Autonomous Agents and Multi-Agent Systems

, Volume 19, Issue 2, pp 153–172

Gossip-based aggregation of trust in decentralized reputation systems

  • Yoram Bachrach
  • Ariel Parnes
  • Ariel D. Procaccia
  • Jeffrey S. Rosenschein


Decentralized Reputation Systems have recently emerged as a prominent method of establishing trust among self-interested agents in online environments. A key issue is the efficient aggregation of data in the system; several approaches have been proposed, but they are plagued by major shortcomings. We put forward a novel, decentralized data management scheme grounded in gossip-based algorithms. Rumor mongering is known to possess algorithmic advantages, and indeed, our framework inherits many of their salient features: scalability, robustness, a global perspective, and simplicity. We demonstrate that our scheme motivates agents to maintain a very high reputation, by showing that the higher an agent’s reputation is above the threshold set by its peers, the more transactions it would be able to complete within a certain time unit. We analyze the relation between the amount by which an agent’s average reputation exceeds the threshold and the time required to close a deal. This analysis is carried out both theoretically, and empirically through a simulation system called GossipTrustSim. Finally, we show that our approach is inherently impervious to certain kinds of attacks.


Reputation systems Trust Gossip Manipulation Game theory 


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Yoram Bachrach
    • 1
  • Ariel Parnes
    • 1
  • Ariel D. Procaccia
    • 2
  • Jeffrey S. Rosenschein
    • 1
  1. 1.School of Engineering and Computer ScienceThe Hebrew University of JerusalemJerusalemIsrael
  2. 2.Microsoft Israel R&D CenterHerzeliyaIsrael

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