ENCRYPTION PROCESSING DEVICE, AND ENCRYPTION PROCESSING METHOD AND PROGRAM

摘要

The present invention realizes a highly safe encryption processing structure that improves resistance to various attacks. Provided are: an encryption processing unit that generates output data by repeating a round operation on input data; and a key scheduling unit that outputs to the encryption processing unit a round key to be applied in the round operations by the encryption processing unit. The key scheduling unit has a key register that stores a secret key (K) and a key conversion unit that generates a conversion key (Kd) by conversion processing that applies a conversion function (G) to the secret key (K), and uses the secret key (K) and conversion key (Kd) as the round key to be outputted to the encryption processing unit or as data for generating the round key. A function that has involution properties whereby the inverse function (G-1) becomes the same function as the function (G) and has full diffusion properties is utilized as the conversion function (G).