---
title: "What is two-factor authentication? | Daniel Christensen"
description: "An extra step at login, a code or approval in addition to your password. Stops most account takeovers."
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last_updated: "2026-09-07T12:05:01.946Z"
locale: en
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[← All terms](https://danielchristensen.no/en/glossary)Glossary

# Two-factor authentication (2FA)

An extra step at login, a code or approval in addition to your password. Stops most account takeovers.

Also called: two-step verification, multi-factor authentication, 2FA, MFA

Two-factor authentication means your password alone isn’t enough to log in: you also confirm with something you have, such as a code from an app, an SMS or a physical security key. Even if your password leaks, the attacker is still stuck.

Not all variants are equally strong. SMS codes can be intercepted, so prefer an authenticator app or a security key where possible. But most important of all: turn it on. Two-factor on your email is the simplest security measure with the biggest effect there is.

The difference between the methods is worth knowing. SMS is better than nothing, but the code can be intercepted and can be talked out of you. An app generating one-time codes is a solid step up. Best is a physical key or a passkey, because they check which site you are actually on and refuse to answer a fake copy. That’s the only variant that stops phishing outright.

Start with your email. It’s the master key to everything else you own online, because that’s where “forgot password” goes. Then your bank, social media and your work account. Keep the recovery codes somewhere you can reach without your phone. The most common reason people turn two-factor back off is that they locked themselves out.

See also: [Create a strong password](https://danielchristensen.no/en/tools/password-generator)

Next step

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