Advanced Key Expansion Algorithm Using a High-Performance Four-Dimensional Chaotic Map and a Strong S-Box for Enhanced Sensitivity and Independence

Abstract

Abstract The round key plays a critical role in the security of block encryption algorithms, being derived from the initial key through the key expansion process to bolster security. In this study, we introduce a novel key expansion algorithm powered by a high-performance four-dimensional chaotic map and a robust S-box, notable for its sensitivity and independence of keys, thereby strengthening defense against various cryptographic attacks. We present a four-dimensional chaotic map, celebrated for its outstanding dynamic properties as confirmed through detailed behavior analysis. Additionally, we propose an S-box generation technique based on operations in the finite field GF(28), resulting in an S-box with high nonlinearity and enhanced security. This S-box is carefully crafted to eliminate typical weaknesses such as fixed points, reverse fixed points, and short periods, making it suitable for key expansion applications. Utilizing the advantages of the chaotic map and S-box, we elaborate on our key expansion algorithm and demonstrate its security effectiveness through thorough evaluation, showcasing its promise as a potent instrument in cryptographic security.