# Security Architecture Specification

## Overview

Security architecture including threat model, security boundaries, and security controls.

## Threat Model

### Threat Categories

**1. External Threats**:
- DDoS attacks
- SQL injection
- XSS attacks
- API abuse

**2. Internal Threats**:
- Privileged user abuse
- Data breaches
- Insider threats

**3. Infrastructure Threats**:
- Node compromise
- Database breaches
- Network attacks

## Security Boundaries

**DMZ**: Public-facing services
**Internal Network**: Backend services
**Data Layer**: Database and storage (isolated)
**Blockchain Network**: Node network (isolated)

## KMS/HSM Integration

### Key Management

**Storage**: Hardware Security Module (HSM)
**Usage**: API keys, signing keys, encryption keys
**Access**: Role-based, audit logged

## Secrets Management

### Secret Storage

**Solution**: Vault, AWS Secrets Manager, or similar
**Encryption**: At rest and in transit
**Rotation**: Regular key rotation
**Access**: Least privilege principle

## Signed Builds and SBOM

### Build Signing

**Process**: Sign all builds
**Verification**: Verify signatures before deployment
**Tooling**: Code signing certificates

### SBOM (Software Bill of Materials)

**Generation**: Generate SBOM for all dependencies
**Storage**: Store SBOM for audit
**Vulnerability Scanning**: Scan SBOM for known vulnerabilities

## References

- Authentication: See `auth-spec.md`
- Privacy: See `privacy-controls.md`