Federal Judge: Police Can't Force Suspects to Unlock Devices Using Biometrics

A federal judge in the US District Court for the Northern District of California has ruled that police cannot force the unlocking of a mobile device using biometrics.

The judge, Kandis Westmore, found that biometric technologies, such as fingerprints or face recognition, deserve the same protection that is currently given to passwords under law.

In this case, the court found while there was probable cause for the search warrant, "probable cause does not permit the Government to compel a suspect to waive rights otherwise afforded by the Constitution, including the Fifth Amendment right against self-incrimination."

The judge also noted the problem has arisen because: "The challenge facing the courts is that technology is outpacing the law."

(Source: iStock)

Now that this case has been settled, enterprises have to be aware of their stakes in this.

The BYOD-era means that it is likely that any business files that may be on the device will be available to someone searching it. Should a worker be compelled to give device access to law enforcement, they would also gain access to possibly confidential enterprise information as well. (See Security Concerns Increasing as BYOD Programs Continue to Grow.)

In the ruling, past practices were considered. The judge wrote:

"While securing digital devices is not a novel concept, the means of doing so have changed. Indeed, consumers have had the ability to utilize numeric or alpha-numeric passcodes to lock their devices for decades."

Courts that have addressed the passcode issue have found that a passcode cannot be compelled under the Fifth Amendment, because the act of communicating the passcode is testimonial, as "[t]he expression of the contents of an individual's mind falls squarely within the protection of the Fifth Amendment."

Biometric information was found to be of the same functionality of a passcode in mobile technology. Further, the court noted that "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."

This is contrary to how law enforcement has viewed biometric information in the past. Previously, police and prosecutors have felt that information obtainable from someone's body was different than information communicated by a suspect. Previous court rulings have tended to agree with this interpretation, thinking that biometric information was "physical evidence" and not a testimony given by the subject.

The Fifth Amendment states clearly that no one "shall be compelled in any criminal case to be a witness against himself," so what constitutes testimony that given by someone is a real concern in these kinds of cases.

This ruling establishes a precedent that the information which unlocks a mobile device -- no matter where it originates -- is protected by the Fifth Amendment.

But this is a decision that could be overturned on appeal. An Illinois decision in 2017 by a magistrate court judge that made a similar finding was later was overturned by a district court.

Adapting the law to new technology is always problematic. More courts may need to weigh in on this matter before privacy concerns can be dealt with in a stable and ongoing manner.

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— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.