关键词: 混沌, 图像加密, 广义猫映射, Lorenz, 替代, 置乱

Abstract: A new image encryption algorithm based on combined high-dimension chaotic system is presented.Firstly，it uses the generalized cat mapping to diffuse the image，then it uses the Lorenz system to confuse the diffused image.The results demonstrate that the algorithm has good properties of confusion and diffusion.The key space is large enough to resist the brute-force attack.For the encrypted image the distribution of pixel-values has a random-like behavior and the values of adjacent pixels satisfy zero correlation，showing that the proposed scheme is of relatively high security.

Key words: Chaotic, image encryption, generalized cat mapping, Lorenz, confusion, diffusion