Comment by sholladay
17 hours ago
This made me think of The Thing, a fascinating listening device made by the Soviets that was completely passive until powered remotely. Very difficult to detect when unpowered.
https://en.wikipedia.org/wiki/The_Thing_(listening_device)
And then I thought, something similar might be possible for video. Turns out, yep.
https://ieeexplore.ieee.org/document/8719264
The Eye of Sauron paper does acknowledge the limitations that would likely prevent it from working against such a device. Impressive nonetheless. True privacy/security is just very hard!
Turns out we're all livestreamers:
> In 1985, Wim van Eck published the first unclassified technical analysis of the security risks of emanations from computer monitors.[2][3] This paper caused some consternation in the security community, which had previously believed that such monitoring was a highly sophisticated attack available only to governments; van Eck successfully eavesdropped on a real system, at a range of hundreds of metres, using just $15 worth of equipment plus a television set.
https://en.wikipedia.org/wiki/Van_Eck_phreaking
In this context "emanations" means a signal allowing the listener to reconstruct the image and read the words on the screen.
I'm not sure if it works with modern monitors (CRTs were pretty high voltage!), but they are also quite "loud" in EMF. A fun experiment is to walk around your house with a portable radio in AM mode. You can "hear" all the electronics!
It seems like it must be much more limited these days. Display transport is packetized, often encrypted (HDCP), and designed to be capable of exceedingly high bandwidths. Versus a CRT that comparatively blasted out a nice sequential analog signal for anyone to listen in on.
That said, if you're using a wireless keyboard it's pretty much a given that the keystrokes can be recovered by timing analysis regardless of the manner of wireless connection. At least unless you happen to hunt and peck painfully slowly.
It would be the scan of the column data lines and sequential row update of the LCD that would be detected. For low spatial frequencies where you're simply mapping changes in the image, it might still be doable, but the real challenge is that the resolution of monitors and refresh rate have increased so much that it's more difficult to resolve characters or images. OLED is even more difficult, because the top cathode layer really shields most emissions (much more than the patterned VCOM of most modern LCDs).
Embedded touch is a whole'nuther issue. One could certainly remotely measure the radiated emissions of a cell-phone to get finger proximity and position in at least one if not both XY dimensions.
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As a Neal Stephenson fan, Van Eck phreaking is where my mind went after reading the abstract. Glad to see the technique is alive and well today :)
Do you have a hankering for antique furniture?
Yup.
My father worked in defense. He shared lore about the genesis of tempest, the requirement to use faraday cages to protect secrets, gear, etc.
The story goes that some kind of red team set up shop down the road from some missile tests (or something) with some simple gear. Afterwards, they shared the launch codes used, shocking all the brass. Hence the need for shielded comms.
I was under the impression that in actual practice all the launch codes are set to 0000. Wouldn't want to delay a launch because someone forgot the code. (I'm only half joking)
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The Thing is full of surprises to this day.
> The Thing was designed by Soviet Russian inventor Leon Theremin, best known for his invention of the theremin, an electronic musical instrument.
Learned about this from a huge intro in an episode of this amazing podcast. https://500songs.com/podcast/episode-146-good-vibrations-by-...
the rabbit hole goes so much deeper than this 'Thing'.
An interesting read is Spy Catchers written by first science officer from MI5 in cold war. he was tasked with reversing listening devices and making them.. it doesnt spill all the beans but givea a good insight into how far they were already then.
u can hardly imagine what tech exists now 40-60 years later as electronics and computers have shrunk drastically and infinitely more weird material properties are discovered....
There's also the Moog synthesizer: https://www.google.com/search?q=moog+synthesizer
And the Moog company, specializing in high tech products, started by a cousin of the synthesizer guy: https://en.wikipedia.org/wiki/Moog_Inc.
Seems like the devices they found in the IBM Selectrics during Project GUNMAN (though, same ‘conflict’).
https://media.defense.gov/2021/Jul/13/2002761779/-1/-1/0/LEA...
Haseltine’s The Spy in Moscow Station is also a fascinating account of events.
I suppose you can activate such device by just sweeping a high power radio wave over a frequency range. At that point, you can see what signals it sends back. Excite, then listen. This is how a lot of detection methods work, including radar, so it is not a weird idea.
Also there are ways to detect diode junctions now.
What if the Thing was supposed to be found? People think it was for surveillance. Maybe it was to make the Americans more paranoid.