# Edge-Net Relay Security Quick Reference

**Last Updated**: 2026-01-03
**Component**: WebSocket Relay Server (`/relay/index.js`)
**Security Status**: ✅ SECURE (development) | ⚠️ NEEDS SIGNATURES (production)

---

## 🔒 Security Features Summary

| Feature | Status | Implementation |
|---------|--------|----------------|
| Task Assignment Verification | ✅ **SECURE** | Tracked in `assignedTasks` Map |
| Replay Attack Prevention | ✅ **SECURE** | `completedTasks` Set with pre-credit marking |
| Credit Self-Reporting Block | ✅ **SECURE** | `ledger_update` rejected, relay-only crediting |
| QDAG Ledger (Firestore) | ✅ **SECURE** | Server-side source of truth |
| Rate Limiting | ✅ **IMPLEMENTED** | 100 msg/min per node |
| Message Size Limits | ✅ **IMPLEMENTED** | 64KB max payload |
| Connection Limits | ✅ **IMPLEMENTED** | 5 per IP |
| Origin Validation | ✅ **IMPLEMENTED** | CORS whitelist |
| Signature Verification | ❌ **NOT IMPLEMENTED** | Placeholder only |

---

## 🎯 Attack Vector Status

### ✅ **PROTECTED**

1. **Task Completion Spoofing**
   - Nodes cannot complete tasks not assigned to them
   - Verified via `assignment.assignedTo === nodeId`

2. **Replay Attacks**
   - Tasks cannot be completed twice
   - `completedTasks` Set prevents duplicates

3. **Credit Self-Reporting**
   - Clients cannot claim their own credits
   - `ledger_update` messages rejected

### ⚠️ **PARTIALLY PROTECTED**

4. **Public Key Spoofing**
   - ✅ Cannot steal credits (assigned at task time)
   - ⚠️ Can check another user's balance (read-only spoofing)
   - ❌ No cryptographic proof of key ownership

---

## 🚨 Critical Issues for Production

### 1. Missing Signature Verification (CRITICAL)

**Current Code** (Lines 281-286):
```javascript
function validateSignature(nodeId, message, signature, publicKey) {
  // TODO: In production, verify Ed25519 signature from PiKey
  return nodes.has(nodeId); // Placeholder
}
```

**Required Fix**:
```javascript
import { verify } from '@noble/ed25519';

async function validateSignature(message, signature, publicKey) {
  try {
    const msgHash = createHash('sha256').update(JSON.stringify(message)).digest();
    return await verify(signature, msgHash, publicKey);
  } catch {
    return false;
  }
}

// Require on sensitive operations
case 'task_complete':
  if (!message.signature || !await validateSignature(message, message.signature, ws.publicKey)) {
    ws.send(JSON.stringify({ type: 'error', message: 'Invalid signature' }));
    break;
  }
```

**Priority**: 🔴 **CRITICAL** - Must implement before production

### 2. Unbounded Memory Growth (MEDIUM)

**Issue**: `completedTasks` Set grows forever

**Fix**:
```javascript
// Add timestamp tracking
const completedTasks = new Map(); // taskId -> timestamp

// Cleanup old completed tasks
setInterval(() => {
  const CLEANUP_AGE = 24 * 60 * 60 * 1000; // 24 hours
  const cutoff = Date.now() - CLEANUP_AGE;
  for (const [taskId, timestamp] of completedTasks) {
    if (timestamp < cutoff) {
      completedTasks.delete(taskId);
    }
  }
}, 60 * 60 * 1000); // Every hour
```

**Priority**: 🟡 **MEDIUM** - Implement before long-running deployment

---

## 🧪 Security Test Suite

### Running Tests

```bash
cd /workspaces/ruvector/examples/edge-net/tests
npm install
npm test
```

### Test Coverage

- ✅ Task completion spoofing (2 tests)
- ✅ Replay attacks (1 test)
- ✅ Credit self-reporting (2 tests)
- ✅ Public key spoofing (2 tests)
- ✅ Rate limiting (1 test)
- ✅ Message size limits (1 test)
- ✅ Connection limits (1 test)
- ✅ Combined attack scenario (1 test)

**Total**: 12 security tests in `relay-security.test.ts`

---

## 📋 Security Checklist

### Before Development Deployment

- [x] Task assignment tracking
- [x] Replay attack prevention
- [x] Credit self-reporting blocked
- [x] QDAG Firestore ledger
- [x] Rate limiting
- [x] Message size limits
- [x] Connection limits
- [x] Origin validation
- [x] Security test suite

### Before Production Deployment

- [ ] **Ed25519 signature verification** (CRITICAL)
- [ ] **Challenge-response on registration** (CRITICAL)
- [ ] Completed tasks cleanup (MEDIUM)
- [ ] Global connection limit (MEDIUM)
- [ ] API key for non-browser clients (MEDIUM)
- [ ] Rate-limit balance queries (LOW)
- [ ] Generic error messages (LOW)
- [ ] Firestore security rules validation (LOW)

---

## 🔍 Code Review Findings

### Security Strengths

1. **QDAG Architecture** - Excellent design
   - Firestore as single source of truth
   - Credits keyed by public key (identity-based)
   - Server-side only credit increases
   - Persistent across sessions

2. **Task Assignment Security** - Well implemented
   - Assignment tracked with metadata
   - Node ID verification on completion
   - Public key stored at assignment time
   - Task expiration (5 minutes)

3. **Defense in Depth** - Multiple layers
   - Origin validation (CORS)
   - Connection limits (per IP)
   - Rate limiting (per node)
   - Message size limits
   - Heartbeat timeout

### Security Weaknesses

1. **No Cryptographic Verification** - Major gap
   - Public key ownership not proven
   - Allows read-only spoofing
   - Required for production

2. **Memory Leaks** - Minor issues
   - `completedTasks` grows unbounded
   - Easy to fix with periodic cleanup

3. **Distributed Attacks** - Missing protections
   - No global connection limit
   - Vulnerable to distributed DoS
   - Can be mitigated with cloud-level protections

---

## 🛡️ Security Best Practices

### For Developers

1. **Never trust client input**
   - All credits server-generated
   - Task assignments server-controlled
   - Ledger state from Firestore only

2. **Validate everything**
   - Check task assignment before crediting
   - Verify node registration before operations
   - Rate-limit all message types

3. **Defense in depth**
   - Multiple security layers
   - Fail securely (default deny)
   - Log security events

### For Operations

1. **Monitor security metrics**
   - Failed authentication attempts
   - Rate limit violations
   - Connection flooding
   - Unusual credit patterns

2. **Configure Firestore security**
   - Validate security rules
   - Restrict ledger write access
   - Enable audit logging

3. **Network security**
   - Use TLS/WSS in production
   - Configure firewall rules
   - Enable DDoS protection

---

## 📊 Security Metrics

### Current Implementation

| Metric | Value | Status |
|--------|-------|--------|
| Authentication | Public key (unverified) | ⚠️ Development only |
| Authorization | Task assignment tracking | ✅ Secure |
| Credit System | Firestore QDAG | ✅ Secure |
| Rate Limiting | 100 msg/min | ✅ Good |
| Max Message Size | 64KB | ✅ Good |
| Connections per IP | 5 | ✅ Good |
| Connection Timeout | 30s | ✅ Good |
| Task Expiration | 5 min | ✅ Good |

### Recommended Production Values

| Metric | Development | Production |
|--------|-------------|------------|
| Authentication | Public key | Ed25519 signature |
| Rate Limit | 100 msg/min | 50 msg/min + adaptive |
| Max Connections | 5 per IP | 3 per IP + global limit |
| Task Timeout | 5 min | 2 min |
| Completed Tasks TTL | None | 24 hours |

---

## 📚 Related Documentation

- **Full Audit Report**: `/docs/SECURITY_AUDIT_REPORT.md`
- **Test Suite**: `/tests/relay-security.test.ts`
- **Test README**: `/tests/README.md`
- **Relay Source**: `/relay/index.js`

---

## 🆘 Security Incident Response

### If you suspect an attack:

1. **Check relay logs** for suspicious patterns
2. **Query Firestore** for unexpected credit increases
3. **Review rate limit logs** for flooding attempts
4. **Audit task completions** for spoofing attempts
5. **Contact security team** if confirmed breach

### Emergency shutdown:

```bash
# Stop relay server
pkill -f "node.*relay/index.js"

# Or send SIGTERM for graceful shutdown
kill -TERM $(pgrep -f "node.*relay/index.js")
```

---

**Security Contact**: [Your security team contact]
**Last Security Audit**: 2026-01-03
**Next Scheduled Audit**: After signature verification implementation