Trustworthy service composition: Challenges and research questions

Web services have been gathering an increasing amount of attention lately. The raison d'etre of Web services is that we compose them to create new services. For Web services to be effectively composed, however, requires that they be trustworthy and in fact be trusted by their users and other collaborating services. In our conceptual scheme, principals interact as autonomous peers to provide services to one another. Trust is captured as a composite relationship between the trusted and the trusting principal. Principals help each other discover and locate trustworthy services and weed out untrustworthy players. The interactions of the principals combined with the needs of different applications induce interesting structures on the network. We apply multiagent systems techniques to model interactions among the principals. By varying the requirements of different applications, the needs of different principals, the existence of special principals such as trusted authorities, and the mechanisms underlying the interactions, we draw attention to a variety of important settings where Web services would be composed. One, leading to superior methods through which trust can be evolved and managed in realistic service-composition settings. Two, studying the relationships. between aspects of trust for Web services and-the evolution of Web structure.