High speed S-box architecture for Advanced Encryption Standard

This paper presents a high speed architecture for composite field arithmetic based SubBytes transformation (S-box) used in Advanced Encryption Standard (AES) encryption. The proposed architecture is derived by extending the pre-computation technique suggested recently by Liu and Parhi to a recently proposed architecture of AES S-box due to Rashmi, Mohan and Anami. The proposed design of S-box is shown to have the shortest critical path with moderate gate count requirement compared to the known composite field based S-box designs described in literature. The FPGA implementation results using Xilinx XC2V6000-6 are also provided to substantiate the claimed reduction in critical path of AES S-box.