The technique takes advantage of the fact that Wi-Fi wireless networking protocols are "promiscuous": the Wi-Fi adaptors in laptops, phones and base-stations reveal a lot of information about those devices as they attempt to negotiate connections with other devices nearby. Even before a device hooks onto a Wi-Fi a network, it continuously spews identifying information, including a unique, factory-set identifier, over the air. Most devices send "probe requests" akin to a town crier shouting out the names of networks which the device has previously connected to, so that a nearby base-station that matches any of these requests can respond. The requests run unremittingly across all available frequencies until a connection is made. Even devices that are seemingly turned off, such as sleeping laptops, send out such probes, though at a slower rate. Place several Wi-Fi base-stations in a shop, then, and you can pick up these probe requests, extract the device IDs, trilaterate the positions of the devices sending them, and thus track the movements of individual shoppers, seeing which racks or displays they stop at, and what paths they follow through the store.rawstory/rs/2013/07/23/how-retail-stores-track-your-in-store-movements-via-smartphone-without-you-connecting-to-their-wifi/
Posted on: Tue, 23 Jul 2013 16:46:29 +0000
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