This Article 
 Bibliographic References 
 Add to: 
PeerTrust: Supporting Reputation-Based Trust for Peer-to-Peer Electronic Communities
July 2004 (vol. 16 no. 7)
pp. 843-857
Ling Liu, IEEE Computer Society

Abstract—Peer-to-peer (P2P) online communities are commonly perceived as an environment offering both opportunities and threats. One way to minimize threats in such communities is to use community-based reputations to help estimate the trustworthiness of peers. This paper presents PeerTrust—a reputation-based trust supporting framework, which includes a coherent adaptive trust model for quantifying and comparing the trustworthiness of peers based on a transaction-based feedback system, and a decentralized implementation of such a model over a structured P2P network. PeerTrust model has two main features. First, we introduce three basic trust parameters and two adaptive factors in computing trustworthiness of peers, namely, feedback a peer receives from other peers, the total number of transactions a peer performs, the credibility of the feedback sources, transaction context factor, and the community context factor. Second, we define a general trust metric to combine these parameters. Other contributions of the paper include strategies used for implementing the trust model in a decentralized P2P environment, evaluation mechanisms to validate the effectiveness and cost of PeerTrust model, and a set of experiments that show the feasibility and benefit of our approach.

[1] Gnutella, http:/, 2000.
[2] HyperBee, http:/, 2001.
[3] PeerCQ,, 2004.
[4] A. Abdul-Rahman and S. Hailes, Supporting Trust in Virtual Communities Proc. 33rd Ann. Hawaii Int'l Conf. System Sciences (HICSS-33), 2000.
[5] K. Aberer, P-Grid: A Self-Organizing Access Structure for P2P Information Systems Proc. Ninth Int'l Conf. Cooperative Information Systems, 2001.
[6] K. Aberer and Z. Despotovic, Managing Trust in a Peer-to-Peer Information System Proc. ACM Conf. Information and Knowledge Management (CIKM), 2001.
[7] Y. Atif, Building Trust in E-Commerce IEEE Internet Computing, vol. 6, no. 1, 2002.
[8] M. Chen and J.P. Singh, Computing and Using Reputations for Internet Ratings Proc. Third ACM Conf. Electronic Commerce, 2001.
[9] F. Cornelli, E. Damiani, S.D.C. di Vimercati, S. Paraboschi, and P. Samarati, Choosing Reputable Servents in a P2P Network Proc. 11th Int'l World Wide Web Conf., 2002.
[10] C. Dellarocas, Immunizing Online Reputation Reporting Systems against Unfair Ratings and Discriminatory Behavior Proc. Second ACM Conf. Electronic Commerce, 2000.
[11] C. Dellarocas, Analyzing the Economic Efficiency of Ebay-Like Online Reputation Reporting Mechanisms Proc. Third ACM Conf. Electronic Commerce, 2001.
[12] C. Dellarocas, The Digitization of Word-of-Mouth: Promise and Challenges of Online Reputation Mechanism Management Science, vol. 49, no. 10, 2003.
[13] E. Friedman and P. Resnick, The Social Cost of Cheap Pseudonyms J. Economics and Management Strategy, vol. 10, no. 1, 2001.
[14] B. Holmstrom, Managerial Incentive Problems: A Dynamic Perspective Rev. Economic Studies, vol. 66, no. 1, 1999.
[15] B.A. Huberman and F. Wu, The Dynamics of Reputation. 2002.
[16] A. Josang and R. Ismail, The Beta Reputation System Proc. 15th Bled Conf. Electronic Commerce, 2002.
[17] A. Josang and N. Tran, Simulating the Effect of Reputation Systems on E-Markets Proc. First Int'l Conf. Trust Management, 2003.
[18] S. Kamvar, M. Scholsser, and H. Garcia-Molina, The EigenTrust Algorithm for Reputation Management in P2P Networks Proc. 12th Int'l World Wide Web Conf., 2003.
[19] S. Ketchpel and H.M. Garcia, "Making Trust Explicit in Distributed Commerce Transactions," Proc. 16th Int'l Conf. Distributed Computing Systems (ICDCS 96), IEEE Computer Soc. Press, Los Alamitos, Calif., May 1996, pp. 270-281.
[20] D. Kreps and R. Wilson, Reputation and Imperfect Information J. Economic Theory, vol. 27, 1982.
[21] R.A. Malaga, Web-Based Reputation Management Systems: Problems and Suggested Solutions Electronic Commerce Research, vol. 1, no. 4, 2001.
[22] D.W. Manchala, E-Commerce Trust Metrics and Models IEEE Internet Computing, vol. 4, no. 2, 2000.
[23] D.H. McKnight and N.L. Chervany, The Meanings of Trust Technical Report WP9604, Univ. of Minnesota Management Information Systems Research Center, 1996.
[24] N.H. Miller, P. Resnick, and R.J. Zeckhauser, Eliciting Honest Feedback in Electronic Markets KSG Working Paper Series RWP02-039, 2002.
[25] L. Mui, M. Mohtashemi, and A. Halberstadt, Notions of Reputation in Multi-Agent Systems: A Review Proc. First Int'l Joint Conf. Autonomous Agents and Multiagent Systems, 2002.
[26] J.M. Pujol, R. Sanguesa, and J. Delgado, Extracting Reputation in Multi-Agent Systems by Means of Social Network Topology Proc. First Int'l Joint Conf. Autonomous Agents and Multiagent Systems, 2002.
[27] S. Ratnasamy, P. Francis, M. Handley, R. Karp, and S. Shenker, A Scalable Content Addressable Network Proc. ACM SIGCOMM, 2001.
[28] P. Resnick, R. Zeckhauser, E. Friedman, and K. Kuwabara, Reputation Systems Comm. ACM, vol. 43, no. 12, 2000.
[29] A. Rowstron and P. Druschel, Pastry: Scalable, Decentralized Object Location and Routing for Large-Scale Peer-to-Peer Systems Middleware, 2001.
[30] J. Sabater and C. Sierra, Reputation and Social Network Analysis in Multi-Agent Systems Proc. First Int'l Joint Conf. Autonomous Agents and Multiagent Systems, 2002.
[31] S. Sen and N. Sajja, Robustness of Reputation-Based Trust: Boolean Case Proc. First Int'l Joint Conf. Autonomous Agents and Multiagent Systems, 2002.
[32] I. Stoica, R. Morris, D. Karger, F. Kaashoek, and H. Balakrishnan, Chord: A Scalable Peer-to-Peer Lookup Service for Internet Applications Proc. ACM SIGCOMM, 2001.
[33] L. Xiong and L. Liu, A Reputation-Based Trust Model for Peer-to-Peer Ecommerce Communities Proc. IEEE Conf. E-Commerce (CEC '03), 2003.
[34] J.E. Youll, Peer to Peer Transactions in Agent-Mediated Electronic Commerce Master's thesis, Massachusetts Inst. of Tech nology, 2001.
[35] B. Yu and M.P. Singh, A Social Mechanism of Reputation Management in Electronic Communities Proc. Seventh Int'l Conf. Cooperative Information Agents, 2000.
[36] G. Zacharia and P. Maes, Trust Management through Reputation Mechanisms Applied Artificial Intelligence, vol. 14, no. 8, 2000.

Index Terms:
Peer-to-peer, trust, reputation mechanisms, data management, security.
Li Xiong, Ling Liu, "PeerTrust: Supporting Reputation-Based Trust for Peer-to-Peer Electronic Communities," IEEE Transactions on Knowledge and Data Engineering, vol. 16, no. 7, pp. 843-857, July 2004, doi:10.1109/TKDE.2004.1318566
Usage of this product signifies your acceptance of the Terms of Use.