Analysis of time-varying collusion attacks in fingerprinting systems: Capacity and throughput

We analyze time-varying collusion attacks for a fingerprinting system using concepts of capacity and throughput in this work. Continuous media provide a limited resource for data embedding, which is analogous to the capacity of a wireless communication channel. Here, we characterize the capacity of a host media using the just-noticeable-distortion (JND) of the human visual system (HVS). Furthermore, the collusion attack can be interpreted as a channel shared by multiple users. Based on this analogy, the colluder detection performance can be understood from the viewpoint of throughput. Specifically, we show how to determine instantaneous throughput using the fingerprint-to-interference-plus-noise ratio (FINR), and extend it to the total throughput and the averaged throughput over a time interval. Our analysis provides a good framework to the understanding of collusion attacks and ways to enhance the traitor tracing performance of a fingerprinting system.