A novel pixel-split image encryption scheme based on 2D Salomon map

Abstract

Images serve as a valuable information carrier for their properties of visualization and holding a large amount of messages. This paper presents a novel chaos-based encryption scheme to protect images from being captured or attacked. Firstly a two-dimensional Salomon map inspired by the Salomon function is proposed and there is a comprehensive comparison with other recent counterparts to validate the effectiveness of this chaotic system. Compared with traditional maps, the results show that 2D Salomon map has larger Lyapunov exponent, Kolmogorov entropy, Correlation dimension and Sample entropy. Especially the values of Lyapunov exponent can reach 11, which indicates that the chaotic sequence generated by Salomon map has strong randomness. Then a pixel-split image encryption scheme supported by 2D Salomom map is presented, itselectively exchanges the high and low bits of the image and globally spreads the altered pixels to random positions, resulting in that the cipher image contains no useful information any more and can only be recovered with a unique key. Ultimately, we have conducted comprehensive tests on the proposed algorithm, including various simulated attack, randomness tests and decorrelation analysis on cipher images, the overall results show that the scheme has excellent cryptographic effect and security.