International Association for Cryptologic Research
The Advanced Encryption Standard (AES) is an iterated block cipher using 10, 12, or 14 rounds depending on the key size of 128, 192, or 256 bits. These variants are named AES-128, AES-192 and AES-256. In this paper, the authors consider the cipher that is derived from the AES by replacing the S-box with a secret 8-bit S-box while keeping everything else unchanged. If the choice of S-box is made uniformly at random from all 8-bit S-boxes, the size of the secret information increases from 128-256bits, the key size in the AES, to 1812-1940bits.