Two-factor authentication: why a second step matters

Two-factor authentication requires two different categories of proof, such as something you know, something you have or something you are. A password plus a time-based code is stronger than a password alone because a stolen password is not enough to sign in.

How it works

The security of the second factor matters. Authenticator apps and hardware security keys are generally more resistant to phishing than text messages, although any method is better than a reused password. Recovery codes should be stored offline in a safe place.

Practical takeaways

Start with email, password manager and financial accounts. Add a security key where available, review active sessions and remove old devices. Never approve a login prompt you did not initiate: attackers sometimes use repeated prompts to exhaust attention.

Two-factor authentication reduces account takeover risk, but it does not remove the need for unique passwords and careful recovery settings.

In short: The best second factor is one you will keep enabled and can recover safely without creating a new weak point.