Which small device is used for two-factor authentication and can be attached to a key chain?

Which small device is used for two-factor authentication and can be attached to a key chain?

• A. Key fob
• B. Smartcard
• C. USB Token
• D. Security Badge

Answer: (A)

Two-factor authentication relies on proving you have something physical in addition to something you know. A key fob fits perfectly as the portable, attachable device that provides the “something you have” factor. It’s small enough to clip to a key chain and often generates a one-time password or responds to a prompt, giving you a fresh credential each time you log in. The other options serve different purposes: a smartcard is a card used with a reader to authenticate, a USB token is a USB device you must insert into a computer, and a security badge is mainly for building or room access rather than a digital 2FA login.

Two-factor authentication relies on proving you have something physical in addition to something you know. A key fob fits perfectly as the portable, attachable device that provides the “something you have” factor. It’s small enough to clip to a key chain and often generates a one-time password or responds to a prompt, giving you a fresh credential each time you log in.

The other options serve different purposes: a smartcard is a card used with a reader to authenticate, a USB token is a USB device you must insert into a computer, and a security badge is mainly for building or room access rather than a digital 2FA login.