Effect of Recompression on Attacking JPEG Steganographic Schemes An Experimental Study

In the implementation of a few JPEG steganographic schemes such as OutGuess and F5, an additional JPEG compression may take place before data embedding. The effect of this recompression on the performances of steganalyzers is experimentally studied and reported in this paper. Through a group of carefully designed experimental works, we show that the training and testing procedures adopted in classification are of great importance. An improper training and testing procedure may lead to poor steganalysis performance even for a powerful steganalyzer or an accurate performance comparison. Some other informative observations are presented in the paper as well.