Technical Documentation

This includes documenting the security architecture (e.g., threat models, security control diagrams, trust boundaries), important security design decisions, security APIs, secure configuration steps, and security operations manuals. Also included is writing security documentation within the code itself (clear comments for security-critical functions, secure implementation notes in README files).

Such security documentation ensures that security knowledge within the team is explicitly recorded and not just kept in the security specialists' heads. This is essential for security continuity: new team members can understand security controls faster, and security issues can be identified and resolved more efficiently, while also supporting compliance requirements and security audits.

Starting Points

• NIST Special Publication 800-18: Guide for Developing Security Plans
• OWASP Application Security Verification Standard Documentation Requirements
• How to Document Security Controls

Key Points

• You have created clear security documentation with instructions for securely configuring/implementing the system, including security dependencies (authentication services, encryption libraries) and secure setup steps.
• Important security design decisions and risk acceptance decisions are documented with justification.
• Security-critical code is provided with adequate security comments and/or detailed explanations, especially on complex security implementations. Security functions and classes have descriptions of their security purpose and proper usage. There is also consistency in security documentation according to any agreed security standards.
• You maintain documentation of security incidents, their resolution, and lessons learned to prevent similar issues in the future.