Pawel Morawiecki

A SAT-based preimage analysis of reduced Keccak hash functions

Abstract In this paper, we present a preimage attack on reduced versions of Keccak hash functions. We use our recently developed toolkit CryptLogVer for generating the conjunctive normal form, CNF, which is passed to the SAT solver PrecoSAT. We found preimages for some reduced versions of the function and showed that full Keccak function has a comfortable security margin against this kind of attack.

Differential and Rotational Cryptanalysis of Round-reduced MORUS.

In this paper we investigate the security margin of MORUS — an authenticated cipher taking part in the CAESAR competition. We propose a new key recovery approach, which can be seen as an accelerated exhaustive search. We also verify the resistance of MORUS against internal differential and rotational cryptanalysis. Our analysis reveals that the cipher has a solid security margin and a lack of round constants does not bring any weakness. Our work helps to reliably evaluate this new, high-performance algorithm, which is particularly important in the context of the ongoing CAESAR competition.

Differential-linear and Impossible Differential Cryptanalysis of Round-reduced Scream.

In this work we focus on the tweakable block cipher Scream, We have analysed Scream with the techniques, which previously have not been applied to this algorithm, that is differential-linear and impossible differential cryptanalysis. This is work in progress towards a comprehensive evaluation of Scream. We think it is essential to analyse these new, promising algorithms with a possibly wide range of cryptanalytic tools and techniques. Our work helps to realize this goal.

Differential-linear and related key cryptanalysis of round-reduced scream

Abstract We have analysed tweakable block cipher Scream which is used by cipher SCREAM, with the techniques linear cryptanalysis, differential cryptanalysis and related key cryptanalysis. Tweakable block cipher Scream is already analysed with linear, differential-linear and impossible differential cryptanalysis in our previous paper. In this paper we extend our work by adding related key attack along with the differential-linear attack.