Specification and analysis of access control policies for mobile applications

Mobile applications allow individuals on-the-move access to resources "anytime, anywhere" using hand-held mobile devices. We argue that for critical and sensitive resources this is often times not desirable -- a lost or stolen mobile device can be tampered with to view or alter sensitive information. We need authorization policies that take into account time of access and location of the user in addition to the credentials of the user. Towards this end, we propose a new spatio-temporal role-based access control model. It improves upon existing models by providing features that are useful for mobile applications. Thus, an application using our model can specify different types of spatio-temporal constraints. We discuss how such an application using our spatio-temporal access control model can be verified using the UPPAAL model checker. We also demonstrate how to reduce the state-space explosion problem that is inherent in model checkers.