- Volume 7 Issue 11
The objectives of access control are to protect computing and communication resources from illegal use, alteration, disclosure and destruction by unauthorized users. Although Biba security model is well suited for protecting the integrity of information, it is considered too restrictive to be an access control model for commercial environments. And, Role-Based Access Control(RBAC) model, a flexible and policy-neutral security model that is being widely accepted in commercial areas, has a possibility for compromising integrity of information. In this paper, We present the role graph model which enhanced flexibility and integrity to management of many access permission. Also, In order to represent those rule and constraints clearly, formal descriptions of role assignment rule and constraints in Z language are also given.