CRYPTANALYSIS PROCESSOR, ENCRYPTION PROCESSOR, METHOD AND COMPUTER PROGRAM

PROBLEM TO BE SOLVED: To obtain a device and a method for conducting an efficient cryptanalysis and an encryption processing device and a method with high security. SOLUTION: In a cryptanalysis by a power differential analysis, the duplicate bit information of key bit information applied to a data converting part in a round function part is extracted, duplicated search processing is eliminated, and search processing is applied only to a new bit. This configuration greatly reduces the number of searching times to enable an efficient cryptanalysis. Also, the minimum number of searching times of search processing obtained by eliminating a duplicate search about the duplicate bit information is calculated to make the security evaluation of encryption processing based on the calculation result possible. In addition, the setting of a round key generating part that can set a round key so as to make the minimum number of searching times large perform an encryption processing algorithm with high security. COPYRIGHT: (C)2005,JPO&NCIPI