What is Two-Factor Authentication (2FA)?
Two-Factor Authentication (2FA) is a security method that requires two different forms of identification to access an account:
- Something you know - Your password
- Something you have - Your phone or authenticator app
This adds an extra layer of security, making it much harder for attackers to gain access to your accounts even if they have your password.
Types of 2FA Methods
| Method | Security Level | Pros | Cons |
|---|---|---|---|
| TOTP Apps (Google Authenticator, Authy) |
High | ✓ Works offline ✓ Very secure ✓ No SIM swapping risk |
✗ Can lose device ✗ Setup complexity |
| SMS Codes | Medium | ✓ Easy to use ✓ No app required |
✗ SIM swapping attacks ✗ Network dependency |
| Hardware Keys (YubiKey, Titan) |
Very High | ✓ Phishing resistant ✓ Very secure ✓ No battery needed |
✗ Can lose key ✗ Additional cost |
| Email Codes | Low | ✓ Easy to use ✓ Always accessible |
✗ Email can be compromised ✗ Not truly 2FA |
TOTP (Time-based One-Time Password) Security
TOTP is the most common and secure form of app-based 2FA:
How TOTP Works:
- A shared secret key is established between you and the service
- Your authenticator app uses this key + current time to generate codes
- Codes change every 30 seconds
- The service verifies the code using the same algorithm
Security Benefits:
- Time-limited: Codes expire every 30 seconds
- Offline generation: No internet required
- Cryptographically secure: Uses HMAC-SHA1 algorithm
- Replay attack resistant: Each code can only be used once
Security Best Practices
🔐 Account Security
- Enable 2FA on all important accounts (email, banking, social media)
- Use unique, strong passwords for each account
- Store backup codes in a secure location
- Regularly review account access and permissions
📱 Device Security
- Keep your authenticator app updated
- Use device lock screen protection
- Enable automatic backups for authenticator apps
- Don't screenshot or share your secret keys
🔄 Recovery Planning
- Save backup codes when setting up 2FA
- Set up multiple 2FA methods when possible
- Keep recovery information updated
- Test your recovery process periodically
Common Security Threats
⚠️ Phishing Attacks
Threat: Fake websites that steal your credentials and 2FA codes
Protection: Always check URLs, use bookmarks, enable hardware keys when possible
⚠️ SIM Swapping
Threat: Attackers transfer your phone number to their device
Protection: Use app-based 2FA instead of SMS, add carrier security PIN
⚠️ Malware
Threat: Malicious software that steals credentials or intercepts codes
Protection: Keep devices updated, use antivirus, avoid suspicious downloads
⚠️ Social Engineering
Threat: Attackers trick you into revealing information or disabling 2FA
Protection: Never share codes, verify requests through official channels