Why does Face ID authenticate two different people?

Question

Level 4

1,345 points

Why does Face ID authenticate two different people?

I'm helping my friend with his new iPhone X. He set up Face ID and it works. Face ID is definitely set. When his phone awakes from sleep the screen says Face ID. If he is looking at the screen and slides up he goes to the Home screen. If we point the phone away from his face then he is asked for his passcode instead. So Face ID is definitely set up and working.

But... it works for me too. I thought that wasn't supposed to happen. Like a 1 in a million chance of a false positive.

It's convenient in that I can help him with stuff, including Apple Pay, more easily. But that's not the point. It's not supposed to happen like that, right?

Here's a photo I took of us today after we tested this. I'm on the left and I'm 61 years old. He's on the right and is 98 years old. We are not related - just friends.

One might say to "reset Face ID" - and maybe if I do it will just recognize him and fail to recognize me. But why does this happen so easily?

MacBook Pro (Retina, 13-inch, Late 2013), i5, 512 GB SSD, 16 GB RAM

Posted on Dec 11, 2017 1:50 AM

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Answer 1

Doug Lerner2 Author

Level 4

1,345 points

Dec 22, 2017 2:20 AM in response to Doug Lerner2

I was helping my friend with his iPhone X again today and confirmed that Face ID recognizes both him and me.

I reported it to Apple, but they haven't replied.

Not impressed with the iPhone X Face ID security.

Also I hate that payment confirmation using a double-click of a mechanical button. I can't imagine why they did that rather than something you can touch on the screen.

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Answer 2

Doug Lerner2 Author

Level 4

1,345 points

Dec 11, 2017 2:42 AM in response to Briansyddall

I don't have to do that. According to this document the chances of it happening are only supposed to be 1 in a million: https://images.apple.com/business/docs/FaceID_Security_Guide.pdf

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Answer 3

Dec 11, 2017 2:35 AM in response to Doug Lerner2

Hi

Go to i books download ios 11 user guide &iPhone X guide both are free.

Cheers

Brian 🇬-1F1E7;

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Answer 4

FelipeV

Level 6

10,636 points

Dec 11, 2017 2:54 AM in response to Doug Lerner2

Try doing what you said you might do again, mainly resetting FaceID again. It could be a glitch. If it keeps validating both of your faces, you both could be part of the 1:1,000,000 anomaly.

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Answer 5

Doug Lerner2 Author

Level 4

1,345 points

Dec 11, 2017 2:57 AM in response to FelipeV

He's 98 years old! 🙂

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Answer 6

FelipeV

Level 6

10,636 points

Dec 11, 2017 3:00 AM in response to Doug Lerner2

I am baffled as you are...

Maybe he is your long lost relative...

Like in the old Roman plays...you sure he doesn't have half of a medallion or ring that fits with a half you have...

😉

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Answer 7

Doug Lerner2 Author

Level 4

1,345 points

Dec 11, 2017 3:15 AM in response to FelipeV

Maybe the Apple engineers concentrated on their millennials demographic and then said, "as for the rest, everybody between 60 and 100 all look basically alike."

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Answer 8

Dec 22, 2017 3:18 AM in response to Doug Lerner2

If you were setting up Face ID with him, then the phone maybe got confused and tried to recognise both of your faces, because the more you unlock the phone, the more the phone tries to recognise you.

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