Security News > 2020 > February > Researchers transmit data covertly by altering screen brightness
Researchers at Ben-Gurion University of the Negev have made a name for themselves figuring out how to get data out of air-gapped computers.
Now, they've figured out a way to retrieve data from a disconnected computer by altering its LCD display's pixel density just enough for a nearby camera to pick it up.
A camera located six metres from the 19-inch screen was nevertheless able to detect the difference.
Abraham Lincoln's Gettysburg address was notoriously brief, but by our calculations, it would still take over 38 minutes to beam it from screen to camera as ASCII text.
The bit rate is also subject to the camera's view of and distance from the screen, along with the display's brightness, so if things weren't positioned just right, you'd be waiting four score and seven years to retrieve any significant data.