Color image encryption algorithm based on a novel five-dimensional chaotic system

Abstract With improved multimedia security and efficiency, the existing chaotic image encryption system faces problems, such as a lack of complexity, brute-force cracking and statistical attacks. This paper presents an image encryption algorithm based on the five-dimensional chaotic system. Firstly, a five-dimensional chaotic system with complex nonlinear behaviour is constructed, and its more substantial randomness and dynamics characteristics are verified by the Lyapunov index, Poincare cross-section, phase diagram, approximate entropy and sample entropy tests. Secondly, the traditional encryption structure is improved, the position cascade permutation strategy is adopted to achieve nonlinear pixel confusion, and the diffusion mechanism is constructed with cat mapping. Through several security and performance tests, the proposed algorithm outperforms the existing schemes in information entropy, correlation of adjacent pixels, NPCR and UACI. The analysis of salt-and-pepper noise and clipping attacks shows that the algorithm performs well in security and robustness, and the encryption speed is better than other algorithms.