基于差分直方图实现LSB信息伪装的可靠检测

Reliable Detection of Spatial LSB Steganography Based on Difference Histogram

在信息伪装技术研究中,图像中隐藏信息的检测对于保障网络信息安全和提高信息伪装算法的安全性具有重要意义.基于对图像差分直方图的统计观察,提出了一种新的可靠检测空域LSB(least significant bit,最不重要比特位)信息伪装的方法.定义差分直方图间的转移系数作为LSB平面与图像其余比特平面之间的弱相关性度量,并在此基础上构造区分载密图像和载体图像的分类器.这一算法不仅可以高度可靠地确定图像中通过空域LSB替换方法嵌入的秘密信息的存在性,还可以准确估计图像中嵌入的秘密信息数据量的大小.算法物理意义直观,实现简单,计算量小.实验结果表明,针对原始无损存储图像可以获得优于RS(regular singular)隐写分析方法的性能,且计算速度显著高于RS隐写分析方法,有利于实现实时检测.该方法也适用于彩色图像.

Detection of hidden messages in images is of great importance for both the network information security and the improvement of security of steganographic algorithms. Based on the statistical observations on the difference histogram of images, a new steganalytic technique capable of a reliable detection of the spatial LSB (least significant bit) steganography is proposed. Translation coefficients between the difference histograms are defined as a measure of the weak correlation between the LSB plane and the remained bit planes, and then used to construct a classifier to discriminate the stego-image from the carrier-image. The algorithm can not only detect the existence of hidden messages embedded using LSB replacement in images reliably, but also estimate the amount of hidden messages exactly. It has a distinct physical meaning and can be implemented conveniently. Experimental results show that for raw losslessly stored images, the new algorithm has a better performance than the RS (regular singular) steganalysis method and improves the computation speed significantly. The new approach is also applicable for color images.