Karlsruhe Institute of Technology researchers reveal Wi-Fi tracking method

Researchers at the Karlsruhe Institute of Technology (KIT) have demonstrated that Wi-Fi signals can be used to identify specific individuals with nearly 100% accuracy. The study, conducted by Julian Todt, Felix Morsbach, and Thorsten Strufe at KASTEL Security Research Labs, utilized data from 197 participants to prove that human movement affects how radio waves propagate through a space.

The method relies on Beamforming Feedback Information (BFI), which contains data exchanged between devices regarding radio channel characteristics. By applying machine learning to these patterns, researchers can create a unique “radio image” of an environment. Crucially, this tracking method does not require the subject to carry a smartphone or any other Wi-Fi-enabled device; the presence of other communicating devices in the vicinity is sufficient to capture the signal distortions caused by a person's body.