# Security Documentation — Functional Specification

**Version**: v1.2.3 | **Status**: Active | **Last Updated**: March 2026

## Purpose

Layered security documentation covering theoretical foundations through practical implementation guides for digital, physical, cognitive, and AI safety domains.

## Design Principles

- **Defense in Depth**: Multiple overlapping security layers
- **Least Privilege**: Minimal access by default
- **Zero Trust**: Verify explicitly, never assume trust

## Contents

- Security theory and foundational frameworks
- Digital security: encryption, authentication, network hardening
- Physical security: hardware, facility, supply chain
- Cognitive security: social engineering, epistemic threat modeling
- AI safety: alignment, containment, monitoring
- Trust and governance: policy, compliance, audit

## Navigation

- **Human Docs**: [README.md](README.md)
- **Agent Docs**: [AGENTS.md](AGENTS.md)
- **Parent**: [docs/](../README.md)
