A decentralized authorization scheme for DRM in P2P file-sharing systems

To enable secure content trade between peers with good scalability and efficiency in Peer-to-Peer (P2P) file-sharing systems, we propose a decentralized authorization scheme for Digital Rights Management (DRM). Based on proxy re-encryption mechanism, our scheme deploys authorization functions on semi-trusted authorization proxy peers who re-encrypt the ciphertext of content keys and issue licenses to content user peers. A trusted server ensures that content users are properly charged for authorization. Our scheme has no alteration to the structure of P2P network and can be implemented with a wide range of proxy re-encryption algorithms. Compared with authorization schemes in existing DRM solutions, our scheme relieves the server from intense authorization processing, and achieves reliable decentralized authorization with good scalability and efficiency.