A Practical Solution for Distribution Rights Protection in Multicast Environments

One of the main problems that remain to be solved in pay-per-view Internet services is copyright protection. As in almost every scenario, any copyright protection scheme has to deal with two main aspects: protect the true content authors from those who may dishonestly claim ownership of intellectual property rights and prevent piracy by detecting the authorized (but dishonest) users responsible of illegal redistribution of copies. The former aspect can be solved with watermarking techniques while for the latter, fingerprinting mechanisms are the most appropriate ones. In internet services such as Web-TV or near video on-demand where multicast is used, watermarking can be directly applied. On the other hand, multicast fingerprinting has been seldom studied because delivering different marked content for different receivers seems a contradiction with multicast basics. In this paper we present a solution to prevent unauthorized redistribution of content in multicast scenarios. The system is based on a trusted soft-engine embedded in the receiver and comanaged by the content distributor. The trusted soft-engine is responsible of the client-side multicast key management functions. It only will allow the decryption and displaying of the actual data if it has previously inserted a fingerprinting mark with the identity of the decoder. Upon finding a pirate copy of any multicast delivered content, this mark can be used to unambiguously reveal the identity of the receiver that decoded the content from which the pirate copies are made.