摘要
整个加密算法分两个过程,首先在DCT变换之前对原始图像进行以8×8图像块为单位的统一图像置乱,使图像整体视觉效果上杂乱无章.其次,DCT变换量化系数之后,将相邻两个8×8系数块的低频系数组成一个新块,高频系数组成一个新块,分别进行块内的系数置乱,在改变原始图像频率成分的同时,可以减少改变零游程结构带来的加密对JPEG图像压缩影响,而且8×8系数块内的非零系数个数发生了变化,可以有效抵御统计非零系数个数攻击.
The whole encryption algorithm includes two steps .Firstly ,scramble the original image before the DCT transformation block by block with the size8 × 8 ;it makes the image disorderly and unsystematic .Secondly ,after the quantization of the DCT coefficients , we recompose the double 8 × 8 DCT blocks border upon , put low coefficients into one 8 × 8 block and put the high coefficients into another one .Shuffle the low coefficients block and high coefficients block with different ergodic matrixes .This algorithm could change the frequent structure while increase the compressed image data a little and change the number of the nonzero DCT coefficients so as to defend the nonzero-counting attack .
出处
《微电子学与计算机》
CSCD
北大核心
2014年第8期139-143,共5页
Microelectronics & Computer
基金
国家自然科学基金(61272043
CSTX2013jjB40009)
关键词
JPEG图像
DCT量化系数
系数重组
置乱加密
JPEG image
DCT quantization coefficients
coefficients recompositon
shuffling encryption
