An Efficient and Secure Image Encryption Algorithm Based on Non- Adjacent Coupled Maps

In this paper, an image encryption algorithm based on non-adjacent coupled map lattices is designed. Compared with coupled map lattices, non-adjacent coupled map lattices have few periodic windows in bifurcation, and larger parameter range in chaos dynamics. Combined with the proposed chaotic system, a new alternative encryption structure between permutation, diffusion and substitution is proposed to improve the security and encryption efficiency of the algorithm. In the diffusion process, multiplication operation in GF (257) and addition operation in GF (2
⁸
) based on look-up table are adopted, which improves the encryption efficiency and enhances the permutation effect by choosing pixel value in Latin Square during the diffusion process. Moreover, based on the good cryptographic characteristics of the s-box, a dynamic s-box related to plaintext is constructed to substitute plaintext pixels. Experimental results and security analysis show that the proposed encryption scheme can resist all types of typical attacks and has good encryption effect.