Establishing trust measurements among peer-to-peer (P2P) networks is fast becoming a de-facto standard, and a fair amount of work has been done in the area of trust aggregation and calculation algorithms. However, the area of developing secure underlying protocols to distribute and access the trust ratings in the overlay network has been relatively unexplored. We propose an elliptic curve-based trust management protocol for P2P systems, which is designed to provide authentication and signature functions to protect the processes of trust value query and rating report. Additionally, instead of using single identities, the protocol generates two verifiable pseudonyms, one is used for transaction, the other is applied when the peer acts as a trust holding peer. A security analysis shows that the proposed protocol is extremely secure in the face of a variety of possible attacks.