Substitution-diffusion based Image Cipher

Abstract

In this paper, a new image encryption scheme using a secret key of 128-bit size is proposed. In the algorithm, image is partitioned into several key based dynamic blocks and further, each block passes through the eight rounds of diffusion as well as substitution process. In diffusion process, sequences of block pixels are rearranged within the block by a zigzag approach whereas block pixels are replaced with another by using difference calculation of row and column in substitution process. Due to high order of substitution and diffusion, common attacks like linear and differential cryptanalysis are infeasible. The experimental results show that the proposed technique is efficient and has high security features.