Multilevel Security for Knowledge-Based Systems

The paper presents results of an initial investigation of multilevel security for knowledge-based systems. Knowledge-based systems are computer programs that give advice using techniques developed in artificial intelligence research. Although many apparently multilevel knowledge-based systems are now being developed, security requirements have not yet been articulated for them. We adopt the production system model as a generalization of knowledge-based systems. We apply noninterference concepts of multilevel security to the production model, and from this we suggest an approach for achieving multilevel secure production systems. Our approach puts control structures at system low, assigns a single classification to entries in the knowledge base, and provide different views both of the database and of the rule base depending upon the clearance of the user. We conclude that it will be possible to achieve multilevel security for many knowledge-based systems. We present a research agenda for further study,