2FA requires two independent factors to verify identity (e.g., password + second proof). It is a specific form of multi-factor authentication (MFA).
Core Benefit Enables ~99% reduction in account compromise risk by blocking automated attacks, phishing, and credential stuffing even if the password is stolen.
Security Ranking of Methods (2026 consensus)
Hardware keys / FIDO2 / Passkeys — Phishing-resistant gold standard (NIST-preferred).
TOTP authenticator apps (Google Authenticator, Microsoft Authenticator) — Strong, offline, recommended default.
Push notifications — Convenient but prone to approval fatigue.
SMS / email OTP — Weakest; NIST classifies as “restricted” due to SIM-swap and interception risks.
