基于混沌序列和CBC模式的数字图像加密算法

Digital Image Encryption Algorithm Based on Chaos Sequence and CBC Mode

为了实现对数字图像信息的有效保护,提出了一种基于Lorenz混沌序列和类似CBC模式的图像加密算法.首先对Lorenz系统输出的三维混沌序列进行改进,使其具有理想的伪随机特性.然后,根据这三维序列移位图像的像素位置.将图像分块,根据这三维序列和CBC模式改变每一块的像素值,从而实现图像加密;解密时,给出一种基于邻域相邻像素特性的加密图像抗剪切攻击恢复算法.最后应用评价指标对加解密效果和安全性进行分析.

In order to protect digital image′s information,an image encryption algorithm based on Lorenz chaos sequence and similar CBC（Cipher Block Chaining） mode is presented.Firstly,3D Lorenz chaotic sequences are improved to be with ideal pseudo-randomness.Then,the image′s pixel positions are shifted by using the 3D sequence.The image is divided into blocks,and the pixel value in each block is altered based on the 3D sequence and CBC,so that the image will be scrambled and encrypted.While doing the decryption,a method is provided based on the neighboring pixels characteristic to renew the image attacked by shearing.Lastly,the effects of encryption,decryption and security are also analyzed by using the method of accessing.