Google has acquired SlickLogin, an Israeli security startup that uses smartphones and high-frequency sounds for identity verification on Web sites.

SlickLogin's three-person team revealed the acquisition in an announcement posted to the company's Web site.

"Today we're announcing that the SlickLogin team is joining Google, a company that shares our core beliefs that logging in should be easy instead of frustrating, and authentication should be effective without getting in the way," the announcement reads.

Terms of the deal were not revealed, but the acqui-hire is said to be valued at "several million," according to Geektime, which first reported the deal.

The early stage company, which has not released a commercial product, develops technology that allows Web sites to generate nearly silent tones through a user's computer speakers as a verification replacement for passwords. An app on the user's nearby smartphone picks up the unique audio signal, analyzes it, and sends it back to the site's servers for login.

The technology could be used as a replacement for the traditional password or as part of a two-factor authentication, which is intended to reduce users' vulnerability to online identity theft, phishing, and other scams by adding a second level of identity verification to an account login.

The three-person company joins a handful of Israel-based companies that Google has acquired in recent years, including the spreadsheet company iRows in 2006, entertainment company LabPixies in 2010, and the $1.3 billion purchase of mapping service Waze last year.