Decentralized peer to peer (P2P) networks offer both opportunities and threats. Its open and decentralized nature makes it extremely susceptible to malicious users spreading harmful content like viruses, trojans or, even just wasting valuable resources of the network. In order to minimize such threats, the use of community-based reputations as trust measurements is fast becoming a de-facto standard. The idea is to dynamically assign each peer a trust rating based on its performance in the network and store it at a suitable place. Any peer wishing to interact with another peer can make an informed decision based on such a rating. An important challenge in managing such trust relationships are to design a protocol to secure the placement and access of these trust ratings. Surprisingly, all the related work in this area either support very limited anonymity or assume anonymity to be an undesired feature and neglect it. We motivate the importance of anonymity, especially in such trust based systems. We then present TrustMe: a secure and anonymous underlying protocol for trust management. The protocol provides mutual anonymity for both the trust host and the trust querying peer. Through a series of simulation-based experiments, we show that the TrustMe protocol is extremely secure in the face of a variety of possible attacks and present a thorough analysis of the protocol.
['Aameek Singh', 'Ling Liu']
TrustMe: anonymous management of trust relationships in decentralized P2P systems