A New S-Box Structure to Increase Complexity of Algebraic Expression for Block Cipher Cryptosystems

In this paper, we propose a new approach to represent general S-Box based on linear-transform and a given non-linear function that increases the complexity of algebraic expression and size of S-Box. In the case of size of 8, the proposed S-Box can archive the maximum number of terms (255 terms) and therefore it can be used to replace the classical S-Box component in the original AES. Furthermore, the proposed S-Box inherits all good cryptographic characteristics of the original AES S-Box, such as nonlinearity, differential uniformity, and strict avalanche.