Analysis of Venkaiah et al.’s AES Design

This paper describes impossible differential (ID) attacks on an AES variant designed by Venkaiah et al.. They claim that their cipher has improved resistance to ID attacks due to a new MixColumns matrix with a branch number 4, which is smaller than that of the original AES. We argue against this statement. The contributions of this paper include ID distinguishers for Venkaiah et al.’s cipher, and a discussion of the susceptibility of such variants to impossible differential and other modern cryptanalytic techniques