Privacy Law

Magistrate judge denies boilerplate warrant request for forced fingerprint unlocking of iPhones

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Federal agents who want to search a premises for electronic devices haven’t justified a request to force people there to provide fingerprints or thumbprints to unlock iPhones and iPads, a federal magistrate judge in Chicago has ruled.

U.S. Magistrate Judge M. David Weisman ruled (PDF) on Feb. 16 when considering the government’s search warrant application in a child pornography case. Ars Technica and Forbes are among the publications that covered the decision after Stanford cryptography fellow Riana Pfefferkorn noted the decision on Twitter.

Weisman said the government’s request for thumbprints and fingerprints was not limited to a particular person or a particular device. Even “itinerant visitors” would be subject to fingerprinting, if the government request were granted, Weisman said.

That would create Fourth Amendment problems as a result of case law limiting the types of searches that can be conducted on people present at a home being searched, Weisman said. Based on the facts in the search warrant application, Weisman said, the Fourth Amendment intrusion is not justified.

Weisman also raised concerns about possible violation of the Fifth Amendment right against self-incrimination. Though the production of physical characteristics don’t generally raise Fifth Amendment concerns, using a fingerprint to unlock an iPhone produces the contents of the device and reveals the subject has some control over it, he said.

The government said its request for fingerprints is standard language in its search warrants. “This declaration of standardization is perhaps the crux of the problem,” Weisman said. “The issues presented here require a fact-intensive inquiry both for the purposes of the Fourth Amendment and Fifth Amendment.”

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