Soft Tempest

taken from

Ross Anderson's Home Page

It is well known that eavesdroppers can reconstruct video screen content from radio frequency emanations. In recent work, we have developed techniques that enable the software on a computer to control the electromagnetic radiation it emanates. This can be used for both attack and defence. To attack a system, malicious code can hide stolen information in the machine's Tempest emanations and optimise them for some combination of reception range, receiver cost and covertness. To defend a system, a trusted screen driver can display sensitive information using fonts which minimise the energy of RF emanations. This technology is now fielded in PGP (from 6.0.2) and in other security products. A paper describing our work is available here; you can download a set of Tempest fonts from here. There is further information on the costs and benefits of Soft Tempest in military environments here, while an earlier version of our paper, which received considerable publicity, is available here. Finally, there's some attack software here, and a recent press article here.

see also

Markus Kuhn's Home Page

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