چكيده به لاتين
Nowadays, useful application of block ciphers in so many branch of science, evaluate the security of them becomes a very active area of research. Cryptanalysis of block cipher has two conceptual phases; first phase consist of study of the structure of the block cipher to discover some property called distinguisher which can be used to distinguish a block cipher from random permutation, the second phase using statistical methods to exploit such a property give a key-recovery attack and obtain a part of secret key.In this theses, we cryptanalysis the block ciphers ststistically and proposed two new attack on block cipher, differential-linear cryptanalysis with correlation zero and multiple differential-linear cryptanalysis. This attack based on concatenation a differential and linear approximation with zero correlation over a part of the block cipher. Our attack is the best known attack on CAST-256 according to the number of rounds. We first, construct a 30-round differential-zero correlation linear distinguisher. Based on the distinguisher, we propose a first 33-round attack on CAST-256 . We also identify a distinguisher for 20 rounds of LBlock, and describe the first 24-rounds attack of LBlock.
Keywords:.Block cipher, statistical cryptanalysis, differential cryptanalysis, linear cryptanalysis
