Mapping Misuse Cases to Functional Fault Trees in Order to Secure Positive Train Control Systems
Mark W. Hartong, Rajni Goel, Duminda Wijesekera · 2006
Use cases specify the higher-level functional requirements of a system under design and misuse cases specify its possible misuses. Analyzing them together prevents the latter from occurring while ensuring that the former are implemented. Independently, functional fault trees (FFT) hierarchically breakdown anticipated system failures with respect to its functional architecture. This work presents an algorithm that transforms higher-level use-misuse case to FFTs, and thereby allows the application of the analytical methods available for the latter to the former. The utility of such a mechanism is illustrated by studying the security vulnerabilities that can be introduced to Positive Train Control (PTC) systems - wireless command and control systems for the safe operation of freight and passenger trains.