Towards a framework for trust negotiations in composite web services

Abstract

Web Services propose a framework for the standardisation of interfaces and interaction, and for publishing software componen1S as services on the Internet By using this framework, composite servi<:es that make use of more than one Web service can be created. Although a composite Web service may provide a unified service to the service requestor~ it cannot be viewed as a single unified entity when its trustworthiness is evaluated, since its constituent services may differ in their nonfunctional attributes. Based on the context of trust (which includes security, reliability, quality of servi~e. etc.), information has to be collected from the constituent services of a composite Web service. Trust negotiation is perfonned to gather infonnation from these services, with the ultimate goal of establishing trust relationships with them. In this dissertation~ the Web Services framework is analysed to determine its support for trust negotiation in any trust context. A trust negotiation procedure is subsequeotly presemed. which can be applied in a composite as well as an elementary Web service.