Password is the first line of defense, but it’s not enough. Database breaches, phishing, brute force - passwords get stolen constantly. Two-factor authentication adds a second barrier that’s much harder to overcome.
What Is 2FA
Principle
Two-factor authentication requires confirmation through two different methods:
- Something you know: password, PIN
- Something you have: phone, hardware key
- Something you are: fingerprint, face
2FA combines at least two of three factors.
Why It Matters
| Password only | Password + 2FA |
|---|---|
| Stolen password = access | Stolen password ≠ access |
| Phishing works | Phishing is harder |
| Brute force possible | Brute force useless |
Statistics: 2FA blocks 99.9% of automated attacks and most targeted ones.
2FA Methods
SMS Codes
How it works: When logging in, an SMS with a code arrives on your phone.
Pros:
- Easy to set up
- No apps needed
- Works on any phone
Cons:
- SIM-swap attacks
- SMS interception (SS7 vulnerabilities)
- No signal = no code
- Code can be observed
Recommendation: Better than nothing, but use only if no other options.
TOTP Apps
How it works: App generates a 6-digit code every 30 seconds based on secret key and time.
Popular apps:
| App | Cloud backup | Platforms |
|---|---|---|
| Google Authenticator | Yes (Google) | iOS, Android |
| Authy | Yes (own) | iOS, Android, Desktop |
| Microsoft Authenticator | Yes (Microsoft) | iOS, Android |
| 2FAS | Yes (optional) | iOS, Android |
| Aegis | No (local) | Android |
Pros:
- Works offline
- Can’t be intercepted over network
- Free
Cons:
- Lost phone = problems (without backup)
- Need to enter code manually
- Vulnerable to phishing (can enter on fake site)
Recommendation: Good balance of security and convenience for most.
Push Notifications
How it works: When logging in, notification arrives: “Is this you?” - tap Yes or No.
Examples: Google Prompt, Microsoft Authenticator, Duo.
Pros:
- Convenient - one tap
- Shows login info (device, location)
- Harder to phish
Cons:
- Needs internet
- Notification fatigue → might tap Yes automatically
- Ecosystem lock-in
Recommendation: Good option if you don’t auto-approve carelessly.
Hardware Keys (FIDO2/WebAuthn)
How it works: Physical device (USB/NFC) confirms login cryptographically.
Popular keys:
| Key | Interface | Price |
|---|---|---|
| YubiKey 5 | USB-A/C, NFC | ~$50 |
| YubiKey Security Key | USB-A/C, NFC | ~$25 |
| Google Titan | USB-A/C, NFC | ~$30 |
| Feitian | USB-A/C, NFC | ~$20 |
Pros:
- Impossible to phish (key verifies domain)
- Works offline
- No battery, doesn’t break
- Most secure method
Cons:
- Need to buy (better 2 - backup)
- Physical loss
- Not all services support
Recommendation: Best choice for critical accounts (email, finances).
Passkeys
How it works: Device biometrics (Face ID, Touch ID, Windows Hello) replaces both password and second factor.
Where it works: Google, Apple, Microsoft, GitHub, many others.
Pros:
- No password = nothing to steal
- Phishing impossible
- Very convenient
- Syncs between devices
Cons:
- New technology, not everywhere
- Ecosystem lock-in (Apple/Google/Microsoft)
- Need modern devices
Recommendation: Future of authentication. Enable everywhere available.
Method Comparison
| Method | Security | Convenience | Phishing protection | Recommendation |
|---|---|---|---|---|
| SMS | ★★☆☆☆ | ★★★★★ | ★☆☆☆☆ | Last resort |
| TOTP | ★★★★☆ | ★★★★☆ | ★★☆☆☆ | Main method |
| Push | ★★★★☆ | ★★★★★ | ★★★☆☆ | Good option |
| Keys | ★★★★★ | ★★★☆☆ | ★★★★★ | For critical |
| Passkeys | ★★★★★ | ★★★★★ | ★★★★★ | Wherever available |
Where to Enable 2FA First
Critically Important
- Primary email: other accounts recovered through it
- Password manager: access to all passwords
- Banks and finances: money
- Work accounts: company data
Very Important
- Social media: reputation, personal data
- Cloud storage: documents, photos
- Messengers: conversations
- Crypto exchanges: cryptocurrency
Recommended
- Stores with saved cards
- Gaming accounts
- Forums and services with personal data
Setting Up TOTP
- Google Account → Security
- 2-Step Verification → Get started
- Authenticator app → Set up
- Scan QR code with app
- Enter code to confirm
Apple ID
- Settings → [Your Name] → Sign-In & Security
- Two-Factor Authentication → Turn On
- Apple uses its own system (not TOTP)
Microsoft
- account.microsoft.com → Security
- Advanced security options
- Two-step verification → Set up
- Authenticator app
GitHub
- Settings → Password and authentication
- Two-factor authentication → Enable
- Set up using an app
- Scan QR code
Recovery Codes
What They Are
One-time codes for login when primary method unavailable (lost phone).
How to Store
Correct:
- Password manager
- Encrypted file
- Paper in safe
Incorrect:
- Screenshot in gallery
- Note on phone
- Email to yourself
Important
- Generate new ones after use
- Store in multiple places
- Verify relevance yearly
What to Do If Device Lost
If You Have Recovery Codes
- Log in with recovery code
- Remove old device
- Set up 2FA again
If No Recovery Codes
- Use service’s recovery procedure
- Verify identity (documents, linked email)
- Wait (can take days)
How to Avoid Problems
- Always save recovery codes
- Set up multiple 2FA methods
- Keep backup hardware key
- Authy/Google Authenticator with cloud backup
Attacks on 2FA
SIM-swap
Fraudster reissues your SIM to their phone.
Protection:
- Don’t use SMS for 2FA
- PIN on SIM with carrier
- Don’t publish phone number
Real-time Phishing
Fake site requests code and uses immediately.
Protection:
- Hardware keys (verify domain)
- Passkeys
- Check URL before entering
Push Fatigue (MFA fatigue)
Multiple notifications → victim taps Yes to stop.
Protection:
- Number matching (enter number from screen)
- Don’t approve unexpected requests
- Report suspicious activity
Social Engineering
“Support” asks for your code.
Protection:
- Never share codes with anyone
- Real support doesn’t ask for codes
2FA Implementation Checklist
Preparation
- Choose TOTP app
- Install on phone
- Consider buying hardware key
Critical Accounts
- Primary email
- Password manager
- Banks
After Setup
- Save recovery codes
- Test login with 2FA
- Set up backup method
Regularly
- Check recovery codes relevance
- Remove old devices from accounts
- Enable 2FA on new services
Summary
2FA is mandatory minimum security in 2026. Start with TOTP app for all important accounts. For critical ones (email, finances) add hardware key. Enable passkeys wherever available.
Spend an hour today - protect accounts for years ahead.
Tainet protects your connection, but account security is your responsibility. 2FA and VPN together provide full protection.
