Colour Image Encryption Scheme Based on Permutation and Substitution Techniques

Abstract

In this paper, a new lossless 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 each block is passed through the eight rounds of permutation as well as substitution process. In permutation process, sequences of block pixels are rearranged within the block by a zigzag approach whereas block pixels are replaced with another by using difference transformation of row and column in substitution process. Due to high order of confusion and diffusion, attacks like linear and differential cryptanalysis are infeasible. The experimental results show that the proposed technique is efficient and has high security features.