iPhone FaceID concerns

Privacy Questions
1

The thing may sound ridiculous but it’s true: I’m using an iPhone 11 Pro with FaceID enabled and no Alternate Faces. However both me (male) and my sister (who is 4yr old younger than me, and I don’t think I look quite like her) can unlock it. I tried to reset but the issue persists.

It’s not a big deal for me, maybe some genetic stuff is haunting; but it raises my concerns that (although almost impossible, in some rare cases) if two people happened to have the same face decided by the algorithm FaceID would fail.

2

This is pretty common if you look it up on the internet.

3

This is why fingerprints could be the better alternative. IIRC while fingerprint unlock is still terrible, face unlock has more false positive match.

As a side note:

Ive tried the no fingerprint sensor/face ID life with just complex passwords and it is horrible. You also have to be concious of the CCTVs around you as well.

Very terrible as I was forced to type my master password in my laptop (because my “burner” phone was fresh and pretty much empty and useless) at the immigration section of the our country’s airport.

4

Why is fingerprint terrible?

5

The best solution is the upcoming GrapheneOS feature, which allows you to use biometrics as a 2FA alongside a PIN or a password. You get the best of both worlds.

6

Unfortunately all modern phones tend to scan your face as a biometric auth

7

You leave your fingerprints on everything you touch, even a high resolution picture where your fingerprints are visible can be enough to unlock your phone.

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8

You could be rendered unconcious against your will and that would let someone use your fingers against you.

Or in more terrible threat models, have someone cut out your finger. Not sure if a cut finger will work though.

9

Will we be able to set this up by having a long password for unlocking BFU, and then in AFU a PIN + biometrics (every time)?

10

Yes.

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11

Maybe if it’s an optical fingerprint sensor.

12

This isn’t the case for Face ID and Touch ID. The likelihood that a random person can unlock your Face ID is less than 1 in a million while the likelihood for Touch ID is 1 in 50,000. Of course siblings and twins significantly increase those odds tho.

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13

That would work for an optical one I suppose.

14

That should really not be the case. Unless you are the proverbial one in a million statistical outlier I would guess something might be wrong with your faceID hardware.

15

For my privacy threat I think this isn’t a big deal. I’m a bit more concern with companies selling my data, or a government somehow spying on me because of something they suspect, and third but the least is someone targeting me however I’m not that important to probably face this problem.

A family member being able to unlock my phone along myself would be very unfortunate but I think I could get along with it. I have quite good relation with my family, everyone respects privacy from each other (nobody reads letters from each other, or journals, etc). Probably if I’d pass away this actually would help in case they need some info that is my phone, :joy:

16

Nah I’ve experienced this with my sibling across two iPhones that were 5 generations apart. I doubt the Face ID hardware was faulty on both phones. Read reports of this issue online too.

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