A Comparative Analysis of Peer-to-Peer Reputation Systems Debmallo Shayon Ghosh and Philippe M. Wilson Carnegie Mellon University Pittsburgh, PA, USA {dsghosh,pmwilson}@cmu.edu ABSTRACT A large problem in many current peer-to-peer systems is the problem of malicious peers, or peers who do not behave according to the expectations of others. Whether intentional or accidental, malicious users can be a serious problem in distributed systems due to the large number of nodes involved and the increased complexity in detecting and dealing with malicious peers. While many peer-to-peer "reputation" systems have been developed to deal with this problem, they have not been compared on a level playing field. This paper aims to compare EigenTrust, DCRC/CORC, and AbererDespotovic both qualitatively and quantitatively. Although all of the algorithms do not require the use of a Distributed Hash Table (DHT), it is an simplifying mechanism to use for the underlying P2P network. We chose to use Pastry, a DHT design that includes some data replication.