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(also Universal 2nd Factor)

U2F definition

U2F, or Universal 2nd Factor, is an open standard for strengthening two-factor authentication (2FA) using specialized USB or NFC devices. Developed by Google and Yubico, with contribution from NXP Semiconductors, U2F provides an additional layer of security to protect against phishing and man-in-the-middle attacks.

See also: two-factor authentication, one-time password

U2F examples

  • Login security: U2F can be used as an additional security measure when logging into sensitive accounts, such as banking or email.
  • Corporate security: Businesses often use U2F to secure access to critical systems and databases, providing each user with a U2F device.

Advantages and disadvantages of U2F


  • Enhanced security: U2F provides robust protection against common cyberattacks, including phishing and man-in-the-middle attacks.
  • Ease of use: With U2F, there's no need to type in codes from a text or an app – just insert the U2F device into a USB port or bring it close to an NFC reader.


  • Device dependence: Users must have their U2F device with them to authenticate, which could be inconvenient and problematic if lost.
  • Compatibility: Not all websites and services support U2F, limiting its usage.

Using U2F

  • Keep your U2F device secure and in a known location to avoid losing it.
  • Ensure the online services you use support U2F before investing in a U2F device.