The YubiKey, manufactured by Yubico, is a device that acts as a USB keyboard and provides secure authentication by a one-time password that is encrypted using the AES encryption algorithm with a 128-bit key.
To set up your YubiKey, log into thewebconsole and click on settings in the top right of the screen.
Click on your settings on the left tab and there will be a section called YubiKey. Click in the text box next to it.
Now insert your YubiKey into a USB Port in your computer and press the button. This will generate a code unique to your YubiKey.
Click Save Settings and your code will be saved. This must be done for every user's YubiKey.
Click on Security Settings on the left tab and you will see a section which says, "Force User YubiKey Authentication". Set this to Yes and Save Security Settings.
Next time you log into your account a page will appear which will say YubiKey Authentication. Press your YubiKey again and it will generate a code that will be authenticated and allow you access to your account.
