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Why Is the TSA Scanning Paper?

schneier.com

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Re: Why Is the TSA Scanning Paper?

#82
post #39
post #22

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.

They tried doing that at an Amtrak station a while ago and were forcibly removed from the premises by Amtrak police.

I was curious, so I went looking. This article seems to describe what you are referring to:

http://www.cnn.com/2012/02/06/opinion/don-phillips-tsa-vipr-...

Re: Why Is the TSA Scanning Paper?

#83
post #59

Summary: Bruce doesn't know, and so he is asking his readers.

Yes, it would have been nice if the title explicitly stated that... i.e., "Does anyone know why the TSA is now scanning paper?"

That's Bruce's fault, OP just copy-pasted the title

Re: Why Is the TSA Scanning Paper?

#84

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…

If this is the case (and I agree that it sounds likely) then what's the appropriate response from a bad guy? You don't take an action without considering a reaction...

Could this method be applied to fabric? Perhaps certain types of plastics? What if the bad guy hints that this is their plan with no actual intent other than misdirection. This could overwhelm screening resources, frustrating passengers, and stressing security agents while the actual threat could travel through another means, if it exists at all.

I traveled this weekend and can't help performing threat analysis against these security models. It's never made me feel better.

Re: Why Is the TSA Scanning Paper?

#85

Does cash have a unique identifier that can be scanned for? If someone was trying to bring a wad of hundreds in a hole cut out in a book, maybe they'd be looking for that?

I'm pretty sure it's perfectly legal to fly as much cash as you want domestically. [1] However, if they're scanning for other paper products that are potentially illegal, LSD comes to mind.

[1]: https://travel.stackexchange.com/questions/36740/is-there-a-...

Re: Why Is the TSA Scanning Paper?

#86

Does cash have a unique identifier that can be scanned for? If someone was trying to bring a wad of hundreds in a hole cut out in a book, maybe they'd be looking for that?

Yep. Metallic ink is used in your green(/blue/red)backs. http://www.dailymail.co.uk/news/article-2120883/A-step-spywa...

Re: Why Is the TSA Scanning Paper?

#87
Given that I've had this happen to me at a checkpoint (in Seattle) and had it explained to me, I think I have a reasonable potential answer: Stacked paper produces false positives in the scanning machines which can be flagged as suspicious substances. By separating the paper into a separate bin, it can be more quickly inspected by human eyes and the flag cleared, allowing the security line to be cleared more quickly.

Re: Why Is the TSA Scanning Paper?

#89
I had my bag pulled out of the scanner while at SAN - was very frustrating as I was going between the 3-9 gates and the 1/2/2A gates on a connection - amazingly had to go back through security - and had only a few minutes before my connection left.

In an exasperated voice I asked the security person why she had to dig through my bag and she indicated that the paperback novel that I had in there was the trigger.

So I replied - guess I'm not going to take a paperback next time. Another freedom impinged.

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