Book ChapterDOI
Deterministic Constructions of 21-Step Collisions for the SHA-2 Hash Family
Somitra Kumar Sanadhya,Palash Sarkar +1 more
- pp 244-259
TLDR
Two different deterministic attacks against 21-step SHA-2 hash family are constructed, and it is provided evidence that the Nikolic-Biryukov differential path is unlikely to yield 21- step collisions for SHA-512.Abstract:
Recently, at FSE '08, Nikolic and Biryukov introduced a new technique for analyzing SHA-2 round function. Building on their work, but using other differential paths, we construct two different deterministic attacks against 21-step SHA-2 hash family. Since the attacks are deterministic, they are actually combinatorial constructions of collisions. There are six free words in our first construction. This gives exactly 2192different collisions for 21-step SHA-256 and exactly 2384different collisions for 21-step SHA-512. The second construction has five free words. The best previous result, due to Nikolic and Biryukov, for finding collisions for 21-step SHA-256 holds with probability 2i¾? 19. No results on 21-step SHA-512 are previously known. Further, we provide evidence that the Nikolic-Biryukov differential path is unlikely to yield 21-step collisions for SHA-512.read more
Citations
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Proceedings ArticleDOI
A new hash family obtained by modifying the SHA-2 family
TL;DR: The general idea of "multiple feed-forward" for the construction of cryptographic hash functions is introduced, which can provide increased resistance to the Chabaud-Joux type "perturbation-correction" collision attacks.
Journal ArticleDOI
A combinatorial analysis of recent attacks on step reduced SHA-2 family
TL;DR: This analysis explains in a unified way the recent attacks against reduced round SHA-2 in a general class of local collisions and shows that the previously used local collision by Nikolić and Biryukov and Sanadhya and Sarkar are special cases.
Posted Content
A New Hash Family Obtained by Modifying the SHA-2 Family.
TL;DR: In this paper, small modifications to the SHA-2 design are suggested to thwart collision attacks against reduced round hash functions, which can provide increased resistance to the Chabaud-Joux type "perturbation correction" collision attacks.
References
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Book
Fast Software Encryption
TL;DR: Simplified variants that omit a quadratic function and a fixed rotation in RC6 are examined to clarify their essential contribution to the overall security of RC6.
Book ChapterDOI
Polynomial reconstruction based cryptography
Aggelos Kiayias,Moti Yung +1 more
TL;DR: A short overview of recent works on the problem of Decoding Reed Solomon Codes (aka Polynomial Reconstruction) and the novel applications that were enabled due to this development.
Journal Article
Differential collisions in SHA-0
Florent Chabaud,Antoine Joux +1 more
TL;DR: In this paper, the authors presented a method for finding collisions in SHA-0 which is related to differential cryptanalysis of block ciphers and obtained a theoretical attack on the compression function SHA-O with complexity 2 61, which is thus better than the birthday paradox attack.
Journal Article
Security analysis of SHA-256 and sisters
Henri Gilbert,Helena Handschuh +1 more
TL;DR: In this article, the security of SHA-256, SHA-384 and SHA-512 against collision attacks was studied. But the authors concluded that neither Chabaud and Joux's attack, nor Dobbertin-style attacks also don't apply on the underlying structure.