Patent ID: 7760871

Claim:
A data transformation apparatus having comprising: a key generating unit, which generates output key data based on input key data; and a data processing unit, which performs at least one of encryption of data and decryption of data based on the output key data, wherein the data processing unit includes plural data transformation units, which perform a non-linear transformation and a linear transformation alternately based on extension keys, wherein the key generating unit includes a key shifting unit, which: performs a rotational shift on at least one of 128 bits of the input key data and 128 bits of data generated from the input key data, the rotational shift being performed by a predetermined number of bits Z 1 , Z 2 , . . . , Z m Z 1 <Z 2 < . . . <Z m , where Z 1 is 0 bits) so as to generate shift data; and generates extension keys to be supplied to the data transformation units from the shift data on which the rotational shift is performed, and wherein the key shifting unit includes: rotational shift registers, which perform a rotational shift by 15 bits or 17 bits at one operation to generate the shift data on which a rotational shift is performed by Z i (2≦i≦m) bits; and a controller, which controls one of the rotational shift registers to perform a rotational shift on the shift data on which the rotational shift is performed by Z i−1 bits so as to generate the shift data on which is performed a rotational shift by Z i bits.