基于Logistic映射的多重图像加密技术

利用Logistic混沌序列的随机性、对初始条件敏感及迭代不重复的特性,对数字图像进行空域像素值扰乱和小波变换域系数位置置乱实现图像的多重加密。首先利用产生的混沌序列进行图像像素值的扰乱,然后利用扩散变换对像素值进一步扰乱,最后再产生一组混沌序列对小波系数进行位置置乱,并对置乱后的小波系数重构得到加密图像。实验证明:文中算法扰乱了图像的直方图分布,使得加密图像能够抵抗明文统计的攻击,且密钥空间大,具有很好的加密效果。

Multiple image encryption technology based on Logistic Mapping

The Logistic chaotic sequence is famous for its randomness, the sensitive of the original value and non-repeatability of iteration. This paper presents a multiple image encryption technology based on scrambling the pixel value of original image and the position of wavelet coefficients. Firstly, we modify the pixel value of original image by using the chaotic sequences based on logistic mapping. Secondly, the pixel value is further to be scrambled by using diffusion transformation. At last, in order to encrypt the image again, we use wavelet analysis to improve the performance of encryption. In this paper, we change the location of wavelet coefficients using another logistic chaotic sequence. An encrypted image is obtained by reconstructing the scrambled wavelet coefficients. The test results show the algorithm disturbs the histogram distribution of original image which enables the encrypted image can resist the statistics attack of known-plaintext. And the algorithm can realize the image encryption with larger key space and good effect.