An Optimized Bit-Slice Implementation of Secure 8-Bit Sbox Based on Butterfly Structure

The S-box is the only non-linear component in primitive symmetric cryptography. However, many S-boxes implementations rely on lookup tables, which can lead to inefficient performance and resource utilization in hardware. In this paper, we present an optimized bit-slice implementation of an 8-bit S-box based on a butterfly structure, as introduced in [1]. An implementation approach is introduced, which optimizes the logical operations within the Boolean functions of the 4-bit cryptographic components that form the considered S-box. The results show that this implementation requires only 191 logic operations. Furthermore, evaluations were conducted on a block cipher to demonstrate the effectiveness of the proposed S-box.