What Is Three-Factor Authentication (3FA)?

3FA is one of the most comprehensive forms of multi-factor authentication (MFA). The user is first asked for something they know, such as a password or PIN, then something they have, such as a phone, smart card or hardware key, and finally something they are, such as a fingerprint, face or iris scan. What matters is not the number of factors but that they come from different categories; asking for two separate passwords does not count as 3FA.

This method is used mostly in corporate systems, data centers and environments where high-value assets are managed. In the crypto world, for example, access to a custody company's cold wallets can be protected by requiring a password, a personal access card and biometric confirmation together. This way, an attacker obtaining a single factor is not enough to gain access.

While 3FA increases security, it reduces ease of use, and every additional step adds cost. The fact that biometric data cannot be changed like a password is also a limitation to consider from a privacy standpoint. For this reason, 2FA is generally preferred for individual user accounts.