Security policies in dynamic service compositions

The paradigm of service composition emerged in the context of service oriented architectures, where it mainly referred to creating value-added services by combinitions of individual services. Nowadays, service composition is getting more and more dynamic and becomes part of pervasive systems. One of the major challenges in this context is to fulfill the security requirements of all involved parties without requiring human interaction to negotiate protection level agreements. In this paper, we propose an approach for composing access control decisions and obligations required by equitable policy domains on the fly. We show that our approach allows a policy-compliant collaboration without requiring the peers to reveal their individual rules and confirm its practicability by a prototype.