一种位置置乱和交叉换位相结合的图像加密算法

提出了一种基于位置置乱和交叉换位相结合的加密算法,该算法首先利用新构造的位置置乱方法将二维矩阵中行和列映射到一维向量中,然后将一维向量中的亮度值转换为8位二进制数,按照交叉换位的方式将8位二进制数进行位置转换;最后交叉换位之后的8位二进制数重新组合成新的亮度值,同时将一维向量按顺序扫描方式还原成二维图像(图像大小可根据实际加密需要而定)。另外本文还将此构造的新算法扩展到彩色图像R、G、B三个分量中,实现了基于彩色图像像素位置和亮度值双重置乱效果。实验结果表明:该算法具有密钥空间大,加密后的图像直方图分布具有白噪声的特性,而且图像相邻像素的相关性更小,这样大大提高了抵抗不法攻击的能力,增加了图像的安全性。

A New Color Image Encryption Algorithm Basic on PixelPosition and Cross-Exchange Scrambling

A new image encryption algorithm based on dual transform about pixel position scrambling and intensity value is proposed. Firstly, the rows and columns of 2D matrix will be mapped into 1D vector by making use of new proposed scrambling method based on pixel position. Then the intensity values in the 1D vector is converted 8 bit binary number.8 bit binary number is finished by cross-exchanged position. Finally the new intensity value is reconstructed by 8 bit cross-exchanged binary number and the scrambled image is recovered by 1D vector. In addition, the new proposed method based on pixel position is extended to color image R G B components and dual scrambling based on color image pixel position and intensity value. The experimental results show that the proposed method has a large key space, and the scrambled image has a histogram distribution of white noise. The correlation of image pixel values is smaller. It is greatly improving the ability to resist the illegal attack and increasing the safety of encrypted image.