Krystian Matusiewicz

Learn More
Grøstl is a SHA-3 candidate proposal. Grøstl is an iterated hash function with a compression function built from two fixed, large, distinct permutations. The design of Grøstl is transparent and based on principles very different from those used in the SHA-family. The two permutations are constructed using the wide trail design strategy, which makes it(More)
In this paper, we investigate the security of SHA-3 candidate BLAKE. We analyse the propagation of differences that are rotation-invariant in the internal function G. We show that by using them, it is possible to obtain near-collisions for the compression function reduced to 4 rounds out of 10. We also discuss the security of some variants of BLAKE.
BLAKE is a hash function selected by NIST as one of the 14 second round candidates for the SHA-3 Competition. In this paper, we follow a bottom-up approach to exhibit properties of BLAKE and of its building blocks: based on differential properties of the internal function G, we show that a round of BLAKE is a permutation on the message space, and present an(More)
In this paper we analyse the role of some of the building blocks of SHA-256. We show that the disturbance-correction strategy is applicable to the SHA-256 architecture and we prove that functions Σ, σ are vital for the security of SHA-256 by showing that for a variant without them it is possible to find collisions with complexity 2 hash operations. As a(More)
In this paper we present a cryptanalysis of a new 256-bit hash function, FORK-256, proposed by Hong et al. at FSE 2006. This cryptanalysis is based on some unexpected differentials existing for the step transformation. We show their possible uses in different attack scenarios by giving a 1-bit (resp. 2-bit) near collision attack against the full compression(More)
Hamsi is one of 14 remaining candidates in NIST’s Hash Competition for the future hash standard SHA-3. Until now, little analysis has been published on its resistance to differential cryptanalysis, the main technique used to attack hash functions. We present a study of Hamsi’s resistance to differential and higher-order differential cryptanalysis, with(More)
This report presents analysis of the compression function of a recently proposed hash function, FORK-256. We exhibit some unexpected differentials existing for the step transformation and show their possible uses in collision-finding attacks on different variants of FORK256. As a simple application of those observations we present a method of finding chosen(More)