A new technology developed by researchers at La Sapienza University of Rome could transform how individuals are identified in connected environments and reignite urgent debates over privacy. In a breakthrough that bypasses traditional biometrics, the research team has demonstrated that a person can be re-identified solely based on how their body alters surrounding Wi-Fi signals.
The method, called WhoFi, leverages the unique way each person’s physical presence disturbs electromagnetic waveforms. Unlike facial recognition, fingerprint scans, or phone-based tracking, WhoFi requires no cameras or wearable devices.
It can passively track people in any area blanketed by Wi-Fi coverage, making it both powerful and controversial.
“As a Wi-Fi signal moves through an environment, it interacts with the objects and people in its path. These interactions subtly change the signal’s characteristics, and those changes carry biometric information,” the researchers explain.
The team composed of computer scientists Danilo Avola, Daniele Pannone, Dario Montagnini, and Emad Emam used variations in Wi-Fi channel state information (CSI), such as amplitude and phase shifts, to build what they call a person’s "Wi-Fi signature."
These invisible disturbances are distinct enough to allow for precise re-identification.
To prove the concept, the researchers trained a transformer-based deep neural network to distinguish individuals by analyzing how they disrupt signals across different locations. When tested against the NTU-Fi dataset, a standard benchmark for Wi-Fi-based human sensing, WhoFi achieved a re-identification accuracy of up to 95.5%.
Beyond Biometric Norms
Wi-Fi-based human sensing has been in development for years, applied in use cases like motion detection, fall alerts for the elderly, and even through-wall monitoring. In 2020, a similar system dubbed EyeFi achieved 75% accuracy in identifying individuals via signal interaction.
However, the creators of WhoFi argue that their system offers superior precision and greater environmental adaptability.
This advancement opens doors for a host of potential applications from seamless authentication in smart homes and offices to non-invasive surveillance in public spaces. But it also raises the specter of surveillance without consent.
The Privacy Dilemma
Because WhoFi requires no explicit action or device on the part of the person being tracked, it introduces ethical and legal complexities. Unlike security cameras, which are visible, or facial recognition systems that often operate in regulated zones, Wi-Fi-based identification could run silently in the background of any networked environment.
Privacy advocates warn that such capabilities could be misused, particularly in authoritarian regimes or by private companies seeking to monitor behavior without permission.
“This kind of passive identification, while technologically impressive, blurs the line between convenience and intrusion,” one digital rights expert noted. “We must ask who controls these systems, and how their use is regulated.”
The Future of Human Sensing
As the Internet of Things expands and ambient computing becomes more embedded in daily life, technologies like WhoFi may become standard components of smart infrastructure. While the researchers position their system as more ethical than invasive surveillance tech, no image data, no personal devices required.
It also challenges conventional ideas of consent and anonymity in public and semi-public spaces.
In the hands of responsible actors, WhoFi could enhance security and accessibility. But without strong data governance frameworks, it could just as easily become a tool for constant, invisible monitoring.
