基于变参混沌的异位异或图像加密算法

目的 解决混沌序列的混沌性能退化，加密算法不能较好地抵御选择明文攻击等问题。方法 提出一种基于变参混沌系统，采用密文反馈的方式，对明文块依次加密的图像加密算法，并在扩散部分摒弃常规的按位异或扩散方式，提出一种按块异位异或算法。结果 对算法进行仿真的结果表明，文中算法对密钥敏感，测试对象的NPCR值分别为99.59%，99.61%，99.61%，UACI值分别为33．44%，33.46%，33.45%，信息熵分别为7.9872，7.9989，7.9977，相较于其他类似算法，文中算法的综合效果更好，密钥空间为(1016)6+1014×9。结论 密文对明文敏感，能抵抗选择明文攻击，该算法不仅有效解决了问题，还具有较高的安全性能。

Ectopic XOR Image Encryption Algorithm Based on Variable Parameter Chaos

The work aims to solve the problem of chaotic performance degradation of chaotic sequences as encryption algorithm cannot better resist the attacks of chosen plaintext. An image encryption algorithm based on variable parameters was proposed. The proposed algorithm used cipher feedback mode to encrypt the plaintext block sequentially. In the diffusion part, a conventional bitwise XOR diffusion method was abandoned, and a block-by-block ectopic XOR algorithm was proposed. The simulation results showed that, the proposed algorithm was sensitive to the key, and the NPCR values of the test subjects were respectively 99.59%, 99.61%, and 99.61%. UACI values were respectively 33.44%, 33.46% and 33.45%, and the information entropies were 7.9872, 7.9989 and 7.9977, respectively. Compared with other similar algorithms, the proposed algorithm had better comprehensive effects. The key space was (1016)6+1014×9. The ciphertext is sensitive to plaintext, and can resist the chosen plaintext attacks. The proposed algorithm not only solves the problem effectively, but also has high security performance.