ENCRYPTION PROCESSING DEVICE, ENCRYPTION PROCESSING METHOD, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To realize an encryption processing configuration improving tolerance to various attacks and high in safety.SOLUTION: The encryption processing device includes: an encryption processing part 385 for generating output data by repeating a round arithmetic operation for input data; and a key schedule part 380 for outputting a round key applied in the round arithmetic operation in the encryption processing part to the encryption processing part. The key schedule part includes: a key register 381 storing a secret key K; and a key conversion part 302 for generating a conversion key Kd by the conversion processing that applies a conversion function G to the secret key. The secret key and the conversion key Kd are used as the round key outputted to the encryption processing part or data for generating the round key. A function having an involution property and a full diffusion property in which an inverse function Gis the same as the function G is applied as the conversion function G.