一种基于光全息的图像混合加密算法

摘要

为了使图像保密性更好,提出一种新的加密算法.研究了传统的Arnold变换,分析其周期性,指出Arnold变换的保密性能与图像尺寸有关.为保证图像直方图均匀化且增大密钥空间,进而提出一种基于随机数序列的像素置乱算法,比较了扭曲法、移位寄存器、修正SWB算法、混沌算法,发现扭曲法生成的随机数序列的周期与密钥空间最大.计算二维图像的光全息图作为加密图像.实验证实了该算法的有效性,对剪切攻击、噪声攻击、JPEG攻击等具有强脆弱性.%In order to increase the security performance, a novel encrypt algorithm is proposed.Traditional Arnold transform is investigated,and its period is analyzed and found to be related with the size of image.A novel pixel scrambling algorithm is advanced to unify the histogram and augment the key space.Several random numbers generator methods, namely twister method,shift-register generator,modified subtract with borrow generator,chaotic generator,are compared.The twister method is found to be best since the corresponding period and key space is the largest.The hologram is calculated to be the final encrypt image.Experiments show the validness and efficiency of the proposed algorithm,and the strong frangibility to cropping attack,noise attack,and JPEG attack.