A Multiple Hierarchies RBAC Model

When a role in the classic hierarchy RBAC model gets more inherited permissions than the anticipant permissions of the administrator, there is the issue of excessive inheritance. This issue is addressed and a multiple hierarchies RBAC model is presented which extends from the classic hierarchy RBAC model in three aspects. Firstly, the multiple hierarchies RBAC model can classify the permissions of the roles. Secondly, it supports multiple hierarchies which are used to classify the partial order relations. Thirdly, it redefines the semantics of partial order to support partial permissions inheritance. The multiple hierarchies RBAC model is more general and flexible than the other modes derived from the classic model, and it improves the capability of the RBAC model.