An algorithm for construction of substitution box based on subfield of galois field GF(216) and dynamic linear fractional transformation

In block encryption algorithms the only nonlinear component, which creates confusion and diffusion, is substitution box (S-Box). Therefore, carefully selection of S-Box is an important task. In this article, an algorithm is presented for the construction of 8 × 8 S-Box based on all subfields of Galois Field G F 2 16 and linear fractional transformation. Proposed algorithm is easy and simple but significantly complex for the attackers as it utilizes all subfields of G F ( 2 16 ) corresponding to all primitive irreducible polynomials for making G F ( 2 16 ) . An illustrating S-Box is also developed which is showing good structural characteristics such as it has no fixed point with 108.5 nonlinearity and 0.5020 strict avalanche. In the last, illustrated S-Box is applied on images for checking the performance under various criteria available in the literature. Obtained results of analyses are compared to well-known S-Boxes and found better in the comparison.