Making Reputation System Traceable without Losing Privacy

Preliminary note In existing reputation system nodes usually adopt regular pseudonyms instead of true identities to gain the anonymity. However complete anonymity will cause watershed and Sybil attack, which look on system be out of control and break the fairness of the reputation system. This paper introduces the conditional anonymity mechanism to check the evaluation between anonymity nodes, evaluation between two nodes if not more than the several times, but not be evaluated between two pseudonyms belong to the same peer. It will be effective, otherwise, the node true identity will be exposed, if number of attacks of the peer within the time exceeds d times, nodes in the evaluation and transaction will be tracked. Analysis shows that this mechanism cannot only protect the identity of peer's anonymity, but identify and track malicious attackers.