Secure Fonts

Simon Cozens

Tempest is a term in the computer security world for being able to read the contents of (amongst other things) computer screens remotely by looking at the electromagnetic emanations leaking from the monitor. You can essentially build a modified analogue TV which can tune into a computer's monitor and see what the remote user sees. This obviously caused quite a freak-out in security circles when it was discovered.

The usual way to deal with it is increased mechanical shielding around monitors to reduce the signal emission, but last night I read about a project (PDF) to defend against electromagnetic snooping by modifying the font rendering:




(I have no larger point here, I just found it fascinating.)

James Puckett

Cool idea, but I think governments started shielding entire buildings with copper mesh long before 1998.

John Savard

I actually mention the Kuhn and Anderson paper in a page on my web site, as I found the idea of some interest myself. It's on the page titled "Hardware Security" in the cryptography section.

SiDaniels

Cool idea. Would wearing a tin foil hat have the same effect?