A high-level model-checking tool for verifying service agreements

In a cloud computing environment, both the client and the provider need assurances that service interactions are in accordance with the service agreement (contract). It should be possible to encode a contract as a set of executable business policies that can be evaluated by either party for controlling service interactions. Naturally, it is important to verify the correctness properties of such a contract before its deployment. To this end, the paper adopts the use of model-checking techniques. A high-level model-checking tool has been developed that enables a designer to encode a contract for model checking directly as event-condition-action rules in terms of contract entities: business operations, role players with their rights, obligations and prohibitions. This not only simplifies the task of model building but also, the designer can specify the correctness requirements, in linear temporal logic, directly in terms of the contract entities. The tool has been implemented by extending the PROMELA language of the SPIN model checker.