Dymic traitor tracing schemes are used to trace the source of piracy in broadcast environments such as cable TV. Dymic schemes divide content into a series of watermarked segments that are then broadcast. The broadcast provider can adapt the watermarks according to the pirate's response and eventually trace him/her. As dymic algorithms are deterministic, for a given set of inputs, the tracing algorithm will execute exactly the same way each time. An adversary can use this knowledge to ensure that the tracing algorithm is forced into executing at its worst case bound. In this paper we review dymic traitor tracing schemes and describe why determinism is a problem. We ammend several existing dymic tracing algorithms by incorporating randomised decisions. This elimites any advantage an adversary has in terms of the aforementioned attack, as he/she no longers knows exactly how the tracing algorithm will execute. Simulations show that the randomising modifications influence each dymic algorithm to run at its average case complexity in terms of tracing time. We provide an efficiency alysis of the amended algorithms and give some recommendations for reducing overhead.

Presented at Conferences

  • International Joint Conference on e-Business and Telecommunications (2006)

    Setubal, Portugal