The so-called lamphone technique allows for real-time listening in on a room that’s hundreds of feet away. 

THE LIST OF sophisticated eavesdropping techniques has grown steadily over years: wiretaps, hacked phones, bugs in the wall—even bouncing lasers off of a building’s glass to pick up conversations inside. Now add another tool for audio spies: Any light bulb in a room that might be visible from a window.

Researchers from Israeli’s Ben-Gurion University of the Negev and the Weizmann Institute of Science today revealed a new technique for long-distance eavesdropping they call “lamphone.” They say it allows anyone with a laptop and less than a thousand dollars of equipment—just a telescope and a $400 electro-optical sensor—to listen in on any sounds in a room that’s hundreds of feet away in real-time, simply by observing the minuscule vibrations those sounds create on the glass surface of a light bulb inside. By measuring the tiny changes in light output from the bulb that those vibrations cause, the researchers show that a spy can pick up sound clearly enough to discern the contents of conversations or even recognize a piece of music.

“Any sound in the room can be recovered from the room with no requirement to hack anything and no device in the room,” says Ben Nassi, a security researcher at Ben-Gurion who developed the technique with fellow researchers Yaron Pirutin and Boris Zadov, and who plans to present their findings at the Black Hat security conference in August. “You just need line of sight to a hanging bulb, and this is it.”

In their experiments, the researchers placed a series of telescopes around 80 feet away from a target office’s light bulb, and put each telescope’s eyepiece in front of a Thorlabs PDA100A2 electro-optical sensor. They then used an analog-to-digital converter to convert the electrical signals from that sensor to digital information. While they played music and speech recordings in the faraway room, they fed the information picked up by their set-up to a laptop, which analyzed the readings.

side by side images of telescope pointing to window and aerial of bridge

The researchers’ experimental setup, with an electro-optical sensor behind the eyepiece of a telescope, pointing at a lightbulb inside an office building more than 80 feet away.COURTESY OF BEN NASSI

The researchers found that the tiny vibrations of the light bulb in response to sound—movements that they measured at as little as a few hundred microns—registered as a measurable changes in the light their sensor picked up through each telescope. After processing the signal through software to filter out noise, they were able to reconstruct recordings of the sounds inside the room with remarkable fidelity: They showed, for instance, that they could reproduce an audible snippet of a speech from President Donald Trump well enough for it to be transcribed by Google’s Cloud Speech API. They also generated a recording of the Beatles’ “Let It Be” clear enough that the name-that-tune app Shazam could instantly recognize it.



The crypto agency has a list of questions for federal employees and contractors to ask as they choose a collaboration tool.

Video conferencing platforms Zoom and Microsoft Teams are both FedRamp approved, but while Zoom offers end-to-end encryption, Microsoft Teams does not, according to the National Security Agency. 

These are just two of nine factors the NSA cites in creating a guide to help federal workers choose commercial telework tools for “safely using collaboration services,” as necessitated by the coronavirus pandemic.

The guide, which NSA released Friday, applies only to commercial applications, and one strong recommendation from the agency is that, when possible, workers use U.S. government services such as Defense Collaboration Services, Intelink Services and others, which were designed specifically for secure government communications. But government workers still need to interact with external entities which might be sending them invitations via commercial applications, and the NSA has detailed a number of factors for them to weigh in deciding which ones to facilitate:

  • Does the service implement end-to-end encryption?
  • Are strong, well-known, testable encryption standards used?
  • Is multi-factor authentication (MFA) used to validate users’ identities?
  • Can users see and control who connects to collaboration sessions?
  • Does the service privacy policy allow the vendor to share data with third parties or affiliates?
  • Do users have the ability to securely delete data from the service and its repositories as needed?
  • Has the collaboration service’s source code been shared publicly (e.g. open source)? 
  • Has the service and/or app been reviewed or certified for use by a security-focused nationally recognized or government body? 
  • Is the service developed and/or hosted under the jurisdiction of a government with laws that could jeopardize USG official use?



MIT engineers have designed a “brain-on-a-chip,” smaller than a piece of confetti, that is made from tens of thousands of artificial brain synapses known as memristors — silicon-based components that mimic the information-transmitting synapses in the human brain.

The researchers borrowed from principles of metallurgy to fabricate each memristor from alloys of silver and copper, along with silicon. When they ran the chip through several visual tasks, the chip was able to “remember” stored images and reproduce them many times over, in versions that were crisper and cleaner compared with existing memristor designs made with unalloyed elements.

Their results, published today in the journal Nature Nanotechnology, demonstrate a promising new memristor design for neuromorphic devices — electronics that are based on a new type of circuit that processes information in a way that mimics the brain’s neural architecture. Such brain-inspired circuits could be built into small, portable devices, and would carry out complex computational tasks that only today’s supercomputers can handle.



Researchers use a ferroelectric glass electrolyte within an electrochemical cell to create simple self-charging batteries.

A new type of battery combines negative capacitance and negative resistance within the same cell, allowing the cell to self-charge without losing energy, which has important implications for long-term storage and improved output power for batteries.

These batteries can be used in extremely low-frequency communications and in devices such as blinking lights, electronic beepers, voltage-controlled oscillators, inverters, switching power supplies, digital converters and function generators, and eventually for technologies related to modern computers.

In Applied Physics Reviews, from AIP Publishing, Helena Braga and colleagues at the University of Porto in Portugal and the University of Texas at Austin, report making their very simple battery with two different metals, as electrodes and a lithium or sodium glass electrolyte between them.

Bistable Energy Landscape for a Lithium-Glass Ferroelectric-Electrolyte

image source:

Bistable energy landscape for a lithium-glass ferroelectric-electrolyte in contact with an aluminum-negative electrode and self-cycling process in an electrochemical aluminum/lithium glass/copper cell. a) Variation of the potential energy with plated lithium leading to negative capacitance/self-charge and negative resistance/self-cycling. b) Self-charge and self-cycling processes upon alignment of the dipoles in the ferroelectric-electrolyte due to the electrical necessity of aligning the Fermi levels. Credit: Braga et al.