Role-Based Access Control (RBAC) models have emerged as a leading access control approach for today’s information systems. Hybrid role hierarchies introduced in the Generalized Temporal RBAC model have shown to be very desirable for capturing fine-grained access control semantics. However, its administration can become significantly complex. Efficient techniques are needed to administer such hierarchies to support the development of high performance access control systems. In this paper, we present two approaches to implementing a hybrid role hierarchy in the context of the GTRBAC model and analyze and compare their complexities.

Access control in enterprises is a key research area in the realm of Computer Security because of the unique needs of the target enterprise. As the enterprise typically has large user and resource pools, administering the access control based on any framework could in itself be a daunting task. This work presents X-GTRBAC Admin, an administration model that aims at enabling policy administration within a large enterprise. In particular, it simplifies the process of user-to-role and permission-to-role assignments, and thus allows decentralization of the policy administration tasks. Secondly, it also allows for specifying the domain of authority of the system administrators, and hence provides mechanism to distribute the administrative authority over multiple domains within the enterprise. The paper also illustrates the applicability of the administrative concepts presented in our framework for enterprise-wide access control.

The modern enterprise spans several functional units or administrative domains with diverse authorization requirements. Access control policies in an enterprise environment typically express these requirements as authorization constraints. While desirable for access control, constraints can lead to conflicts in the overall policy in a multidomain environment. The administration problem for enterprise-wide access control, therefore, not only includes authorization management for users and resources within a single domain but also conflict resolution among heterogeneous access control policies of multiple domains to allow secure interoperation within the enterprise. This work presents design and implementation of X-GTRBAC Admin, an administration model that aims at enabling administration of role-based access control (RBAC) policies in the presence of constraints with support for conflict resolution in a multidomain environment. A key feature of the model is that it allows decentralization of policy administration tasks through the abstraction of administrative domains, which not only simplifies authorization management, but is also fundamental to the concept of decentralized conflict resolution presented. The paper also illustrates the applicability of the outlined administrative concepts in a realistic enterprise environment using an implementation prototype that facilitates policy administration in large enterprises.