Quantitative Steganalysis of LSB Embedding in JPEG Domain

We construct new quantitative steganalyzers for steganographic techniques that hide data using LSB embedding in quantized DCT coefficients of a JPEG file. Two approaches are explored - change-rate estimation using the maximum likelihood principle with a precover model and a heuristic approach based on minimizing a penalty functional obtained from a combined analysis of the embedding operation and properties of natural images. The techniques are applied to Jsteg and its modified version called symmetric Jsteg. Experiments are used to compare the new methods with current state of the art.