Radiation emitted by wired keyboard

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Discussion Overview

The discussion revolves around the concept of radiation emitted by wired keyboards when keys are pressed. Participants explore the feasibility of detecting this radiation for the purpose of building a keylogger, examining both the theoretical and practical aspects of the phenomenon.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant expresses interest in building a keylogger based on the radiation emitted by wired keyboards, noting the lack of information available online about the spectrum of this radiation.
  • Another participant mentions that any electrical switch emits a small amount of electromagnetic radiation, primarily 'white noise' at low frequencies, but doubts the ability to distinguish which key was pressed due to similar emissions from all keys.
  • A later reply questions the specific frequencies emitted by the keyboard and suggests the use of an antenna to detect differences between keys, asking for recommendations on antenna types.
  • One participant recalls historical concerns from the 1980s about reading CRT displays from their electromagnetic emissions, indicating that such detection has been demonstrated in the past.
  • Another participant explains that keyboards are scanned row by row, and pressing a key alters the scan pulse, which can be detected by a sensitive receiver, suggesting a method for identifying key presses.
  • Concerns about the legality of using such technology are raised, with one participant expressing skepticism about any legal applications for keylogging.
  • A participant identifies themselves as a second-year electrical engineering student looking for a challenging project, indicating their intent to explore the topic further.

Areas of Agreement / Disagreement

Participants express varying levels of skepticism about the feasibility of detecting specific key presses from a wired keyboard, with some agreeing on the general principle of electromagnetic emissions while others doubt the practicality of distinguishing between keys. The discussion remains unresolved regarding the specifics of the emitted radiation and its detectability.

Contextual Notes

Limitations include the lack of empirical data on the spectrum of radiation emitted by wired keyboards and the uncertainty surrounding the effectiveness of different antenna types for detection purposes.

YanivW
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Hi,
I heard before that wired keyboards emits radiation when a key is clicked. My goal is to build a keylogger based on this phenomenon (for fun, of course). I've already seen some variations of this idea, but they were all using wireless keyboard, where it is much more simple to detect and process the RF radiation.
I want to learn more about this, but can't find anything on the internet (the spectrum of the emitted radiation for example). I'll be glad if someone could help me find more information that can be relevant, or share from his own knowledge.
Thanks!
 
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You'll need to give a link to this supposed phenomenum.
However any electrical switch will emit a tiny amount of EM radiation when the contact is closed.
Mainly 'white noise' at the very low end of the spectrum (aka radio).
In the case of a keyboard I doubt there is a way to determine which particular key was pressed,
All of them would emit a similar radio 'click'
 
:wink:Too bad you can't send your question to the NSA. If it can be done, they probably did it.
 
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rootone said:
You'll need to give a link to this supposed phenomenum.
However any electrical switch will emit a tiny amount of EM radiation when the contact is closed.
Mainly 'white noise' at the very low end of the spectrum (aka radio).
In the case of a keyboard I doubt there is a way to determine which particular key was pressed,
All of them would emit a similar radio 'click'

Well, do you have any idea of what frequencies it probably emitting? I guess the phenomenon is basically what you mentioned, but I still want to get an antenna and figure out if there's any way to determine the differences between the keys. What type of antenna should I buy? Will regular RF antenna be good, in your opinion?
 
Not surprised it's been done. Way back in the 1980s there was concern that it was possible to read a CRT display by decoding it's electromagnetic emissions at a distance. If I remember correctly it was even demonstrated on a UK TV program. Obviously it was much easier back then when monitors were similar to TV's.
 
The keyboard is scanned row by row. Those scan pulses generate electromagnetic waves. If a key is pressed, it changes the corresponding scan pulse slightly - and that can be picked up remotely by a sensitive receiver. Knowing the row scan sequence allows you to guess what key is pressed.

This is very general, but it is what I was told when the military wanted a keyboard that could not be tapped remotely. My solution was to introduce a short pseudo-random generator in front of the row scanner, so the row sequence was undecipherable. In any case, they were satisfied and ordered a bunch of those keyboards.
 
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This sort of thing is done all the time by spies and hackers. I'm sure there's equipment on the darknet.

I could give advice, but first I would need some assurances you were using it for legal purposes. Personally I can't think of any legal purposes, but perhaps you can.

Imagine reading someone's bank password... Lucrative, but not really legal.
 
Nidum said:
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Thanks a lot! This is really helpful.
Jeff Rosenbury said:
This sort of thing is done all the time by spies and hackers. I'm sure there's equipment on the darknet.

I could give advice, but first I would need some assurances you were using it for legal purposes. Personally I can't think of any legal purposes, but perhaps you can.

Imagine reading someone's bank password... Lucrative, but not really legal.
Well I'm just a 2nd year EE student seeking for some cool challenging project to start with (-:
 

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