Chinese researchers detect smartphone activity via leaked radio signals

Chinese researchers have devised a novel method capable of identifying smartphone applications and user activities by analyzing the low-frequency electromagnetic radiation emitted by devices, even when they are offline or locked.

The technique, developed by researchers at the People's Public Security University of China, functions as a non-contact forensic tool. It operates by detecting faint electromagnetic signals without needing to access the phone's operating system or stored data. This approach offers a way to gather objective technical evidence for digital forensics and investigations.

Published in the journal Radioengineering, the study detailed tests conducted on three smartphone models: an iPhone 15 Pro, a Xiaomi 15 Pro, and an Oppo Reno 13. The system demonstrated remarkable accuracy, achieving up to 99.07% in identifying various applications. These included popular platforms like Douyin, WeChat video calls, Baidu Maps, SMS messaging, browsers, cameras, and cloud storage services.

The researchers highlighted the potential of this method for intelligence gathering and forensic analysis, particularly in scenarios where traditional access to device data is impossible. The findings suggest a significant advancement in non-invasive methods for monitoring smartphone usage.

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This technical approach can provide objective technical corroboration for evidence reinforcement in digital forensics and non-contact investigations.