A Social Network Integrated Reputation System for Cooperative P2P File Sharing

In current reputation systems for peer-to-peer (P2P) file sharing networks, reputation querying generates high overhead in file service. Also, a high-reputed node may be reluctant to further increase its reputation in these reputation systems. Recently, social network-based P2P systems that favor file sharing among friends have been proposed for reliable file sharing. However, this approach contradicts the objective of widely file sharing in P2P systems. To overcome these drawbacks, we propose a social network integrated reputation system, namely SocialTrust, that synergistically leverages the concept of "friendship fosters cooperation\´\´. In SocialTrust, each node maintains trusted relationships for the purpose of file sharing, which are resulted from both real life acquaintance and online partnership established between high-reputed and frequently-interacted nodes. Given a number of server options, a client first chooses a friend or a partner, if available, without querying their reputations. Otherwise, it chooses the server with the highest reputation. The benefits of friendship and partnership on file sharing and cost saving encourage nodes to be continuously cooperative. Further, in order to realize accurate reputation evaluation and strong cooperation incentives, SocialTrust considers the number of friends/partners and reputation of a node in the process of reputation rewarding and punishment. Extensive trace-driven simulation demonstrates the effectiveness of SocialTrust.