It’s official: Your cell phone, like your home, is a private environment to which even law officials must have explicit permission to enter.

The Supreme Court said as much today in a unanimous ruling that establishes police need a warrant to search cell phones of people who are arrested. However, there are exceptions to this rule in cases in which imminent danger to life is involved or there’s a chance that evidence will be destroyed.

"The court recognized that the astounding amount of sensitive data stored on modern cell phones requires heightened privacy protection, and cannot be searched at a police officer's whim,” said Hanni Fakhoury, staff attorney for the Electronic Frontier Foundation, a non-profit organization founded in 1990 to defend civil liberties in the digital world. “This should have implications for other forms of government electronic searches and surveillance, tightening the rules for police behavior and preserving our privacy rights in our increasingly digital world."

The ruling came in the wake of two cases.

In one, San Diego Police found photos of guns on the smartphone of a man, who was stopped on a traffic violation, to link him to a street gang and shooting. An officer searching the man took the cell phone from the man’s pants pocket, and noticed on the cell phone repeated use of a term associated with a street gang. Later at the police station, law enforcement specializing in gangs further investigated the phone’s contents, which led to the state of California charging the man in connection with a shooting that occurred a few weeks earlier.

In the other, a person in Boston was arrested on suspicion of selling drugs, and information on that individual’s flip phone offered information about the whereabouts of crack cocaine.