A novel image encryption scheme of dynamic S-boxes and random blocks based on spatiotemporal chaotic system

In this paper, a novel image encryption scheme based on spatiotemporal chaotic system is proposed. In the scheme, we adopt the dynamic S-boxes and random blocks algorithms. Firstly, the image is brought into SHA-512 to generate system key. And the key is introduced into Logistic-Dynamic Coupled Logistic Map Lattices (LDCML) spatiotemporal chaos system to initialize the values of dynamic S-boxes and set the parameter values in image encryption. Then, the image is grouped horizontally and vertically in order. Each group consists of non-adjacent rows or non-adjacent columns and is encrypted by the different S-boxes. Lastly, every scrambled pixel is processed by random blocks algorithm. With this encryption scheme, the image is scrambled and diffused simultaneously, which can be scrambled sufficiency and diffused uniformity. Simulation results show that the scheme provides a satisfying level of security and has the advantages of large key space, anti-differential attack, high efficiency and good statistical performance in comparison with other image encryption schemes.