tempest-for-eliza¶
Makes a monitor radiate music on an AM radio — a TEMPEST demonstration
- Version recorded: 1.0.5
- Categories:
electronics,rf-research - Upstream: http://www.erikyyy.de/tempest/
What it does¶
Draws patterns on the screen chosen so that the video signal's own electromagnetic emissions carry an audio tone. Tuned to the right frequency on an ordinary AM radio nearby, the monitor plays music. Nothing is transmitted deliberately -- the display is simply driven so that what it already leaks becomes intelligible.
Why you would want it¶
It is the clearest possible demonstration that computers radiate their contents, and the reason TEMPEST shielding standards exist. Reading about compromising emanations convinces nobody; hearing a tune come out of a radio because of what is on a screen convinces everybody, immediately. As a teaching tool for why RF security is a real discipline it has no equal.
Before it will work¶
An AM radio and a monitor. It works best with an analogue VGA display and considerably less well with the shielded digital links modern hardware uses, which is itself the point being demonstrated.
How it installs¶
- apt:
tempest-for-eliza
Known problems¶
Modern displays leak far less than the CRTs and analogue links this was written for, so on current hardware the effect may be weak or absent -- that is progress, not a bug. The emissions are unintentional and low power, but they are emissions: what is lawful to radiate is jurisdictional and is yours to know. This is in the rf-security category and reaches an operator through a profile requiring explicit opt-in.
Keeping it current¶
- probe: apt policy
- strategy: apt_upgrade
Where to get help with the software itself¶
Erik Thiele's original page above. This is a 2001 demonstration rather than a developed project.