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Looks like we'll all have to switch to tablet PCs!

  1. Oct 21, 2008 #1


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    Staff: Mentor

  2. jcsd
  3. Oct 21, 2008 #2


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    Not mine, all my keys have little tinfoil hats.
  4. Oct 21, 2008 #3


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    Hmm, my new Mac's keyboard has an aluminum body. Maybe that will help!
  5. Nov 14, 2008 #4
    This is only possible if you are typing the individual keystrokes REALLY slowly.

    I've seen it in action, Also the tests were done with just a single keyboard powered by a shut (unplugged) laptop to avoid interference. Basically a battery.

    Combine a Keyboard, Mouse, Monitor, Power source and any other electrical device in your system and the noise/interference makes it pretty much impossible to detect individual keystrokes. (for now)
  6. Nov 14, 2008 #5


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  7. Nov 15, 2008 #6
    A worry for quite a long time! People at the encrypted transmission service told me about that as I visited an embassy in 1975 or 1976. I didn't hear "Tempest" then, but they knew the weakness and tried to protect their data against it.

    Which doesn't mean that the radiation could already be analysed then - only that they felt useful to take the possibility into account.

    As for the Swiss experiment: most keyboards use contacts with high impedance, either because the contacts themselves are made by carbon-filled elastomers or because load resistors a big to reduce consumption, so I bet the contacts radiate very small (and indistinct!) fields, and the researchers picked data from the USB transmission instead, where keys are already encoded. The cable itself is more or less shielded, but the connectors not so much, and the electronics at both ends even less.

    So put your aluminium foil rather there...

    As for interferences, many of them can (and must!) be removed before analysing the leak by a keyboard. Though if your screen is a cathode ray tube, the attacker won't waste his time at the keyboard.
  8. Nov 22, 2008 #7
    20 metres? Isn't there a dampening system for these emissions?
  9. Nov 22, 2008 #8


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    Sure there is. Back when CRT monitors where more common you could buy military spec monitors that were shielded to prevent anyone from picking up the signal from them using an antenna (which turns out to be quite easy and can be done at a large distance). I would be suprissed if there aren't shielded keyboard as well.

    Electronic surviellance has been around for a long time and most high-security building should already already have some protection in place (metal films on the wall, windows with conducting films etc to create a Faraday's cage and so on).
    So I don't think this is anything new.
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