Google extends two-factor authentication with physical USB keys

Google is letting users protect their accounts against password compromises by adding support for two-factor authentication based on physical USB keys.

The new feature expands the company's 2-Step Verification mechanism that is already available for Google accounts, and requires users to input one-time-use codes received via text message or generated with a mobile app when they log in from a new device.

"Today we're adding even stronger protection for particularly security-sensitive individuals," said Nishit Shah, a Google Security product manager, in a blog post. "Security Key is a physical USB second factor that only works after verifying the login site is truly a Google website, not a fake site pretending to be Google."

The Security Key, which is what the special USB devices are called, only works with Chrome version 38 or newer for now. Starting with this version, the browser has built-in support for an open protocol called Universal 2nd Factor (U2F) that was developed by the FIDO Alliance, a multivendor association focused on developing authentication protocols that reduce reliance on passwords.

The good news is that since the protocol is supported by Chrome, other websites besides Google can use it to provide stronger authentication options to their users.

"As more sites and browsers come onboard, security-sensitive users can carry a single Security Key that works everywhere FIDO U2F is supported," Shah said.

The Security Key does more than authenticate the user; it also uses cryptography to ensure that the site a person is trying to use it on is actually the real website and not a phishing page.

Two-factor authentication based on one-time-use codes is stronger than simple password-based authentication, but is still susceptible to phishing attacks. Users can be tricked into inputting both their passwords and their temporary second factor codes on a fake site, allowing attackers to bypass this protection.

Users who want to start using the new authentication method will need to buy a Security Key device from one of the vendors producing them. They're available to order from Amazon.com and possibly other shopping sites and they should have a "FIDO U2F Ready" logo on them.