Trust Network Analysis with Subjective Logic

Abstract

Trust networks consist of transitive trust relationshipsbetween people, organisations and software agents connected through a medium for communication and interaction. By formalising trust relationships, e.g. as reputation scores or as subjective trust measures, trust between parties within the community can be derived byanalysing the trust paths linking the parties together. Thisarticle describes a method for trust network analysis usingsubjective logic (TNA-SL). It provides a simple notationfor expressing transitive trust relationships, and definesa method for simplifying complex trust networks so thatthey can be expressed in a concise form and be computationally analysed. Trust measures are expressed as beliefs,and subjective logic is used to compute trust between arbitrary parties in the network. We show that TNA-SL isefficient, and illustrate possible applications with examples.