Every piece of electronic and electromechanical information processing equipment produces unintentional, intelligence-bearing emanations that, if captured, could be read and then analyzed. These emanations could actually disclose the information that is handled, received, or transmitted. Thus, governments have become concerned about these emanations for homeland security reasons.
In George Orwell’s book 1984, the author spoke of a future in which citizens would have no real expectations of privacy because the government could monopolize the technology of spying. Essentially, Orwell was suggesting that citizens’ actions would be watched by government officials from the time of their birth until the time of their death, and no one could protect himself or herself from such scrutiny because of surveillance and countersurveillance technology measures—what is known as TEMPEST Equipment.
TEMPEST technology can now be used to intercept information stored in digital computers or displayed on computer terminals. It can then be reconstructed to provide helpful intelligence without having to go near the target. Though using TEMPEST equipment is legal in the United States and in England, Canada has laws criminalizing its use for eavesdropping. However, critics have said Canada’s laws in this regard actually hinder surveillance countermeasures more than stop TEMPEST equipment surveillance. In the United States, it is illegal for individuals to use countermeasures against TEMPEST surveillance equipment to protect their privacy.
So, it seems, note critics and those in the Computer Underground, that Orwell was not too far off with his predictions. Currently, the U.S. government and its designated agents apply TEMPEST Equipment countermeasures in proportion to the relative threat of exploitation.
Having TEMPEST Equipment on hand and in good use makes for a rather costly proposition. First, to make sure that TEMPEST countermeasures work well, maintenance procedures routinely need to be implemented. Moreover, because this equipment has special suppression circuitry, it needs to be maintained by knowledgeable technicians to ensure proper TEMPEST performance. Also, the suppression technology needs to be protected from general distribution; therefore, disposition of the equipment is to prevent technology transfer. The market for this kind of specialized equipment exceeds a billion dollars annually.
Atkinson, J. A Review of TEMPEST Legal Issues. [Online, 2002.] Granite Island Group Website. http://www.tscm.com/TEMPESTLegal.html; National Security Telecommunications and Information Systems Security Committee. Maintenance and Disposition of Tempest Equipment. [Online, March 24, 2001.] National Security Telecommunications and Information Systems Security Committee Website. http://www.nstissc.gov/Assets/pdf/nstissam_ tempest_1-00.pdf.