Investigation for 8-bit SKINNY-like S-boxes, analysis and applications

Abstract

Nowadays, ciphers have been widely used in high-end platforms, resource-constrained, and side-channel attacks vulnerable environments. This motivates various S-boxes aimed at providing a good trade-off between security and efficiency. For small S-boxes, the most natural approach of constructing such S-boxes is a comprehensive search in the space of permutations, which inevitably becomes more challenging when the size grows. For large S-boxes (e.g., 8-bit), previous works concentrated on creations from finite fields or smaller ones (e.g., 4-bit). This paper proposes a new algorithm with a layered structure to search for 8-bit SKINNY-like S-boxes. We compare our new S-box with the original 8-bit SKINNY S-box by analyzing its security properties. Besides, due to our searching algorithm’s rules and constraints, SKINNY-like S-boxes have other features of lightweight implementation, low multiplicative complexity, low AND depth, and an effective inverse. Eventually, the searching algorithm outputs 224000 8-bit SKINNY-like S-boxes. The cipher designers can use these new S-boxes to construct lightweight block ciphers with easy-to-mask property and efficient implementation performance.