No, faceid unlocks a Cryptographic key stored in a TPM like device. Of someone can run arbitrary code on your iPhone, they can get it to unlock the TPM. If they

No, faceid unlocks a Cryptographic key stored in a TPM like device. Of someone can run arbitrary code on your iPhone, they can get it to unlock the TPM. If they can't, it would be challenging to fake FaceID right now. It uses a bunch of stuff, IR cameras, a depth camera I think, probably some kind of eularian video magnification for pulse detection. Possible to fake but expensive, probably need to hire some old-timers from industrial light and magic to do it with practical effects. Or you mean literally hold the iPhone to your face, in which case they'd also need to force you to keep your eyes open. The greatest weakness of cryptography has always been that you can beat someone with a five dollar wrench until they unlock the system.