WLAN signals as a monitoring tool: New technology discovered!

WLAN signals as a monitoring tool: New technology discovered!

Researchers at the Karlsruhe Institute of Technology (KIT) have developed a groundbreaking method that makes it possible to identify people based solely on WiFi signals. This discovery could have far-reaching implications for data protection, as identification works even if people do not have their own smartphone or tablet with them. Professor Thorsten Strufe explains that the technology uses communication between WiFi devices in the area to create an image of the people present. Switching off WLAN devices does not offer any protection, as active devices in the area are sufficient to enable identification. WLAN routers could thus mutate into surveillance devices and create a comprehensive surveillance infrastructure.

The method is similar to how conventional cameras work, but it is based on radio waves. The researchers analyzed unencrypted feedback signals from users connected to a WiFi network. In a study with 197 participants, almost 100% accuracy in identification was achieved. The results of this research will be presented at the ACM Conference on Computer and Communications Security (CCS) in Taipei, while the original publication will be available from October 13, 2025. According to the researchers, the planned WLAN standard IEEE 802.11bf should also contain protective measures and data protection mechanisms to protect privacy.

New technology for personal identification

Additionally, a related technique known as “WhoFi” was developed by scientists at La Sapienza University in Rome. It also works via WiFi signals and uses the interference that human bodies leave in the WiFi signal. Each person creates a kind of invisible Wi-Fi fingerprint that is captured using an AI model. This model analyzes minimal signal changes in channel state information (CSI), which extracts important biometric features such as body shape, size and movement.

The Deep Neural Network (DNN) processes this information and can achieve recognition accuracy of up to 95.5 percent. Not only is this method less susceptible to external influences than traditional biometric systems, but it can also be used in various environments such as homes, offices or public buildings without visible surveillance technology or the consent of those affected. In particular, the use of WLAN signals to identify people raises concerns about surveillance and data protection, as similar identification processes can also be carried out without the knowledge of those affected.

Implications for privacy and ethics

The technology for biometric personal identification via WLAN, as developed by both KIT and the University of La Sapienza, brings with it numerous challenges in terms of data protection. Privacy advocates and ethics experts are raising concerns, particularly about the possible invisible surveillance enabled by these technologies. The fact that cameras are not required and therefore physical presence in the field of vision is not required compounds the problem.

In fact, these developments could revolutionize the landscape of modern surveillance systems. Traditional re-identification (Re-ID), which previously relied heavily on visual data, is being supplemented by the new approaches with WLAN signals, which is attracting attention from data protectionists and ethicists alike. Robust data protection mechanisms are essential to protect individual privacy and ensure ethical use of such technologies.