New Delhi, May 26 -- Researchers from the Karlsruhe Institute of Technology (KIT) have warned about a new kind of surveillance technology that can turn a WiFi router into invisible tracking tools capable of identifying people even if they are not carrying a smartphone or any connected device.

"This technology turns every router into a potential means for surveillance," Julian Todt, one of the authors of the study warned, "If you regularly pass by a cafe 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 researchers explained that the attack called BFId uses Beamforming Feedback Information (BFI) which is a feature introduced in Wi...