Research On Digital Watermarking Security

Digital watermarking consists of hiding subliminal information into digital media content, also called host data. It can be the basis of many applications, including security and media asset management.Digital watermarking studies have always been driven by the improvement of robustness. Most of articles of this field deal with this criterion, presenting increasingly more impressive experimental assessments.On the contrary, security has received little attention in the watermarking community. The first difficulty is that security and robustness are neighboring concepts, which are hardly perceived as different. The intentionality behind the attack is not enough to make a clear cut between these two concepts. An image compression is clearly an attack related to robustness, but it might happen intentionally, i.e., with the purpose of removing the watermark, or not. Robust watermarking is defined as a communication channel multiplexed into original content whose "capacity degrades as a smooth function of the degradation of the marked content" in a nonperceptible way. We add that the degradation is due to a classical content processing (compression, lowpass filtering, noise addition, geometric attack ...). The attacker has three known strategies to defeat watermark robustness: to remove enough watermark signal energy, to jam the hidden communication channel, or to desynchronize the watermarked content.On the other hand, security deals with intentional attacks whose aims are not only the removal of the watermark signal, excluding those already encompassed in the robustness category since the watermarking technique is assumed to be robust.In the chapter 3 and chapter 4 of this paper, we address the usually...