Big wifi Brother is watching you!
All those shops with free wifi networks that you walk or drive past on your way to work or elsewhere could be inadvertent surveillance zones. They have the potential to identify you, generating a complete profile of your movements. And all this without your knowledge or consent. What if you’re not connected, you ask? Or better yet, what if you’re not even carrying a mobile device? No matter, claims a research team from Germany’s Karlsruhe Institute of Technology (KIT) in their paper(opens in new window). In a study involving nearly 200 volunteers, they found that wifi networks can identify people with almost 100 % accuracy based on their distinctive movements and physical characteristics.
Somebody’s watching me
“By observing the propagation of radio waves, we can create an image of the surroundings and of persons who are present,” explained cybersecurity expert Thorsten Strufe, professor of IT security at KIT, in a press release(opens in new window). “This works similar to a normal camera, the difference being that in our case, radio waves instead of light waves are used for the recognition. Thus, it does not matter whether you carry a WiFi device on you or not.” He added that a switched-off device doesn’t change anything either: “It’s sufficient that other WiFi devices in your surroundings are active.” “This technology turns every router into a potential means for surveillance,” warned PhD student Julian Todt, who worked on the study. “If you regularly pass by a café that operates a WiFi network, you could be identified there without noticing it and be recognized later – for example by public authorities or companies.” The technology can produce images of surroundings and identify someone in real time by analysing how their bodies disrupt radio waves. Conventional cameras depend on visible light reflecting off surfaces. However, this technology uses radio waves, such as those from a standard router found in homes or cellular signals, that have much longer wavelengths. These radio waves can pass through drywall, wooden doors and clothing. When the waves hit a human body, they bounce back or scatter. Researchers used several antennas and sophisticated AI algorithms to analyse the specific way the waves deflect and spread out when they hit an object. By doing so, they can reconstruct the shape, position and even the movement of individuals in a room. Felix Morsbach, another PhD student, emphasised the fact that there are simpler techniques nowadays for government security agencies, intelligence agencies or cybercriminals to track people. “However, the omnipresent wireless networks might become a nearly comprehensive surveillance infrastructure with one concerning property: they are invisible and raise no suspicion.”
Privacy anyone?
Wifi networks exist in almost all public spaces, from homes and offices to cafes and restaurants. “The technology is powerful, but at the same time entails risks to our fundamental rights, especially to privacy,” concluded Strufe. The researchers urgently call for privacy protections and protective measures so this technology doesn’t fall into the wrong hands and extensive exploitation takes over.