Cybersecurity experts talk about how a simple light bulb allows you to eavesdrop on conversations
Miscellaneous / / October 14, 2021
You can make out someone else's speech even through a closed window from a distance of 25 meters.
A group of Israeli cybersecurity experts have proven that a light bulb can be used to eavesdrop on conversations. True, this requires special conditions and some equipment. About it writes IFLScience portal.
This method is based on monitoring the microvibrations of the light bulb surface, which are generated in response to sound waves. From these slightest movements, you can determine with fairly high accuracy what people are talking about in the room.
This method of surveillance began to be investigated back in 2020. A group of Israeli researchers from Ben-Gurion University of the Negev and the Weizmann Institute of Science have named it "Lamphone Attack."
In the course of numerous experiments, experts have confirmed that the method is really effective. In one test, a group of researchers tried to listen to an isolated room through a window from a distance of at least 25 meters. To do this, they used a telescope with an electro-optical sensor aimed at a light bulb in the room. The signal from it passed through an analog-to-digital converter and was studied by a special algorithm.
People in the room were playing a snippet of Donald Trump's speech, and experts outside the room were able to hear it. The recording was of rather low quality, as if the president was drunk and talking on the radio in a submarine. However, this was enough for the words to be parsed using the Google Speech automatic speech recognition system.
In another test, the experts were also able to recover the signals of several songs that were played in the room. One of them was the composition "Let It Be" by the Beatles. The vibrated text was easily recognized by Shazam.
The researchers note that even very small vibrations of just a couple of milli-degrees are enough to restore speech and non-speech sound. However, there are some important conditions. Firstly, this method will work only with ordinary incandescent lamps and LED counterparts, but nothing will work with fluorescent lamps, since they practically do not produce vibrations. Secondly, the light bulb must be constantly on, hang next to the sound source and must be clearly visible from afar - without obstacles and shadows.
Wiretapping through a light bulb is far from the only non-obvious way to spy on someone. For example, spy on smartphone owners can by accessing the gyroscope or light sensor on the device. And you don't even need a GPS to find out the owner's location.
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