Research And Design On A ROLE And Task-Based Access Control Model Of Workflow System

. In the recent years, Workflow technology has been rapidly developed in the field of computer applications. It has been widely used in some manpower intensive office environment such as banks , securities and administration management. At the same time, more and more attentions are paid to the security problem of workflow management system, this paper is focusing on one of the most important means to secure the information safety of workflow system: Access Control Technique.Access control technique has a close relationship to the access control model theory, until now various access control models have been raised, such as Discretionary Access Control(DAC), Mandatory Access Control(MAC), Role Based Access Control(RBAC) and etc, however, neither of these models would completely meet the needs of access control under workflow environment. On the basis of analysis and comparison of various kinds of existing access control model theory, this paper raised a new type of secure access control model: T-RBAC, which combined the merits of Task Based Access Control(TBAC) and Role Baseed Access Control(RBAC). It provided a preferable solution to the security problems of today's workflow systems.Besides we've designed a new constraint description language-ETCL, which is dedicated to the new model. There is also a prototype system which is designed and implemented to verify the new model. In the prototype system, users will be able to customize workflow templates and their tasks; they can also use a description language that based on ETCL to realize interrelated authorization. Much creative work has been done in the following aspects:1. Design a new type of secure access control model: T-RBAC, which combines the merits of TBAC and RBAC;2. Raise a new arithmetic to resolve the private privilege spreading problem in T-RBAC;3. Raise ETCL constraint description language which is based on modification...