A Security Model for Information Systems with Multi-level Security

With the rapid development of informationization process, the fundamental, global and strategic role of critical information systems is increasingly significant. For addressing the access control problem of information systems with multi-level security, the BLP model of stand-alone computer systems is extended to information systems, the new interpretations of subjects and objects in the information systems are presented, the security level ranges of subject and object are introduced, and a security model for information systems with multi-level security is proposed. Then, the formal description of the security model is included, the full set of access rules is established, and the security of the model is proved. The new security model maintains the multi-level security of information systems, while allows security level ranges of subject and object being dynamically changed.