Abstract: Users' demands for the security of peer-to-peer network stimulate the development of trust model. By analyzing the previous trust and reputation systems,we proposed a novel feedback correlation based dynamic trust model for P2P systems, namely CoDyTrust. The trust model adopts fake trust filtering and trust aggregation mechanisms based on the time frames,and introduces several factors in the calculation of the global trust value, including correlation cocffident, trust forgetting factor, abused trust value and recommended trust. The factors can be adjusted dynamically through the feedback control mechanism. Copy Trust can reflect the trust status of a node in the system, while providing the function of detecting malicious behaviors. I}he experimental results indicate that CoDyTrust can accurately detect malicious peers, which has the ability of defending strategic altering behavior, lying and collusive attack as well.

Key words: Peer-to-peer network, Trust model,Fake trust filtering, Trust aggregation