ABSTRACT
By nature of a P2P system, trust is a fundamental issue because each peer interacts with another peer which does not have any well-known authority (as in a Web server) and worse still, may “disappear” afterward. Indeed, even for a fully cooperative peer (possibly due to the existence of an incentive system), it is necessary for the peer to determine whether its counterpart in a P2P transaction (e.g., a file downloading operation) is trustworthy or not. For instance, in simple terms, an untrustworthy peer might be one which deliberately injects wrong file data into the network. Consequently, a “good” peer might download some malware from an untrustworthy peer.
