ENCRYPTION PROCESSING DEVICE, ENCRYPTION PROCESSING METHOD, AND PROGRAM

PROBLEM TO BE SOLVED: To realize an encryption processing device which is very safe because of supply control of a round key.SOLUTION: One aspect of this invention comprises: an encryption processing unit which divides configuration bits of data to be processed into a plurality of lines and inputs the same, and then repeatedly executes a data conversion process in which a round function is applied to the data in each line as a round operation; and a key schedule unit which outputs a round key to a round operation execution unit in the encryption processing unit. The key schedule unit is a permutation-type key schedule unit which divides previously held secret keys into a plurality of units, to generate a plurality of round keys. The key schedule unit outputs the plurality of generated round keys in a setting in which there is no repetition of a fixed sequence, to the round operation execution unit sequentially executing the round operations in the encryption processing unit. This configuration can realize an encryption processing configuration which is very safe and is strongly resistant to a related-key attack or the like.