TEMPEST is a standard for electromagnetic shielding for computer
equipment. It was devised to address the threat that information
might be easily read from a distance via emanation of radiation
from computer systems. For instance, an attacker might intercept
the radiation from the CRT of a terminal that is not protected
against emission of stray radiation, thwarting any cryptographic
protection that might otherwise be in place. TEMPEST describes
techniques for countering these threats. For more details about
TEMPEST, see [RG91].