Cops can force you to unlock your phone with your fingerprint, but not with your passcode, according to a judge in the US state of Virginia.

The question of whether a phone passcode is constitutionally protected has been batted around for a while, with varying outcomes.

It surfaced again in this case, which involves an Emergency Medical Services captain by the name of David Baust who was charged in February with trying to strangle his girlfriend.

According to The Virginia Pilot, there might be footage recorded on video equipment in Baust’s bedroom that shows the couple’s fight.

If there is, the video could be on his mobile phone, and prosecutors want the judge to force Baust to unlock his phone so they can get at it.

Courts have held, however, that passcodes are protected by the Fifth Amendment, which prohibits forced self-incrimination.

That’s kept defendants from being forced to cough up passcodes, given that they are knowledge stored in our heads.

But as privacy and legal experts have been saying ever since Apple introduced Touch ID, biometric information such as fingerprints are like our DNA samples or our voice imprints: they don’t reveal anything that we know, meaning they don’t count as testimony against ourselves.

Internet and privacy lawyer Marcia Hoffman, writing for Wired, explained it a year ago:

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.

Take this hypothetical example coined by the Supreme Court: If the police demand that you give them the key to a lockbox that happens to contain incriminating evidence, turning over the key wouldn’t be testimonial if it’s just a physical act that doesn’t reveal anything you know.

However, if the police try to force you to divulge the combination to a wall safe, your response would reveal the contents of your mind — and so would implicate the Fifth Amendment. (If you’ve written down the combination on a piece of paper and the police demand that you give it to them, that may be a different story.)

Virginia Circuit Court Judge Steven C. Frucci agreed with that logic.

He ruled this week that giving police a fingerprint is akin to providing a DNA or handwriting sample or an actual key, which the law permits, while a passcode requires the defendant to divulge knowledge, which the law protects against.

The ruling doesn’t clear the road for the prosecutors, however, given that Baust’s phone may well be protected by both a passcode and Touch ID.

In fact, this ruling doesn’t mean it’s open season on Touch ID-enabled iPhones.

If Touch ID hasn’t been used for 48 hours, a passcode, in addition to a fingerprint, is required in order to unlock a device. The same thing goes for using the device after restart.

Prosecutors were still considering whether to appeal the judge’s decision as of Thursday.

Via: nakedsecurity