A Formal Verification Model for Trustworthiness of Component Interface

Components are considered as black boxes and are connected with other components through required interfaces and provided interfaces. Therefore, the correct specifications of components are the basis of using and assembling components. The connection between two components is trustworthy only if all their interfaces are correctly compatible. B method is applied to define the specification of component interfaces and verify trustworthiness of component connections in this paper. UML class diagram and state diagram are firstly applied to intuitively describe the syntactic and semantic information of component interface, then the formal specification of component interface defined by B abstract machine is presented. The trustworthiness of component connection is further verified in terms of B refinement mechanism which can prove that the machine of the provided interface is a correct refinement of the machine of the required interface. Since B tools could be used to verify whether a provided interface is a correct refinement of a required interface, the complex manual verifying process could be simplified, and the verifying result is more accurate and reliable.