Feds Can't Force You to Unlock Your iPhone with Finger or Face, Judge Rules
Relevant excerpt:<p><i>> “The undersigned finds that a biometric feature is analogous to the 20 nonverbal, physiological responses elicited during a polygraph test, which are used to determine guilt or innocence, and are considered testimonial.”</i><p>So it's analogous to a passcode because you're divulging something stored by your body, as opposed to e.g. a metal key which is artificial.<p>Tangentially related, it's astounding to me that polygraphs are still considered valid evidence given how widely they've been discredited.