\input zb-basic \input zb-ioport \iteman{io-port 05823022} \itemau{Sachan, Amit; Emmanuel, Sabu; Kankanhalli, Mohan S.} \itemti{A geometric approach for efficient licenses validation in DRM.} \itemso{Jonker, Willem (ed.) et al., Secure data management. 7th VLDB workshop, SDM 2010, Singapore, September 17, 2010. Proceedings. Berlin: Springer (ISBN 978-3-642-15545-1/pbk). Lecture Notes in Computer Science 6358, 132-149 (2010).} \itemab Summary: In DRM systems contents are distributed from the owner to consumers, often through multiple middle level distributors. The owner issues redistribution licenses to its distributors. The distributors using their received redistribution licenses can generate and issue new redistribution licenses to their sub-distributors and new usage licenses to consumers. For the rights violation detection, all the newly generated licenses must be validated. The validation process becomes complex when there exist multiple redistribution licenses for a content with the distributors. In such cases, it requires the validation using an exponential number of validation equations, which makes the validation process much computation-intensive. Thus to do the validation efficiently, in this paper we propose a method to geometrically derive the relationship between different validation equations to identify the redundant validation equations. These redundant validation equations are then removed using graph theory concepts. Experimental results show that the validation time can be significantly reduced using our proposed approach. \itemrv{~} \itemcc{} \itemut{} \itemli{doi:10.1007/978-3-642-15546-8\_10} \end