Evaluation of an optimal watermark tampering attack against dirty paper trellis schemes

Benchmarking watermarking systems now goes beyond only evaluating the ability of the embedded watermark to withstand common signal primitives such as filtering, resampling, lossy compression, D/A-A/D conversions, etc. Evaluation procedures have to consider how much information leaks from a watermarking system since such knowledge could prove most helpful to design very powerful attacks. This paper further refines an attack on dirty paper watermarking schemes which relies on security weaknesses i.e. information leakage. In particular, additional constraints are introduced to be able to handle 'complex' trellises. Moreover, the efficiency of this attack has been evaluated for different trellis configurations. Quite counter-intuitively, increasing the number of states in the trellis seems to enhance both the robustness and the security of the system.