一种基于耦合映像格子的彩色图像加密算法

摘要

In order to effectively improve the security of the color image encryption algorithm,this paper presented a color image encryption algorithm based on coupled map lattice.Firstly,it used the one-dimensional robust chaotic map for disposing three primary matrices of the color image,achieved the pretreatment based on bit computing.Then,it divided processed matrix into blocks and completed the round encryption.Generated S-boxes by the coupled map lattice,used the secondary key for selecting S-box and achieved the nonlinear replacement each round.Pairwise combined the replacement matrix and encrypted two-way to reduce the correlation of the same pixel corresponded to three color components.Obtained initial value of system by combining logistic map and plaintext,which effectively improved the sensitivity of the keys and plaintext.Theoretical analysis and experimental results show that the proposed algorithm has better security and encryption effect.%为了改进彩色图像加密算法的安全性等性能,设计了一种基于耦合映像格子的彩色图像加密算法.首先通过一维鲁棒混沌映射对彩色图像的三个基色矩阵基于比特运算完成预处理的置乱操作并分块,对子矩阵进行轮加密,通过耦合映像格子生成S盒,每一轮加密过程先根据辅助密钥选择S盒进行非线性替换,替换后矩阵再两两组合进行双向加密,实现在分量内扩散加密的同时降低相同像素对应三基色分量的相关性.算法将Lo-gistic映射结合明文信息得到混沌系统的初值,有效提高了加密算法对系统初值和明文的敏感性.理论分析及实验表明该算法具有更好的安全性和加密效果.