Locating steganographic payload via ws residuals

The literature now contains a number of highly-sensitive detectors for LSB replacement steganography in digital images. They can also estimate the size of the embedded payload, but cannot locate it. In this short paper we demonstrate that the Weighted Stego-image (WS) steganalysis method can be adapted to locate payload, if a large number of images have the payload embedded in the same locations. Such a situation is plausible if the same embedding key is reused for different images, and the technique presented here may be of use to forensic investigators. As long as a few hundred stego images are available, near-perfect location of the payloads can be achieved.