“Researchers have devised a novel way to recover confidential messages processed in doctors’ offices and elsewhere by analyzing the sounds made when documents are reproduced on dot-matrix printers.
This so-called side-channel attack works by recording the “acoustic emanations” of a confidential document being printed, and then processing it with software that translates the sounds into words. The method recovers as much as 95 per cent of the printed words when an attacker has contextual knowledge about the text being printed, such as the words included in a medical prescription or a living-will declaration. Up to 72 per cent of the text can be recovered when no context is known.
The attack, which so far works only on English text, was carried out under what the researchers described as “realistic — and arguably even pessimistic —– circumstances,” in which there was no shielding from ambient noise such as that made by people chatting in a nearby waiting room. Despite the wide availability of inkjet and laser printers, about 60 per cent of doctors in Germany continue to use dot-matrix devices. About 30 per cent of banks in Germany do so as well, according to the researchers.
Countries such as Germany, Switzerland, and Austria require carbon-copy-capable dot-matrix printers to be used for printing prescriptions for narcotics, they said.”
Read more at The Register (Thanks @XxLadyClaireXx)
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Wow! I’m armed and ready with my dictaphone!
When I read “ancient”, I was expecting some Greek thing on the bottom of the Adriatic, not a dot matrix printer. Extending the dot matrix printer side-channel attack idea, anything that can be profiled (produces certain sounds for certain operations and they don’t vary much for a given repeatable operation) and be attacked using this or similar method. Some heuristics may be needed if more than one operation produces a sound or set of sounds (that is the math function used to map things is not surjective). If my keyboard procudes slightly distinctive sounds for each and every key when the keys are pressed, then you can listen to everything I type.
this reminds me of how some people usta get free phone calls by playing a recording into the receiver of coins dropping into a pay phone1
Hehe! Free payphone calls trick we used to do round our way was the “quick nothing”.
Basically it worked on the old round dial phones – you would dial the number and wait for the person to answer, as soon as the phone was lifted you quickly dialled ’0′ and you could get the call for free for as long as you liked.
Ah, the goold old days!
oops, or possibly “good”.
Isn’t this just replicating the way we communicate, via sounds passed between individuals?
We think something. Encode that as a sounds associated with that notion. Verbalize it. Hear it. Then decode that into hopefully the same thought. Unfortunately, no two of us are using cipher books that match.
Reminds me of a spy story from the cold war involving agents beaming directional microwaves across the street to detect which characters were being typed by embassy secretaries using golf-ball typewriters.