# Security

Security configuration for AgentIdP — JWT key management, CORS, and secret storage.

---

## JWT Key Management

AgentIdP uses RS256 (RSA + SHA-256) to sign and verify JWT access tokens. This asymmetric scheme means:

- The **private key** signs tokens — must be kept secret, known only to the server
- The **public key** verifies tokens — can be shared with any system that needs to validate tokens

### Generate a keypair

Generate a 2048-bit RSA keypair:

```bash
# Generate private key
openssl genrsa -out private.pem 2048

# Extract public key
openssl rsa -in private.pem -pubout -out public.pem
```

Verify the files:

```bash
# Confirm private key is valid RSA
openssl rsa -in private.pem -check -noout
# Expected: RSA key ok

# Confirm public key is readable
openssl rsa -in public.pem -pubin -noout -text | head -5
```

### Load keys into environment

**Option 1 — Inline in `.env` (development only)**

Encode newlines as `\n` and wrap in double quotes:

```bash
echo "JWT_PRIVATE_KEY=\"$(awk 'NF {sub(/\r/, ""); printf "%s\\n",$0;}' private.pem)\"" >> .env
echo "JWT_PUBLIC_KEY=\"$(awk 'NF {sub(/\r/, ""); printf "%s\\n",$0;}' public.pem)\"" >> .env
```

**Option 2 — Load from file at runtime (recommended for production)**

In the startup script, read the key files and export as environment variables before running the server:

```bash
export JWT_PRIVATE_KEY="$(cat /run/secrets/jwt-private.pem)"
export JWT_PUBLIC_KEY="$(cat /run/secrets/jwt-public.pem)"
npm start
```

With Docker secrets or a secrets manager (Vault, AWS Secrets Manager), mount the key as a file and read it this way.

### Key rotation

Rotating the JWT keys invalidates all currently active tokens — every authenticated request will fail until clients re-authenticate. Plan rotation for low-traffic windows.

**Rotation procedure:**

1. Generate a new RSA keypair:
   ```bash
   openssl genrsa -out private-new.pem 2048
   openssl rsa -in private-new.pem -pubout -out public-new.pem
   ```

2. Update `JWT_PRIVATE_KEY` and `JWT_PUBLIC_KEY` in your environment or secrets store.

3. Restart the application:
   ```bash
   # Graceful restart — send SIGTERM, let in-flight requests complete, then start with new keys
   kill -SIGTERM <pid>
   npm start   # or docker restart <container>
   ```

4. All previously issued tokens are now invalid (wrong signature). Clients will receive `401 UNAUTHORIZED` and must call `POST /token` again with their `client_id` and `client_secret` to get a new token.

5. Remove the old key files:
   ```bash
   rm private-old.pem public-old.pem
   ```

**Important:** There is no grace period or dual-key support in Phase 1. All tokens issued with the old private key are immediately rejected after rotation. If zero-downtime key rotation is required, it is a Phase 2 feature.

---

## CORS Configuration

Cross-Origin Resource Sharing is configured via the `CORS_ORIGIN` environment variable.

| Value | Behaviour |
|-------|-----------|
| `*` (default) | All origins permitted — appropriate for a public API |
| `https://app.example.ai` | Only the specified origin permitted |

Set in `.env`:

```
CORS_ORIGIN=https://app.example.ai
```

The CORS header is set by the `cors` middleware applied globally in `src/app.ts`. Credentials (cookies) are not used — all auth is Bearer token.

For production deployments where the API is only called server-to-server (agent to AgentIdP), setting `CORS_ORIGIN` to a specific origin or removing browser-facing CORS entirely is recommended.

---

## Client Secret Storage

Client secrets are **never stored in plaintext**. The flow:

1. On credential generation or rotation, AgentIdP generates a random secret string (`sk_live_...`)
2. The plaintext is returned to the caller **once only** in the API response
3. AgentIdP immediately hashes the secret with **bcrypt** (cost factor from `bcryptjs` defaults) and stores only the hash in the `credentials.secret_hash` column
4. On every `POST /token` call, the provided `client_secret` is verified against the stored hash using `bcrypt.compare()`

**Implication:** If a client loses their `client_secret`, it cannot be recovered. They must rotate the credential to get a new one.

---

## Secret Storage Guidance

| Environment | Recommendation |
|-------------|---------------|
| Local development | `.env` file, not committed to git |
| CI/CD | Environment variables injected by the CI platform (GitHub Actions secrets, GitLab CI variables, etc.) |
| Production (Docker) | Docker secrets or bind-mounted files from a secrets manager |
| Production (cloud) | AWS Secrets Manager, GCP Secret Manager, HashiCorp Vault (Phase 2) |

**Never:**
- Commit `.env` to version control
- Log environment variables
- Pass secrets as command-line arguments (visible in `ps aux`)
- Store keys in the database

Add `.env` to `.gitignore`:

```bash
echo ".env" >> .gitignore
echo "*.pem" >> .gitignore
```

---

## Token Lifetime

JWT access tokens expire after **3600 seconds (1 hour)**. This is hardcoded in `src/utils/jwt.ts`. There is no refresh token — clients must re-authenticate via `POST /token` when the token expires.

The 1-hour lifetime is a balance between security (short-lived tokens limit exposure if stolen) and operational load (clients don't need to authenticate every few minutes).