Security — Secrets, API Key Rotation, Audit Logs, Guardrails

Eliminate secret sprawl via centralized vaults (HashiCorp Vault, AWS Secrets Manager, Azure Key Vault). Never store credentials in config files, env files in VCS, spreadsheets. Use IAM roles over static keys; OIDC for CI/CD. The AI-gateway pattern is the 2026 solution: apps → gateway → model provider, with gateway pulling credentials from vault at runtime. Rotate in vault and all apps pick up in minutes — no redeploys, no Slack "who has the new key" messages. Rotation policy ≤90 days; scan with TruffleHog / GitGuardian / Gitleaks on every commit. Zero-trust: MFA, SSO, RBAC/ABAC, short-lived tokens, device posture. PII scrubbing uses entity recognition to mask PHI/PII before forwarding; consistent tokenization (Mesh approach) maps sensitive values to stable placeholders so the LLM preserves code/relationship semantics. Network egress: LLM services in dedicated VPC/VNet subnet whitelisting only `api.openai.com`, `api.anthropic.com` etc; block all other outbound. The 2026 incident driver: Vercel supply-chain attack via compromised CI/CD credentials exfiltrated env vars across thousands of customer deployments.

Prerequisites: Phase 17 · 19 (AI Gateways), Phase 17 · 13 (Observability)