Last Seen is a Wi-Fi packet sniffer that was a part of Laura Poitras’ show, Astro Noise, at the Whitney museum of art.
Our devices have memories. They store a list of places (via Wi-Fi networks) where they’ve previously been. If you have Wi-Fi activated on your device (smartphone/laptop) then that device will send Probe Request Frames looking for known networks. Once it’s found one to connect to, it ceases to send these Probe Request Frames.
Probe requests frames are sent over the air completely unencrypted and can be picked up by any device that is listening on that Wi-Fi channel. This technique is used in the 802.11 (Wi-Fi) protocol to allow seamless connection between a client and router.
While it is hard to determine a persons identity from this information it is fairly easy to understand the demographic they fall in . Conferences they’ve been to, hotels they’ve stayed at, museums and universities they have visited - this information is constantly being broadcasted by our Wi-Fi enabled devices and is used by advertising companies to track us.
This piece replicates the method used to collect this data in order to reveal the parts of our personal history we are broadcasting.
For more background information check out From The Dark
A fun highlight for me was this tweet that shows Edward Snowden explaining how the piece works when he got a tour of the show.