Evan Schuman's StorefrontBacktalk

Attorney Mark D. Rasch is the former head of the U.S. Justice Department’s computer crime unit and today serves as Director of Cybersecurity and Privacy Consulting at CSC in Virginia.

The ongoing debate about how far retailers can—and should—go when tracking customers through their mobile devices is getting confused, thanks to the illegal misinterpretations made by some of the vendors pushing these approaches.

Let’s be clear: Be ahead of the curve in tracking consumers, and do it before case law and legislation have a chance to play themselves out, and you could find yourself with legal headaches for years—potentially having to somehow remove all of that ill-gotten data from your systems.

The most prominent player in this space is U.K. vendor Path Intelligence, which had planned to launch its FootPath system in two U.S. malls on Black Friday. But it abandoned the effort after major pushback from a U.S. senator.

FootPath relies on the provisions of Federal Law 18 USC 2511(2)(g)(i), for the proposition that it is not illegal to measure signaling information and infer a person’s location. That provision, which is part of the wiretap law that makes it a crime to intercept people’s communications, notes that it is not illegal “to intercept or access an electronic communication made through an electronic communication system that is configured so that such electronic communication is readily accessible to the general public.” Sounds good, no? These impulses are configured in a way that is accessible to the general public, right? Anyone can capture them.

The problem here is that this particular statute was aimed at the interception of the contents of communications—wiretapping. Eavesdropping. Listening in. And the FootPath system makes a sensible exception to the wiretap law. If you are on the FM radio, then listening to the conversation ain’t illegal. Same is true for things like walkie-talkies, FRS band radios, Ham radios or other services that are “configured so that the communication is readily accessible to the public.” In the case of my cell-phone signals, I doubt that I have configured the device so that any communication is readily accessible to the public.

What the FootPath technology appears to do is pretend to be half a cell tower (the receiving half) and capture, record and measure the signaling information from the consumer’s handset. Here is where the company likely ran afoul of the law. Federal Law 18 USC 3121 makes it illegal to install or use either a “trap and trace” device or a “pen register.” Under the statute, “the term “pen register” means a device or process which records or decodes dialing, routing, addressing or signaling information transmitted by an instrument or facility from which a wire or electronic communication is transmitted. A “trap and trace device” is a device or process which captures the incoming electronic or other impulses which identify the originating number or other dialing, routing, addressing and signaling information reasonably likely to identify the source of a wire or electronic communication, provided, however, that such information shall not include the contents of any communication.

Because the FootPath technology records signaling information transmitted by an instrument [telephone], it is likely a “pen register,” for which a court order is required. As such, using the information gained through it without a pen register order is likely illegal.

As a side note, the FBI actually had a clever idea to use a technology very similar to FootPath. Rather than subpoenaing phone companies or others for information about the location of a particular subscriber’s phone, the bureau used a technology called “Stingray” (among others), which mimics a cell tower and sends a signal to the targeted phone. The strength of the signal back would determine the location. Unlike getting information from the phone company (which would require either a subpoena or a warrant), this technology would only require the lower standard of a “pen register”—that is, a certification by the government that the information is relevant to some investigation. Now unlike FootPath, Stingray identifies a specific phone and actively “pings” that phone to determine its location. Nevertheless, both Stingray and FootPath are, under the law, “pen registers.” Therefore, you need a court order to monitor their results.