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submitted 2 years ago by [email protected] to c/[email protected]
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[-] [email protected] 128 points 2 years ago* (last edited 2 years ago)

This is exactly why I don't store my passwords as giant metal 3D cutouts of letter shapes

[-] [email protected] 48 points 2 years ago

I need to stop but it’s just so convenient.

[-] [email protected] 20 points 2 years ago

but how else can you remember them

[-] [email protected] 15 points 2 years ago

I don't even know any of my passwords

[-] [email protected] 58 points 2 years ago

The tech to scan objects in a room using WiFi is not new. It's very unsettling.

[-] [email protected] 44 points 2 years ago

I spy, with my little wifi...

[-] [email protected] 32 points 2 years ago

And here I am thinking that hanging my passwords on the wall as art was hack proof. I guess it's time to redecorate.

[-] [email protected] 7 points 2 years ago* (last edited 2 years ago)

You just need to write it smaller than the Wi-Fi wavelength (~~about 60 nm~~) and you should be fine. If someone wants to read it, they have to use smaller wavelengths (i.e. higher frequencies), which means there’s a good chance that they will be blocked by your walls.

Edit: c/2.4 GHz ≈ 125 mm I took the first value from Wikipedia, without thinking about it enough.

[-] [email protected] 6 points 2 years ago* (last edited 2 years ago)

I think your fag packet calculation has got a power of ten wrong somewhere. Wi-fi is GHz so that would be on the order of centimetres I think.

[-] [email protected] 4 points 2 years ago

Yes. Wifi is 2.4 GHz, speed of light is 0.3 Gm/s. Therefore one wavelength is 0.3/2.4 m/s/Hz = 12.5 cm

[-] [email protected] 2 points 2 years ago

Or 0.001 football pitches

[-] [email protected] 1 points 2 years ago

Yeah, you’re right. Writing it smaller than 12.5 cm should do it, which is entirely reasonable.

[-] [email protected] 2 points 2 years ago

What if I use an awesome font like Comic Sans and round the faces like party balloons? Still visible?

[-] [email protected] 1 points 2 years ago

It’s all about the size. You can’t use an optical microscope to look at details smaller than the wavelength of visible light. You need an electron microscope for that. Similarly, a wifi camera can’t see details smaller that the wavelength.

If you made a camera that can see in 100 MHz radio waves, you could probably see mountains, rivers and houses, but anything smaller than 3 m would be nothing but blur.

[-] [email protected] 24 points 2 years ago

Seriously, yikes. This is going to be very bad in the wrong hands. Cool concept though.

Researchers at the University of California, Santa Barbara, have developed a novel method for imaging objects beyond the line of sight, which they've named "Wiffract." This technique leverages the interaction of Wi-Fi radio-frequency (RF) signals with the edges of objects that need to be imaged, guided by the principles of geometrical diffraction theory (GTD). With the appropriate mathematical model, Wiffract can produce remarkable outcomes, such as "reading" shapes and letters through walls.

The researchers explain that when an RF wave encounters an edge point, it generates a cone of outgoing rays known as a "Keller cone" in accordance with GTD. Wiffract's mathematical model can capture the edges of stationary objects by utilizing GTD theory and the corresponding Keller cones. Once it identifies "high-confidence edge points," Wiffract can reconstruct the shapes of objects while enhancing the resulting edge map further through advanced computer vision techniques.

[-] [email protected] 13 points 2 years ago

This is vaguely similar to Van Eck phreaking.

[-] [email protected] 10 points 2 years ago

Lucius Fox hates this

[-] [email protected] 8 points 2 years ago

"baby i can read letters through walls"

the letters

[-] [email protected] 8 points 2 years ago* (last edited 2 years ago)

This is super creepy

[-] [email protected] 6 points 2 years ago

Are there ways to design a room or things to put in a room (or the walls?) that would inhibit this ability?

I suppose lead shields or something...

[-] [email protected] 21 points 2 years ago

No need. If you skim the article, you'll see it only works on sharp edges. The letters being read here are metal cutouts.

[-] [email protected] 9 points 2 years ago

Note to self: "decorate with crystal balls..." Got it!

[-] [email protected] 5 points 2 years ago

Lemmy is so damn salty. All you did was explain what was said in the article and some guy disliked your comment lmao

[-] [email protected] 2 points 2 years ago

Yeah, but it was only one person. No big deal.

[-] [email protected] 1 points 2 years ago

There he iiiiis

[-] [email protected] 8 points 2 years ago

Faraday cage?

[-] [email protected] 4 points 2 years ago

No need for lead. Just make something similar to those microwave door mesh plates and embed it in with the insulation.

[-] [email protected] 0 points 2 years ago

Well, if it's using WiFi, then anything you do will also kill your WiFi signal. So, bare minimum, no WiFi router, only LAN lines.

[-] [email protected] 3 points 2 years ago

Yeah sure why not.

[-] [email protected] 2 points 2 years ago
this post was submitted on 16 Sep 2023
232 points (97.5% liked)

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