Multilevel Security in Database Management Systems

Multi-level secure database management system (MLS-DBMS) security requirements are defined in terms of the view of the database presented to users with different authorizations. These security requirements are intended to be consistent with DoD secure computing system requirements. An informal security policy for a multi-level secure database management system is outlined, and mechanisms are introduced that support the policy. Security constraints are the mechanism for defining classification rules, and query modification is the mechanism for implementing the classification policy. These mechanisms ensure that responses to users' queries can be assigned classifications which will make them observable to the querying users.