I recently watched a 1980s computer television programme about the problems of spying. Basically, they showed how anyone could buy relatively cheap and common hardware and then be able to sit outside a house, or drive around in a car, and receive the signals going from the computers to the monitors, or even generated by the electronics inside the computer, which leak out everywhere like radio signals, and get a somewhat foggy but fully readable visual representation of the text and/or images displayed currently on the screen.
They even drove by the bank district and were able to read all sorts of private information.
This was in the 1980s.
I never heard of this until a few years ago. It seems to still be the case except for ultra-expensive, special "TEMPEST" computers which no normal person can afford or even buy even if they can and want to shell out all that money!
One of the guys said:
Anyone who cares about their security has their computer inside a fully shielded building anyway.
Yeeeeeeeah... right. If I can't afford TEMPEST hardware, I most definitely cannot afford a "fully shielded building".
Later in the show, they finally showed some kind of mitigation technique. It was a cheap device which you flicked on and which would then generate garbage noise on the same frequencies, so that anyone listening nearby with their antenna pointed to my computer/apartment/house would just get garbage data. He also mentioned that it was specifically not illegal (as radio transmitters can be). But then nothing more was mentioned about it.
- Did that jammer thing actually work?
- Was it cheap/affordable?
- Why have I never heard of this critical security problem? I would never have dared to do countless things "in private" if I knew about this!
- Do all modern computers have such a jammer device built-in?
- Do modern computers in some other way prevent this from happening, or am I still wide open for anyone to just remotely read my screen from outside?!
- Where do I buy such a device today and is it necessary?