Google has several options for intelligently locking your home screen already, including trusted places or devices. Now, it’s adding a new option: trusted voice. If you say “Ok, Google”, your phone can unlock, but someone else’s voice won’t unlock it.
Source Lifehacker http://feeds.gawker.com/~r/lifehacker/full/~3/an33X9LKuHo/google-starts-rolling-out-trusted-voice-smart-lock-opti-1697437287
