关键词: 信任模型, 粒子群算法, BBK信任模型, 防止联合欺诈

Abstract: There are many malicious nodes spreading false information in P2P networks，because of its open and anonymous characteristics.So it is of great importance to build a sound mechanism of trust in the P2P environment.To avoid the shortage of the existing trust model，the paper provides a Trust Model based on PSO.In the model，after initializing the particle swarm，each particle can update the speed and location according to its information，then produce a new particle with better value.Doing that process continually and implementing the global search of the space，finally，they can get a better overall value，that is the better trust path in the networks.The simulation results show that it can get the overall optimum solution in a relatively short time after many times of iteration，and the more times it iterates，the better the trust path is.It can be proved that the algorithm can prevent the fraud.

Key words: trust model, Particle Swarm Optimization algorithm, BBK trust model, preventing the fraud