Foundational and applied research in access control

We discuss components of our works in access control here at CERIAS. Our work includes the following: - A theory for gauging the expressive power of an access control model, and the use of that theory to compare the expressive power of different models, - Analysis of safety, availability and mutual exclusion properties of access control models, specifically, the hierarchical role based access control model, - Administrative models for hierarchical role based access control that satisfy both pragmatic and formal requirements. The administrative model we are building scales well with large numbers of users and roles, supports complex role hierarchies and lends itself to automation. It has favorable complexity properties in deciding safety, availability and mutual exclusion, and, - The relationship of hierarchical role based access control to other models, such as the HRU model (DAC) and Trust Management languages.