An Introduction to TEMPEST

National Communications Security Committee Directive 4 sets U.S. TEMPEST standards. The requirements are set out in document NACSIM 5100A, which is classified. TEMPEST certification for private sector usage is extremely expensive and, as a result, it has led to a newer standard, called ZONE, which is more cost effective, though somewhat less secure. Approved TEMPEST-shielded devices are classed into 3 categories. Type 1 is extremely secure and available only to the U.S. government and approved contractors, who must undergo strict vetting. Type 2 is somewhat less secure, but still requires government approval to use. Type 3 is for general commercial use. For more information on TEMPEST certification, see the NSA TEMPEST Endorsement Program. NATO has a similar standard called the AMSG 720B Compromising Emanations Laboratory Test Standard. In Germany, the TEMPEST program is administered by the National Telecom Board. In the UK, Government Communications Headquarters (GCHQ), the equivalent of the NSA, has their own program.