What Is MFA (Multi-Factor Authentication)?
MFA (Multi-Factor Authentication) — authentication requiring two or more independent proofs of identity — something you know (password), something you have (phone/token), or something you are (fingerprint).
How it works
A password alone fails the moment it's stolen or guessed. MFA adds a second, independent factor — typically a one-time code from an app or SMS, a hardware key, or a biometric. An attacker with your password still can't log in without also possessing your phone or fingerprint.
Why it matters
MFA is the single most effective control against account takeover — it defeats credential stuffing, most phishing, and password leaks. Every security framework mandates it, and "why is MFA important?" is a standard security interview question.
Frequently asked questions
What are the three factors in MFA?
Something you know (password/PIN), something you have (phone, hardware token), and something you are (fingerprint, face) — MFA combines at least two different types.
Is SMS-based MFA secure?
Better than no MFA, but weaker than app-based codes or hardware keys — SMS can be intercepted via SIM-swapping attacks. Authenticator apps are the recommended baseline.
Does MFA stop phishing?
It blocks most phishing (a stolen password alone is useless), though sophisticated real-time phishing can relay codes — hardware security keys resist even that.
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