gr-tempest

Out-of-tree GNU Radio module available in GNU Radio World

Display image reconstructed from unintended electromagnetic emissions — Project-site screenshot

gr-tempest is a GNU Radio implementation of Van Eck phreaking, the reconstruction of display content from unintended electromagnetic emissions produced by video cables and electronics. Its synchronization and resampling stages estimate or apply the horizontal and vertical timing of VGA and HDMI signals, correct sampling error, align the raster, and turn the recovered intensity stream back into an image. The module supports recorded captures, simulations, and live radio input, with manual, semi-automatic, and experimental automatic workflows for finding stable video geometry under noisy reception conditions.

Main authors: Federico Larroca, Felipe Carrau
Last modified: 2025-02-10
Project: Upstream repository

Example flowgraphs

These GNU Radio World examples contain one or more blocks from gr-tempest.

TEMPEST from a VGA RecordingRecovers the picture on a VGA monitor from a recording of the emissions its cable leaks (TEMPEST), using gr-tempest. The screen was 1024x768 @ 60 Hz, sampled at 30 MS/s by a USRP B200; only 620 of every 1344-pixel line fit in that bandwidth, so the recovered frame is 620 samples wide. Fine Sampling Synchronization locks to the line and frame periods, the two Delays pan the frame, Normalize Flow maps magnitude to 0..255 luma, and Framing crops the vertical blanking before the Video Sink paints it.