Reasoning about public-key certification: on bindings between entities and public keys

Public-key certification is of crucial importance for advancing the global information infrastructure, yet it suffers from certain ambiguities and lack of understanding and precision. This paper suggests a few steps toward basing public-key certification and public-key infrastructures on firmer theoretical key. In particular, we investigate the notion of binding a public to an entity. We propose a calculus for deriving conclusions from a given entity Alice´s (for instance, a judge´s) view consisting of evidence and inference rules valid in Alice´s world. The evidence consists of statements made by public keys (e.g., certificates, authorizations, or recommendations), statements made physically toward Alice by other entities, and trust assumptions. Conclusions are about who says a statement, who owns or is committed to a public key, and who transfers a right or authorization to another entity, and are derived by applying the inference rules.