[gantz]

Totally different concept, but this reminds me of the anecdotes my professor would tell us about the possibility of eavesdropping on a monitor (CRT then) based on the light radiation emitted, and not from seeing the actual image itself

[Robin_Message]

You're thinking of Optical Time-Domain Eavesdropping Risks of CRT Displays by Markus G. Kuhn in Proceedings of the 2002 IEEE Symposium on Security and Privacy, Berkeley, California, 12–15 May 2002.

Available here: http://www.cl.cam.ac.uk/~mgk25/ieee02-optical.pdf

Pretty amazing that this actually works, just using a high-speed photo-sensor – and doesn't even require line of sight, a reflection off a wall is enough. Unfortunately, I don't think it will work on LCD screens.

[snippyhollow]

Maybe he was talking about project TEMPEST https://en.wikipedia.org/wiki/TEMPEST

[artmageddon]

I don't have a link to the paper, but I recall reading a whitepaper about it as far back as 2002.