基于组合混沌系统的时空彩色图像加密算法

Spatiotemporal color image encryption method based on combined chaotic systems

为增强现有彩色图像的加密效果及安全性能,给出一种基于组合混沌系统的时空彩色图像加密算法。将彩色图像作为一个三维矩阵进行处理,利用仿射变换对彩色图像的三基色进行三维矩阵置乱,利用Logistic混沌序列作为控制参数和辅助密钥参数,对图像矩阵进行置换加密,具体的加密方式包括两种:一种是用Logistic映射和Henon映射生成混沌序列,分别与置乱后的R′、G′和B′分量进行异或操作,实现加密处理;另一种是采用二值化Logistic序列对置乱后R′、G′、B′图像的像素位置进行选择,通过加入辅助密钥的Henon映射和Logistic映射分别对其进行置换加密,合成为加密图像。实验结果表明,该算法加密效果良好,安全性较高。

To effectively improve the color image encryption effect and security,a spatiotemporal color image encryption method was designed based on combined chaotic system.Taking the color image as a three-dimensional matrix,the tri-primary colors of color image was scrambled by three-dimensional affine transformations.A sequence with Logistic mapping was generated,and the last value of the sequence was taken as control parameter and auxiliary key parameter.The 3D-matrix of color image was proceeded with replacement operation.Specific encryption methods included two methods：In the first encryption method,Logistic and Henon mappings were used to generate chaotic sequence with the processed images R′,G′and B′color component pixels exclusive,achieving color image encryption.Another encryption method used a sequence of binarization Logistic mapping to choose the processed images R′,G′and B′color component positions of pixel,and the image encryption was replaced by Henon and Logistic mapping.Three encryption images were combined into one image.Experimental results show that this encryption method obtains preferable encryption effect and security performance.