LSB匹配通过随机地修改像素值的LSB,打破了LSB替换的值对关系,使得安全性有了质的提高。针对灰度图像空间域LSB匹配算法,以8邻域内像素与中心像素的像素值差值定义区域内像素之间的相关性,分析嵌入信息对相关性的影响,提出了基于区域相关性的检测算法,与已有算法相比,该算法复杂度低,运算简单并且误检率低,当嵌入率高于0.3时检测结果具有较高的可靠性。
LSB matching improves the security of hidden message through changing the pixel’s LSB randomly, which breaks the rules of pairs of values of LSB replacement. A new steganalysis technique which focuses on LSB matching embedding based on the local area’s smoothness in grayscale images was proposed. The detection method defines the difference between the sum of 8-neighbor pixels and the center pixel as the correlation between regional pixels. The existence of embedded information can be detected by observing the change of the regional correlation before and after embedding. Compared with the existing algorithms, the advantages of the proposed method include simplicity, computa- tional efficiency and low false positive rate. The detection achieves high reliability when embedding rate is above 30%.