Inference Control for relational databases

Multilevel relational databases store information at different security classifications. An inference problem exists if it is possible for a user with a low clearance to draw conclusions about information at higher classifications. We are developing a new tool, called DISSECT, for analyzing multilevel relational database schemas to assist in the detection and elimination of inference problems. This tool would be used interactively by a data designer to analyze a candidate database schema for potential inference problems. DISSECT creates a graphical representation of the multilevel database schema and of discovered potential inference channels in the database. Inferences can be blocked by upgrading the classification of some of the foreign key relationships. DISSECT will then discover any new inference problems that may have been introduced by the repair of previously-detected problems.