Soft Tempest { An Opportunity for NATO

NATO countries spend billions of dollars a year on electromagnetic security, of which the Tempest shielding of personal computers, workstations and peripherals is a large component. In the absence of a capable motivated opponent such as the former Soviet Union, this burden on both traditional and new members is increasingly difficult to justify. As a result, many systems at a medium level of sensitivity are migrating from a shielded to a zoned mode of protection. Over the last year, a new technology has emerged which complements zoning in an attractive way. Soft Tempest consists of the use of software techniques to filter, mask or render incomprehensible the information bearing electromagnetic emanations from a computer system. This may give complete protection to some system components, and while the level of protection available for others is only of the order of 10–20 dB, this translates to a difference of about one zone, which can still give a very significant cost saving. It is already available in COTS products; here we discuss its introduction into NATO systems.