Two-Factor Authentication

Definitions

1. An authentication scheme requiring two distinct forms of verification — typically something you know (password) and something you have (phone, hardware key) — before granting access.

   In plain English: Logging in with both a password AND a second proof of identity, like a code texted to your phone, so that stealing just the password isn't enough.

   Example: "If your only argument against 2FA is that it's inconvenient, wait until you experience an account takeover."

Etymology

1986

RSA Security introduces the SecurID token, one of the first commercial two-factor authentication devices

2000s

Banks begin requiring 2FA for online banking, typically via SMS codes

2011

Google launches Google Authenticator, popularizing TOTP-based 2FA for consumer accounts

2018

Security researchers demonstrate SIM-swapping attacks, pushing the industry toward hardware keys and app-based 2FA over SMS

Related Terms

• Brute Force
• Credential Stuffing
• JWT
• TOTP
• OAuth
• Multi-Factor Authentication
• Time-Based One-Time Password
• Brute Force Protection
• Hardware Key
• Login Attempt
• One-Time Password
• Physical Token
• Remote Access