During a USAF security briefing it was mentioned that we were not to type classified information in a room with windows. I asked them what they were worried about? My office was on the tenth floor and the typewriter faces away from the window. The briefer said that the vibrations from the key strokes are transmitted to the glass and that these vibrations could, easily, be read by a third party with a type of laser.
My question is…
Can this be done? If so, what with what and from how far away?
I’ve heard of this regarding speaking, not typing, and it makes sense when you consider that talk is just air vibrations. But keystrokes… I doubt it.
Yeah, sounds like the confusion of the speech one with, say Van Eck phreaking.
From what I’ve been told by experts, the answer is a big YES! Occasionally one of our clients get’s bugged, so we contract out to services that locate hidden transmitters. The investigators that perform these services are usually former military and government intelelligence agents.
I’ve brought this subject up to them. The simple story is the window acts as a speaker/microphone. It vibrates sounds that are in the room. A sophisticated laser microphone can pick up these vibrations and transfer them back into sound.
These systems are expensive, but are getting cheaper. MUCH cheaper!! I don’t know what the range is, but it can, and is, being done!!! Spooky, ain’t it?
Sure, it could be done, and from as far away as the laser could detect the vibration. The only problem would be that “they” would have to calibrate what key went with each noise… on YOUR keyboard. In other words, they would either have to have an inside guy, or they would have to somehow know what you were typing during a calibration.
“Nice to meet you madd1, here’s my e-mail address. I’m new in town. Could you e-mail me a list of some nice places to eat around town? Thanks. I’d appreciate it.”
Wouldn’t each key stroke provide a differnt vabrational signature?
If they could distinguish individual keystrokes by sound, and if you were typing normal sentences, it would be easy to find out which character corresponds to which. The frequency (how often each character comes up) and pattern contains a lot of information. With some computer use, it’s not hard to find the one and only mapping where the observed key sequence corresponds to coherent sentences. Numbers aren’t much harder, if you happen to type the date or something like that.
Laser microphones work by shining a laser at a surface in your room. By measuring the phase shift (or frequency shift) of the reflection, you can tell when the wall is moving towards you, and when it’s moving away from you. A bit like a radar gun used by the police. With a fast enough system, you get a complete record of the movement of the surface - i.e. recording of the sound. I think you can shine the laser at the outside surface of your window, or even the ceiling, wall or shades inside the room.
I take it this warning was only for mechanical typewriters? I find it hard to believe that computer or word processor keys make distinct sounds.
The military is still using old fashioned “clickty click click” typwriters? What am I paying all these taxes for? :rolleyes:
You mean to tell me that there would not be enough slop built into the whole keyboard to air to window to laser to sensor chain to make identifying individual KEYSTROKES impossible? With the window also picking up the outdoor vibrations too? And with a touch-typist, not a clumsy hunt&pecker (like me)?
I’ve got an open mind, but it sounds a bit far-fetched. Just my opinion.
Hey, they couldn’t afford the $4,000 IBM Selectrics after they spent all your money on the $600 toilet seats.
It seems that it would be easier for someone to plant a camera than try to decipher window vibrations. I suspect that vibrations from the HVAC system or traffic passing by on the road or even a light breeze would swamp out anything from a keyboard. I’m thinking ‘urban legend’ too. It’s more likely that the concern with the window is with telephoto lenses peering in.
Sound like the TEMPEST program. It’s able to recognize every keystroke on your screen through EMF. Higher-level government installments use “Anti-Tempest” protection(basically some awesome shielding), in the form of like a mesh cover for the monitors and computers.
It’s not the vibes from the windows, it’s the EMF signals given off by the computer. It’s not a UL, it’s reality. Read some TOm Clancy books, or a documentary book on security(I read one that included TEMPEST, but I don’t remember the name), and it’ll explain how it works to the extent that the civilian world knows.
-Sam
Tempest is also known as Van Eck Phreaking, and it is very cool stuff. The problem is it can only see what’s on your screen via it’s electromagnetic signature. If you’re clever like the guy in Neal Stephenson’s Cryptonomicon, (a way cool book) and put up decoy stuff on your screen while your computer talks to you via morse code (with the keyboard lights!) then it’s useless. As for the keystrokes; if you had a laser microphone sophisticated enough to distinguish each individual key, it would be a simple matter of monoalphabetic cryptanalysis to find out which vibration corresponds to which letter.
If each character, when typed, produces a unique sound (which I think is likely with a regular or Selectric typewriter), then “traffic passing by on the road or even a light breeze” or “slop built into the whole keyboard to air to window to laser to sensor chain” would not make it impossible tell what was being typed by “listening” to the window but would only make it necessary to listen longer before you could identify each key and might cause you to fail to read an occasional stroke. Using noise cancelling technology and filtering out the frequencies you don’t want should help a lot.
I have always heard that another way to “read” what is being typed on Selectric typewriters is to monitor slight variations in either power usage by the motor or electromagnetic emanations from it. The idea is that the little ball rotates discrete amounts in each of two planes to select a character and that each pair of discrete rotational movements corresponds to a specific character.
Ya, I thought so, but I only remember it by its’ “Codename”. Real cool stuff, real dangerous stuff, IMO.
And, I’m still pretty sure that this is what they person was speaking of. I don’t think the Russians have signature sounds of all of the typewriters and computer keyboards of the world, or even the armed forces on file. It sounds pretty far-out.
There’d be wayyy too many variables in how the machine, if the correct profile was chosen, could sound. Also, different manufacturing plant, or parts from a different company or plant would probably sound different too.
-Sam
I saw plans years back for a laser that can hear what people are saying in the room by reading the window vibrations. You can buy it now.
As for the keyboard sounds, that’s all a bit of a stretch, unless you have a TTY which makes a real audio sound for each key.
I really think government employees should stop typing in Morse Code. Much too easy to decifer.
Ok. so each key has a different (very slightly) sound. One thing seems to be overlooked here. Not every keystroke is hit with the same force. Different Force = Different Sound Signature. Or so I have found out by whacking my keys with different amounts of THWACK.
I read on the web page of a respected cryptographer (Bruce Shneier, http://www.counterpage.com ) how he was working on a project to try and break encryption through Tempest-like espionage. It would work something like this: Encryption uses a fairly repetative set of mathematical operations to encrypt or decrypt data. Every once in a while, though, there are mathematical short cuts that come up. 0 * 0 does not take a computer as long to compute as 123 * 457.
What the device would do is listen to the rhythm of the power consumed by what the processor was doing. Everytime the processor did something different, it would take note. Then it would try to use that data to guess parts of the key, narrowing down the number of guesses it has to make to pick the right one. The rest would be done brute force.
You guys. I swear. As far as the discreet sound pattern of each Selectric Ball shift-and-strike, I really find the solutions offered here to be a bit far-fetched. IF it was needed, the paranoid Gummint agency in question could use good old phase cancellation, and / or confusing rhythms to make decoding a typed letter impossible.
Flashing lights on monitors??? Puh-leese.