A key issue in computer system security is to protect information against unauthorized access. Emerging workflow-based applications in healthcare, manufacturing, the financial sector, and e-commerce inherently have complex, time-based access control requirements. To address the diverse security needs of these applications, a Role Based Access Control (RBAC) approach can be used as a viable alternative to traditional discretionary and mandatory access control approaches. The key features of RBAC include policy neutrality, support for least privilege, and efficient access control management. However, existing RBAC approaches do no address the growing need for supporting time-based access control requirements for these applications.
This research presents a Generalized Temporal Role Based Access Control (GTRBAC) model that combines the key features of the RBAC model with a powerful temporal framework. The proposed GTRBAC model allows specification of a comprehensive set of time-based access control policies, including temporal constraints on role enabling, user-role and role-permission assignments, and role activities. The model provides an event-based mechanism for supporting dynamic access control policies, which are crucial for developing secure workflow-based enterprise applications. In addition, the temporal hierarchies and separation of duty constraints facilitated by GTRBAC allow the development of security policies for commercial enterprises. The thesis provides various design guidelines for managing complexity and building secure systems based on this model. X-GTRBAC, an XML-based policy language has been developed to allow specification of GTRBAC policies.