A colour image encryption algorithm using 4-pixel Feistel structure and multiple chaotic systems

In recent years, chaos-based image encryption algorithms have attracted much attention. Particularly, with larger data capacity and higher correlation among pixels, encryption of colour images demands better statistic and diffusion properties of image algorithms than that of grey images. In this paper, a chaos-based algorithm aiming at colour image encryption is proposed. Two 3D chaotic systems are used as key generators for three colours of colour images’ pixels. 4-Pixel Feistel structure and functions based on multiple chaotic maps are used to improve the statistic and diffusion properties of cipher image. Dependent encryption progress is used to resist certain cryptanalysis methods, such as known-/chosen plaintext attack and chosen cipher attack. According to large number of simulation experiments, with good speed performance being taken into account, our algorithm has better properties and higher security level than certain other chaos-based colour image encryption algorithms.