Abstract: A colour image cipher based on ergodic matrix and chaos is proposed.Firstly，the red，green and blue channels of the input image are permuted independently by using the ergodic matrixes，which are generated by discrete chaotic maps.Then two rounds of diffusion and encryption operation with the 3D chaotic sequences are adopted to realize the tricolor substitution pixel by pixel.The security of the proposed image encryption technique has been analyzed using various statistical analysis，key sensitivity analysis，differential analysis，key space analysis.The results demonstrate that the algorithm has good properties of confusion，diffusion and statistic distribution of pixel value.The key space is large enough to resist the brute-force attack，showing that the proposed scheme is of good practicability.

摘要： 提出了一种基于混沌和遍历矩阵的彩色图像密码算法。首先，利用离散混沌映射生成整数遍历矩阵，利用遍历矩阵在空域分别实现彩色图像三基色置乱。然后，结合像素扩散操作和三维混沌序列分别对彩色图像三基色通道实施两轮逐像素加密。从统计特性、密钥敏感性、差分分析和密钥空间等诸方面对算法的安全性进行了分析。各种分析结果表明，该算法具有良好的像素值混淆、扩散和统计分布特性；密钥空间大而足以抵抗强力攻击；表明所提出的方案具有良好的实用性。