Researchers can now spy on conversations with a light bulb (yes, really)

There are plenty of things to worry about in 2020. Apparently, light bulbs are one of them. A team of researchers from Israel’s Ben-Gurion University of the Negev and the Weizmann Institute of Science has created a way to eavesdrop on conversations from afar by watching the subtle vibrations of a light bulb in the room.

They claim that anyone could recreate the set up with less than a thousand dollars’ worth of equipment. While demonstrating the technique, researchers were able to clearly hear a conversation and even recognized a piece of music.

Evaporation of Privacy

The list of methods to eavesdrop on a distant conversation has become increasingly sophisticated. A determined spy could use a wiretap, a hacked phone, or plant a physical bug somewhere in the room. However, being able to steal sound with a regular light bulb that already exists in a room is a game-changer.

“Any sound in the room can be recovered… with no requirement to hack anything and no device in the room,” says Ben Nassi, a security researcher from Ben-Gurion who co-developed the eavesdropping technique, dubbed the Lamphone.

The series requires just two components to function — a telescope and a $400 electro-optical sensor. Of course, a light also needs to be turned on in the room. While that doesn’t exactly sound like spy equipment, the researchers note that the eavesdropper wouldn’t need to be particularly close to their target. The method works from hundreds of feet away.

Wannabe spies use the telescope to obtain a close-up view of the room while the electro-optical sensor converts light into an electrical signal. That can then be processed by a laptop in real-time.

But, how can looking at a light bulb reveal sound? Just like bumping into a hanging light fixture causes the light in the room to change, so too do sound waves. The difference, of course, is that sound waves create extremely small changes that the human eye can’t detect. A sensitive detector has no problem with it.

Sophisticated Listening

Unlike some theoretical breakthroughs, the technique that the researchers created is surprisingly sophisticated. They set up three telescopes, each with a different lens diameter, 25 meters away from their target.

At that distance, the system captured sound from the remote room. The team picked up The Beatles’ “Let It Be” clearly enough for Shazam to identify the song. It also replicated a speech from President Trump that Google’s speech recognition API successfully transcribed.

If that isn’t impressive enough, the researchers note that a more powerful telescope and/or more sensitive detectors could make the technique work from even further away.

It isn’t clear if the type of lighting in a room affects the eavesdropping technique. However, it would likely work to some degree with just about any fixture if the right equipment is used.

Still, everyday individuals probably don’t have anything to worry about. Unless you’re hiding a massive secret then the only ones listening will be Google and Alexa.

Originally published at https://www.theburnin.com on June 13, 2020.