一种改进的数字图像置乱方法

An Extended Method for Digital Image Scrambling

图像置乱技术利于图像的保护,有效地保护数字图像内容为目的,结合Rijndael算法理论,提出了一种新的图像置乱算法。算法在原Rijndael算法的密钥扩展方案上进行了改进,综合运用了像素值置乱、像素位置乱、块置乱等技术,增强了图像置乱的效果。同时,算法改进了种子密钥的长度策略,使其与待加密图像的像素个数相等,以便适应于各种尺寸的数字图像,并有效提高了算法执行效率。采用图像相似度和图像直方图的评价方法对置乱的效果进行仿真计算。计算机仿真结果表明,与传统方法相比,算法对图像置乱简单高效,达到了很好的效果。

According to the principle of Rijndael algorithm, an image scrambling encryption method based on Ri- jndael is proposed to protect context of image effectively. Such a method includes improving on Rijndael algorithm of the key schedule and integrated application of three of pixel scrambling, position scrambling and block scrambling to enhance the effect of image scrambling. At the same time, the algorithm improves the length strategy of seed secret key to make length of it to be equal to the number of encrypted image pixels in order to adapt to different sizes of digital images, and the efficiency of the algorithm implementation. Using evaluation method of image similarity and image histogram to do experimental analysis for the scrambling effect, the results have given very good effects. The security of algorithm is also analyzed, and the results show that the image scrambling algorithm is high in efficiency and simple in computing.