Security Enforcement on Web Services Compositions Web services (WS) composition is the center of many different types of information systems such as ecommerce, financial and healthcare systems, where sensitive data are shared, which raises important security problems. WSBPEL is a standard to specify business processes, however, this orchestration language does not support users to meet their security requirements. This paper proposes a formal and automatic approach for enforcing security policies in WS composition. More precisely, given a composition of WSs written in WSBPEL and a security policy specified in the LTL logic, this paper aims to generate a new version of the services that respects the security policy. The LTL policy is transformed to a new service that can monitor some activities of the others.

Formal specification and validation of refinement from WSCDL to BPEL Service composition is a primary task in the development of serviceoriented systems. The Web Service Process Execution Language (WSBPEL) and the Web Service Choreography Descriptor Language (WSCDL) are two major languages for Web services modeling and implementation. Although these two composition models are of a different nature, they are complementary. WSCDL serves as a behavioral modeling language for collaboration between multiple participants (web services) within the same business process from a global point of view. However, WSBPEL allows a service composition process to be described at different levels of abstraction. At a high level, the description follows a global point of view and deals only with the exchange of messages between participating abstract services (represented abstractly by roles). WSCDL descriptions are thus considered as a specification of the abstract service composition from which more concrete WSBPEL processes are extracted. In this article, we present a formal modeling and analysis approach based on sequential communication process (CSP) in order to verify the behavioral consistency between abstract choreographic descriptions and executable BPEL processes, thereby proving the correctness of the translation process.