Engineering Requirements for System Reliability and Security

Requirements engineering (RE) is concerned with the elicitation of the objectives to be achieved by the system-to-be, the operationalization of such objectives into specifications of requirements and assumptions, the assignment of responsibilities for those specifications to agents such as humans, devices and software, and the evolution of such requirements over time and across system families. Getting high-quality requirements is difficult and critical. Poor requirements were recurrently recognized to be the major cause of system failures. The consequences of such failures may be especially harmful in mission-critical systems. This paper overviews a systematic, goal-oriented approach to requirements engineering for high-assurance systems. The target of this approach is a complete, consistent, adequate, and structured set of software requirements and environment assumptions. The approach is model-based and partly relies on the use of formal methods when and where needed for RE-specific tasks, notably, goal refinement and operationalization, analysis of hazards and threats, conflict management, and synthesis of behavior models.