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TouchID accepting prints it shouldn't

M

MEJHarrison

macrumors 68000
Original poster
Feb 2, 2009
1,522
2,723
So I took my roommate to pick up her new iPhone 6 on Friday. Picked it up at the Apple store and then went to the food court for some dinner. While eating, I watched her setup her new phone. I watched her input her index finger for TouchID. And that's it. She just did the one finger.

What's odd is that she can use that index finger or her thumb (on the same hand). None of her other fingers will unlock the phone. Just the one she entered and her thumb that she did NOT enter. And it wasn't a fluke. She can unlock with her thumb over and over and over. Completely repeatable.

Anyone heard of anything like this? The phone seems secure. No one else is able to unlock it (so far). Is this something to be concerned about? Should she make an appointment at Apple to get it looked at? Could her fingerprint and thumbprint just be really, really similar enough? I'm not really sure what to do at this point.
 
MEJHarrison said:
So I took my roommate to pick up her new iPhone 6 on Friday. Picked it up at the Apple store and then went to the food court for some dinner. While eating, I watched her setup her new phone. I watched her input her index finger for TouchID. And that's it. She just did the one finger.

What's odd is that she can use that index finger or her thumb (on the same hand). None of her other fingers will unlock the phone. Just the one she entered and her thumb that she did NOT enter. And it wasn't a fluke. She can unlock with her thumb over and over and over. Completely repeatable.

Anyone heard of anything like this? The phone seems secure. No one else is able to unlock it (so far). Is this something to be concerned about? Should she make an appointment at Apple to get it looked at? Could her fingerprint and thumbprint just be really, really similar enough? I'm not really sure what to do at this point.
Click to expand...
She's a witch and should be burned at the stake!
Barring that, try resetting the phone and setting up TouchID again and see if the issue persists. However, if it's still really only unlocking for her, then I don't see a big issue at this point.
 
MEJHarrison said:
So I took my roommate to pick up her new iPhone 6 on Friday. Picked it up at the Apple store and then went to the food court for some dinner. While eating, I watched her setup her new phone. I watched her input her index finger for TouchID. And that's it. She just did the one finger.

What's odd is that she can use that index finger or her thumb (on the same hand). None of her other fingers will unlock the phone. Just the one she entered and her thumb that she did NOT enter. And it wasn't a fluke. She can unlock with her thumb over and over and over. Completely repeatable.

Anyone heard of anything like this? The phone seems secure. No one else is able to unlock it (so far). Is this something to be concerned about? Should she make an appointment at Apple to get it looked at? Could her fingerprint and thumbprint just be really, really similar enough? I'm not really sure what to do at this point.
Click to expand...
Unpossible. You can add multiple fingers under ONE of the five touch IDs allowed - perhaps she did both her thumb and index finger on the same one. Even if she briefly touched the sensor with her thumb while adding the index finger this could happen.
 
MEJHarrison said:
So I took my roommate to pick up her new iPhone 6 on Friday. Picked it up at the Apple store and then went to the food court for some dinner. While eating, I watched her setup her new phone. I watched her input her index finger for TouchID. And that's it. She just did the one finger.

What's odd is that she can use that index finger or her thumb (on the same hand). None of her other fingers will unlock the phone. Just the one she entered and her thumb that she did NOT enter. And it wasn't a fluke. She can unlock with her thumb over and over and over. Completely repeatable.

Anyone heard of anything like this? The phone seems secure. No one else is able to unlock it (so far). Is this something to be concerned about? Should she make an appointment at Apple to get it looked at? Could her fingerprint and thumbprint just be really, really similar enough? I'm not really sure what to do at this point.
Click to expand...

If this is true Apple's ID system is cr^p!

I have big doubts and there must be more to this story!
 
Last edited:
nikhsub1 said:
Unpossible. You can add multiple fingers under ONE of the five touch IDs allowed - perhaps she did both her thumb and index finger on the same one. Even if she briefly touched the sensor with her thumb while adding the index finger this could happen.
Click to expand...

I'm telling you, I sat there eating my dinner and watched her set it up. She did NOT enter her thumb. Had she done so, I would have seen it. I'm 100% positive that she ONLY entered her finger. I witnessed the entire process. She absolutely did not enter her thumb.
 
Before you reset anything, go to Settings -> Touch ID & Passcode and enter the passcode, then scroll down to "fingerprints." There should only be one finger there.

Then, have her put each finger on the home button to get the finger scanned, and see if the enrolled fingerprint darkens when her finger gets scanned. If it darkens, that means it's recognizing the fingerprint.


That'll both verify that you really do only have one fingerprint registered, and whether or not the iPad really is thinking that her thumb and index are the same.
 
Video or it didn't happen. On my 5S, TouchID wouldn't even let my own fingers open it half the time.
 
MEJHarrison said:
I'm telling you, I sat there eating my dinner and watched her set it up. She did NOT enter her thumb. Had she done so, I would have seen it. I'm 100% positive that she ONLY entered her finger. I witnessed the entire process. She absolutely did not enter her thumb.
Click to expand...

Then she is obviously a freak of nature that has an identical thumb and index finger print. Lose her at once!
 
nikhsub1 said:
Then she is obviously a freak of nature that has an identical thumb and index finger print. Lose her at once!
Click to expand...

Or market her for her own reality show, TV show execs love freaks of nature. Honey BooBoo just got canned, I'm sure TLC is looking to replace them.
 
scaredpoet said:
Before you reset anything, go to Settings -> Touch ID & Passcode and enter the passcode, then scroll down to "fingerprints." There should only be one finger there.

Then, have her put each finger on the home button to get the finger scanned, and see if the enrolled fingerprint darkens when her finger gets scanned. If it darkens, that means it's recognizing the fingerprint.


That'll both verify that you really do only have one fingerprint registered, and whether or not the iPad really is thinking that her thumb and index are the same.
Click to expand...

Thanks. That's actually a good idea. I'll pass it on to her. If nothing else, I'm curious to see the results.
 
I'm in the "need more evidence" camp. Seems unlikely that she truly only enrolled one finger, and has two working. I would wager that she enrolled her thumb first, and you just missed it.

Even on the same person, fingerprints across different fingers are as different as they are across different people. That's why you need to enroll your left thumb separately from your right thumb.

But, of course, while fingerprints are massively varied from individual to individual, it is possible for two people to share a "similar-enough" fingerprint (on one finger) for a digital device to recognize them as "the same" - just highly highly rare. And since it's possible for two people to have it, it's also very possible for a single person to have prints on two fingers that are similar enough to pass for being the same finger. Again, extremely unlikely/rare, but not impossible. It could very well be that your friend is one of those "one in a billion". Or maybe TouchID is lower resolution than we think...
 
Or her two prints are similar enough, which is statistically possible genetically. The chance of two random fingerprints matching is only 1 in 50,000 (but much better than the 1 in 10,000 odds of guessing a 4-digit passcode). The odd of this happening is improved if it's the same person rather than two random individuals.
 
touch id

Newtons Apple said:
If this is true Apple's ID system is cr^p!

I have big doubts!
Click to expand...

you could always put more than one finger print on each one. that is the way we used to do it so we would have a better chance of it working. Now with the improvements you don't have to do it this way.
 
There is a chance that her index and thumb have identical pattern. I assume once she sets up the Touch ID the system is not completely done. It learns. And since her thumb and index might be close enough it is working for her. Now since she has used it multiple times Touch ID is assuming that the print is just a different angle on the finger.
 
sau124 said:
There is a chance that her index and thumb have identical pattern. I assume once she sets up the Touch ID the system is not completely done. It learns. And since her thumb and index might be close enough it is working for her. Now since she has used it multiple times Touch ID is assuming that the print is just a different angle on the finger.
Click to expand...

The chances are SO slim that there must be something else going on here.
 
scaredpoet said:
Before you reset anything, go to Settings -> Touch ID & Passcode and enter the passcode, then scroll down to "fingerprints." There should only be one finger there.

Then, have her put each finger on the home button to get the finger scanned, and see if the enrolled fingerprint darkens when her finger gets scanned. If it darkens, that means it's recognizing the fingerprint.


That'll both verify that you really do only have one fingerprint registered, and whether or not the iPad really is thinking that her thumb and index are the same.
Click to expand...

This won't prove anything - if both finger and thumb were used when registering 'one' finger then it will darken for both the finger and thumb when you test it...doesn't mean that the device thinks they are the same, just that both prints were presented when learning for that slot.
 
MEJHarrison said:
I'm telling you, I sat there eating my dinner and watched her set it up. She did NOT enter her thumb. Had she done so, I would have seen it. I'm 100% positive that she ONLY entered her finger. I witnessed the entire process. She absolutely did not enter her thumb.
Click to expand...

I don't think he's saying she registered her thumb as a separate finger. When registering her index finger she could have touched the button with her thumb for just a moment. Both fingers would unlock the phone.
 
swordfish5736 said:
I don't think he's saying she registered her thumb as a separate finger. When registering her index finger she could have touched the button with her thumb for just a moment. Both fingers would unlock the phone.
Click to expand...

I know exactly what he's saying. And I know her thumb didn't touch the sensor or come anywhere close to it.

I don't have my new toy yet (should be getting my 128GB Space Gray 6+ on Thursday), and being a bit of a tech geek and a computer programmer for 25 years, I was fascinated. Trust me (or not) when I say I was watching her like a hawk. It was my first up-close experience with one of the new devices. So when I say she didn't put her thumb on the button, I'm not saying I didn't see her put her thumb on the button, I'm saying it did not happen.

I realize how hard that is to accept. I've been on the other side of crazy stories and understand the doubt. But I have no reason to lie. I'm a happy Apple customer as is she. It's not my intention to make Apple look bad here (my posting history should prove I'm not just trolling). Nor am I trying to claim that TouchID is crap. My guess is she's one of those rare people where the prints are just close enough. But that's just a guess. My intention was to find out if is a known problem (it's not) and if she should contact Apple about it (from what I've heard, I'd say no at this point). Plus I was genuinely curious. I posted. I learned new things. I'm happy at this point. If it were my phone, I'd probably dig a little deeper. But it's her phone. She can do what she wants with it (she couldn't care less that her thumb works after NOT scanning it in). I'm just collecting information.

----------

When my new phone does get here, I'll probably see if we can repeat it on my device. But regardless of that outcome, I'm still 100% positive she did not scan her thumb intentionally or accidentally. She ONLY used her finger. Still, I'm obviously curious to see if it can be repeated as that would be a small indication that perhaps she should contact Apple. If it works on mine, she has weird fingerprints. If not, then something is up with her phone or it's some bizarre fluke (that she'll probably ignore and move on).
 
MEJHarrison said:
My guess is she's one of those rare people where the prints are just close enough. But that's just a guess.
Click to expand...

Yes, it's only 1 in 50,000 odd to get two matching random fingerprints and this improves if it's the same person. Still better than the 1 in 10,000 odds of guessing the correct 4-digit passcode though.
 
JayLenochiniMac said:
Yes, it's only 1 in 50,000 odd to get two matching random fingerprints and this improves if it's the same person. Still better than the 1 in 10,000 odds of guessing the correct 4-digit passcode though.
Click to expand...

Do you have a source for that claim? Even identical twins don't have identical finger prints (meaning the determinants are not purely genetic)
 
JayLenochiniMac said:
Yes, it's only 1 in 50,000 odd to get two matching random fingerprints and this improves if it's the same person. Still better than the 1 in 10,000 odds of guessing the correct 4-digit passcode though.
Click to expand...

Well hopefully I'll know the answer to that in a few days. Like I said, I'll try to repeat the process on my new phone when it arrives. If she's truly 1 in 50,000, that would be interesting to know.
 
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