TEMPEST is the covername utilized by the NSA as well as other companies to talk about emissions from computing machinery that can divulge what the devices is processing. We’ve covered a few jobs in the past that particularly intercept EM radiation. TEMPEST for Eliza can transmit through AM utilizing a CRT monitor, as well as just last autumn a group showed exactly how to screen USB keyboards remotely. with the flexibility of info Act, an fascinating short article from 1972 has been released. TEMPEST: A Signal issue (PDF link dead, try Web Archive version) covers the early history of exactly how this phenomenon was discovered. Uncovered by Bell Labs in WWII, it impacted a piece of encryption gear they were supplying to the military. The plaintext might be checked out over that air as well as likewise by tracking spikes on the powerlines. Their new, heavily shielded as well as line filtered version of the gadget was rejected by the armed forces who just told commanders to screen a 100 feet around their publish to avoid eavesdropping. It’s an fascinating checked out as well as likewise covers acoustic monitoring. This is just the us history of TEMPEST though, however from the anecdotes it seems like their enemies were not just keeping speed however were likewise much better informed.
[via Schneier]