Analysis and Mitigation of the False Alarms of the Reverse JPEG Compatibility Attack

International audience; The Reverse JPEG Compatibility Attack can be used for steganalysis of JPEG images compressed with Quality Factor 100 by detecting increased variance of decompression rounding errors. In this work, we point out the dangers associated with this attack by showing that in an uncontrolled environment, the variance can be elevated simply by using a different JPEG compressor. If not careful, the steganalyst can wrongly misclassify cover images. In order to deal with the diversity associated to the devices or softwares generating JPEGs, we propose in this paper to build a deep learning detector trained on a huge dataset of downloaded images. Experimental evaluation shows that such a detector can provide operational false alarms as small as 10^{−4} , while still correctly classifying 90% of stego images. Furthermore, it is shown that this performance is directly applicable to other image datasets. As a side product, we indicate that the attack is not applicable to images developed with a specific JPEG compressor based on the trunc quantization function.