Criminal suspects can refuse to provide phone passcodes to police under the US Constitution's Fifth Amendment privilege against self-incrimination, according to a unanimous ruling issued today by Utah's state Supreme Court. The questions addressed in the ruling could eventually be taken up by the US Supreme Court, whether through review of this case or a similar one.

The state argued "that, even if providing a passcode could be considered testimonial, the only meaningful information it would have conveyed here was that Valdez knew the passcode to the phone," the court said. Because police already knew the phone belonged to Valdez and that he would know his own passcode, the state contended that "this information would not convey anything new to law enforcement" and that it thus "triggers the foregone conclusion exception."

There is a difference between communicating a passcode to police and physically providing an unlocked phone to police, the court said. Though these two acts "may be functionally equivalent in many respects, this functional equivalency is not dispositive under current Fifth Amendment jurisprudence," the court said. "We conclude that the act-of-production analytical framework makes sense only where law enforcement compels someone to perform an act to unlock an electronic device."