This is such an obvious flaw. It will almost certainly generate huge amounts of user frustration and many complaints.
The type of person they are intending to use the sensor are those that normally don't use authentication in the first place. So these folks (and I know them well) will put in a passcode to start using the sensor and then immediately forget what it is.
At some point they will leave the phone alone for too long and get locked out. Then the only way back in is to remember that password they put in months or possibly years ago and never had to re-enter. It's a virtual certainty that they won't remember this passcode, and there won't be anything for it but a trip to the Apple store.
Don't worry about the users you describe, their password is 'Password123', they won't forget
I completely see the need to retain passcodes in the event of sensor failure or finger damage.
But why is the finger print considered less secure after 48 hours or a reboot? Is it possible that the system only "trusts" finger prints for a short duration, and needs to update them frequently, ie incrementally update them?
That's incorrect. If you know about hashes, then you know that they are not tolerant to small changes, as you would expect as fingerprints aren't read with 100% accuracy. How fingerprint readers work is that they extract a series of features, for example, where ridges end and split. These features are then aligned and compared to the features in the stored template and scored depending on which ones match.
The information between features is discarded so the whole fingerprint image cannot be reconstructed, but the important parts of the fingerprint are stored. Therefore, it's not as "one-way" as you make it to be.
You are correct that the hashes won't be 100% matched. It will be 99.95 or better match typically. But the hashes are compared, not the images. No useful information can be derived from the stored hash.
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Don't worry about the users you describe, their password is 'Password123', they won't forget
Oh no. Duck! TouchIDgate alert!!
Just don't finger it that way.
Sent from my iPhone
I completely see the need to retain passcodes in the event of sensor failure or finger damage.
But why is the finger print considered less secure after 48 hours or a reboot? Is it possible that the system only "trusts" finger prints for a short duration, and needs to update them frequently, ie incrementally update them?
Lots of people turn their phones off at night.