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Communications Network Wireless Networking Technology

Engineers Say They've Created Way To Detect Weapons Using Wi-Fi (gizmodo.com) 91

An anonymous reader quotes a report from Gizmodo: The researchers, which include engineers from Rutgers University-New Brunswick, Indiana University-Purdue University Indianapolis (IUPUI), and Binghamton University, published a study this month detailing a method in which common wifi can be used to easily and efficiently identify weapons, bombs, and explosive chemicals in public spaces that don't typically have affordable screening options. The researchers' system uses channel state information (CSI) from run-of-the-mill wifi. It can first identify whether there are dangerous objects in baggage without having to physically rifle through it. It then determines what the material is and what the risk level is. The researchers tested the detection system using 15 different objects across three categories -- metal, liquid, and non-dangerous -- as well as with six bags and boxes across three categories -- backpack or handbag, cardboard box, and a thick plastic bag.

The findings were pretty impressive. According to the researchers, their system is 99 percent accurate when it comes to identifying dangerous and non-dangerous objects. It is 97 percent accurate when determining whether the dangerous object is metal or liquid, the study says. When it comes to detecting suspicious objects in various bags, the system was over 95 percent accurate. The researchers state in the paper that their detection system only needs a wifi device with two to three antennas, and can run on existing networks.

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Engineers Say They've Created Way To Detect Weapons Using Wi-Fi

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  • They forgot I think to think about the trivial countermeasures, like lining the suitcases with aluminum foil, or using aluminum suitcases, or putting absorbent ferrite sheets in instead. You can't see what doesn't reflect or reflects all or absorbs a lot.

    • by swb ( 14022 ) on Wednesday August 15, 2018 @03:24PM (#57133206)

      I always figured the way to beat baggage screening was a kind of x-ray stenography. Pack your contraband items in close proximity to familiar and non-contraband items that are readily identifiable to x-ray screeners. Unless its entirely obvious, they will just assume the contraband is another similar item to what they can "see" and let it pass, or the item density and overlap will be such they can't quite make out anything and might just assume it's a collection of toiletries or some other innocuous content.

      Of course I just made this all up and don't have any experience in smuggling, so perhaps this is all just errant speculation.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      > trivial countermeasures, like lining the suitcases with aluminum foil

      Yes, because having a suitcase lined with aluminum foil is totally benign.

      > You can't see what doesn't reflect or reflects all or absorbs a lot.

      No, but you can make a note of something that DOES all those things. Normal suitcases don't.

    • by Anonymous Coward

      Nah. If the baggage inspectors can't detect what's in the suitcase with their machines, they'll just open the suitcase. With a five-dollar wrench, if need be.

    • Easy Solution (Score:5, Insightful)

      by Roger W Moore ( 538166 ) on Wednesday August 15, 2018 @04:06PM (#57133528) Journal

      They forgot I think to think about the trivial countermeasures

      Not really because these have trivial solutions: just flag any bag which shows a huge amount of reflection or none at all as suspicious. Then, instead of a quick automated scan, you can be detained by security and wait while they rummage through your bag.

      • This is precisely why I get stopped at the airport for an additional check. I often carry large lenses through in hand baggage and at Schiphol they happily show you a picture of your bag, including the fact that you can't see anything in most of the bag when the bag is filled with large chunks of glass.

    • The answer to that: "I'm sorry sir, we're going to need your consent to open your bag. If you don't give your consent, feel free to not enter the building / concert / stadium / whatever."

  • Terrifying (Score:5, Insightful)

    by shaitand ( 626655 ) on Wednesday August 15, 2018 @03:12PM (#57133110) Journal
    This is absolutely horrific. You are telling me that these idiots who've gone along with the NSA illegally monitoring our traffic can now use state backdoors to identify every bit of gold/silver/gun wealth and resistance across the country? Wifi is everywhere and *I* can get into half the systems using nothing but default credentials.
    • Assuming the gold/silver are in the form of jewelry, highly unlikely it will be distinguishable from wiring at a distance. This looks like it needs a device with a specific type of antenna to scan bags or people at close range.
      • I'll have to finish reading the paper. But this doesn't sound good...

        "In this work,
        we leverage the fine-grained channel state information (CSI)
        that is readily available in low-cost WiFi devices to detect
        and identify suspicious objects hidden in baggage without
        intrusion (e.g., opening the bag)."
        • This doesn't mean the device can be arbitrarily far away from the bag, though.
        • >"low-cost WiFi devices to detect and identify suspicious objects hidden in baggage without intrusion (e.g., opening the bag)."

          I guess that depends on one's definition of "intrusion" because I consider searching me or my stuff without probable cause to be intrusion, whether you do it with a physical search or some automated one at a distance. In fact, the latter is probably WORSE because it enables far more searching and the real possibility of it being done clandestinely.

          And, of course, just about anyt

    • Re:Terrifying (Score:5, Informative)

      by Headw1nd ( 829599 ) on Wednesday August 15, 2018 @04:00PM (#57133496)
      No need to panic, this is a method that uses a purposefully arraigned setup of wifi antennas to detect objects roughly 2 feet away, not some miracle technology that makes your home wifi able to scan your house. It's basically like cheaper version of an x ray machine at the airport monitored by an algorithm.
      • *arranged
      • I haven't thoroughly reviewed everything in the paper but I did scan it and the hardware used was off the shelf wifi cards, the rig was no more specialized than what you'd see geeks playing with in vans roaming around vegas at defcon and it was indicated that all that was needed was a commodity wifi device with 2-3 antennas. Although there are images of the setups they tested on and I could have missed it skimming, I didn't see any explicit mention of distances or range.

        The concern isn't what a handful of s
    • Yeah, this requires a specific device that uses specific metrics of the radio waves to do what it does. You can't just turn some shit on in someone's off-the-shelf-at-Bestbuy router and image their whole house.

      Paranoid much?

    • by AHuxley ( 892839 )
      The FBI sets a utility pole surveillance camera. https://arstechnica.com/tech-p... [arstechnica.com] (6/16/2016)
      Now another team looks in with wifi to map out the location from the outside in.
  • by Thud457 ( 234763 ) on Wednesday August 15, 2018 @03:12PM (#57133112) Homepage Journal
    I'll stick with my trusty ADE 651, thankyouverymuch!
  • by b0s0z0ku ( 752509 ) on Wednesday August 15, 2018 @03:14PM (#57133120)
    This is using 2.4GHz microwaves to scan for certain types of objects (large metal objects, nitrogen-containing explosives). Basically a more advanced metal detector.
    • Basically a more advanced metal detector.

      ... aaaand now I'm trying to figure out how to rig it for finding gold nuggets in the earth...

      • Basically a more advanced metal detector.

        ... aaaand now I'm trying to figure out how to rig it for finding gold nuggets in the earth...

        And my first thought is that it wouldn't have much use with a 2' range. Then I started thinking about placer deposits in river bed rocks. Might be able to use it to determine if an area was worth digging up into a mining sluice. Of course, I have no real clue to the realities of prospecting for placer gold...or how these wifi things work.

    • by Tablizer ( 95088 )

      So it's basically sneaky marketers renaming existing stuff, such as "agitation engineer" instead of "troll".

  • meaningless measures (Score:5, Interesting)

    by Chris Dodd ( 1868704 ) on Wednesday August 15, 2018 @03:14PM (#57133124)
    Unfortunately, from reading the paper, it seems like they've failed to measure the real effectiveness of their system -- they only measured the false negative rate and used just that for their "effectiveness". They never even bothered to check for or measure false positives. With such useless measures its easy to get a 100% effective system -- simply categorize everything as dangerous. Then your false negattive rate is 0% and your "effectiveness" is 100%.
    • by rahvin112 ( 446269 ) on Wednesday August 15, 2018 @04:56PM (#57133826)

      Not just that, but it was 15 samples and they knew what was in the bags/boxes. Talk to me when they've done a thousand samples in a double-blind environment with real packed luggage that contains all the weird shit people put in bags like prescriptions, breast milk, vibrators, etc that the "scanner" operator has no idea what's in each bag.

      They ran off and claimed 95%+ detection and they've got no evidence at all of that kind of reliability. Scanning bags for dirt simple things like guns is hard, and scanning for anything like explosives is 100x as hard.

  • Time to fire the TSA! ;)

    • by Anonymous Coward

      The time to fire the TSA was the day it was created, along with the moronic self-serving politicians that created it.

    • by nwf ( 25607 )

      Step 3: Profit!

  • Percentage errors (Score:5, Insightful)

    by Todd Knarr ( 15451 ) on Wednesday August 15, 2018 @03:22PM (#57133186) Homepage

    Even 99% accurate is absolutely horrid for real-life situations. Let's take a case where one in a thousand items encountered are dangerous. I'm going to scale the numbers to make the results come out as integers. At 1 in 1000, if we start with 100,000 items we'll have 100 dangerous items and 99,900 non-dangerous. Of the dangerous items, the system will flag 99 as dangerous and 1 as non-dangerous. Of the non-dangerous items, the system will flag 98,901 as non-dangerous and 999 as dangerous. So out of 1,098 items flaged as dangerous, 90.98% of them will be non-dangerous. So a system that claims a 99% accuracy rate will have a 91% error rate when it comes to sounding the "Danger!" alarm. Only 9% of the time will that alarm actually indicate danger, the other 91% of the time it's a false alarm.

    The above is why 5-nines (99.999% accuracy) is the baseline for workable systems.

    • Re:Percentage errors (Score:5, Informative)

      by ebrandsberg ( 75344 ) on Wednesday August 15, 2018 @03:36PM (#57133314)

      You apparently don't understand the failure rate of traditional TSA detection methods: https://abcnews.go.com/US/tsa-fails-tests-latest-undercover-operation-us-airports/story?id=51022188, and that is for airports.

    • by AvitarX ( 172628 )

      I go to a festival, they search every bag for liquid, with I don't know what kind of a failure rate, but it's more than 1% of the bags of wine wrapped in towels that get through.

      With this system, they can more thoroughly search 1% of the bags, and only have 1% get through.

      Seems like it could be useful to me.

    • This is a common argument against 99% type solutions, however you are misusing in this case. Using this device when the items are "flagged", all that means is that a human will have to check the item. In the current system, humans have to check every item, so by your numbers they will be checking 100,000 the items, with a detection rate of 0.1%! Using this system as a prescreener can reduce the number of items humans must check by 100 times, improving the detection rate by almost as much.
    • The above is why 5-nines (99.999% accuracy) is the baseline for workable systems.

      There are no systems in the world meeting your imaginary requirements.

      Don't let perfect become the enemy of good.

  • iGun (Score:5, Funny)

    by Oswald McWeany ( 2428506 ) on Wednesday August 15, 2018 @03:28PM (#57133254)

    That's why I always put my iRifle on airplane mode when I don't want to be detected.

  • strange
  • It can't hurt to ask.

  • Positive Molecular Locator is well-known device which works exactly in the same way. https://en.wikipedia.org/wiki/... [wikipedia.org]
  • by Jfetjunky ( 4359471 ) on Wednesday August 15, 2018 @04:57PM (#57133838)
    This was an interesting experiment done by some students. It's not some amazing new idea that is going to revolutionize security. First off, they only tested it by putting the object directly between the transmitter and the receiver. And like 10m apart. So, basically like every other type of scanner around. You're still going to have to walk through it. So while that might make it easier to implement a scanner type device, it's not like suddenly anywhere with WIFI can start scanning all the people around it at will.

    Unfortunately, the reporting is lacking in highlighting this. I suspect, frankly, because those reporting on it don't really understand what they're looking at.

    The method of detection in this case is rather crude. In reality, no fancy countermeasures are necessary. Take your contraband item and simply enclose it in the shape of something harmless, and this system would be immediately fooled.
    • It's worse than that. They used wifi because that's what they had at hand. It had nothing to do with computers, only with having electromagnetic response on a certain spectrum.

      The article doesn't understand anything about the practicality of the study, nor the real technologies, and don't care a bit because they want clickbait articles to make money. The fact that this study is relayed (out of maybe hundred of others) is actually because they used wifi devices for their experiments, which people know and u

    • by AHuxley ( 892839 )
      Experiment, sure...
      New police radars can 'see' inside homes (Jan. 19, 2015)
      https://www.usatoday.com/story... [usatoday.com]
      Technologies that see through the walls (July 7, 2015)
      https://www.kaspersky.com/blog... [kaspersky.com]
  • In tomography [wikipedia.org], you shoot a known signal through a target at a certain location and direction. Then based on how the signal is altered at your receiver, you back out what it could've gone through to cause that alteration. Do this at enough locations and directions, and you can build up a picture of what's in between. Basically how a CAT scan works (Computer Aided Tomography - shoots x-rays through the body in different directions).

    There's nothing particularly new about tomography. It's been known abou
  • ... because it will be monetized.

    "Psst ... wanna buy newer underwear?"

  • Mold crushed up aluminium foil in the shape of a gun and put it in your carry on bag, watch the expression on the face of the xray operator!

  • I wonder if is able to distinguish between a metal laptop case filled with explosive and a real laptop. If it does not, then it is of little help.
  • It FIRST detects if something is dangerous, with 99% accuracy, and THEN detects if it is metal or liquid? Don't you all see that this is mumbo jumbo? It makes no sense at all.
  • The article is missing some vital information, making it look like it works excellent. BUT it really doesn't, it only works with 0,5 meter range and only detected the stuff correctly if it was in a specific position... Wake me up when it works in a range of 3-5 meter (a normal passage way in a subway/airport/whatever) and detects it correctly in any position. Also wonder how it works if one would line the inside of a bag with aluminiumsheets (or even some copper wiring)

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