Reasoning about dynamic delegation in role based access control systems

This paper proposes a logic based framework that supports dynamic delegation for role based access control systems in a decentralised environment. It allows delegation of administrative privileges for both roles and access rights between roles. We have introduced the notion of trust in delegation and have shown how extended logic programs can be used to express and reason about roles and their delegations with trust degrees, roles' privileges and their propagations, delegation depth as well as conflict resolution. Furthermore, our framework is able to enforce various role constraints such as separation of duties, role composition and cardinality constraints. The proposed framework is flexible and provides a sound basis for specifying and evaluating sophisticated role based access control policies in decentralised environments.