California law requires that all smartphones made beginning next July include a "kill switch" that allows them to be disabled when stolen, and Google has just built one into Android. Recode reports that Android Lollipop includes a feature called "Factory Reset Protection," which can make a phone require that a password is entered before it's reset. When combined with the ability to remotely lock your phone, which Google introduced last year, it appears that Android devices now have a full "kill switch" that can make a phone useless when stolen and then bring it back to life should it be recovered.

"We applaud Google for including a ‘kill switch’ solution."

"We applaud Google for including a ‘kill switch’ solution in its new version of Android, one of the most popular smartphone operating systems in the world," San Francisco district attorney George Gascón and New York attorney general Eric Schneiderman say in a statement. "The majority of smartphone owners now have access to a theft-deterrent solution." That said, Gascón and Schneiderman says that there's still work to be done, as they want to see all smartphones enable this solution by default "so violent criminals lack the incentive to steal any smartphone."

The kill switch could come to make a big difference for owners of Android smartphones: since Apple added various theft protections to iOS, Gascón and Schneiderman say that they've seen thefts of iPhones plummet. On top of all of that, Android Lollipop also encrypts user data by default, which adds another major layer of security. Of course, Android users will have to actually update to Lollipop — which could take a while — so the results may not be so widespread and immediate. Microsoft is also preparing a kill switch for Windows Phones.