Abstract: Reputation is a new method to build trust. In Pecr-to-Peer networks, trust mechanism based on reputation can isolate inferior peers and recommend excellent peers in order to evade potential risk and provide better service. Some shortcomings were found in related research such as overly dependency on network structure, neglect of collusion cheat and disregard of dynamic reputation change. Aiming at these shortcomings, RepTrust, a novel trust model based on reputation was presented. In this model, reputation unrelated with raters and routes through that it been gotten was used to compute trust. Mendacious reputation was filtrated and an attenuation factor was introduced into to amend the dynamic reputation. According to the simulation experiment, this model is effective in trust computing, dealing with collusion cheat and dynamic reputation.

Key words: Peer-to-Peer, Reputation, Trust model, Collusion cheat, Dynamic