An Optimized S-Box for Advanced Encryption Standard (AES) Design

Abstract

This work presents an optimized Substitution Box (S-Box) for Advanced Encryption Standard (AES) design. The S-Box is one of the most important components of AES. During SubByte transformation, the eight bit input is substituted by eight bit output using the S-Box. S-Box is constructed by composing two transformation - multiplicative inverse in Galois Field GF(2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> ) followed by an affine transformation. The S-Box is the most time and power consuming component of AES Algorithm. In this paper, we have modified the affine transformation and tried to reduce the time complexity of AES. The time consumption for AES S-Box is decreased by the proposed affine transformation.