基于分层Arnold变换的置乱算法

针对数字图像信息隐藏存在的安全问题，提出一种基于按位分层Arnold变换的置乱算法。算法将秘密图像按位平面分层，同时考虑图像的位置迁移和像素的灰度变换，对每个位平面进行不同次数的Arnold变换，经像素交叉换位，相邻像素间按位异或得出置乱图像。实验结果表明，秘密图像分层置乱后直方图分布更加均匀，与白噪声相似度在0.962左右，置乱图像可近无损地还原和提取，提高了信息隐藏的鲁棒性。与其他置乱算法相比，置乱图像具有更高的置乱度、更强的抵御攻击能力，提高了空域信息隐藏的安全性。

Scrambling algorithm based on layered Arnold transform

Concerning the safe problem of digital image information hiding, a scrambling algorithm based on bitwise layered Arnold transform was proposed. The secret image was stratified by bit-plane, taking into account the location and pixel gray transform, each bit-plane was scrambled for different times with Arnold transforma, and the pixel was cross transposed, and adjacent pixels were bitwise XOR to get a scrambling image. The experimental results show that the secret image histogram is more evenly distributed after stratification scrambling, its similarity with the white noise is around 0.962, and the scrambling image can be restored and extracted almost lossless, which improves the robustness. Compared with other scrambling algorithms, the proposed algorithm is more robust to resist attack, and improves the spatial information hiding security.