A detection model based on Petri nets of SMER constraints violation in dynamic role translation

Kapadia et al. proposed the IRBAC (interoperable role-based access control) 2000 model, which can be used to accomplish security interoperation between two or more administrative domains via role association and dynamic role translation. Separation of duties (SoD) is one of three basic security principles supported by the RBAC (role-based access control) model. However, SSoD (static separation of duties) is not considered in the IRBAC 2000 model, so the problem of inter-domain static mutual exclusive roles constraints violation can arise while performing security interoperation between domains. This problem has been discussed in some literatures, but these researches are all from the perspective of mathematical logic and logical reasoning, which is abstract, complicated and not intuitive. On the basis of these researches, this paper introduces a novel method of analyzing the problem based on Petri net, which is very easy and visualized to be used to analyze the SMER (static mutual exclusive roles) constraints violation problem. A construction algorithm of Petri net is used to convert an IRBAC2000 model into a corresponding Petri net model, and the necessary and sufficient condition for SMER constraints violation of the IRBAC 2000 model in the Petri net model are proposed and proved. A detection model based on Petri net of violation of SMER constraints is also presented, and at last a case is used to illustrate the efficiency of the proposed model. To avoid SMER constraints violation while adding new role association or user/role assignment, the prerequisites to guarantee the security are also discussed, analyzed and detailed in this paper.