No abstract

Despite the widespread adoption of Role-based Access Control (RBAC) models, new access control models are required for new applications for which RBAC may not be especially well suited and for which implementations of RBAC do not enable properties of access control policies to be adequately defined and proven. To address these issues, we propose a form of access control model that is based upon the key notion of an event. The access control model that we propose is intended to permit the representation of access control requirements in a distributed and changing computing environment, the proving of properties of access control policies defined in terms of our model, and direct implementations for access control checking.Research partially funded by the EU project Implementing access control mechanisms using rewriting techniques, Marie Curie Intra European Fellowships Programme.

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We describe a metamodel for access control, designed to take into account the specific requirements of distributed environments. We see a distributed system consisting of several sites, each with its own resources to protect, as a federation, and propose a framework for the specification (and enforcement) of global access control policies that take into account the local policies specified by each member of the federation. The framework provides mechanisms to specify heterogeneous local access control policies, to define policy composition operators, and to use them to define conflict-free access authorisation decisions. We use a declarative formalism in order to give an operational semantics to the distributed metamodel. We then show how properties of policies can be directly obtained from standard results for the operational semantics of access request evaluation.