Enhanced Substitution-Diffusion Based Image Cipher Using Improved Chaotic Map

Abstract

This paper proposes an enhanced substitution-diffusion based image cipher using improved chaotic map. The first step consists of permutation which uses the odd key values. Byte substitution is applied in the second step to improve the security against the known/chosen-plaintext attack. Finally, confusion and diffusion are obtained using the sub diagonal diffusion of adjacent pixels and XORing with the chaotic key. The numbers of rounds in the steps are controlled by combination of pseudo random sequence and original image. The security and performance of the proposed image encryption technique have been analyzed thoroughly using statistical analysis, key sensitivity analysis, differential analysis, key space analysis and entropy analysis. Results of the various types of analyzes are showing that the proposed image encryption technique is more secure and fast. © Springer-Verlag Berlin Heidelberg 2010.