Two-factor authentication adds another layer of security protection to a user's account. Take your email account for example. What's normally required for you to log in are your username and password. That is called a single-factor authentication. A second-factor authentication or 2FA requires the user to provide two out of the types of verification.

These three types are:

• Something you know, such as your password, PIN, or a pattern
• Something you have, including ATM cards, fob or phone
• Something you are, like your fingerprint, voice, or biometric.