What is the essence of technical channels of information leakage? PEMIN, LF (HF) AED, spurious interference, etc.?

Question

Information Security

So, the point. There are several types of information leakage channels. When they talk about the leakage of information through technical channels, they mean the leakage of speech information, since it most often contains an informative part. Many documents on GT protection and threat models (even Pdn) provide for channels such as pamin, acoustoelectric transformations, HF imposition, etc.
Can someone explain to me how it is really possible to implement such leakage channels? All this will work only in laboratory conditions.
Well, even take an example with the interception of an image from a monitor (or a printer, I have seen such studies) due to its radiation according to PEMIN. Let's say there are 100 such monitors in the building and how to intercept the right one? Let's even assume that we managed to penetrate beyond the boundaries of the short circuit, where it is still possible to remove an informative signal from the fields with some cool antenna and a nanovoltmeter.
I really don't understand, sorry if this is a dumb question. For example, in order to certify the premises where the GT will be processed, there must be a bunch of noisy devices that cost money, and it’s not clear who needs it if this channel is extremely difficult to implement in practice. Scientifically speaking, the attacker's potential should be the highest :)

Answer 1

Very simple. In the case of a monitor, its design is known, all the interference that occurs during its operation is known, and the frequencies at which the components operate are known. To an amateur eye, an electrical circuit is just a mountain of microcircuits and wires between them. For professionals, each wire is an antenna that is capable of emitting radio waves. Knowing what and where to catch and at what frequencies, you can isolate this signal and use it for your own purposes.
Conduct an experiment: bring a radio receiver operating in the AM range to an LCD monitor - you will be pleasantly surprised by the presence of very strong interference. In this case, the selectivity of the radio receiver can be very small, so. you can hear a bunch of signals that merge into noise. In the case of specialized devices, you can select the desired signal and somehow interpret it.
Those. the most important thing in such means is the interpretation of the received signal.
Second example: A conversation in a room. Here you are, maybe not even loudly. And you don’t even suspect that your voice is able to shake the glass in the window openings. But it is so.
Now the task is to remove this vibration, filter it out from the noise in the street and the wind - and we will get your vote. Of course it will not be MP3 quality - 320 kbps). It will be 2-3Kbps with noise and so on. but still, real technical means will allow you to isolate related information that will be used against you)
How is it done? Yes, it's simple. A laser shines on the window, and by the vibration of the spot, you can remove the vibrations of the glass, and then process it all.
Reading topics: digital signal processing, types of modulation, noise-like signals.

Answer 2

Do metal detector frames + [expensive] introscopes at subway entrances cause you any questions?
It's a theater of safety.

Answer 3

You set a short circuit in a dedicated room, vibration generators are placed inside the windows to prevent audio from being read from the window, reflective films can be applied to the glass itself, or whether there are enough thick curtains to exclude visual contact.
Who needs, well, let's say foreign intelligence services, needed to find out what kind of features there are in the development of certain aircraft components, in order to then exploit the identified vulnerability to disable enemy equipment. Here you can fantasize as much as you like.
Do you seriously believe that the RD and safety standards were written by people with nothing to do?