Abstract: In order to improve the performance of chaotic image encryption, a new hybrid chaotic encryption algorithm based on generalized cat map is proposed. It uses the generalized cat mapping to iterate over the pixels firstly, and then uses the generalized cat map to make multiple scrambling. The number of scrambling is closely related to the pixel value of the image itself. Then the chaotic sequences generated by the generalized Henon map are used to encrypt the image. The results of experiment and simulation show that the algorithm can overcome the flaws of the previous algorithm which can not resist chosen plaintext（ciphertext） attacks, and can effectively solve the problems of chaotic system in poor randomness, entropy attack and less control parameters. At the same time, the algorithm has the advantages of large key space, simple encryption algorithm, better resistance to differential attack, statistical characterization, and has high security, good encryption effect.

Key words: generalized Henon maps, image encryption, generalized cat map, chaotic sequence

摘要： 针对混沌图像加密的特点，为了提高加密的效果，提出了一种二次广义猫映射的混合混沌加密算法。该方法首先利用广义cat映射对像素点进行多次迭代，然后再利用广义cat映射进行多次置乱，并且置乱的次数与图像本身的像素值密切相关。再用广义Henon映射产生的混沌序列与置乱后图像进行扩散加密运算。实验和仿真结果表明该算法克服了以往算法不能抵抗选择明（密）文攻击的缺陷，并且有效解决了混沌系统随机性差、熵攻击、控制参数少等问题。同时具有密钥空间大，加密算法简单，能够较好地抵抗差分攻击、统计特性分析的优势，安全性高，加密效果好。

关键词: 广义Henon映射, 图像加密, 广义猫映射, 混沌序列