Scientists at La Sapienza University of Rome have created a new technology that can track and identify people through walls using just Wi-Fi signals. The system is called “WhoFi,” and it uses regular Wi-Fi routers to detect how a person’s body changes the signal. By studying those changes, the system can recognize each individual with up to 95.5 percent accuracy.
The WhoFi system does not need cameras, phones, or wearable devices. It only relies on how the body affects the path of a Wi-Fi signal. The team behind the research described the system as a new kind of biometric identifier that doesn’t use visuals or touch, but instead detects small differences in the way Wi-Fi waves bounce off each person’s body.
They wrote, “The core insight is that as a Wi-Fi signal propagates through an environment, its waveform is altered by the presence and physical characteristics of objects and people along its path. These alterations contain rich biometric information.”
To test their idea, scientists used a deep learning AI system called a transformer model. This model is able to study small changes in the Wi-Fi signals and recognize which person is causing them.
They tested it using a public dataset called NTU-Fi and tried it on 14 different people in different clothes and different places. The system could recognize people with an accuracy of up to 95.5 percent, even through walls and in places with poor lighting.
This is much better than a previous system called EyeFi, which was introduced in 2020 and reached only 75 percent accuracy. With WhoFi, the researchers have used Wi-Fi for human sensing.
The idea of using Wi-Fi to detect people is not new. For years, scientists have explored how to use it to detect movements, gestures, and even if someone falls. But identifying people through walls without a camera or a device is something new — and also a little worrying.
Experts say this kind of technology raises big questions about privacy. Unlike cameras or RFID tags that people can see or choose to use, Wi-Fi is always around us, and we don’t usually think about it as a tracking tool. The system can work silently in the background, and that makes it more difficult for people to know if they are being watched.
A privacy expert said, “This research opens up new possibilities for non-invasive monitoring, but also for covert surveillance. If deployed irresponsibly, it could allow for passive re-identification without a person’s knowledge or consent.”
The researchers understand this concern. They said that WhoFi does not collect personal information or reveal someone’s identity directly. However, they also agreed that any technology that can track people so accurately should have strong rules to make sure it is not misused.
Right now, the WhoFi project is only a research study. There are no plans to use it in commercial products or for government surveillance. But the scientists admit that as more buildings and cities use smart Wi-Fi networks, this kind of tracking could become a part of everyday life.
Researchers said, “We believe WhoFi can be used in a responsible way, but we also recognize the need for privacy. It is important to set limits before this technology becomes widely used.”
The full research paper is currently available as a preprint on arXiv.
