Design of Trust Metrics Based on Dempster-Shafer Theory

This paper introduces a mechanism to quantify propagation of trust in an e-commerce environment. Using principles derived from Dempster-Shafer theory of evidence, we propose a method to propagate and quantify trust. More specifically, we answer the question: if A trusts B, and B trusts C, then with how much certainty may A trust C? This reasoning can be extended to an arbitrary length of trust chains. Thus we use previous knowledge and trust relationships to extend trust formalism between two unknown parties. We also give examples illustrating our model. Our approach can be compared favorably to existing models of trust.