Bias-Based Binary Fingerprinting Code under Erasure Channel

Robustness against collusion attack has been measured under the marking assumption in fingerprinting codes. However, if codeword symbols are embedded into segments of multimedia content, the assumption must be relaxed. In this study, we investigate erasures both in segments of multimedia content and in codeword symbols. The former erasure represents the case of a clipping attack, and the latter occurs at the signal processing domain in which a watermark is embedded. We propose an optimal tracing algorithm under the erasure attack and theoretically estimate the number of erasure symbols in a pirated codeword. To suppress false-positive detections, a cutoff parameter is introduced into the tracing algorithm.