Just use fingerprint scanner on a Nexus 6P?
November 2, 2016 5:04 PM   Subscribe

How to *just use* fingerprint scanner to unlock a Nexus 6P?

In my case, I have the fingerprint scanner enabled, which should make my phone secure.

I was wondering if the fingerprint scanner on a smartphone (in my case a Nexus 6P) is intended to be for convenience or for security.

But I can also get into the phone by drawing a "secret" pattern to unlock the screen; I can't disable the pattern screen lock.

Having to different methods to unlock a phone seems to me to be unsecure, or at least not totally secure. Having just the fingerprint scanner would seem to be the best option.... but as mentioned I can't figure out how to disable the pattern-unlock.

If anyone has any general comments they can include with their answer about how secure a "locked" Android device is (is there a back door someone can use to get in?) it would be appreciated.

I use the phone for 2FA for my email account (Gmail) and have a banking app on it too.
posted by My Dad to Computers & Internet (7 answers total)
There are several mechanisms on Android 6 & 7 to unlock the phone:

- screen lock setting (may include face unlock)
- fingerprint
- smart lock
- BLE smart lock

None of them are mandatory unless your device administrator sets a policy. That said I believe fingerprint does require a screen lock to be set as the screen lock pattern is what drives the key for device encryption if you use it.

You can set a very big password in place of a pattern. I would not recommend setting a random one and then forgetting it as the system may want you to use it in places where fingerprints aren't supported.
posted by GuyZero at 5:19 PM on November 2, 2016 [2 favorites]

The fingerprint data is protected by the PIN, password, or pattern, so you can't unlock the phone with a fingerprint until you have unlocked it at least once at manually.

After the initial unlock that enables the fingerprint reader to be used, the manual methods continue to be offered as a backup, in case the fingerprint reader has stopped working, or you need someone else to unlock the phone in an emergency, for example.

Having two ways to get in is not really any less secure than one. Actually, the fingerprint reader is a good deal less secure than the other methods, especially the password, since it is so easy to collect a fingerprint from something you have touched and spoof the sensor. The other methods will shut down the phone, wipe it, or begin enforcing long delays between attempts after a few wrong entries, making brute force less feasible.

Also, from a law enforcement standpoint, police cannot compel you to enter a password, but they can compel you to unlock a device with a fingerprint (at least in the US), so if you are really concerned about security, you should disable the fingerprint reader and stick with a password.
posted by kindall at 5:39 PM on November 2, 2016 [7 favorites]

Reference on that last point, by the way. The legal basis seems to be that making you enter a password is compelling you to reveal something you know, i.e. the password, which is against the Fifth Amendment. But your fingerprints are public; anyone can see them, so using it to unlock your phone isn't forcing you to reveal anything. If you have been arrested and booked, the police already have your fingerprint.
posted by kindall at 5:59 PM on November 2, 2016 [1 favorite]

From one point of view, you could say that it widens your attack surface. From another though, it de-incentivizes to some extent, going with no passcode or a short lazy passcode. The behavior aspect is important too.

Security is only as strong as the weakest link. Usually that's a social engineering trick (like a plea deal).

If you are worried about your phone being used against you in a cop situation, turn it off. And get a lawyer.
posted by oceanjesse at 7:12 PM on November 2, 2016 [1 favorite]

My 6P requires I use the pattern whenever I download new/update the operating system even though I use the fingerprint. And it has a little blurb on the screen saying I HAVE TO use the pattern to get back in.
posted by atomicstone at 8:04 PM on November 2, 2016 [1 favorite]

I have had the fingerprint sensor on my phone crap out for a period of weeks before it started working again. If that was my only way to access the phone then I would have had to buy a new one.
posted by any portmanteau in a storm at 8:51 PM on November 2, 2016 [1 favorite]

If you are worried about your phone being used against you in a cop situation, turn it off. And get a lawyer.

I live in Canada, so I don't know what the law is around that. I sometimes travel to the States, or to other countries, so it's good to know how to protect myself there. Thank you.

I was just worried about losing my phone (I have the tracking app installed and so on) and therefore allowing someone to get into my email (which I've had since 2004; I use 2FA) and my main bank accounts (password kept off the device). It seems like it's not a big worry.

My question has been answered. Thanks, everyone, for answering.
posted by My Dad at 9:26 PM on November 2, 2016

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