A model of OASIS role-based access control and its support for active security

OASIS is a role-based access control architecture for achieving secure interoperation of services in an open, distributed environment. The aim of OASIS is to allow autonomous management domains to specify their own access control policies and to interoperate subject to service level agreements (SLAs). Services define roles and implement formally specified policy to control role activation and service use; users must present the required credentials, in an appropriate context, in order to activate a role or invoke a service. All privileges are derived from roles, which are activated for the duration of a session only. In addition, a role is deactivated immediately if any of the conditions of the membership rule associated with its activation becomes false. These conditions can test the context, thus ensuring active monitoring of security.To support the management of privileges, OASIS introduces appointment . Users in certain roles are authorized to issue other users with appointment certificates , which may be a prerequisite for activating one or more roles. The conditions for activating a role at a service may include appointment certificates as well as prerequisite roles and constraints on the context. An appointment certificate does not therefore convey privileges directly but can be used as a credential for role activation. The lifetime of appointment certificates is not restricted to the issuing session, so they can be used as long-lived credentials to represent academic and professional qualification, or membership of an organization.Role-based access control (RBAC), in associating privileges with roles, provides a means of expressing access control that is scalable to large numbers of principals. However, pure RBAC associates privileges only with roles, whereas applications often require more fine-grained access control. Parametrized roles extend the functionality to meet this need.We motivate our approach and formalise OASIS. We first present the overall architecture through a basic model, followed by an extended model that includes parametrization.