基于分数阶logistic映射与随机变换的双图像加密算法

Double Image Encryption Algorithm Based on Fractional Logistic Map and Random Transform

为了实现对两幅图像进行同步安全加密,提高密文在网络传输中的抗攻击能力,提出了基于离散分数阶logistic映射与混沌随机变换的双图像加密算法.将分数阶理论引入到Logistic映射,建立了离散分数阶Logistic映射,设置不同的初始条件,通过对其迭代,输出两个随机序列,对输入明文进行置乱,混淆像素位置;并将其中一个置乱图像进行编码,获取纯相位掩码,联合另外一个置乱图像,输出复合明文信号;随后,再次迭代离散分数阶Logistic映射,将其输出的两个混沌序列转变为矩阵,通过设计相位掩码函数,得到两个混沌掩码;最后,基于混沌分数阶随机变换,构建了加密函数,输出合成密文.实验结果显示:本算法可对多幅图像进行同步加密,具有较高的安全性.

In order to achieve the synchronization security encryption of two images and to en- hance the anti attack capability of the cipher in the network transmission, a double-image eneryption algorithm based on discrete fractional logistic map and chaotic random transform is proposed. Firstly, the discrete fractional Logistic map is constructed by introducing the fractional theory into logistic map,and the input plains are permutated by iterating the discrete fractional Logistic map with different initial conditions for transforming the pixel position. And one of the scrambling image is coded for the acquisition of a pure phase mask,and combines with another scrambling image to out- put the complex signals. Then, the two chaotic sequences are transformed into a matrix by iterating fractional Logistic map again,and then the chaotic mask is obtained by designing the phase mask function. Finally, based on the chaotic fractional random transform, an encryption model is constructed and synthetic ciphertext is output. The experimental results show that the proposed algorithm is able to encrypt multiple images at the same time with high security.