In his backpack, Wouter Slotboom, 34, carries around a small black device, slightly larger than a pack of cigarettes, with an antenna on it. I meet Wouter by chance at a random cafe in the center of Amsterdam. It is a sunny day and almost all the tables are occupied. Some people talk, others are working on their laptops or playing with their smartphones.
Wouter removes his laptop from his backpack, puts the black device on the table, and hides it under a menu. A waitress passes by and we ask for two coffees and the password for the WiFi network. Meanwhile, Wouter switches on his laptop and device, launches some programs, and soon the screen starts to fill with green text lines. It gradually becomes clear that Wouter’s device is connecting to the laptops, smartphones, and tablets of cafe visitors.
On his screen, phrases like “iPhone Joris” and “Simone’s MacBook” start to appear. The device’s antenna is intercepting the signals that are being sent from the laptops, smartphones, and tablets around us.
via Here’s Why Public Wifi is a Public Health Hazard — Matter — Medium.