A proposal of distributed management scheme of content key information for pure P2P networks

Peer-to-Peer (P2P) content distribution becomes more and more popular because of dissemination of various high bit rate services such as high definition video streaming. To realize it with sufficient scalability, structured network is considered and actually adopted. In order to prevent a problem of thefts of content, P2P hybrid model is normally employed, which adopts a central server that manages authentication information of users. On the other hand, recently, pure P2P scheme is proposed to omit such a central server that causes the problem of single point of failure, and as a result, scalability can be increased. In the proposed scheme, (k, n) secret sharing scheme is employed to realize content key distribution among potentially unreliable P2P nodes. In this paper we propose a new content key management scheme that attains several important security requirements for dynamic content delivery such as forward secrecy, which did not realize in the previously proposed scheme. We also propose a design method of system parameters in a systematic manner for the proposed scheme by using Chernoff inequality. Finally, we evaluate a relation between the probability of successful recovery of content key for malicious nodes and the probability of content key recovery failure for legitimate nodes.