Ordinary WiFi networks possess the capability to identify individuals with nearly 100% accuracy, even when they do not have any connected devices like smartphones or laptops with them, according to recent research. This discovery raises the potential for widespread surveillance, turning everyday wireless networks into an invisible tracking system.
Scientists from the Karlsruhe Institute of Technology in Germany have developed a method that utilizes unencrypted signals routinely exchanged between WiFi devices and routers. These signals can be analyzed to create radio-based images, functioning similarly to a camera, to recognize people within seconds. The findings suggest that millions of WiFi routers could form a vast, undetectable surveillance network, potentially enabling corporations or governments to identify individuals without their knowledge.
"The technology is powerful, but at the same time entails risks to our fundamental rights, especially to privacy," stated Professor Thorsten Strufe of the Karlsruhe Institute of Technology. The method exploits normal communications produced by legitimate users connected to WiFi networks in various locations, including homes, offices, and cafes. Connected devices regularly transmit information back to routers to optimize wireless communications. These signals, known as beamforming feedback information, are transmitted without encryption, allowing individuals within range to potentially analyze them without the tracked person being aware.
"This technology turns every router into a potential means for surveillance," warned co-researcher Julian Todt. "If you regularly pass by a café that operates a WiFi network, you could be identified there without noticing it and be recognized later." The research team tested the technique with 197 participants and reported that their system achieved an accuracy rate of almost 100% in inferring identities.
The researchers are now advocating for the implementation of protective measures and privacy safeguards in new WiFi systems to address the potential risks before they become widespread.