Research On Rijndael Algorithm's Differential Cryptanalysis And Square Cryptanalysis

With the rapid development of computer and communication technology, designing and analyzing block cipher uses widely and researches deeply。Block cipher can provide more secure algorithm in transporting data 。Block cipher analyzing can prove algorithm security in theory and in practice,and it can help block cipher designing development。 There are more fruit in block cipher designing。The most typical technology is AES,Rijndael algorithm 。But block cipher analyzing is all kinds of analyzing methods。Some of these is general ,some is special。Differential cryptanalysis is just a typical general method,but Square method is a special one 。 With deeply research in Rijndael algorithm,based on Rijndael algorithm chart,it builds 2 round encryption process matrix。By this way,it can find the key of Rijndael algorithm,but the method is useless to three round and more。Impossible differential cryptanalysis can break down five round Rijndael algorithm,the result is that plaintext pairs is 2123.5 and computing is 2124.5。Duration the cryptanalysis, it also verify the resisting differential cryptanalysis in theory. For four-round Rijndael, the maximum probability of differential cryptanalysis is 2-150,and eight- round Rijndael, the maximum probability of differential cryptanalysis is 2-300, which proves that pure DC is useless to find key in four-round and more rounds 。Using Square method analyzes,finding out that it can find key of using based on four-round,five-round and six-ground。It proves that it only useful to to Rijndael-192 and Rijndael-256。At last ,it also do some work in strengthening Rijndael algorithm。During this process,it proves that is more resistant to all the cryptanalysis capabilities。...