基于混沌选择的自适应图像加密算法

Self-adaptive Image Encryption Algorithm Base on Chaos Choice

提出一种高维混沌与多轮选择加密相结合的图像加密新算法.首先对明文图像做2×2分块处理,然后在主密钥流的控制下任意选择一种子块加密顺序.顺序选定后,用上一子块全部像素灰度值的异或运算结果作为四维混沌映射的初值,产生密钥流复合加密下一子块,直到四个子块全部加密完毕后再次选择新一轮子块加密顺序.实验结果表明,新的算法改进了原算法单方向加密的不足,使得明文一个像素值的变化能影响到更多密文像素值,在速度不变的情况下安全性有了提高.

A new image encryption algorithm combined with high-dimensional chaos and multi—wheel choice encryption was presented.Firstly,original images was divided into 2×2 size blocks,the encryption orders of blocks was chosen by main key stream.Secondly,the XOR operation result of all pixels＇ grey scale value in the last block was used as initial of four—dimensional chaos key stream to composite encrypting the next block.A single wheel operation would complete while all four blocks were encrypted,and a new wheel was chosen by main key stream. The experiment result indicated that the new algorithm enhanced the conventional algorithm and the macro change of original pixels would influence more cryptograph pixels while operation time unchaged.