Credibility Enhanced Reputation Mechanism for Distributed E-communities

P2P communities are online communities of entities which offer services to each other without a central administration. Community members that need a specific service have to choose the transaction partner which they believe that will provide them with a required service of the expected quality, thus, they need mechanisms to support trust decisions regarding who they will transact with. P2P reputation systems provide trust mechanisms for P2P communities. Due to their decentralized and social nature, they are vulnerable to various types of attacks which distort their credibility and effectiveness. In our paper we first identify the credibility factors of a P2P reputation system. Then we describe a dynamic reputation mechanism for P2P communities, which integrates some of these credibility factors and which can be used as part of a comprehensive reputation system enhancing its robustness against some types of attacks. Simulation results show the effectiveness of our mechanism in relation to other reputation mechanisms which do not integrate such factors.