对空域BPCS密写的统计分析

Statistical Analysis Against Spatial BPCS Steganography

位面复杂度分割(BPCS)密写法将复杂度较高的位平面小块用秘密信息替换,可以嵌入较多的秘密信息并维持较好的隐蔽性,但含密图像的位平面小块复杂度直方图中存在两个明显的不连续点·据此,提出了针对BPCS密写的分析方法,由复杂度直方图的不连续性可以判断秘密信息的存在性,并确定秘密信息块的复杂度范围,准确测算秘密信息嵌入量·这种分析方法的原理同样适用于变换域位面复杂度分割密写·

Bit-plane complexity segmentation (BPCS) steganography replaces bit-plane blocks of high complexity with secret data, providing large embedding capacity and good imperceptibility. By constructing a histogram of bit-plane block complexity, however, a security flaw in the BPCS method is revealed. Two striking discontinuities in the complexity histogram unambiguously announce the presence of BPCS-based hidden information. Furthermore, the complexity criterion used in data embedding can be estimated quite accurately, leading to a good estimation of the embedding capacity. The steganalytic technique proposed in this paper is equally effective against BPCS steganogrphy both in the spatial (temporal) domain and in the transform domain.