Why Is the TSA Scanning Paper? • Hacker News Board

Re: Why Is the TSA Scanning Paper?

#61

Post by csydas » Fri, May 05, 2017, 5:47 PM UTC

learc83 wrote: post #42

csydas wrote: post #37

Earlier quoted context omitted.

I lack the expertise to comment on the sensitivity of the cellulose specifically, but the metro stations where I live will perform random stops as you enter, and the monitors are in plain sight. Notebooks, stacks of paper, and note cards are usually pretty clearly detected by whatever software they're using to help highlight items. It seems weird to me that there could be such difficulty with TSA scanners versus the…

>Notebooks, stacks of paper, and note cards are usually pretty clearly detected by whatever software they're using to help highlight items How do you know the problem isn't that the software flags dangerous items as paper incorrectly (which I think is the mostly likely problem here)? I doubt you've seen the X-ray image of someone smuggling nitrocellulose. The software is just using density--if you have an explosive o…

Well, I was more specifically replying to the comment "It is the cellulose in the paper. Blocks of it are homogenous enough that they look similar in density to something dangerous."

Every time I've seen it on the scanners here, or the glimpses I've seen at airports last I was in the US, usually it's very clear what you're looking at - books and other paper products are plain to see.

If they obfuscate, sure, possibly. But just from personal experience it doesn't seem like it would be indistinguishable.

I'm not saying that these tools are infallible by any means, just that the particular claim didn't mesh with my experience.

Re: Why Is the TSA Scanning Paper?

#62

Post by glup » Fri, May 05, 2017, 5:49 PM UTC

I thought this might have something to do with printer steganography [1] but not if they are just X-raying the paper. Also I'm not sure whether that practice is ongoing--I haven't heard anything about it for years.

[1] https://en.wikipedia.org/wiki/Printer_steganography

Re: Why Is the TSA Scanning Paper?

#63

Post by pavel_lishin » Fri, May 05, 2017, 5:51 PM UTC

I've had agents ask me to take out a card game from my bag - apparently the thick stack of cards can look like C4 on the scanner.

Re: Why Is the TSA Scanning Paper?

#64

Post by kbenson » Fri, May 05, 2017, 5:55 PM UTC

philipkglass wrote: post #45

pfooti wrote: post #44

Earlier quoted context omitted.

They're not putting them through a different detector, though. They take out the books and all papers the passenger has, put them in one of the normal trays, and run the trays through the xray. My wife traveled out of Kansas City last weekend and was subject to this. She's a teacher, and traveled with grading, so they took out tests, her books, everything that was paper. The line agent said they were worried about pa…

Trying to de-clutter the images by separating paper would fit the observed procedure too. It seems a little odd that it would start only now. Maybe screener testing recently showed better performance when paper is separated out.

Or perhaps there was some intel, or some cases where luggage was searched post scanner that came up with items that should have been caught. That might trigger a revision in procedures to prevent or reduce future cases, which is how I would expect and want a program that was actually meant to reduce danger to operate.

Re: Why Is the TSA Scanning Paper?

#65

Post by valuearb » Fri, May 05, 2017, 5:58 PM UTC

CaliforniaKarl wrote: post #2

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

A better summary is that Bruce is bring it to his readers attention because it's interesting.

Re: Why Is the TSA Scanning Paper?

#66

Post by jandrewrogers » Fri, May 05, 2017, 6:06 PM UTC

philipkglass wrote: post #21

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…

It doesn't need to be nitrocellulose, you can impregnate ordinary paper with military high explosive using an appropriate solvent. But I doubt that is the purpose here because that could be handled by normal explosive detection mechanisms.

Re: Why Is the TSA Scanning Paper?

#67

Post by valuearb » Fri, May 05, 2017, 6:07 PM UTC

If the TSA was shutdown entirely leading to terrorists blew up 10 planes a year in the US, flying would still be as safe as it was in the 1960s.

http://www.sfgate.com/nation/article/U-S-commercial-airlines...

Re: Why Is the TSA Scanning Paper?

#68

Post by phkahler » Fri, May 05, 2017, 6:08 PM UTC

badloginagain wrote: post #34

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 think cash is already detectable.

Re: Why Is the TSA Scanning Paper?

#69

Post by bogomipz » Fri, May 05, 2017, 6:17 PM UTC

tuna-piano wrote: post #19

exabrial wrote: post #11

Earlier quoted context omitted.

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

It's true. Turns out blue shirts can be worn by just about anybody. Here's a story from last summer about the private security at Kansas City Airport: http://www.kansascity.com/news/local/article79795177.html

Oh interesting. I am curious is the experience of the privatized screening any better?

Or is the amount of humiliation, infantilizing and browbeating of regular honest people about the same as the non-privatized TSA?

There was big uproar about privatizing the TSA about a year ago when the time spent in lines was growing even more excessive. That narrative about privatizing seemed to go dark. Is the Kansas City Airport itself a pilot program for privatization of the TSA?

Re: Why Is the TSA Scanning Paper?

#70

Post by bogomipz » Fri, May 05, 2017, 6:18 PM UTC

throwaway287391 wrote: post #27

exabrial wrote: post #11

Earlier quoted context omitted.

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...)

Is this a recent development?