Web Services are currently the base of a lot e-commerce application. Today's security solutions proposed for Web services help to protect communications confidentiality and integrity between Web services and to control access to Web services. Nevertheless, clients often use these services without knowing anything about their internals. Moreover, they have no clue about the use of their personal data inside the global application. BPEL (Business Process Execution Language) is a programming language orchestrating Web Services within Service-Oriented Architecture (SOA). As one feature of SOAs is the dynamic discovery of services actually used during execution, a BPEL user does not know prior to the execution how, and by whom, the data he provides will be used. In this thesis we propose a model of political control information flow suitable for service-oriented architectures and in particular orchestrations of services. This model offers the opportunity to the user to specify constraints on the use of its personal data. This policy is configured at runtime by the user of the BPEL program. However, the dynamic aspects of the web services lead to situations in which the policy prohibits the nominal operation of the orchestration (e.g., when using a service that is unknown by the user). To solve this problem, we suggest the user to dynamically allow exceptional unauthorized flows. In order to make his decision, the user is provided with all information necessary for decision-making. We then applied this approach to BPEL orchestration language. In particular, we presented the main information flow involved in this language. Finally, we proposed an implementation of these information flow control mechanisms by modifying an existing BPEL orchestrator.
