On the security of the delay-based fingerprint embedding scheme

The delay-based fingerprint embedding was recently proposed to support more users in secure media distribution scenario. In this embedding scheme, some users are assigned the same fingerprint code with only different embedding delay. In fingerprint detection, the fingerprint codes are detected and the delays between them are determined, which tells the users who participated in the collusion. The algorithm's robustness against collusion attacks is investigated, while the robustness against common desynchronization attacks, e.g., cropping and time shifting, is not considered. In this paper, desynchronization attacks are used to break the delay-based fingerprint embedding algorithm. To improve the robustness, two means are proposed to keep the embedded fingerprint codes synchronized, i.e., adding a synchronization fingerprint and adopting the comparative embedding delay to detect users. Analyses and experiments are given to show the improvements.