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Smartphone Can Be Tracked Through Electromagnetic Signals: If you think that no one can track your activity after locking the smartphone, turning on flight mode or turning off the internet, then a new research challenges this notion. Chinese researchers have claimed that by analyzing the extremely weak electromagnetic (EM) signals emanating from smartphones, it can be found out which app is running on the phone and what the user is doing.

However, this technology is still in the early research stages and has only been tested in a controlled lab environment. At present it has not become a practical surveillance technology for the common people.

This is new technology

Researchers at the People’s Public Security University of China have developed this technology for digital forensics. This is a non-contact forensic technique, that is, some technical clues can be obtained without unlocking the phone, without accessing the operating system and without even extracting data.

According to research, when a smartphone works, very weak low-frequency electromagnetic signals are emitted from its hardware. The pattern of these signals changes with different apps and during different activities. By analyzing these patterns, it can be guessed which app is being used in the phone.

Claims more than 99 percent accuracy

The research team tested this technology on smartphones like iPhone 15 Pro, Xiaomi 15 Pro and Oppo Reno 13. The researchers claim that their AI model was successful in identifying which app was running on the phone with 99.07 percent accuracy.

During testing, apps like Douyin, WeChat Video Call, Baidu Maps, SMS, Browser, Camera and Cloud Storage were included.

Additionally, the model also identified with about 95.61% accuracy whether the user was pausing the video or audio, playing it at normal speed or watching at double the speed. Platforms like YouTube, Bilibili and Tencent Video were used for this.

This is how an app is identified by signal

Every mobile app uses the phone’s hardware in different ways. Some apps put more stress on the processor and graphics chip, while others keep the GPS, Wi-Fi, storage controller or wireless communication systems more active.

This different use of hardware changes power consumption patterns, which emit different electromagnetic signals. By recognizing these signal patterns, AI guesses which app and what type of activity is running on the phone.

Signals collected in research like this

Researchers in China placed a special induction coil on the back of a smartphone, which was connected to a high-precision digital monitoring receiver. The instrument recorded electromagnetic signals between 150 kHz and 650 kHz.

Later these signals were converted into time-frequency spectrograms and analyzed with the help of deep learning based AI models. Researchers say that this technology can prove useful in the future for digital investigation agencies in gathering additional technical evidence.

Do common users need to worry?

At present there is no need to panic about this research. The equipment used in the study is highly specialized and expensive. Additionally, the entire testing was conducted in a controlled lab environment, where the monitoring device was placed very close to the smartphone.

It is not clear in the research paper how effective this technology will be in crowded electromagnetic environments, long distances or normal conditions. That is, it has not yet been proven that a person’s phone can be easily tracked in this manner in real life.

Research will proceed in this direction

Researchers say that in the future they will work on developing such a technology that can take the specific electromagnetic ‘fingerprint’ of different smartphones. Could recognize. Research will also be done on the possibility of recording signals with less specialized equipment.

The research team has also suggested that in the future, the possibilities of collecting such signals can be worked on with the help of magnetometers of smartphones or sensors of wearable electronic devices.