• JWT-based authentication with access and refresh tokens
• Password hashing with bcrypt (12 rounds)
• Role-based access control (RBAC)
• Token expiration and refresh mechanism
• Session management with database storage
• Secure password requirements (min 8 characters)
• Rate limiting on authentication endpoints

• Encrypted wallet balances (AES-256-CBC)
• HTTPS-only communication (production)
• SQL injection prevention (parameterized queries)
• XSS prevention (input sanitization)
• CSRF protection (SameSite cookies, CORS)
• Secure headers (Helmet.js)

• HMAC-SHA256 signature validation
• Time-bound expiration (5 minutes default)
• Replay attack prevention (one-time use)
• Redis caching for fast validation
• Database tracking of QR usage

• Atomic transactions (prevents double-spending)
• Row-level locking (FOR UPDATE)
• Double-entry accounting
• Transaction rate limiting (1 per 10 seconds)
• Balance validation before debit
• Idempotent transaction processing

• Rate limiting (standard, auth, QR, transaction)
• Input validation (Zod schemas)
• Error message sanitization
• Request size limits
• CORS configuration
• API versioning

• Immutable audit logs
• Transaction history with before/after balances
• Database triggers for automatic audit logging
• Comprehensive logging (Winston)
• IP address and user agent tracking

• Environment variable protection (.env files)
• Database connection encryption
• Redis authentication
• Regular security updates
• Dependency vulnerability scanning
• Secrets management (use secrets manager in production)

• Security event monitoring
• Anomaly detection
• Automated alerts for suspicious activity
• Incident response plan
• Regular security audits
• Penetration testing

Before deploying to production:

1. Environment Variables

   • Change all default secrets
   • Use strong JWT secrets (32+ characters)
   • Use strong encryption keys (32 characters)
   • Use secrets manager (AWS Secrets Manager, HashiCorp Vault)

2. Database

   • Enable SSL/TLS for database connections
   • Use strong database passwords
   • Restrict database access (firewall rules)
   • Enable database audit logging
   • Regular database backups

3. Redis

   • Enable Redis AUTH
   • Use Redis over TLS
   • Restrict Redis access (firewall rules)

4. API

   • Enable HTTPS only
   • Configure proper CORS origins
   • Set up API gateway/WAF
   • Enable DDoS protection
   • Set up rate limiting at infrastructure level

5. Application

   • Remove debug logging in production
   • Disable stack traces in error responses
   • Set secure cookie flags
   • Enable HSTS headers
   • Set up monitoring and alerting

6. Access Control

   • Implement IP whitelisting for admin endpoints
   • Use MFA for admin accounts
   • Regular access reviews
   • Principle of least privilege

7. Compliance

   • GDPR compliance (if applicable)
   • Data retention policies
   • Privacy policy
   • Terms of service
   • Regular security assessments

1. Never commit secrets: Use environment variables
2. Validate all inputs: Use Zod schemas
3. Use parameterized queries: Prevent SQL injection
4. Sanitize outputs: Prevent XSS
5. Handle errors securely: Don't leak sensitive information

1. Regular updates: Keep dependencies updated
2. Security patches: Apply security patches promptly
3. Backup strategy: Regular encrypted backups
4. Access logs: Monitor access logs regularly
5. Incident response: Have a plan for security incidents

1. Code reviews: All code changes reviewed
2. Security testing: Regular security testing
3. Dependency scanning: Scan for vulnerabilities
4. Static analysis: Use linters and security scanners
5. Secure defaults: Secure by default configuration

1. QR Code Expiration: Currently 5 minutes, adjust based on usage patterns
2. Transaction Rate Limiting: 1 per 10 seconds may need adjustment
3. Session Timeout: Refresh tokens expire in 7 days, consider shorter for sensitive operations
4. Audit Log Retention: Implement retention policy based on compliance requirements
5. Encryption Key Rotation: Plan for key rotation strategy

If you discover a security vulnerability, please report it to:

• Email: security@campussync.edu
• Include: Description, steps to reproduce, potential impact

Do not disclose publicly until the issue is resolved.