# Encryption Key Rotation Runbook — SentryAgent.ai AgentIdP

**Control:** SOC 2 CC6.1 — Encryption at Rest
**Service:** `src/services/EncryptionService.ts`
**Vault path:** Configured via `ENCRYPTION_KEY_VAULT_PATH` env var (default: `secret/data/agentidp/encryption-key`)

---

## Overview

AgentIdP uses AES-256-CBC column-level encryption for sensitive PostgreSQL columns.
The encryption key is a 64-character hex string (32 bytes) stored in HashiCorp Vault.
The `EncryptionService` fetches the key once and caches it in process memory.

Encrypted format: `base64(IV):base64(ciphertext)` where IV is 16 random bytes per encryption call.

---

## Key Rotation Procedure

### Prerequisites

- Access to HashiCorp Vault with write permissions to the encryption key path
- Access to the production application environment (to trigger restart)
- At least one backup of the current key stored securely offline

### Step 1: Generate a New Key

Generate a cryptographically strong 32-byte (64-character hex) key:

```bash
openssl rand -hex 32
# Example output: a1b2c3d4e5f6...  (64 hex chars)
```

Record the new key securely.

### Step 2: Backup the Current Key

Before overwriting, read and securely store the current key:

```bash
vault kv get -field=encryptionKey secret/agentidp/encryption-key > /secure/backup/encryption-key-$(date +%Y%m%d).txt
```

Store in a hardware security module (HSM) or offline key store.

### Step 3: Write the New Key to Vault

```bash
vault kv put secret/agentidp/encryption-key encryptionKey="<new-64-char-hex-key>"
```

Verify the write:

```bash
vault kv get secret/agentidp/encryption-key
```

Confirm the `encryptionKey` field contains exactly 64 hex characters.

### Step 4: Restart the Application

The `EncryptionService` caches the key in process memory. A restart forces a re-fetch from Vault:

```bash
# Kubernetes rolling restart
kubectl rollout restart deployment/agentidp

# Docker Compose
docker-compose restart agentidp

# PM2
pm2 restart agentidp
```

### Step 5: Verify Key Pick-Up

Check the application logs for:

```
[AgentIdP] EncryptionService enabled — sensitive columns encrypted at rest (SOC 2 CC6.1)
```

Call the compliance controls endpoint to confirm the control is passing:

```bash
curl -s https://api.sentryagent.ai/v1/compliance/controls | jq '.controls[] | select(.id == "CC6.1")'
```

Expected output:
```json
{ "id": "CC6.1", "name": "Encryption at Rest", "status": "passing", "lastChecked": "..." }
```

### Step 6: Re-encryption of Existing Rows

Existing rows encrypted with the old key will fail to decrypt after key rotation.
Re-encryption happens lazily: the next time each row is read and re-written (e.g. credential rotation,
webhook update), the application will decrypt with the old key and re-encrypt with the new one.

For immediate full re-encryption, use the re-encryption script:

```bash
# Run the re-encryption migration script (reads old key from backup, encrypts with new key)
# Note: This script requires both old and new keys to be available
ts-node scripts/reencrypt-columns.ts --old-key-file /secure/backup/encryption-key-<date>.txt
```

---

## Emergency Rollback

If the new key causes issues (e.g. test failures, decryption errors), roll back:

### Step 1: Restore Old Key to Vault

```bash
vault kv put secret/agentidp/encryption-key encryptionKey="<old-64-char-hex-key-from-backup>"
```

### Step 2: Restart the Application

```bash
kubectl rollout restart deployment/agentidp
```

### Step 3: Verify Recovery

```bash
curl -s https://api.sentryagent.ai/v1/compliance/controls | jq '.controls[] | select(.id == "CC6.1")'
```

### Step 4: Investigate Root Cause

Review application logs for `AES-256-CBC decryption failed` errors and audit the cause before
reattempting rotation.

---

## Troubleshooting

| Symptom | Likely Cause | Resolution |
|---|---|---|
| `Invalid encryption key ... expected a 64-character hex string` | Key in Vault is wrong length or encoding | Re-write correct key to Vault, restart |
| `AES-256-CBC decryption failed — possible key mismatch` | Key rotated but rows still encrypted with old key | Rollback to old key, then migrate properly |
| `CC6.1` status shows `unknown` | Vault unreachable, key fetch failed | Check Vault connectivity, `VAULT_ADDR`, `VAULT_TOKEN` |

---

## Audit Evidence

After rotation, record the following for SOC 2 evidence:

- Date of rotation
- Who performed the rotation (approver + executor)
- Vault audit log entry confirming the key write
- Application log confirming EncryptionService initialised with new key
- `GET /compliance/controls` response showing CC6.1 = passing
