From my understanding - important files are encrypted, and the ability to decrypt is lost when the user sleeps their phone. So iOS needs the user to enter a passcode before the data can be read again.
Finger unlock is nice when you're in a non-hostile environment, but now with a 100ms finger brush, the entire phone opens up wide and says "take all my data!"
I wish iPhones had a feature like "if dropped on the floor (or after any 'significant' impact), remove session key to disable finger print auth and require password again." Then when you gotta cheese it, you just throw and go.
But, trying to revoke the finger auth key in an emergency (less than 5 seconds) is difficult. Your only option is to try and quickly power off the device, but you're at the mercy of the "press and hold sleep/wake button for 5 seconds, then slide to turn off" delay timer.
Of course if ever you have an opportunity in an arrest you should shut down the iPhone... Unlock would require passcode.
1: https://securityledger.com/2013/09/iphone-touchid-falls-to-w...
Similar to the idea of having a second PIN on your credit card that allows access but indicates acting-under-duress to the bank.
Sounds like you are alluding to being able to use a reverse version of your PIN on an ATM when in duress?
It's a trope [0].
> It's a trope
Is there a reason that they couldn't employ this countermeasure for your suggested security?
[0] http://blog.dustinkirkland.com/2013/10/fingerprints-are-user...
Being DA 101
There's no emergency evac situation. You either have basically no protection from hostile action or you avoid finger auth.
as far as "international spy," we have national level security directors storing secrets in AOL accounts. We can't protect people from themselves, so we have to make systems better for everybody.
just like it needs passcodes that do that same, if not more. a passcode to let you in, one to CALL the cops, and another to thwart them
Not sure if it's been fixed yet or not, but you can just turn off Siri from the lock screen.
1: http://lifehacker.com/ios-9-lock-screen-exploit-gives-evildo...
I have no idea how this works in regard to the encryption. It isn't likely anyone else here does either. They are just speculating.
I hope that it is good, but I don't trust it. No one should trust it.
I would look, but I don't own an iPhone.
I don't mean this as a claim that the iPhone is a secure device, since it obviously isn't in several different ways, but rather just that I can't reproduce this specific behavior.