Abstract: With the development and application of Web services technologies, the security issues of Web services composition are increasingly prominent. The present security specifications of Web services arc only specified for a single Web service, and there is no architecture for security of composite Web services being approved by most people. The insufficiency of present research on Web services composition security architecture was pointed out and the requirements of Web service composition security were analyzed. We proposed a hierarchical security model for Web services composition (HSM-WSC) based on Web services stack according to the Web service application mode,and analyzed the security function of each layer in the model. This model has the advantages of flexibility and extensibility, and satisfies various requirements of secure composite Web services. The paper also described the Implementation architecture of HSM-WSC in the end.

Key words: Security model, Web services composition, Reliable cooperation, Business process