2 Problem Formulation
A number of attacks as well as some countermeasures have been reported in the literature.[3][4][5][6][7][8][9][10] Most of the previous attacks target at specific types of watermarking schemes, for which analysts have full knowledge of the watermarking algorithms. The analysts are able to perform experiments with many watermarked, non-watermarked, and attacked samples, and to observe the results in real time [3]. In this paper, we will discuss attacks under