Secure Systems Design
Building security into the foundation of every system
What is Secure Systems Design?
Secure systems design is the practice of architecting software and infrastructure with security as a fundamental requirement, not an afterthought. It encompasses threat modeling, secure defaults, least privilege, and defense in depth.
Key Principles
- Least Privilege — Grant only the minimum permissions needed for each component.
- Secure Defaults — Ship with the most restrictive configuration that still works.
- Fail Securely — When components fail, they should fail closed, not open.
- Complete Mediation — Every access to every resource must be validated.
- Separation of Duties — No single component should have unchecked authority.
How Signando Implements These Principles
Signando's Application Layer Gateways enforce complete mediation by inspecting every request and response. The four-zone architecture implements separation of duties with increasing isolation levels. All ALGs default to deny-all policies, ensuring secure defaults.