Embedding Access Control Policy in Web Service Path Composition Algorithm

Web services can accomplish requirements, which are generally complicated functions. To apply web services for a requirement, the requirement should be decomposed into sub-functions in which each sub-function can be accomplished by a web service. After the decomposition, web services are selected to compose paths for the requirement. During composition, secure access of web services should be considered. This paper proposes a two-leveled web service access control policy and a web service composition algorithm. We embed the policy in the algorithm. During selection, the upper level access control policy uses attributes and credentials to filter out the web services that cannot be invoked by a requester. The lower level policy then compares the credit level numbers of web services with the security level numbers of arguments. It then evaluates the possibility of leaking the arguments by a web service. The possibility facilitates evaluating the successfulness of executing a path. After the two-leveled access control, the composition algorithm composes multiple paths. The requester can select more than one path. One of the selected paths can be executed and the others are spare ones to reduce path replanning effort through replacement