Modeling and Re-Evaluating Security in an Incremental Development of RBAC-Based Systems Using B Method

Abstract

Incremental software development through the addition of new features and access rules potentially creates security flaws due to inconsistent access control models. Discovering such flaws in software architectures is commonly performed with formal techniques that allow the verification of the correctness of a system and its compliance with applicable policies. In this chapter, the authors propose the use of the B method to formally, and incrementally, design and evaluate the security of systems running under role-based access control (RBAC) policies. They use an electronic marking system (EMS) as a case study to demonstrate the iterative development of RBAC models and the role of the B language in exploring and re-evaluating the security of the system as well as addressing inconsistencies caused by incremental software development. Two formal approaches of model checking and proof obligations are used to verify the correctness of the RBAC specification.