Screen privacy

I know a lot of people a little scared of “the big brother” type of stuff: “not sharing my photos with google photos”, “making sure to disable location services”, etc (like @Pharap for example :smile: ? )

So I wonder what is their opinion about the posibility of capturing whats on a screen just using the residual noise of the screen circuitry (not the transmission)

I have been playing with that tool and I was really surprised that it actually works. When I was in hischool I got hook to a book called F2F that portrayed a “hacker” eavesdroping on a crime remotely with his “CRT” remote capturing tool (he was mostly spying on people’s screens but he got into a transmission of an ongoing torture)…

So… that science fiction thing now it is way easier/cheaper to implement, and does not only require high-energy-photon-emiting-CRTs to work.


I’m aware it’s possible.

I’d be interested to know what its limitations are. In particular:

  • Its effective range
    • (I’m under the impression that it needs to be in relatively close proximity to work.)
  • What the most complex inputs it can handle are
  • Which (if any) materials are capable of blocking the effect
  • What circumstances cause sufficient disturbance to its functionality

As a theoretical threat it’s concerning due to its potential,
but the immediate practical threat is (from what little I know) minimal.
(Especially to me personally, which is the important thing. :P)

I think if someone wants to target you, it is hopeless (cars can be easily tracked via the TPMS, phones via IMSI catchers, etc).

About the screen eavesdroping: It is limited for now, but it is only matter of progress. I am using a fairly insensitive (but broad) 8 bit SDR, no amplifier, etc. For blocking the effect I guess you could have a jammer of that RF noise :smiley: which sounds like a new tinfoil hat for future people.

By the way what you are describing is totally possible, there are machines that government spies use that are very expensive and very dedicated equipment to point an RF antenna at a display and get out a pretty decent quality image, from a surprising distance away. You can get a pretty clear signal if you have some kind of LOS, but even through a wall or two it’s pretty good. Especially if the monitor is on the other side of a wall.

Governments in embassy and other secure locations very often have special monitors complete EM shielded and do things like lead lining on windows too to prevent these kind of attacks.

Source: My uncle works in counter-intelligence :rofl:

Amazing what the SDR is able to do. Just a little more advancement in AI and natural language programming and anyone can have the power…

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That part is probably already doable now but it does not has a very seductive market proposal :stuck_out_tongue: maybe as a thesis or such.

I had to spend a lot of time trying to tune to the specific freq. It is very faint.

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This some control center at your work or something?

Yes. With corona I can do some tests since everything was empty :stuck_out_tongue: i.e. indoor drone race. However it has the drawback that I need to turn off all the lights :rofl:

I set up the surveillance center for Vestas wind turbines in the USA and it had 6 flatscreen TVs in front of 2 pcs with 3 monitors each, and I set them all to be different LCARS screens, I can’t find the photo it was like 10 years ago, but it was rad. I did it entirely on my own after work one day and thought I was gonna get in trouble but it turns out the manager is a huge startrek fan and it was like a dream come true for him.

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yes, something like that, there are few rooms with walls of 4K screen, they are so HOT I cannot imagine how hot was back then when you did that> scotty why my balls are sweating?

They were actually smart and picked a room that had it’s own A/C system so they could crank it way harder than the rest of the office. It was actually always freezing in there because thats how the guys liked it. I loved going to visit them though in the surveillance center it was my “people”, as far as what lets just say it being nerds. They were the only people in the company who actually knew how computers worked.

The IT department was staffed with people who do it as a “career” and learned to fix computers by going to like a vocational school or something so they did everything off a script it was a nightmare.

anyways why are you doing this are you a spy?

aside: can you do this TO AN ARDUBOY SCREEN?>?!? :open_mouth:

:astonished: maybe, but it is probably too slow

Sometimes you can hear the coil whine inside the OLED…

There isn’t a coil (inductor) in the OLED but ceramic capacitors, like the external ones you add for the charge pump, can act as piezoelectric speakers at certain frequencies.

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Oh right the voltage booster is just a bunch of caps and diodes.