基于分数阶统一混沌系统的图像加密算法

Image encryption algorithm based on fractional order unified chaotic system

为了解决数字图像信息传输所面临的安全性问题,基于分数阶统一混沌系统,提出了一种新的图像加密算法。采用经典的置乱—扩散机制,整个加密策略分为图像像素位置置乱和像素值替代两个过程。在像素置乱的过程中,采用排序的方式分别对图像的行和列进行置乱。在像素值替代的过程中,通过与密钥序列进行异或运算来实现加密。而混沌系统则作为伪随机序列发生器,并作用于加密的各个阶段。安全性和时间复杂度分析表明:该算法具有高的安全性和低的时间复杂度,且能够抵御几种常见的攻击方式。

In order to solve the security problem during transmitting digital image information,a novel image encryption algorithm based on fractional order unified chaotic system is proposed. This algorithm utilizes the classical confusion and diffusion mechanism,and the whole encryption strategy can be divided into two stages：image pixel position permutation and pixel value substitution. In the first stage,each row and column of the image are respectively scrambled by the way of ranking. In the second stage,the pixel values of image are substituted by the XOR operation with key sequence. Besides,the chaotic system is used as pseudo-random sequence generator,and acts on the two stages. Security and time complexity analysis shows that the algorithm has high security and low time complexity,and can resist several common cryptogram attacks.