Google has already been pretty great about supporting two-factor authentication. Now, the company is adding another option: authentication with a secure USB key.
The new method will work based on the U2F (or Universal 2nd Factor) protocol. Supported sites and keys can be used in place of the codes you typically receive sent to your phone. Instead, you’ll use a secure USB key (like the Yubikey NEO) to provide the second factor. This is along the same line as the system we’ve shown you how to build with LastPass.
Strengthening 2-Step Verification with Security Key | Google Online Security Blog via Android Police