Although this method can be used for de-anonymization and fingerprinting, you can't fully reconstruct the screen contents from such a low bandwidth signal.
If your private spaces are bugged with microphones or cameras (ie most mobile devices, home audio "assistants", smart TVs, untrusted software etc) expect the owner of the sensor to do the best in their abilities to spy on you.
Ultrasonic ad fingerprinting is another interesting way your home spies can communicate with each other.[1]
> We assume that the attacker knows the content displayed on the attacked monitor, except
for the textual letters. This assumption holds in many cases, for example, when the victim is
filling a form on a known website. We also assume that the font is monospace and sufficiently
large. The requisite size of the text depends on the granularity of the leak, which changes
among different monitors. Another assumption is, again, that the screen is in portrait layout.
They go on to state that in their proof of concept they had 3-6 letter word in black against a white background. They recorded audio for 5 seconds, and the letters were 175 px wide using a monospace font.
Note that they do mention they expect that any background could work, as long as it is fixed and you can train your model on that background.
My point being, this is far from a practical way to read what is on screen.
I think it's better to treat it as a proof of concept attack. It's more just to say: hey this type of thing is possible, maybe with better equipment and more research.
Is it really that good?
I have been putting that and Permutation City off for quite some time now.
Needless to day, I am quite a fan of Neal Stephenson.
I re-read it recently. It still holds up fine, but as the technological equivalent of historical fiction now. When it came out, it had a 1940s section built around the tech of the time, and a "modern" section built around "modern" tech. The only real difference is that the later section is now a 1990s section built around 1990s tech.
For CRT - yes, but to get a picture from a smartphone's screen the gear would be massive. Saw one used by russian FSS (former name is KGB) on a security audit of some special place.
I've noticed this a few years ago, after reading some psychophysics papers, I was generating some pattern images based on what I read, when my monitor started emitting tunes (not by radio emissions), I suspect piezo effect in some capacitor. I instantly realized my monitor could be intercepted accoustically...
If your private spaces are bugged with microphones or cameras (ie most mobile devices, home audio "assistants", smart TVs, untrusted software etc) expect the owner of the sensor to do the best in their abilities to spy on you.
Ultrasonic ad fingerprinting is another interesting way your home spies can communicate with each other.[1]
[1] https://arstechnica.com/tech-policy/2015/11/beware-of-ads-th...