Abstract: Most of previous work concentrates on how to rate peers' behaviors with the trust mechanism and how to establish the reputation-based trust management system (TMS)，but takes less consideration of the security problems in TMS. As for this issue, this paper proposed a security protocol for protecting the P2P trust information management (SPRI). I}heoretical analysis and simulation experiments show that, SPRI can effectively suppress the sybil attackers and trust information tamper peers in transmissions with little time overhead. Moreover, it can be easily integrated into various reputation-based TMSs.

Key words: P2P, Security, Trust management, Reputation