Efficient Aggregate Licenses Validation in DRM

DRM systems involve multiple parties such as owner, distributors and consumers. The owner issues redistribution licenses to its distributors. Distributors in turn using their received redistribution licenses can issue new redistribution licenses to other distributors and usage licenses to consumers. For rights violation detection, all newly generated licenses must be validated against the redistribution license used to generate them. The validation becomes complex when there exist multiple redistribution licenses for a media. In such cases, it requires evaluation of an exponential number of validation equations with up to an exponential number of summation terms. To overcome this, we propose a prefix tree based method to do the validation efficiently. Experimental results show that our proposed method can reduce the validation time significantly.