Abstract
The S-Box is a major step of the Advanced Encryption Standard (AES). In the current AES, the step uses a table lookup based on the Galois Field GF(2(n)) to map the plaintext to the ciphertext with confusion. This paper proposes an AES S-Box implementation that is based on modified lookup table. The proposed platform for implementing the S-Box builds upon the hypothesis that the set of residues of any prime number forms a mathematical field. Two sparse lookup tables with irregularly distributed entries are used to add more confusion to the process. The inverse of any entry in either of the tables is stored on one of them. The goal of this paper is therefore twofold: the first is to find an alternative to the Galois Field implementation and the second is to add more confusion to the S-Box implementation.