In an effort to increase the adoption of FIDO U2F second factor authentication, we’re releasing Soft U2F—a software-based U2F authenticator for macOS.

Soft U2F currently works with Google Chrome and Opera’s built-in U2F implementations, as well as with the U2F extensions for Safari and Firefox.

When a site loaded in a U2F-compatible browser attempts to register or authenticate with the software token, you’ll see a notification asking you to accept or reject the request. You can experiment on Yubico’s U2F demo site:

U2F authentication with Soft U2F

And as of today, you can download the Soft U2F installer and configure it for use with your GitHub account.

Interested in learning more? Head over to our Engineering Blog and read more about the motivations for the project plus the security considerations of hardware vs. software key storage.