A Philosophy of Security Architecture Design

Digital systems are almost always vulnerable, yet we increasingly depend on these systems. There will be many threats towards these system. In a fully networked system, the vulnerabilities will literally be exposed to the whole world. The exposed vulnerabilities may be transformed into attacks. To counter this state of "vulnerability", the standard remedy is to conduct security requirements analysis and security threat modeling. Threats are assessed, and various countermeasures are devised. The totality of these measures may be described as a security architecture. The goal of a security architecture will largely be to make the system robust and resilient in the face of an adversary. However, we shall argue that this is not enough. Security architecture designs should go one step further, and actually improve the defenses when faced with hostile actions. That is, the security architectures must become antifragile.