Drug dogs, cell towers, and the expectation of privacy

Attorneys representing the U.S. Department of Justice are expected to defend warrantless use of stingray devices, which trick mobile devices into connecting to them by impersonating legitimate cell towers. Prosecutors yesterday filed court documents saying stingrays were used in investigations in Arizona and Wisconsin going back to 2008.

via FBI prepares to defend ‘Stingray’ cell phone tracking | Politics and Law – CNET News.

The Supremes just decided Florida v. Jardines, a case in which the question was if a drug-sniffing dog invaded the constitutional rights of a suspect when it alerted to the scent of drugs outside the suspect’s home. The police used the dog’s reaction to obtain a search warrant, and did find drugs. In a 5-4 decision, the Court held such a ‘search’ by the dog to be unconstitutional. But was it a victory for privacy rights? The Court’s view is that the officers’ venturing onto private property with the dog was the problematical aspect. This decision will have no effect upon a drug dog ‘search’ if the home or apartment is close enough to public property–a sidewalk, for example–for the dog to do his thing.

Well, the electronic analog of this case is coming to the lower Courts now. Your cellphone listens to the cell towers in range, decides which signal is the best, and negotiates which tower it uses. For years, the FBI has used Stingray, a box that emulates a cellphone tower, to track a subject’s cellphone and to record the numbers calling and called by that cellphone. It is also possible to record conversations using this technique. Apparently, the FBI (and local law enforcement) have been quiet about the full power of this technology and the extent of its use when obtaining warrants.

So what is the relationship between drug sniffing dogs and cellphone sniffing electronics? In both cases, specialized equipment can reveal information not readily apparent to humans. I don’t know about you, but I have a reasonable expectation of privacy about what goes on in my private residence and what my cellphone reveals about my friends and my location. If we accept that, and I think the Courts will as well, what is the difference? Here’s a big one. Stingray can be used while located on public property (e.g., public roads, public right of way, und so weiter). Fido might need to get close to your home, but Stingray works as long as its signal can win the tower selection algorithm. Fido and Stingray both pull information from the air, but Stingray has a more sensitive nose that needn’t be located on private property.

Prediction: the Supremes are going to see cases involving Stingray, and they are will need to define privacy rights in a world where we carry devices that can be snooped from public areas. They’d better start thinking about this.

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