一种自适应的循环迭代数字图像加密算法

依据Shannon提出的实现数据加密的基本操作以及分组密码学的加密机制,提出一个新型的自适应循环迭代数字图像加密算法。该算法借用进化算法中的交叉和变异过程,对数字图像进行循环迭代操作。交叉过程采用广义猫映射实现图像坐标矩阵的置换变换,变异过程采用Logistic混沌系统实现像素灰度值的替代运算。在每一轮迭代加密过程中,通过对初始密钥进行循环移位来生成相应的加密轮密钥,使得加密密钥随着加密次数而改变,从而有效提高加密算法的安全性。算法最终以数字图像加密效果评价准则作为停止依据。实验分析表明,所提加密算法具有良好的安全性和效率。

A self-adaptive circulation iterative image encryption algorithm

According to the basic operators proposed by Shannon for data encryption and based on the encryption mechanism of black cipher,a new self-adaptive circulation iterative image encryption algorithm is proposed.The proposed algorithm referencing the crossover and variation processing in evolutionary algorithm,to cyclic iterative encrypt image.Cyclic iteration contains two processing: crossover and variation,Cat map is used in crossover processing for diffusion transfer of image coordinate matrix and Logistic map is used in variation processing for substitution operator of pixel gray values.In each iterate encryption processing,encryption subkey is generated by cyclic shifting of initial cipherkey,making the encryption subkey is changed according with the encryption iterative number,and the safety is enhanced effective.The algorithm is stopped by image encryption effective evaluation criteria.Simulation results show that the proposed encryption algorithm has good safety and efficiency.