Patent ID: 8094815

Claim:
An integrated arithmetic apparatus for supporting Advanced Encryption Standard (AES) and Academy, Research Institute and Agency (ARIA) encryption and decryption functions, the apparatus comprising: a key scheduler for generating a round key using an input key; and a round function calculator for generating encrypted/decrypted data using input data and the round key, wherein the round function calculator comprises an integrated substitution layer and an integrated diffusion layer configured to perform both AES and ARIA algorithms, wherein the integrated substitution layer comprises: a first block for serving as an AES S-box; and a second block for serving as an AES and ARIA S-box such that the second block uses an isomorphism function and an affine transformation function transforming an element of the second block into an element in a finite field GF(((2 2 ) 2 ) 2 ), wherein the second block selects an isomorphism function having the smallest number of “1”s among the isomorphism function, the affine transformation function, and an combined function of the isomorphism function and the affine transformation function.