A US court has ruled that police and other law enforcement agencies must obtain a search warrant before acquiring location data stored in cellphones and smartphones.
Three judges in the US Appeals Court for the 11th Circuit agreed on Wednesday that acquiring records of which cell towers connect to a smartphone and tablet, as well as when they connect, constitutes a search under the Fourth Amendment, which prevents unreasonable searches and seizures.
It comes almost a year after a ruling by the US Appeals Court for the 5th Circuit, which ruled that location data stored on mobile devices is not protected under the constitution.
Wednesday's ruling by the 11th Circuit — covering Florida, Alabama, and Georgia — will not overrule the 5th Circuit's decision due to jurisdiction, but it will add another voice to the argument that mobile device location data should be protected under federal law.
The courts gave their opinion in a 38-page ruling [PDF], but the nugget that stands out was on page 10:
...It concerned location information obtained by a technology sufficiently similar to that furnished in the cell site location information to make it clearly relevant to our analysis.
However, in the twentieth century, a second view gradually developed: that is, that the Fourth Amendment guarantee protects the privacy rights of the people without respect to whether the alleged 'search' constituted a trespass against property rights.
The ruling later said that it "cannot be denied that the Fourth Amendment protection against unreasonable searches and seizures shields the people from the warrantless interception of electronic data or sound waves carrying communications."
"In short, we hold that cell site location information is within the subscriber's reasonable expectation of privacy," the ruling added. "The obtaining of that data without warrant is a Fourth Amendment violation."
The American Civil Liberties Union (ACLU), which was involved in arguing in favor of the case's eventual outcome, said in a tweet following the ruling, that it was a "huge privacy victory."
The court's judges said in their ruling: "The question whether cell site location information is protected by the Fourth Amendment guarantees against warrantless searches has never been determined by this court or the Supreme Court."
The full ruling can be found below.