A magistrate judge in California has ruled that police can’t compel people to unlock their phones with biometric methods like fingerprints and facial recognition. Before this ruling, biometrics weren’t protected in the same way that alphanumeric passcodes are – while police can’t force a suspect to give up a passcode, those rules didn’t apply to biometric unlocking methods. Now, it seems, the two methods of locking and unlocking mobile devices are seen as equal in the eyes of the law (at least for the time being).
If you’re wondering why passcodes would be protected while biometrics aren’t, you’re definitely not alone. Courts have previously ruled that since a suspect would actually need to speak a passcode at will, they were considered “testimonial” in nature. Forcing someone to say a passcode to unlock a device-of-interest would therefore violate the Fifth Amendment of the US Constitution, which protects citizens from self-incrimination.
Forbes reports that those same protections now apply to biometric unlocking methods, per a ruling from magistrate judge Kandis Westmore of the US District Court for the Northern District of California. The order, which is available on DocumentCloud, came after police requested a search warrant while investigating a Facebook extortion crime. While police had been granted a warrant to search their suspect’s property, Judge Westmore didn’t give them permission to search the devices inside.
She noted that the requested warrant was overly broad, as it applied to all devices at the property regardless of who they belonged to. “If a person cannot be compelled to provide a passcode because it is a testimonial communication, a person cannot be compelled to provide one’s finger, thumb, iris, face, or other biometric feature to unlock that same device,” she also wrote.
Westmore goes onto say that the biometric methods we use to unlock phones are “analogous to the 20 nonverbal, physiological responses elicited during a polygraph test,” which are considered testimonial as well. In this case, at least, police had other methods of obtaining the information they were looking for, as Westmore pointed out that they could have asked Facebook for Messenger chat transcripts instead of requiring full access to mobile devices that were in the property they planned to search.
So, this is a pretty big win for privacy rights, since it means that Face ID and fingerprint scanners are just as secure as passcodes in regards to search warrants and the police. Forbes notes that Westmore’s decision can be overturned at some point down the road, but hopefully her ruling is indicative of a shift in how courts view matters of privacy in the information age.