U2F security keys are physical devices that strengthen two-factor authentication by requiring a verified key press during login. Unlike codes sent by text message, they help protect accounts from phishing, SIM-swapping, and stolen passwords.
Compatible with many online services, U2F security keys provide a convenient, privacy-focused layer of protection for email, banking, cloud storage, and other consumer technology accounts.
U2F security keys are physical devices used for two-factor authentication. They provide an additional sign-in factor after a password, helping protect online accounts from unauthorized access caused by stolen or reused credentials.
A key connects through USB, while some models support NFC or Bluetooth. During registration, it creates a unique cryptographic credential for a specific website or service. The private key remains stored on the device.
When signing in, the user enters a password and activates the key by touching it or following the device’s instructions. The service verifies a digitally signed response without receiving the private key.
U2F was developed by the FIDO Alliance and is designed to resist phishing because credentials are bound to the legitimate website’s domain. Compatibility depends on the account provider, browser, operating system, and security-key model.