Effective detection method for CDMA-based fingerprinting scheme

One of the serious problems in a fingerprinting system is the collusion attack such that several users combine their copies of a same content to modify/delete the embedded fingerprints. In IWSEC2007, we have proposed a collusion-resilient fingerprinting scheme based on the CDMA technique. In this paper, we formalize the model of collusion from the viewpoint of a communication channel, and design an effective detector considering the hierarchically embedded signals as a fingerprint.