TRIAD: a framework for survivability architecting

High confidence in a system's survivability requires an accurate understanding of the system's threat environment and the impact of that environment on system operations. This paper describes a framework for intrusion-aware design called trustworthy refinement through intrusion-aware design (TRIAD). The spiral structure of TRIAD iterates through three sectors of activity for developing the architectural strategy, for instantiating the architecture using technical components, and for analyzing the impact of the threat environment on system operations. TRIAD helps developers of complex, internetworked information systems to formulate, implement, and maintain a coherent, justifiable, and affordable survivability strategy that addresses mission-compromising threats for their organization. TRIAD facilitates planning for the inevitable change to the threat and operational environment and helps trace the effect of change back to the survivability requirements and architecture.