2FA (Two-Factor Authentication)
2FA stands for Two-Factor Authentication. It adds an extra check when you log in, in addition to your password.
What is 2FA?
With 2FA, you confirm in two different ways that you're allowed to access an account. For example, you use a password only you know and a unique code from an authenticator app on your phone.
You usually enter your password first. Then the service asks for a temporary code, a confirmation on your phone, or a physical security key. An authenticator app can generate codes like these without an internet connection.
Two PINs don't count as 2FA. You know both of them, so they represent only one type of proof. For 2FA, you always need two different types of proof.
An example of 2FA
You log in to a crypto exchange with your password. Then the exchange asks for the code from your authenticator app.
Someone who has stolen only your password normally can't log in. They also need your phone or another linked security method.
Why is 2FA important in crypto?
Crypto exchanges and other crypto services use 2FA to better protect accounts that contain crypto and personal information. Some services also ask for a second check when you make a withdrawal or change your security settings.
That's why 2FA often comes up in discussions about account takeovers, phishing, and SIM swapping. With SIM swapping, an attacker takes control of your phone number. This makes SMS codes more vulnerable than some other methods. A physical FIDO security key is more resistant to phishing than codes you have to type in.
2FA doesn't make an account invulnerable. Phishing can intercept temporary codes, and a stolen logged-in session can bypass the check. Also, a service's 2FA doesn't automatically protect the private key or recovery phrase for a self-custody crypto wallet.
