Modality conflicts in semantics-aware access control

Security is a crucial concern for commercial and mission critical applications in Web-based environments. Semantic Web-style context descriptions aim at supporting wide-spread distribution of resources and cooperation of autonomous agents on the Web in a secure way. In this paper, context information associated with Access Control (AC) management policies is defined according to basic operators that can be represented using the Web Ontology Language (OWL). The same primitives are used, in the specification of authorizations, to compose domain scope expressions. Standard inference procedures of Description Logics (DL) can then be used to check the consistency of context information referred to by policy conditions and, more interestingly, to pre-process context information for grounding policy propagation and enabling conflict resolution. This work aims at extending the notion of modality conflict in the evaluation of AC policies to take into account semantic Web-style, ontology-based definitions of the entities involved.