Image encryption algorithm based on cascaded chaotic map and improved Zigzag transform
Jiming Zheng, Tianyi Lv
Abstract
Abstract In this paper, an image encryption algorithm based on cascaded chaotic map and improved Zigzag transform is proposed. Firstly, a cascade chaotic system is improved to make its chaotic sequence evenly distributed and improve its parameter range. The purpose is to obtain high random chaotic sequence and make the ciphertext image more secure. Secondly, the improved Zigzag transform is used to scramble the image. Compared with the standard Zigzag transform, the improved Zigzag transform can fully scramble all the pixels and improve the randomness of the ciphertext image. Thirdly, a wave‐shaped diffusion algorithm is designed, its characteristic is that it can alternate between different row and column for diffusion. The combination of SHA256 algorithm and plain image makes the cipher image better resist the select plaintext attack. Simulation results show that the algorithm has fast encryption efficiency, high security and can effectively resist various attacks.