Multiple-Image Encryption Scheme Based on an N-Dimensional Chaotic Modular Model and Overlapping Block Permutation–Diffusion Using Newly Defined Operation

Abstract

Some existing chaotic maps have the drawbacks of a narrow range of chaotic parameters and discontinuities, which may be inherited by new chaotic systems generated from them as seed maps. We propose a chaotic model that can generate N-dimensional chaotic systems to overcome the problem. By fixing the original parameters of the seed map in the chaotic range, we then introduce new parameters and use modular operations to widen the range of the parameters and increase the complexity. Simulation results show that the generated chaotic system has good chaotic dynamics. Based on this chaotic model, we propose a multiple-image encryption algorithm that is not limited by image type, number, and size. The resistance to plaintext attacks is enhanced by a permutation–diffusion algorithm based on overlapping blocks. We design a newly defined lookup table operation based on Latin squares with enhanced nonlinearity and randomness. By adjusting the overlapping block parameters and the number of Latin squares, users can design different encryption levels to balance encryption efficiency and encryption effectiveness. The experimental results show that the proposed image encryption algorithm can effectively encrypt multiple images, and all the evaluation indexes reach the expected value.