The NIST Model for Role-Based Access Control: Towards A Uni ed Standard

This paper describes a uni ed model for role-based access control (RBAC). RBAC is a proven technology for large-scale authorization. However, lack of a standard model results in uncertainty and confusion about its utility and meaning. The NIST model seeks to resolve this situation by unifying ideas from prior RBAC models, commercial products and research prototypes. It is intended to serve as a foundation for developing future standards. RBAC is a rich and open-ended technology which is evolving as users, researchers and vendors gain experience with it. The NIST model focuses on those aspects of RBAC for which consensus is available. It is organized into four levels of increasing functional capabilities called at RBAC, hierarchical RBAC, constrained RBAC and symmetric RBAC. These levels are cumulative and each adds exactly one new requirement. An alternate approach comprising at and hierarchical RBAC in an ordered sequence and two unordered features|constraints and symmetry|is also presented. The paper furthermore identi es important attributes of RBAC not included in the NIST model. Some are not suitable for inclusion in a consensus document. Others require further work and agreement before standardization is feasible. Laboratory for Information Security Technology (LIST), George Mason Univ., [email protected], www.list.gmu.edu. The work of Ravi Sandhu is partially supported by NIST and by NSF. Information Technology Lab., National Institute of Standards and Technology (NIST), [email protected], [email protected], www.itl.nist.gov