It Puts the Finger on the Button
The iPhone 5S fingerprint sensor will protect you from snoopers -- but will it protect you from Uncle Sam's prying eyes? Read:
While there’s a great deal of discussion around the pros and cons of fingerprint authentication — from the hackability of the technique to the reliability of readers — no one’s focusing on the legal effects of moving from PINs to fingerprints.
Because the constitutional protection of the Fifth Amendment, which guarantees that “no person shall be compelled in any criminal case to be a witness against himself,” may not apply when it comes to biometric-based fingerprints (things that reflect who we are) as opposed to memory-based passwords and PINs (things we need to know and remember).
For the privilege to apply, however, the government must try to compel a person to make a “testimonial” statement that would tend to incriminate him or her. When a person has a valid privilege against self-incrimination, nobody — not even a judge — can force the witness to give that information to the government.
But a communication is “testimonial” only when it reveals the contents of your mind. We can’t invoke the privilege against self-incrimination to prevent the government from collecting biometrics like fingerprints, DNA samples, or voice exemplars. Why? Because the courts have decided that this evidence doesn’t reveal anything you know. It’s not testimonial.
If biometrics aren't the very essence of who we are, of our right to be secure in our persons, then what the hell may we keep private?