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Why Is the TSA Scanning Paper?

schneier.com

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Re: Why Is the TSA Scanning Paper?

#21

Post by philipkglass »

My guess, already voiced by "Ron" on Schneier's blog: they're looking for nitrocellulose. Nitrated paper is not obviously different in appearance from ordinary paper. Sheets of nitrocellulose have negligible vapor pressure and little dust so they could be missed by other means like the "puffer" detectors.

If they're putting these materials through a separate machine my guess would be another detector based on optical spectroscopy - maybe Raman? Something like that. It wasn't clear from the article whether the paper products in their separate bin just went through the same inspection chute as everything else.

Re: Why Is the TSA Scanning Paper?

#22

Post by eli »

Seems like TSA does a lot of pilot programs that (luckily, imho) don't end up going anywhere. They once set up a folding table and searched everyone boarding my Greyhound bus.

Re: Why Is the TSA Scanning Paper?

#23

Post by rosalinekarr »

There seem to be a lot of people theorizing that it could be something about the paper itself that they're looking for, i.e. flash paper, paper circuits or physical one-time encryption pads, but what if it's not about the paper at all? Maybe, the TSA is simply trying to discourage passengers from traveling with or using paper, thereby encouraging people to store their information digitally on phones and laptops where that data can be more easily copied and analyzed?

Re: Why Is the TSA Scanning Paper?

#25

Post by UnoriginalGuy »

exabrial wrote: post #18
ferentchak wrote: post #13

Earlier quoted context omitted.

They seem to like dense things to be in their own bin. Books are pretty dense.

Maybe someone got caught with a lead-lined hollow book concealing a weapon?

Going a little off topic now...

I'm surprised nobody has combined 3D X-Ray Scanning with computer vision technology. At the moment we're depending on the human eye flicking between three dimensions and spotting bad things, with very basic shape detection to "hint" at objects of interest. This system kind of works, but has human error weaknesses.

If you fed 3D X-Rayed objects into a computer vision engine, eventually you'd have a big enough catalogue so the computer could list off every object inside and flag things which may be odd or problematic, for example a book with seemingly no internal dimensions.

Now this is an imperfect system, for example when a new form factor of laptop started getting sold it might flag it as unusual, but isn't that somewhat working as intended? Then they can scan it, clear it, and send back the scan as a reference image.

Eventually it could speed up and improve the reliability of bag checks.

Re: Why Is the TSA Scanning Paper?

#26

Post by wyldfire »

swiley wrote: post #8
emiliobumachar wrote: post #3

Okay, tin foil hat time. Maybe they have new machines that can see the print through the paper, and actually scan and store the contents of all these papers in a timely fashion?

There was an MIT reasearcher a while ago (it may have been posted here) using THz wave radar to do this. I think it's the same band (ish) the body scanners use.

I kinda doubt those body scanners have anything remotely close to the spatial resolution required to find text written on a sheet of paper.

Re: Why Is the TSA Scanning Paper?

#27

Post by throwaway287391 »

exabrial wrote: post #11
tuna-piano wrote: post #7

Kansas City Airport doesn't use TSA screeners, they have a private contractor doing the screening: https://www.tsa.gov/for-industry/screening-partnerships That said, it seems like this policy is likely a TSA imposed pilot program: https://thepointsguy.com/2017/05/paper-products-new-tsa-secu...

I don't believe this is true, how does one tell? They appear to be TSA agents, in the blue uniforms with the TSA badges

SFO also doesn't have TSA screeners, and I believe the agents' uniforms actually don't have TSA badges. (Not sure about Kansas City, but I'd be surprised if any non-TSA agents had TSA badges...)

Re: Why Is the TSA Scanning Paper?

#29

Post by exabrial »

UnoriginalGuy wrote: post #25
exabrial wrote: post #18

Earlier quoted context omitted.

Maybe someone got caught with a lead-lined hollow book concealing a weapon?

Going a little off topic now... I'm surprised nobody has combined 3D X-Ray Scanning with computer vision technology. At the moment we're depending on the human eye flicking between three dimensions and spotting bad things, with very basic shape detection to "hint" at objects of interest. This system kind of works, but has human error weaknesses. If you fed 3D X-Rayed objects into a computer vision engine, eventually…

That already exists, but are commonly used on baggage, not at checkpoints. I can't remember what airport I was at, but they were scanning bags in the terminal area before loading them on a belt.I saw a TSA employee stick a bag through the machine, and the machine found a bottle of wine wrapped and taped in bubblewrap and outlined the wine bottle with a red outline. The guy they set the bag off to the side (presumably for 'enhanced interrogation').

Envision, or invision was the brand name of the scanner?

Re: Why Is the TSA Scanning Paper?

#30

Post by neuronexmachina »

sandworm101 wrote: post #5

Because blobs of paper look to similar to blobs of potential explosives when xrayed. They arent scanning it so much as removing it from the scan of everything else.

Yup, my guess is that it was causing time-consuming false positives when jumbled together with everything else in the bag, so they set it aside. That way they're easier to verify as safe, since they're isolated and laid flat, and if a closer inspection is required they don't have to go through the whole bag. I'm guessing that's the same reason laptops are scanned separately as well.
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