optical TEMPEST

[blitz]

as they say (http://applied-math.org/optical_tempest.pdf) now:
"Modulated optical radiation from LED status indicators appears to be a previously unrecognized source of compromizing emanations.
Primarily, data communication equipment is affected, although data encryption devices also pose a high risk of information leakage, potentially leading to loss of plaintext end encryption keys"

[Unregistered]

Yes, There is a way with light sensitive diodes to read plain text off of screens. You can even read the plain text off of a wall or surface that the monitor is reflecting off of. theoretically there is even a way to read plain text from light diodes from a telescope as far away as 1/4 mile!

This security issue is due to the refresh rate that monitors work at. If you are in the security business and don't want to have your plain text snooped on then I prefer that you invest in some high voltage floresent lights to minimize the chance that light sensing diods can pick up your text!!!!!!!

Later,
Lockman