Two-Factor Authentication (2FA): A Complete Guide

Two-factor authentication stops most account takeovers, even when your password leaks. Here is how each method compares and how to set it up safely.

What is two-factor authentication?

Two-factor authentication (2FA) asks for two different kinds of proof when you sign in: something you know (your password) and something you have or are (your phone, a security key, your fingerprint). A stolen password alone is no longer enough.

2FA methods, from strongest to weakest

MethodHow it worksPhishing-resistant
Hardware security keyA USB/NFC key (e.g. YubiKey) signs a challengeYes
Passkey / biometricsFace ID, Touch ID or Windows Hello unlocks a device keyYes
Authenticator app (TOTP)A 6-digit code that changes every 30 secondsPartly
Push notificationApprove a prompt on your phonePartly (beware “prompt bombing”)
SMS codeA code sent by text messageNo (SIM swapping)

Any 2FA is far better than none. Where you can, prefer passkeys or security keys; otherwise use an authenticator app.

Which accounts need 2FA first?

  1. Your email — it can reset every other password.
  2. Your password manager — it holds the keys to everything else.
  3. Banking and payments.
  4. Your phone’s cloud account (Apple ID, Google account).
  5. Social media and work accounts.

How to set up an authenticator app

  1. Install an authenticator app on your phone.
  2. In the website’s security settings, choose “Authenticator app”.
  3. Scan the QR code shown on screen.
  4. Type the 6-digit code to confirm.
  5. Save the recovery codes somewhere safe — a password manager note is ideal.

Don’t lock yourself out

Real-time phishing: why codes are not enough

Modern phishing kits sit between you and the real site, forwarding your password and your 6-digit code instantly. Passkeys and security keys defeat this because they check the website’s real domain. A password manager helps too: it will not offer to fill your password on a fake domain — a strong hint something is wrong.

2FA in Lockvero

Lockvero supports passkeys and hardware keys (WebAuthn) and authenticator apps (TOTP) for your account, emails you about new sign-ins and 2FA changes, and lets you sign out any device remotely. See all features.

Put it into practice

Lockvero keeps every password strong, unique and encrypted on your device. Free forever plan.

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