The one piece of information from here that is new about the TouchID -
"And what is stored in that secure location are not fingerprint images, but cryptographically hashed values, unique both to your finger’s biometric data and the device itself on which you scanned it. Even if someone does figure out how to obtain the fingerprint data from the secure storage on your iPhone, that fingerprint data should prove useless anywhere but on the unique Touch ID sensor on the iPhone itself"
Always thought it will be done this way. But "security experts" just assumed it will be stored on disk in "consumable" form and warned not to use it ever.
The issue is more a one of trust, as pretty much all computer security issues boil down to. Apple (and Gruber) says one thing; but since the code is not available for inspection, and since you presumably can't alter the code on your actual iPhone, you must take what they're saying at their word.
Whether or not you want to do that is entirely up to you. The overwhelming majority of people wouldn't think twice about trusting Apple. But, as has been has revealed, government influences are powerful and are already deeply (and secretly) entwined with private enterprise. To snidely dismiss people warning you about who to really, truly trust with things as fundamentally identifiable of you as your fingerprint is doing yourself, and them, a disservice in the post-Snowden era.
That's not new. It was painstakingly clarified during the announcement keynote and the promotional video (you know, the one with Jony Ive in an empty white void) which released during the announcement.
So, I have a credit card attached to my iTunes account. Say my phone with TouchID gets stolen.
If what is said holds true, the absolute worst case scenario that could happen is that the thief actually hacks the device and gains access to the storage place of the encrypted hashes that should only be accessible by the sensor itself. He then somehow reverses this hash into a form that the iOS system would expect to come from the sensor. Then, he would be able to forego to fingerprint sensor and send the spoofed fingerprint signal to the system, making it seem like the owner touched the sensor. And since he now has access to my phone, he can do everything someone can do with an unlocked iPhone plus make purchases with my iTunesID.
This spoofed signal should be useless anywhere else outside the iOS system. I very much doubt that someone could re-factor this hash into an actual image of a fingerprint.
And if I get my phone stolen, TouchID or not, I would of course go and a) remote wipe the device which I hope includes the deletion of these encrypted fingerprint hashes and b) Maybe cancel the credit card attached to the iTunes account.
"And what is stored in that secure location are not fingerprint images, but cryptographically hashed values, unique both to your finger’s biometric data and the device itself on which you scanned it. Even if someone does figure out how to obtain the fingerprint data from the secure storage on your iPhone, that fingerprint data should prove useless anywhere but on the unique Touch ID sensor on the iPhone itself"
Always thought it will be done this way. But "security experts" just assumed it will be stored on disk in "consumable" form and warned not to use it ever.