So my phone (Marshmallow) was locked. I said Ok Google, to search something. It searched directly from the lockscreen and when I tapped home, it actually unlocked the phone.

Is it a security hole or something?

My phone is Moto G4 Plus


3 Answers 3


Trusted voice ("OK Google")

  • Trusted voice

    When you say "Ok Google" from a secure lock screen and we're able to recognize your voice, you can ask Google to do things for you, or visit sites, without manually unlocking your device.

    "OK Google" settings options (How to turn on/off OK Google and its settings (Trusted voice, etc)): Google Support

Source: Google

  • But another answer says that it's not accurate and hence not reliable. Is it so? Sep 9, 2016 at 13:04
  • I think it's quite good to recognize a learned voice but it's not so reliable because not so hard to mimic another person's voice unless if he/she has a very uniqe one. Sep 9, 2016 at 13:06
  • Yeah, anyways that's fine for me as I do not spend time around hackers etc ;). So will keep it turned on. Thanks Sep 9, 2016 at 13:08
  • 8
    @BálintBabics Actually, the research I've seen suggests that even voices that sound very similar appear quite different as a waveform -- giving lots of points to distinguish them via software. A replay attack is more likely. Sep 9, 2016 at 14:23
  • 2
    @ReeshabhRanjan There's no need for "hackers". a coworker could use his magical device (called smartphone) to record you when you say "Ok Google" and then just replay that to access your device...
    – Bakuriu
    Sep 9, 2016 at 18:12

It is a feature as you can see in Lenovo forums

Long press on home screen and then press on settings.

Go to voice -> ok google detection and then turn off trusted voice.

Another post there says

Its not a bug. It just recognizes your voice but its not safe. As the feature is not accurate it may unlock even with others voice. Better turn off trusted voice. The voice command works even from lock screen works if your turn on option to Ok google from any app.

  • Bro you have the same answer, probably a better one. But why so many upvotes to the other one, who gave even wrote an answer after you? Sep 11, 2016 at 14:37

It's part of smart lock as trusted voice. I'm using trusted location as my smart lock. Whenever I'm at home and office phone get unlocked automatically when pick it up. My home and office co ordinates are as trusted locations.

You can also use trusted devices, such as your fitbit, Bluetooth devices. Whenever you make phone contact with these devices phone get unlocked.

I liked this feature a lot, more convenient to unlock phone. But with caution. Keep backup security as pin or pattern.

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