A California judge ruled this week that police officers can’t force people to unlock their smartphones via biometrics such as a fingerprint scanner.

Judge Kandis Westmore of the U.S. District Court for the Northern District of California ruled this week that police are not allowed to force citizens to unlock their smartphones with their biological features, such as their fingerprint or face.

The case in question involved a denial for a search warrant. The warrant was filed in relation to an extortion crime, in which a victim was asked to pay an exorbitant amount of money in exchange for the deletion of an embarrassing video that would have otherwise been posted to social media.

The case is significant due to its strong emphasis on privacy rights for smartphone users. Westmore ruled that the government does not have the right, even with a warrant, to force a citizen to unlock their smartphone via biometrics.

“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,” the judge wrote in the opinion.

“The undersigned finds that a biometric feature is analogous to the 20 nonverbal, physiological responses elicited during a polygraph test, which are used to determine guilt or innocence, and are considered testimonial,” Westmore continued.

An analyst from the Electronic Frontier Foundation praised the court’s decision, arguing that recent American jurisprudence has made it clear that citizens have a right to privacy when it comes to their smartphones.

“While that’s a fairly novel conclusion, it’s important that courts are beginning to look at these issues on their own terms,” the analyst said in a comment. “In its recent decisions, the Supreme Court has made clear that digital searches raise serious privacy concerns that did not exist in the age of physical searches—a full forensic search of a cellphone reveals far more than a patdown of a suspect’s pockets during an arrest for example.”