Modeling System Threat Probabilities Using Mixed-Radix Multiple-Valued Logic Decision Diagrams

Design for security has become an area of increasing importance. This includes securing systems from both natural and intentional threats. Extremely large and complex systems can have an accordingly large number of threat scenarios, thus simply listing the threats and devising countermeasures for each is ineffective and inefficient. The components of a large system may also have various states of failure, which cannot be captured by contemporary binary system models. To address this problem, we describe a threat cataloging methodology whereby a large number of threats can be efficiently cataloged and analyzed for common features. This allows countermeasures to be formulated that address a large number of threats that share common features. The methodology utilizes Mixed-Radix Multiple-Valued Logic for describing the state of a large system and a multiple-valued decision diagram (MDD) for the threat catalog and analysis.