An LA-group based design of the non-linear component of block cipher

Abstract

An S-box is a crucial component of modern block ciphers, providing confusion and making them attack-resistant. For the last three decades, researchers have designed S-boxes using techniques mainly based on associative algebras of Galois fields. In this work, the non-associative structure of an LA-group (left almost group) is employed to design 8 × 8 S-boxes. An LA-group-based design S-box offers appealing properties, such as the inverse of zero element, non-associativity, and fewer constraints. These characteristics increase robustness and expand the key space compared to cyclic groups and Galois fields. Furthermore, an RGB image encryption scheme is also presented in this work to judge the impact of proposed S-boxes. The proposed S-boxes create confusion in a plain image “Red, Green, and Blue” channels, whereas for diffusion, the linear transformation K=(i×32)mod127 is operationalized. In the last, we compared our encryption scheme to some existing benchmarks, revealing that our encryption technique is adequate for image security.