6 ms·

My friends son can unlock his older sister's iPhone using Face ID. Rare?

8 points by dougSF70 5y ago

dougSF70 5y ago
I was surprised that this could happen, then I thought how frequently does this happen. Any other examples y'all are aware of?
- geoah 5y ago
  Other possibility: Ios allows you to register a second face to unlock the device through face id. Could it be that they registered their face on the device?
  - dougSF70 5y ago
    No, that was suggested but apparently they haven't done this.
olliej 5y ago
How old is older? - faceid can have issues with young siblings, and of course identical twins.
- dougSF70 5y ago
  Boy is 13, his sister is 17. They have different noses.
  - taxcoder 5y ago
    I should hope. Sharing noses would come with great difficulties.
  - olliej 5y ago
    I realized another thing that can happen is that if you have two sufficiently similar looking people. Basically person B tries to use their face to unlock A’s phone and then A unlocks it. If they are sufficiently similar the phone could theoretically expand its knowledge of what A looks like so that B’s face triggers a positive match. I have no idea how close in appearance they’d need to be for Faceid to do this though.
redlaw 5y ago
happens more often than you think, if you look there's a long history of flaws with the technology https://youtu.be/FE3kMdtH7M4 https://youtu.be/FE3kMdtH7M4
lb417 5y ago
duxup 5y ago
It lets you register an “alternate appearance”, could that be what is being used?
gregjor 5y ago
Not rare. Approximately 80% of people have a brother or sister. On average siblings are less than three years apart, and share 50% of their genes. Children from the same parents tend to look alike. Apple has researched this: > The probability that a random person in the population could look at your iPhone X and unlock it using Face ID is approximately 1 in 1,000,000 (versus 1 in 50,000 for Touch ID). […] The probability of a false match is different for twins and siblings that look like you as well as among children under the age of 13, because their distinct facial features may not have fully developed. https://9to5mac.com/2017/09/27/face-id-iphone-x-white-paper/ https://9to5mac.com/2017/09/27/face-id-iphone-x-white-paper/ Family members unlocking phones documented previously: https://www.theverge.com/2017/11/14/16650394/10-year-old-unlock-mom-iphone-face-id https://www.theverge.com/2017/11/14/16650394/10-year-old-unl... http://mashable.com/2017/10/31/putting-iphone-x-face-id-to-twin-test/ http://mashable.com/2017/10/31/putting-iphone-x-face-id-to-t...
- dougSF70 5y ago
  The very last people I would want to expose my secrets to, would be family members. Whereas if a stranger hacked into my phone, beyond those secrets that have some fixed frame of reference, such as Bank Details and Social Security Number etc, a lot of other information is context-less and therefore hard to determine whether it has value. Siblings on the other hand would know the value immediately; "you sent [x] to person [y]", 'you said [z] about [a]".
  - gregjor 5y ago
    Use a PIN or passcode instead of Face ID.
girishso 5y ago
Not Face ID, but my wife’s sister could unlock my wife’s android phone with Touch ID. That should be pretty rare I guess.
- dougSF70 5y ago
  That is very rare. Android should employ your wife and her sister as Touch ID edge cases.
hkc 5y ago
My brother was able to unlock mine through Face ID even though my phone had only one face registered. Face ID updates you face as it changes[0]. So, I guess whenever my brother used my phone it added my brother's face features since algorithm probably found some similarities in face features. [0] https://www.theverge.com/2017/9/27/16373710/face-id-iphone-x-apple-facial-recognition-impostor https://www.theverge.com/2017/9/27/16373710/face-id-iphone-x...

8 points by dougSF70 5y ago

I was surprised that this could happen, then I thought how frequently does this happen. Any other examples y'all are aware of?

geoah 5y ago
Other possibility: Ios allows you to register a second face to unlock the device through face id. Could it be that they registered their face on the device?
- dougSF70 5y ago
  No, that was suggested but apparently they haven't done this.

olliej 5y ago

How old is older? - faceid can have issues with young siblings, and of course identical twins.

dougSF70 5y ago
Boy is 13, his sister is 17. They have different noses.
- taxcoder 5y ago
  I should hope. Sharing noses would come with great difficulties.
- olliej 5y ago
  I realized another thing that can happen is that if you have two sufficiently similar looking people. Basically person B tries to use their face to unlock A’s phone and then A unlocks it. If they are sufficiently similar the phone could theoretically expand its knowledge of what A looks like so that B’s face triggers a positive match. I have no idea how close in appearance they’d need to be for Faceid to do this though.

redlaw 5y ago

happens more often than you think, if you look there's a long history of flaws with the technology https://youtu.be/FE3kMdtH7M4 https://youtu.be/FE3kMdtH7M4

lb417 5y ago

duxup 5y ago

It lets you register an “alternate appearance”, could that be what is being used?

gregjor 5y ago

Not rare. Approximately 80% of people have a brother or sister. On average siblings are less than three years apart, and share 50% of their genes. Children from the same parents tend to look alike. Apple has researched this: > The probability that a random person in the population could look at your iPhone X and unlock it using Face ID is approximately 1 in 1,000,000 (versus 1 in 50,000 for Touch ID). […] The probability of a false match is different for twins and siblings that look like you as well as among children under the age of 13, because their distinct facial features may not have fully developed. https://9to5mac.com/2017/09/27/face-id-iphone-x-white-paper/ https://9to5mac.com/2017/09/27/face-id-iphone-x-white-paper/ Family members unlocking phones documented previously: https://www.theverge.com/2017/11/14/16650394/10-year-old-unlock-mom-iphone-face-id https://www.theverge.com/2017/11/14/16650394/10-year-old-unl... http://mashable.com/2017/10/31/putting-iphone-x-face-id-to-twin-test/ http://mashable.com/2017/10/31/putting-iphone-x-face-id-to-t...

dougSF70 5y ago
The very last people I would want to expose my secrets to, would be family members. Whereas if a stranger hacked into my phone, beyond those secrets that have some fixed frame of reference, such as Bank Details and Social Security Number etc, a lot of other information is context-less and therefore hard to determine whether it has value. Siblings on the other hand would know the value immediately; "you sent [x] to person [y]", 'you said [z] about [a]".
- gregjor 5y ago
  Use a PIN or passcode instead of Face ID.

girishso 5y ago

Not Face ID, but my wife’s sister could unlock my wife’s android phone with Touch ID. That should be pretty rare I guess.

dougSF70 5y ago
That is very rare. Android should employ your wife and her sister as Touch ID edge cases.

hkc 5y ago

My brother was able to unlock mine through Face ID even though my phone had only one face registered. Face ID updates you face as it changes[0]. So, I guess whenever my brother used my phone it added my brother's face features since algorithm probably found some similarities in face features. [0] https://www.theverge.com/2017/9/27/16373710/face-id-iphone-x-apple-facial-recognition-impostor https://www.theverge.com/2017/9/27/16373710/face-id-iphone-x...