基于改进Logistic混沌映射的数字图像加密算法研究

Research on Image Encryption Algorithm Logistic Chaotic Based on an Improved Digital Mapping

摘要:

混沌序列具有伪随机性、遍历性、对初始条件极其敏感性以及具备白噪声的统计特性等特点;文章利用Logistic混沌映射的改进算法产生的混沌序列所具有的这些特性,对数字图像进行空域像素进行位置置乱,然后对置乱后的图像序列按照一定的方法进行异或处理得到加密图像；实验在图像的竖直、水平、对角线方向,随机选择像素点,利用其灰度值,图像像素个数,计算数学期望,方差,协方差,相关系数；结果表明文章算法扰乱了图像像素间的相关性,使得加密图像能够抵抗明文统计的攻击,且密钥空间大,运算速度快,具有非常好的加密效果。

Abstract:

Chaotic sequence has a pseudo-random ergodic,which is extremely sensitive to initial conditions as well as with the statistical properties of white noise characteristics.This paper use the characteristics of the improved algorithm Logistic chaotic map chaotic sequence generated by these characteristics,making airspace pixels for digital image and scrambling for position, and then getting the scrambling image sequence according to a certain method or process which is encrypted exclusive image. Experiments on image vertical, horizontal, diagonal, randomly selecting pixel,using the gray value, image pixel number, and calculating mathematical expectation,variance, covariance, correlation coefficient. Results showing that:the proposed algorithm disrupts the correlation between the image pixels,which made the encrypted image can resist plaintext attack statistics, and the key space is large with a fast operation speed, also with a very good effect of encryption.