Effective June 4, 2019, Two-Step Login now supports using your security key, or U2F token, with Firefox as well as Chrome. After this date, the first time you log in using your security key, you will be prompted to update the key. Simply click Continue at the prompt. Once the security key registration is updated via Chrome, you can use that key in both Chrome and Firefox. More information is available at Two-Step Login Security Key Update.

Support for Safari on iOS and macOS, and Windows Hello for Windows 10, is expected at some point in the future.

Plus, you can now securely authenticate with Two-Step Login using Touch ID on macOS. You will need a MacBook Pro or MacBook Air with a Touch ID button, and Chrome version 70 or later. For more information, see How to Enroll and Use Touch ID with Duo.