基于可逆记忆CA融合时间延迟的图像加密算法研究

针对当前的元胞自动机加密系统不具备记忆功能,使其安全性\加密速度不理想;且目前的图像加密算法都忽略考虑时间延迟现象,无法体现加密的真实过程。对此,提出一种可逆线性记忆元胞自动机(cellular automata-CA)与时间延迟函数,采用二者相融合的加密算法来克服上述问题;并将非线性耦合置乱方法引入算法中。首先迭代一维线性分段映射所得到的一维数组,该数组通过非线性耦合置乱方法后得到一个置乱数组,并利用该数组对初始图像进行置乱处理,改变像素位置;然后将时间延迟引入到Logistic映射中,利用可逆线性记忆元胞自动机的演变规则对二者相融合所生成的时间延迟伪随机数组进行迭代,得到迭代数组。利用该迭代数组根据像素扩散机制对置乱图像进行扩散加密处理,改变其像素值。借助MATLAB仿真软件来验证算法。结果表明:提出的图像加密新算法具有优异的加密性能,加密机制高度安全,其密钥空间巨大,抗攻击能力大幅度提升。

The Simulation Study on Image Algorithm Based on the Reversible Linear Memory Cellular Automata Integration with Time Delay

To the cellular automata encryption system does not having the memory function, resulting in the low security and encryption speed, and all of the current image encryption algorithms were ignored the time delay phenomenon to cause it not reflecting the actual encryption process. The reversible linear memory cellular automata (CA) and time delay function were proposed by this paper to overcome above problems, and also the non-linear coupled permutation method was introduced into this algorithm. Firstly, iterating the one dimension piecewise linear chaotic map to get the array, and then the non-linear coupled permutation method was designed according to the array, as a result, the permutation array was got, used the permutation array to permute the plain-image to change the pixel position; secondly, the time delay was introduced into the logistic map, the pseudo-random number on time delay obtained by logistic map integration with time delay function was iterated by evolution rule of reversible linear memory cellular automata to get the iteration array, then this array was used to diffuse the permutation image to change the pixel value by pixel diffusion mechanism. The simulation software MATLAB was used to test the algorithm in this paper, the results showed that this image encryption algorithm based on the reversible linear memory cellular automata integration with time delay had an excellent encryption performance, the encryption system was highly; the key space was huge, and the anti-attack property significantly increased.