It's ten o'clock, do you know where your cell-phone signal is?

  • Joseph Alfe

    Joseph Alfe

  • Grant Talabay

    Grant Talabay

By Joseph C. Alfe and Grant D. Talabay
Guest columnists
Posted1/23/2019 1:00 AM

Have you noticed strange-looking antenna-like structures being erected on city streets, or hung on traffic lights or telephone poles? They might be stealing your digital location and data. Here is what they are and how they do it.

Consider the following: A law enforcement agency obtains a "pen register/trap and trace" court order or search warrant to obtain phone company "business records" containing numbers dialed and duration of calls for a particular device at a particular place in time.


At least this is what the law enforcement agency represents to the court in order to obtain the court order or warrant. In actuality, what happens is law enforcement often uses a surreptitious electronic cell-signal emulator, often known by trade names such as "Stingray" or "Hailstorm." These secretive electronic cell-signal emulators do more than just log phone numbers. Devices such as Triggerfish can pinpoint phone and user location, even within physical structures.

These emulators are eerily effective and can disrupt or hijack a cellphone device, gather information on non-target devices in the search area, and even access the data within these phones. Even more troubling, once these devices are activated, they not only steal the target's data and location, but also those of every device within range.

If our digital information described was captured by the signal emulators, law enforcement contends that the collected data fit precisely within the confines of the third-party doctrine set forth in Smith v. Maryland. In that case, The United States Supreme Court held that "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.

Here, the third-party being the phone service provider is compelled to turn over to law enforcement a particular phone number and non-content call logs pursuant to a pen register order. The Smith Court expressly condones such a practice. This is not what is at issue here. This is, however, how law enforcement often represents its intentions to courts in order to justify a pen register/trap and trace order.

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What law enforcement may be really after when using signal emulators is to determine the device's (and therefore the user's) precise location at any given time.

In Katz v. United States, the Supreme Court asked, "Did the subject intend to keep his affairs private?" Contrasting the Katz query with Smith's third-party doctrine necessarily begs the questions: "Does one voluntarily convey his location to third parties just by existing?" and "What if a device is located within a dwelling or other structure?" In answering either question, one quickly realizes that a serious privacy right is implicated and thus exposes the difficulty in granting law enforcement permission to access precise device location data without a warrant.

The extent of those privacy rights was recently addressed by the Supreme Court. In United States v. Jones, the court found that a GPS device obtained without a warrant, attached to a vehicle constituted a search under the Fourth Amendment.

When law enforcement uses signal emulator technology under false pretenses, and uses that technology to spy on citizens' location, that should also be an unreasonable search in violation of the Fourth Amendment, and something we should all be worried about. The court has yet to address this question.


The Fourth Amendment of the Bill of Rights commands that: "The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."

Fundamentally and foundationally, security "in [our] persons" ought to stand for security "of our person's location." Security in our "papers, and effects" ought to also mean security "in our digital possessions and privacy," and thus, no warrants shall issue without probable cause.

Joseph C. Alfe, of Chicago, and Grant D. Talabay, of Woodstock, are members of the board of directors of the Chicago Lawyer Chapter of the American Constitution Society.

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