Elimination of inference channels by optimal upgrading

摘要

An inference channel exists if it is possible for a low-clearance user to infer high-classification data from low-classification data. Inference channels can be blocked by upgrading the security classification of some of the low-level data. The task of eliminating inference channels is formulated for solution by the Davis-Putnam theorem-proving procedure. The procedure is augmented to search for solutions with minimum total upgrade cost.