Abstract: Based on an analysis of the characteristics of P2P network and related security issues, this paper proposed a global trust model which has a high resistance to malicious acts and free riders. Specifically, if the malicious nodes or free riders try to reregister into the system to white wash their low credibility and trust, the model can quickly trace and isolate them, showing high white washing resistance. The results of simulation showed that this model can easily isolate malicious behaviors, especially has high resistance to white washing.

Key words: trust model, cooperative cheating, free rider, white washing, overlay, trust model, cooperative cheating, free rider, white washing