Diawali tahun 1985 ketika seorang peneliti Wim Van Eck membuktikan pancaran gelombang elektromagnetik dari monitor CRT (dan peralatan elektronik lainnya termasuk keyboard) dapat ditangkap dan ditampilkan dilayar monitor lainnya dari jarak belasan – puluhan meter.

Bocornya informasi sensitif melalui gelombang elektromagnetik menarik minat penulis novel Neal Stephenson dalam bukunya berjudul Cryptonomicon.

5 tahun yang lalu, peneliti Joe Loughry dari Lockheed Martin Space Systems dan David Umphress di Auburn University melaporkan bahwa pancaran gelombang elektromagnetik optik dapat ditangkap dari jarak hingga 30 meter

Kebocoran Informasi Melalui Pancaran Optic “…Modulated optical radiation from LED status indicators appears to be a previously unrecognized source of compromising emanations. This vulnerability is exploitable
at a considerable distance. Primarily, data communication equipment is affected, although data encryption devices also pose a high risk of information leakage, potentially leading to loss of plaintext and encryption keys.

A taxonomy of optical emanations was developed according to the amount of “useful” information available to an attacker. Experiments showed that Class III optical emanations, which should never be permitted, were present in36% of devices…”

Markus Kuhn dengan sebuah antena radio dan radio penerima seharga 1400USD berhasil menangkap pancaran gelombang elektromagnetik monitor LCD walaupun terhalang tembok pemisah berbahan plasterboard.