Dynamic Traitor Tracing Schemes, Revisited
This work addresses the need for more efficient collusion-resistant traitor tracing in digital content protection, though it is incremental as it builds on prior schemes.
The paper tackles the problem of improving efficiency in dynamic traitor tracing schemes by combining and enhancing existing methods, resulting in faster tracing with code lengths reduced from quadratic to linear in some cases and up to twice as fast in others.
We revisit recent results from the area of collusion-resistant traitor tracing, and show how they can be combined and improved to obtain more efficient dynamic traitor tracing schemes. In particular, we show how the dynamic Tardos scheme of Laarhoven et al. can be combined with the optimized score functions of Oosterwijk et al. to trace coalitions much faster. If the attack strategy is known, in many cases the order of the code length goes down from quadratic to linear in the number of colluders, while if the attack is not known, we show how the interleaving defense may be used to catch all colluders about twice as fast as in the dynamic Tardos scheme. Some of these results also apply to the static traitor tracing setting where the attack strategy is known in advance, and to group testing.