Modeling And Designing Secure Workflow Management System Based On Petri Nets

Workflow Management System provides the way to automation of business process, so it has been developed quickly and becomes more and more popular. Already used products lean to realization of system itself, but ignore the securities. As a system of information, it is worth of regarding the security problems in workflow management system. Common threatens to system are restriction of time, static access control and dynamic authorization control, special security mechanism has to be provide for each threaten.Petri Nets System is an advance tool to describe asynchronies computing model, since that time it has been studied in depth, and possess stability theory basis and analyses technology. A Model constitute by Petri Net can be frankly examined and powerful supported by Petri Net's theory. So constitute a model of workflow process by Petri Net can provide a distinctness graphic and ensure correctness of workflow process.In order to increase system security, we need to constitute process by HLPN(High-Level Petri Net) farther more. Aimed at different problem, we introduce Time Petri Net, Colored Petri Net and combination of them two. Time Petri Net can solve restriction of time of running process, via add a time restriction model. Colored Petri Net take advantage of color, different color present different permission, a access control matrix has been provide to control subject's behavior. Dynamic authorization mechanism is actually a combination of time restriction and access control, so we can use the formal two mechanism to meet this requirement, and assure synchronization of authorization flow and workflow, consequently provide a maximal guarantee for workflow management system.Basic on the models, designed an archetype system of security workflow management system. In the workflow process design tool, uses a method like Petri Nets to represent the process, and when dispatching activity of process, the system uses static access control and dynamic authorization mechanism. The archetype system achieved typical functions of a workflow management system, as well as implement of security on activities' execution.