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I am Comp-sci student doing a software engineering paper about designing a program, planning the software like you were actually planning a real-life software project, short of writing actual pseudo-code or code. For my project, I picked doing an app that can detect a physical man in the middle attack. Like monitoring for a tap on the line.

It got me thinking, can you monitor for someone catching wireless communication? Like the latest WEP2 hack. If someone were monitoring your wireless traffic passively to capture your secure handshake, could you detect them snooping wirelessly without them transmitting packets?

My knowledge of EE stops at MOSFETs and timing of electrical currents through logic gates and metastable currents propagating through circuits because the timing of logic gate was off. My knowledge of EE certainly falls short of radio broadcasting. So I am not even sure if such a feat is possible, I suspect it isn't but it's out of my ken.

I suspect if you were close enough a receiver would leave behind some kind of detectable EM footprint.

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  • $\begingroup$ looks like a question pasted from google translate :) ... to make a short guessed answer: you cannot detect much using EM fields, the reason is because the flux is constant (result from Maxwell B = 0) you can only eventually protect yourself from them. $\endgroup$ – Jonathan Oct 19 '17 at 13:49
  • $\begingroup$ If you are referring to krack, that attack only works if you have an active sender that can trigger resend of certain packets $\endgroup$ – ratchet freak Oct 19 '17 at 15:14
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many radio receivers contain a circuit called an IF oscillator. the output of this oscillator is added to the radio frequency signal that the radio is receiving to downconvert the incoming high frequency to a lower frequency that is easier to process. Old radios used IF oscillators that were powerful enough to actually transmit signals on their IF frequency which other receivers could then pick up and home in on. during the second world war, this technique was used to find enemy ships at night, until they learned how to shield their receivers so they would not inadvertently transmit on their IF frequency and thereby reveal their location. I do not know how well-shielded radios of recent manufacture are against "spurious transmission", which is what this effect is called.

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Yes, kind of.

You could create a sensitive/specialized metal detector, which would induce/detect a current in any piece of metal (including an antenna)

There are antennas specifically designed to be detected (rfid technology); you broadcast a particular frequency, and they resonate and respond. However the ratio of produced to response power is like 10^6 or more

Practically, no. Think about this- the sun is emitting EM energy, just like a wifi router. Does the sun get dimmer or brighter if more people look at it?

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  • $\begingroup$ Yeah i figured it was some in the range of a full counter-surveillance sweep, not something that could be run using hardware or even peripherals on a lap top to detect it. $\endgroup$ – torrey garcia Oct 19 '17 at 21:04

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