A color image encryption and hiding algorithm based on hyperchaotic system and discrete cosine transform

Some existing image encryption schemes based on chaotic systems have various security defects, such as non-uniform distribution of the chaotic system's phase trajectory, narrow chaotic range, and the encryption algorithm easily to be cracked, etc. To solve these problems, a new color image encryption and hiding algorithm is proposed in this paper. Firstly, a two-dimensional cross-coupled chaotic model (2D-CCCM) is designed, which can generate a variety of hyperchaotic maps. Performance analysis demonstrates that they exhibit more complex chaotic behavior and a wider range of chaotic distribution than existing chaotic systems, and all of them enter the hyper-chaotic state when the system parameters are in the range of [1, ∞). Further, based on this chaotic system, a new color image encryption algorithm is proposed. The algorithm applies the cyclic shift operation and the improved out-inside shuffling algorithm to simultaneously scramble and diffuse the R, G, and B planes of the color image. Finally, two-dimensional discrete cosine transform is employed to embed the ciphertext image into the visually meaningful carrier image to further improve the security of the encryption algorithm. The main contributions of this study are twofold: firstly, the 2D-CCCM is proposed, and the generated chaotic system overcomes the drawbacks of existing chaotic systems; secondly, simulation analysis and security evaluation demonstrate that the proposed color image encryption and hiding algorithm has better encryption performance and higher security than several advanced image encryption algorithms.