Schemes for Privately Computing Trust and Reputation

  • Nurit Gal-Oz
  • Niv Gilboa
  • Ehud Gudes
Part of the IFIP Advances in Information and Communication Technology book series (IFIPAICT, volume 321)


Trust and Reputation systems in distributed environments attain widespread interest as online communities are becoming an inherent part of the daily routine of Internet users. Several models for Trust and Reputation have been suggested recently, among them the Knots model [8]. The Knots model provides a member of a community with a method to compute the reputation of other community members. Reputation in this model is subjective and tailored to the taste and choices of the computing member and those members that have similar views, i.e. the computing member’s Trust-Set. A discussion on privately computing trust in the Knots model appears in [16]. The present paper extends and improves [16] by presenting three efficient and private protocols to compute trust in trust based reputation systems that use any trust-sets based model. The protocols in the paper are rigorously proved to be private against a semi-honest adversary given standard assumptions on the existence of an homomorphic, semantically secure, public key encryption system. The protocols are analyzed and compared in terms of their privacy characteristics and communication complexity.


Secret Sharing Scheme Reputation System Homomorphic Encryption Reputation Model Online Phase 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© IFIP 2010

Authors and Affiliations

  • Nurit Gal-Oz
    • 1
  • Niv Gilboa
    • 1
  • Ehud Gudes
    • 1
  1. 1.Dept. of Computer Science and Deutsche Telekom LaboratoriesBen-Gurion UniversityBeer-ShevaIsrael

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