New Semantic Model for Authentication Protocols in ASMs

A new semantic model in Abstract State Model (ASM) for authentication protocols is presented. It highlights the Woo-Lam's ideas for authentication, which is the strongest one in Lowe's definition hierarchy for entity authentication. Apart from the flexible and natural features in forming and analyzing protocols inherited from ASM, the model defines both authentication and secrecy properties explicitly in first order sentences as invariants. The process of proving security properties with respect to an authentication protocol blends the correctness and secrecy properties together to avoid the potential flaws which may happen when treated separately. The security of revised Helsinki protocol is shown as a case study. The new model is different from the previous ones in ASMs.