Design options for privacy-respecting reputation systems within centralised internet communities

Abstract

Reputation systems play an important role in Internet communities like eBay. They allow members of the community to estimate other members' behaviour before an interaction. Unfortunately the design of current reputation systems allows to generate user profiles including all contexts the user has been involved in. A more privacy-enhancing design of reputation systems is needed while keeping the trust provided to the members by the use of reputations. We will present design options for such a system and analyse the privacy it provides with common information-theoretic models. The analysis of our reputation system also allows to analyse similar aspects of privacy in other systems, especially privacy-enhancing identity management. © 2006 International Federation for Information Processing.