U2F (Universal 2nd Factor) Definition

KZero Staff
Oct 19, 2023

U2F, or Universal 2nd Factor, is a security standard that adds an extra layer of authentication to online accounts and services. It’s designed to enhance security beyond traditional usernames and passwords by requiring the use of physical hardware tokens or devices.

Key Terms Associated with U2F

  • Physical Tokens: U2F relies on physical tokens, such as USB security keys or hardware tokens, to verify a user’s identity. These tokens are something the user possesses – and are something a hacker cannot possess.
  • Two-Factor Authentication: U2F is a form of two-factor authentication (2FA). To access an account, users must provide something they know (e.g., a password) and something they have (the physical U2F token).

The Power of U2F

There are numerous advantages to implementing a U2F-based authentication system for your organization.

  • Phishing Resistance: U2F is highly resistant to phishing attacks. Even if an attacker steals a user’s password, they cannot access the account without the physical U2F token.
  • Better Security: The use of hardware tokens ensures robust security, as these tokens are challenging for attackers to compromise remotely.


U2F is gaining popularity as a secure authentication method for online accounts and services, including email providers, social media platforms, and large organizations. It offers an additional layer of protection against unauthorized access and is user-friendly, as it doesn’t require users to remember complex passwords.

KZero Staff

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