, Dengguo Feng, Hui Chen, and Xiuyuan Yu
EUROCRYPT 2005, LNCS 3494, pp. 1-18, 2005.,-0001,():
-1年11月30日
MD4 is a hash function developed by Rivest in 1990. It serves as the basis for most of the dedicated hash functions such as MD5, SHAx, RIPEMD, and HAVAL. In 1996, Dobbertin showed how to find collisions of MD4 with complexity equivalent to 220 MD4 hash computations. In this paper, we present a new attack on MD4 which can find a collision with probability 2-2 to 2−6, and the complexity of finding a collision doesn't exceed 28 MD4 hash operations. Built upon the collision search attack, we present a chosen-message pre-image attack on MD4 with complexity below 28. Furthermore, we show that for a weak message, we can find another message that produces the same hash value. The complexity is only a single MD4 computation, and a random message is a weak message with probability 2−122. The attack on MD4 can be directly applied to RIPEMD which has two parallel copies of MD4, and the complexity of finding a collision is about 218 RIPEMD hash operations.
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【期刊论文】Efficient Collision Search Attacks on SHA-0
王小云, Xiaoyun Wang, Hongbo Yu, and Yiqun Lisa Yin
Crypto 2005, LNCS 3621, pp. 1-16, 2005.,-0001,():
-1年11月30日
In this paper, we present new techniques for collision search in the hash function SHA-0. Using the new techniques, we can find collisions of the full 80-step SHA-0 with complexity less than 239 hash operations.
Hash functions,, Collision search attacks,, SHA-0,, SHA-1.,
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【期刊论文】The Second-Preimage Attack on MD4
王小云, Hongbo Yu, Gaoli Wang, Guoyan Zhang, and Xiaoyun Wang
CANS 2005, LNCS 3810, pp. 1-12, 2005.,-0001,():
-1年11月30日
In Eurocrypt'05, Wang et al. presented new techniques to find collisions of Hash function MD4. The techniques are not only efficient to search for collisions, but also applicable to explore the secondpreimage of MD4. About the second-preimage attack, they showed that a random message was a weak message with probability 2−122 and it only needed a one-time MD4 computation to find the second-preimage corresponding to the weak message. A weak message means that there exits a more efficient attack than the brute force attack to find its secondpreimage. In this paper, we find another new collision differential path which can be used to find the second-preimage for more weak messages. For any random message, it is a weak message with probability 2−56, and it can be converted into a weak message by message modification techniques with about 227 MD4 computations. Furthermore, the original message is close to the resulting message (weak message), i. e, the Hamming weight of the difference for two messages is about 44.
Hash function,, collision differential path,, second-preimage,, weak message.,
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【期刊论文】Secure and Practical Tree-Structure Signature Schemes Based on Discrete Logarithms
王小云, X. Y. Wang, L. C. Hui, K. P. Chow, W. W. Tsang, C. F. Chong, and H. W. Chan
PKC 2000, LNCS 1751, pp. 167-177, 2000.,-0001,():
-1年11月30日
In this paper, we present another tree-structure signature scheme based on discrete logarithm problem modulo p, where p is a large prime. The basic signing algorithm is the original ELGmal signature scheme. The scheme attains ideal security, i. e, finding existential forgeries under adaptively chosen message attacks is equivalent to solving the discrete logarithm of any random integer y∈Z*p. The scheme is also efficient, it can be implemented almost as efficiently as the original ELGamal signature scheme. We can regard the scheme as an application of ELGamal signature scheme in tree-structure signature schemes.
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【期刊论文】The Differential Cryptana]ysis of an AES Finalist-Serpent
王小云, X. Y. Wang*, L. C. K. Hui*, K. P. Chow*, C. F. Chong*, W. W. Tsang*, H. W. Chan*
,-0001,():
-1年11月30日
Serpent is one of the five AES finalists. In our paper, we give solne differentials about Serpent, two of the differentials are a 5-round differential with the probability of 1/207 and a 6-round diffierential with the probability of 1/207. The best known differential before our paper is a 5-round differential with the probability of 1/207 given in [9]. Additionally, we provide all the possible best differentials for some cases about Serpent. From these best differentials, we eonclude that the 16-round best differential is not higher than 1/207 and that the 17-round differential is less than 1/2128.
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