>I'd like to be able to set up a "duress fingerprint" which immediately disables fingerprint authentication, as an easier alternative to turning off the phone.

>I'd like to be able to set up a "duress fingerprint" which immediately disables fingerprint authentication, as an easier alternative to turning off the phone. Coercion codes would certainly be a great next step for Apple to implement, not just with fingerprints but with actual pass phrases/PINs as well. Ideally a coercion code system would allow a couple of different levels of response depending on a user's needs and the situation they faced. For example, one simple PIN/finger print could just revert the system to needing the full passphrase, while another (or a longer passphrase for that matter) could cause the machine to activate pre-scripted actions, wipe itself, or even simulate a malfunction. For what it's worth you can actually already do a limited version of this under iOS if you jailbreak. Touch ID can handle up to five separate fingerprints, and in vanilla iOS AFAIK any successful read is the same as any other in terms of system action. Interestingly however, internally Apple actually registers a separate system event for each different finger. Either writing your own tool or using a tweak like Activator, you can thus set different fingers to trigger different actions, including shutting down/rebooting the device (which in turn activates a long pass phrase) or running a script (which allows alerts, photos, erasure, boot looping, or potentially even something proximate to bricking via messing with nvram). I'm actually quite curious what, if anything, Apple plans to do with Touch ID in the future because they've clearly left themselves some flexibility in the underlying system that I don't think they're presently using anywhere in iOS. Maybe they're more leaning towards features like "select a different payment system with a different finger" or "unlock and launch straight into a favorite app with different fingers", or even some form of multiuser access based on different finger prints, but if Apple decided to start implementing features against rubber-hose cryptanalysis in iOS 10 it'd genuinely be pretty exciting. I'm not aware of any mainstream consumer electronics even attempting anything like that yet, though if anyone has some existing/historical examples I'd really love to read about them.