混淆和扩散相结合的图像混沌加密方法

摘要

为了提高算法抵御统计分析和差分攻击的能力,提出一种改进的基于混沌的图像加密算法.首先将原图像做分块处理；然后采用基于位运算的像素混淆算法对图像块进行处理,使每个分块图像内的所有像素充分扩散到其他各个图像块中,有效地削弱了图像相邻像素相关性.最后采用像素扩散操作能有效提高算法抵御已知明文攻击的能力.实验结果表明,该算法不仅密钥敏感性强,而且比均匀置乱和二维混沌加密算法具有更强的抵御差分攻击的能力.%In order to improve the encryption algorithm' s resistance ability to differential attacks, a modified image encryption algorithm was proposed based on confusion and diffusion.First original image is divided into several blocks, and then each pixel in the block is executed confusion substitution based on bitwise operation, each sub-block pixel was fully diffused to other sub-blocks in turn to weaken the image correlation between adjacent pixels effectively.Finally, using the pixel diffusion operation can effectively improve the algorithm's ability to resist known plaintext attack.The experimental results show this algorithm not only has highly sensitive key, but also has higher scrambling degree and stronger resistance ability to differential attack than uniform scrambling and two-dimensional chaotic system of image encryption.