Security security authentication

What is Multi-Factor Authentication (MFA)?

Definition

MFA requires two or more independent verification factors to authenticate a user: something you know (password), something you have (phone, hardware key), or something you are (fingerprint). TOTP codes and hardware keys like YubiKey are common second factors.

Why It Matters

MFA blocks 99.9% of automated attacks according to Microsoft. Even if a password is compromised, the attacker cannot log in without the second factor. All critical accounts (email, cloud, code repositories) should use MFA.

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