# Security Requirements Engineering
One-sentence definition: Write verifiable security requirements tied to risks, standards, and acceptance tests.
## Key Facts
- Use concrete criteria (e.g., “TLS 1.2+ with AEAD; HSTS enabled”).
- Traceability: requirement ↔ test case ↔ evidence in CI.
- Include non-functional reqs: logging, rate limits, privacy, resilience.
- Derive from threat modeling and data classification.
- **Verify:** check official (ISC)² CBK and current exam outline.
## Exam Relevance
- Spot vague vs testable requirements in questions.
**Mnemonic:** “If you can’t **test** it, don’t **trust** it.”
## Mini Scenario
Q: “Use strong encryption” appears—improve?
A: Specify protocol, cipher suites, key lengths, and rejection rules.
## Revision Checklist
- Two non-functional security requirements.
- Traceability value.
- Link to threat model.
## Related
[[Threat Modeling for Developers (STRIDE DFD)]] · [[Secure Design Principles (Least Privilege Fail Safe Economy of Mechanism)]] · [[Secure Error Handling and Logging for Apps]] · [[Security Testing Strategy (Unit Integration E2E Fuzz)]] · [[Domain 8 - Index]]