Dropbox today announced that it has started to allow users to log in using USB keys as a universal second factor (U2F) of authentication.

U2F, a protocol promoted by the FIDO Alliance, isn’t the most trendy form of secure authentication for consumer web services. What’s far more common is two-factor authentication that you can sign on with by entering a code that’s sent to your phone. Dropbox already allows its users to do that, but now it’s gone further.

“After typing in your password, just insert your key into a USB port when you’re prompted, instead of typing in a six-digit code,” Dropbox’s Patrick Heim and Jay Patel wrote in a blog post today. “And unlike two-step with a phone, you’ll never have to worry about your battery going dead when you use a security key.”

Dropbox has been looking to pick up more deals with large companies, and security methods that enterprises can trust should help Dropbox keep growing. Currently Dropbox says 100,000 companies are using Dropbox for business, but it’s facing competition from companies that can provision great amounts of storage gear quickly, including Google and Microsoft.

Indeed, last year Google introduced support for USB security keys for U2F and was giving out such keys from the company Yubico (which is also partnering with Dropbox) at the Google I/O developer conference in San Francisco. Meanwhile, Microsoft has been developing new ways to authenticate users, namely with Windows Hello and Microsoft Passport.

Yubico itself has a blog post on the Dropbox news here.