Two Step Authentication Essentials

Greatly enhance user security by allowing support for YubiKey two step authentication. Google's two step authentication generates a 6 character code of only integers (1,000,000 possible codes). YubiKey generates a 44 character key containing a 12 character identifier (public key) that does not change, as well as a 33 character unique one time use private key that changes every time you press the OTP button on your YubiKey, this is nearly 5 sexquadragintillion (5 followed by 46 zeroes) possible keys.