Wired’s Threat Level blog has an interesting piece on the NSA’s release of paper’s regarding the discovery of electromagnetic vulnerabilities in encyption machines which led to various bits of research in cracking during the Cold War. TEMPEST, the name for the attack, was proved in 1943 but it appears disppeared until 1951 when the CIA rediscovered it as did the Russians and the Japanese. There are more documents yet to be realeased – the idea of a seismic version of Tempest boggles the mind and intrgue. Sadly its still classified.
Why the interest? Simple, Neal Stephenson’s Cryptonomicon.