Evidence processing and privacy issues in evidence-based reputation systems

Issues related to processing of evidence in evidence-based reputationsystems, with a particular concern for user privacy, are discussed inour paper. The novel idea of evidence-based reputation (or trust)systems is that such systems do not rely on an objective knowledge ofuser identity. One has instead to consider possible privacyinfringements based on the use of data (evidence) about the previousbehaviour of entities in the systems. We provide a brief introductionto evidence-based trust/reputation systems, as well as to the privacyissues, addressing the common problem of many papers that narrow theconsiderations of privacy to anonymity only. We elaborate on theconcept of pseudonymity through aspects of evidence storing andprocessing. This, together with a consideration of current work ontrust models, leads to our specification of requirements for the trustmodel for evidence-based systems supporting pseudonymity.