In this paper, we present more powerful 6-round impossible differentials for large-block Rijndael-224 and Rijndael-256 than the ones used by Zhang et al. in ISC 2008. Using those, we can improve the previous impossible differential cryptanalysis of both 9-round Rijndael224 and Rijndael-256. The improvement can lead to 10-round attack on Rijndael-256 as well. With 2 chosen plaintexts, an attack ...

© 2014 ETRI Journal, Volume 36, Number 6, December 2014 http://dx.doi.org/10.4218/etrij.14.0113.1335 The Lai-Massey scheme, proposed by Vaudenay, is a modified structure in the International Data Encryption Algorithm cipher. A family of block ciphers, named FOX, were built on the Lai-Massey scheme. Impossible differential cryptanalysis is a powerful technique used to recover the secret key of b...

SIMON is a family of lightweight block ciphers that was proposed by U.S National Security Agency (NSA). A cipher in this family with K-bit key and N -bit block is called SIMON N/K. In this paper we analyze the security of SIMON against linear cryptanalysis. We present several linear characteristics for all variants of SIMON with reduced number of rounds. Our best linear characteristic covers SI...

Recently, a new concept called the c-differential uniformity was proposed by Ellingsen et al. (2020), which generalizes notion of differential measuring resistance against cryptanalysis. Since then, finding functions having low has attracted attention many researchers. However it seems that, at this moment, there are not non-monomial permutations uniformity. In paper, we present classes (almost...

Functions with low c-differential uniformity have optimal resistance to some types of differential cryptanalysis. In this paper, we investigate the power functions over finite fields odd characteristic. Based on known almost perfect nonlinear functions, present several classes $$f(x)=x^d$$ $$_{c}\varDelta _f\le 3$$ . Especially, two new c-nonlinear are proposed.

Symmetric key cryptographic algorithms provide confidentiality, integrity, and authentication in modern communication systems. Our confidence in these algorithms is largely based on the fact that intense cryptanalysis has been carried out over several years without revealing any weakness. This thesis makes three independent contributions to the cryptanalysis of symmetric key primitives and hash...