混沌系统耦合2D离散分数随机变换的双图像同步加密算法研究

Double-image Synchronous Encryption Algorithm Based on Chaotic System Coupled 2D Discrete Fractional Random Transform

当前图像加密算法都具有较高的安全性,但是,这些只能对单幅图像完成扩散,无法同步加密多个图像。而现有的多图像加密主要是借助信息压缩思想,将多个图像压缩成单图像,继而完成加密。然而,这种压缩技术易丢失图像信息,造成较大失真。为此,设计了混沌系统耦合2D离散分数随机变换的双图像同步加密算法。首先,利用Chen’s系统生成混沌序列,构造置乱引擎,对其中一个图像完成扰乱,并将该置乱图像编码成相矩阵;再联合相矩阵与另外一幅明文图像,形成复杂矩阵;最后,迭代Logistic映射,生成随机矢量,设计对称随机矩阵,嵌入2D离散分数随机变换中,基于复杂矩阵,构造双图像并行加密机制,完成图像像素扩散。实验数据显示:其图像加密算法能同时多两幅图像完成加密,拥有较高的安全性;且算法的失真度较小,较好地保留了明文图像信息。

The current image encryption algorithms have high security.But these algorithms can only complete diffusion single image,and they can't synchronize encrypted multiple images.The existing multiple images encryption algorithms mainly use the thought of information compression to compress multiple images into single image,and then complete the encryption.However.this compression technology results in the loss of image information and biggish distortion.Therefore,a double-image synchronous encryption algorithm coupled chaotic system with 2D discrete fractional random transformation is designed.Firstly,use Chen's system to generate chaotic sequence and scrambling engine.Then complete the scrambling for one of these two images and code it into phase matrix.Secondly.use the phase matrix and the other image to generate complex matrix.Finally,the double image parallel encryption mechanism is constructed by complex matrix and it is embedding the random matrix produced by iterating the logistic map into 2D discrete fractional random transformation to diffusion the image pixels.Experimental data show that this image encryption algorithm can simultaneously encrypt two images,and it also has high security.