A State-Based Model for Certificate Management Systems

A Certificate Management System (CMS) is used to generate, distribute, store and verify certificates. It supports secure electronic communication through its functions. This paper presents a state-based model for certificate management systems. The axiomatization of CMS structures and the security policy followed by CMSs is discussed. The main functions of a CMS, including certificate issuing, certificate revocation and certificate rekeying, are formally described through transitions that change states of the CMS. A major CMS client function, certificate verification, is also formally discussed. With this model, an approach to the formal specification of the structure and behavior of a CMS is provided. The approach is very general, and would be useful in guiding the developer and the evaluator of a CMS with the design, analysis and implementation of the system.