Image encryption algorithms based on two-dimensional discrete hyperchaotic systems and parallel compressive sensing

In this paper, a new two-dimensional discrete hyperchaotic system is proposed. Verification using the phase-track map, bifurcation map and Lyapunov exponent of the chaotic system shows that the chaotic system has better traversal, hyperchaos, unpredictability and wider chaotic region compared with the existing two-dimensional discrete chaotic systems. To improve the efficiency and security of the image encryption algorithm, this paper firstly uses parallel compressive sensing-aware image processing to greatly improve the efficiency of the image encryption. Secondly, index scrambling and forward and backward diffusion using a combination of a subset of discrete data sequences generated by a two-dimensional discrete hyperchaotic system improves the security of the image encryption algorithm. In addition,the initial key and the sum of some pixel values of the original image are used to generate the initial values and control parameters of the 2D-SLS chaotic sequence using the hash of SHA-512, making the proposed algorithm robust to known plaintext and selected plaintext attacks. Simulation and experimental results show that the proposed algorithm is more efficient and secure than recently proposed encryption algorithms.