Abstract: Trust problem is the key issue for Mobile P2P (MP2P) network security．In MP2P network,terminal devices’ addressing mode,communication mode and identifiers are different to traditional P2P network．Some security issues such as:allusion attack,malicious slander and collusion,“free ride” phenomenon,are even more serious compared to traditional P2P network．Aiming at these above issues,a Proxy-based Security-Feedback Trust Model (PSTM) was proposed in this paper．Different types of terminal devices access to different proxy servers to shield the discrepancy between different terminal equipments on MP2P device access network layer．Meanwhile,proxy servers can reduce the problem of single point failure with the method of related information’s backup and recovery．Certificate Feedback Ra-ter’s identification and qualification through security resource-selection protocol,then integrate trust information accor-ding to similarity of terminal and resource types with weighted method．Furthermore,set global contribution value and evaluation value in multi-granularity trust computation to motivate mobile peers’honest feedbacks．Divide mobile peer’s direct trust value into peer-oriented and resource-oriented values to make trust feedbacks more authentic．Simulation experiments show that PSTM can reduce malicious slander and collusion effectively．It also can restrain selfish peers’ free ride behaviors and increase successful cooperation rate of high-contributed peers in MP2P network.

Key words: Structured mobile P2P network,Trust model,Proxy server,Security feedback,Weighted by similarity