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Government The Courts Science Technology

Crystal Pattern Matching Recovers Obliterated Serial Numbers From Metal 133

chicksdaddy writes Criminals beware: researchers at the National Institute of Standards and Technology (NIST) have figured out how to recover serial numbers obliterated from metal surfaces such as firearms and automobiles — a common problem in forensic examinations. According to this report, NIST researchers used a technique called electron backscatter diffraction (EBSD) to read, in the crystal structure pattern, imprints on steel that had been removed by polishing. ... The more perfect the crystal structure, the stronger and clearer the pattern. Software can then calculate the pattern quality to reveal crystal damage; areas with more damage produce lower quality patterns. In the NIST experiments, described in Forensic Science International, researchers hammered the letter 'X' into a polished stainless steel plate. The letter stamps were as deep as 140 micrometers, meeting federal regulations for firearm serial numbers. The researchers then polished the metal again to remove all visible traces of the letters, and collected the EBSD diffraction patterns and pattern quality data and analyzed them for evidence of the imprints.
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Crystal Pattern Matching Recovers Obliterated Serial Numbers From Metal

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  • Overstamp First? (Score:5, Interesting)

    by theshowmecanuck ( 703852 ) on Saturday February 21, 2015 @04:15AM (#49099483) Journal
    What if you use some tool and hammer to overstamp the serial numbers. Like scribbling over it. Then grind it down. Or if it is in a place that can be heated and cooled... like annealing... where any loss in strength from the operation, were it to happen, wouldn't be an issue. Would that change the underlying crystal structure significantly. I'm sure it would affect it some, but would it be enough to allow the crystal structure to 'reset' and erase the original stamp marks?
    • by Anonymous Coward

      My first thought as well, a cheap punch kit and a hammer seems like a way to disrupt the "background" crystal pattern.

      If you do it stupidly, like put a "1" through an "A", it would be fairly obvious and narrow the search down. But using a variety of punches and changing "1"s into "l"s and overlapping repeatedly might do the trick.

      • Overstamp twice. (Score:4, Interesting)

        by Okian Warrior ( 537106 ) on Saturday February 21, 2015 @05:01AM (#49099551) Homepage Journal

        If you do it stupidly, like put a "1" through an "A", it would be fairly obvious and narrow the search down.

        Punching 1 through an A leaves the firearm with two possible choices in that digit. Do this for 9 digits, and you get 2^9 = 512 possibilities. Punch twice through each digit and you get 3^9 possibilities.

        In fact, punch *all* the digits in each position, then file it down.

        This will rapidly be entered into the "big book of best practices" for criminals.

        And it's also a moot point, since easy access to guns reduces crime, and it's likely that 3-d printed guns will be easily available in the next decade or so.

        (And so what if the 3-d printed gun is reliable for only the first couple or shots? That only means that you use your 3-d printed gun that took 2 hours to print and $3 to build a couple of times and then melt it down.)

        • by Anonymous Coward

          Furthermore it will be easy to distinguish the different fonts of the letters you stamp into the gun. Criminals got to have a machine that can stamp with the same font of the official serial numbers and how many criminals really have such a device?

          • now? probably not many. as soon as this tech is mainstream? probably alot
          • Why would you need anything resembling the original font? You are trying to disrupt the original number shape enough so that the crystallized pattern remaining after everything is filed off won't resemble the original number.

            You could overstamp the original number with a symbol of a duck if this would disrupt the original pattern enough.

            ~~
        • Re: (Score:1, Interesting)

          by Anonymous Coward

          This will rapidly be entered into the "big book of best practices" for criminals.

          And it's also a moot point, since easy access to guns reduces crime, and it's likely that 3-d printed guns will be easily available in the next decade or so.

          Criminals are pretty notorious for not following "best practices". A majority of violent criminals suffers from ADHD and acts without thinking. It is unlikely that the few that thinks about getting rid of the serial number are bright enough to know about technologies like this.
          As for easy access to guns reducing crime that sound like bullshit propaganda to me, do you have a credible source for that?

          • Actually I'd think it would be the opposite... the criminals who are already going through the trouble of erasing serial numbers would be exactly the type to know about how to do it properly. Because it's usually not done by the lowest level guys. Guns are an organized crime type deal, and when it comes to things like that, only the very bottom rungs are populated by truly stupid people. Especially for larger gun running or drug dealing or car theft rings, towards the top you tend to find fairly intelligent
        • by Anonymous Coward

          "since easy access to guns reduces crime".

          Yeah, this must be the reason the UK has such a high crime rate in comparison with the US.

          Oh wait...

          • I think the result may differ depending of the number of guns already circulating and also if guns are illegal/legal and how strong is law enforcement in this regards and the previous absolute level of gun crime. Would be good if people quote studies rather than just saying studies, as you could find pretty rubbish studies on any topic.
            • Re: (Score:2, Insightful)

              US states with tougher gun laws have less relative crime than even neighbouring states with weak gun laws. The parent poster is obviously an NRA type who has drank too much of the Koo-aid.
              • Let's see: I live in Utah. In the vast majority of cities in Utah, there is a 50% ownership per household. (Of those households, the majority own more than one firearm.) There are LOTS of firearms here to be had. There is very little crime. The same holds in Wyoming, Nevada, Idaho, Texas, Oklahoma, Tennessee, South Carolina, etc. etc. etc.

                On the other hand states like California, New York, Illinois (Chicago especially), Massachusetts, Hawai'i etc.etc. etc. by in large have significantly higher crime
                • by dbIII ( 701233 )
                  So there you go - people cause crime and there's not a lot of it when they are not many people. Who would have thought?

                  If you have to drive half an hour to shoot that neighbour that is pissing you off how many would bother?
            • It's a well-established fact [google.com] at this point.

              The study cited includes data from the UK, which is seeing a massive increase in crime over the last two decades. From that study:

              bytheyear2000violentcrimehadsoincreasedthatEnglandandWaleshadEurope’shighestviolent
              crimerate,farsurpassingeventheUnitedStates.

              This should, at the very least, satisfy everyone's demand for a study, which includes England and the UK.

              Also, US states with relatively easy access to guns *do* see a lower crime rate. Compare New Hampshire and Texas with, for example, Illinois and Louisiana.

          • actually the UK does have a fairly high crime rate https://stevengoddard.wordpres... [wordpress.com]

            According to the FBI, there were 1.2 million violent crimes committed in the US during 2011. FBI — Violent Crime

            According to the UK government, there were 1.94 million violent crimes in the UK during 2011. www.ons.gov.uk/ons/dcp171778_296191.pdf

            There are almost exactly five times as many people in the US as in the UK – 314 million vs. 63 million. The violent crime rate in the UK is 3,100 per 100,000, and in the US it is 380 per 100,000 population.

          • by 0123456 ( 636235 )

            Yeah, this must be the reason the UK has such a high crime rate in comparison with the US.

            Oh wait...

            It does have relatively high crime rates (just not murder), and those rates were significantly lower when gun ownership was common and anyone could carry one so long as they had ten shillings to pay for a license.

        • I know old school forensics teams put acid on the site and the cold-worked area would have more fractures in the microstructure which would reveal a scraped serial number. If they did this with EBDS, I would guess you could see differences in the cumulative cold work and still resolve the original pattern (you only need a few reference points).

          If a criminal wants to use the gun, or bike, I'm not sure how much stamping they could do before they damage the material enough to prevent use.

        • by mysidia ( 191772 )

          See... why we should require the manufacturer of every firearm to include microstamping technology, where the serial number will be imprinted on the cartridge of every round fired.

          Also, should include scannable RFID tags, one scannable by the public, another RFID tag only detectable and scannable by law enforcement.

          And some concealed serial number imprints, also scannable.

          I figure the manufacturer could punch out a pinhole in certain places with a punch containing adjustable ridges and serial number

          • No need for such over-complicated and over-engineered solutions.

            Each gun already imprints a unique microscopic signature on a bullet and casing. Just submit a scan of a fired bullet and cartridge to a central database for each new firearm sold, where it's linked to the serial number. They're test-fired before use anyhow, so I'll bet the manufacturer could easily add a forensic-type scanner to the manufacturing process, likely completely automated as well. Then we wouldn't have to rely on serial numbers o

            • by jafiwam ( 310805 )

              No need for such over-complicated and over-engineered solutions.

              Each gun already imprints a unique microscopic signature on a bullet and casing. Just submit a scan of a fired bullet and cartridge to a central database for each new firearm sold, where it's linked to the serial number. They're test-fired before use anyhow, so I'll bet the manufacturer could easily add a forensic-type scanner to the manufacturing process, likely completely automated as well. Then we wouldn't have to rely on serial numbers on the gun at all then. Any bullet in good condition could likely be linked with the serial number using that database.

              Law enforcement already uses this technique, but can only perform matching tests if the gun or additional fired rounds are found. This wouldn't require any new technology at all, only new procedures.

              Not really. Those "unique" qualities are only such for a limited time.

              Using, or even cleaning, the firearm will cause them to change.

              Someone wanting to use the firearm, and change it's ballistics characteristics needs only a few minutes with the a few tools. File, sandpaper, perhaps a punch.

              If the gun is fired and then tossed, they can match them. Fired and kept and the owner wants to change it's profile, it's really easy.

              Get yourself a firearm, and use it. Stop watching so much TV.

              • I own several guns already, thanks. No need for the snarky attitude though.

                I suppose you're right that those characteristics can be easily modified, as from what I understand, they're largely there because of the hand-finishing / cleanup that guns go through during the manufacturing process. So, it would make sense that they'd rapidly change as well.

                As is so often the case, if there's a "simple" idea that hasn't been implemented, there's probably a pretty good reason *why* it hasn't been implemented. I'v

              • by Altrag ( 195300 )

                What they really need to do is figure out a way to etch the serial number inside the metal.. similar to how they laser-etch diamonds. That way it could essentially only be removed by melting the weapon down.

                Of course while they could probably figure out a way to manufacture it, I'm not sure how easy it is to scan the internals of the metal. Maybe encode it in some sort of magnetic material that could be encased in the metal during casting? Of course it would have to be something that couldn't get "overwr

                • by mysidia ( 191772 )

                  I'm not sure how easy it is to scan the internals of the metal.

                  Acoustic microscopy.

                  Also, since the identification info could be encoded in various formats... such as microscopic dimples in the metal, magnetic elements, digital circuit elements such as passive RFID, or other methods

                  It's possible that the criminal could be unable to know whether or not there is a serial number that is still readable which the criminal themselves cannot see, since mostly just law enforcement and gun shops would have b

            • by mysidia ( 191772 )

              Each gun already imprints a unique microscopic signature on a bullet and casing. Just submit a scan of a fired bullet and cartridge to a central database for each new firearm sold

              They already tried that in Maryland, and I understand it turned out very poorly, the government itself instead of the manufacturer wound up bearing huge costs; there were error-prone and labor-intensive steps involved in taking in test-fired casings submitted by manufacturer, photographing , logging to database.

              But it was also

          • See... why we should require the manufacturer of every firearm to include microstamping technology, where the serial number will be imprinted on the cartridge of every round fired.

            As long as you believe in fairy tale technology like microstamping, why not just require every crime lab have a CSI-type "enhancing" microscope? That way you could code a GUI in Visual Basic and then have the computer tell you who committed the crime.

            For those who are uninformed, read about how cartridge microstamping (doesn't) work in practice, and even if it *did* work, think about how trivial it is to defeat. The microstamping system is supposed to use a rather weak force to stamp a tiny serial number? N

        • by jafiwam ( 310805 )

          If you do it stupidly, like put a "1" through an "A", it would be fairly obvious and narrow the search down.

          Punching 1 through an A leaves the firearm with two possible choices in that digit. Do this for 9 digits, and you get 2^9 = 512 possibilities. Punch twice through each digit and you get 3^9 possibilities.

          In fact, punch *all* the digits in each position, then file it down.

          This will rapidly be entered into the "big book of best practices" for criminals.

          And it's also a moot point, since easy access to guns reduces crime, and it's likely that 3-d printed guns will be easily available in the next decade or so.

          (And so what if the 3-d printed gun is reliable for only the first couple or shots? That only means that you use your 3-d printed gun that took 2 hours to print and $3 to build a couple of times and then melt it down.)

          It's also simply illegal (to various degrees in various states and jurisdictions) to have a serial number removed.

          Knowing it goes only a little ways toward solving the crime it was used in.

          On the other hand, it is VERY useful if you are a gun grabber and want to make a political point.

          This particular technique has been known for over two decades. I heard about it in college.

          Up next on slashdot! New device for putting on an axle to reduce friction of your cart! Carry heavier loads longer distances mo

        • by gl4ss ( 559668 )

          it's not so much for future reference as it is that the technique could be used to trace guns already in the possession of the police.. cold cases and such.

          "zip" guns aren't popular in USA only because proper guns are so easy to get.

        • This will rapidly be entered into the "big book of best practices" for criminals.

          Are these the same criminals that post photos of themselves bragging about their crimes on social media? I think you're overestimating the IQ of your average thug.

      • by Kardos ( 1348077 )

        You'd want to match the force used on the original stamp, else your 'decoy' numbers and letters will leave crystal deformation pattern that differs in intensity from the real digits. Probably easy if you're the manufacturer, but a touch harder if you're some guy with a hammer.

    • You think the purpose of the research is to help FBI find the original numbers? ha! The real purpose is to let an FBI expert witness testify that "FBI forensic labs recovered this A12345 X73464, of the weapon known to be owned by the defendant from this weapon entered into evidence as prosecution exhibit A23".
    • by mrmeval ( 662166 )

      The serial is usually in a non critical spot. Just drill it out and fill it with silver solder.

      If you want a perfect solution, live in a state in the US which isn't a liberal distopia you can build your own firearm legally as long as it's not covered under the NFA.

      If it's one of the cast zinc firearms have your cat pee on it. It will be destroyed within days. ;)

    • Not only that, but they polished the test plate down. What happens when you use a nasty low grit number sandpaper that will leave behind gauges and scratches?

      Not only that, but:
      What happens when water gets in the crystal structure? It may take weeks+ but water can and will diffuse into the material.
      What happens after firing? It doesn't take extreme amounts of heat to alter the crystal structure of steels... you can change the structure of regular / high carbon steel with a home oven quite easily, and dest

      • by dbIII ( 701233 )

        What happens when you use a nasty low grit number sandpaper

        If you use if for long enough you can completely remove the layer damaged by the stamp.
        With weld testing (an extreme case of it using microscopes in high temperature high pressure pipes) you have to go pretty deep to remove the damage from an angle grinder, then a bit of time with fine grit to remove the damage from course grit, then finer again until you polish to get rid of the damage from fine grit. If you haven't gone anywhere near deep enough

    • Or if it is in a place that can be heated and cooled... like annealing

      Then it's gone - but with steels the time and temperatures required not only make it impractical but would also make the thing the numbers are stamped on useless. Even though iron (thus steel) is not a good conductor it's still enough of a conductor that if you anneal one part of it the rest of the engine block (for example) is going to be heated up enough for long enough that it will ruin the structure that makes the steel useful. Anne

  • by invictusvoyd ( 3546069 ) on Saturday February 21, 2015 @04:27AM (#49099511)
    And this becomes largely irrelevant
    • Re: (Score:2, Informative)

      by Anonymous Coward

      Why 3d print? Easier to just go to the hardware store and get some plumbing parts. Also won't explode in your hands after a few shots.

    • by ls671 ( 1122017 )

      There is a legislation coming up forcing all 3d printers to incorporate a serial number in all 3d printed guns.

      • by schwit1 ( 797399 )
        The only way this would work is if everything printed was serialized and that data was accessible by law enforcement. Good luck with that.
    • Re: (Score:2, Interesting)

      by Anonymous Coward

      Removing markings from metal is an easy process that can be done with hand tools and power tools. If you were to remove all of the metal behind the markings i would expect the analysis to fail.
      A polymer gun is easier, as you only have to grind off the metal plate holding the markings and are still left with an intact tool.
      Creating a working gun, or the part of the gun that requires a serial number is not easy. You can try to use a 3D printer, a CnC Mill or in come cases, like the AK-47, a shovel and hammer.

  • Is this new? (Score:4, Informative)

    by tsotha ( 720379 ) on Saturday February 21, 2015 @04:56AM (#49099543)
    The FBI has been recovering filed off serial numbers for at least a decade based on the changes in metal grain that result from stamping. Is this just a more sensitive method for doing that?
    • It looks like this is a more advanced method to accomplish the same thing. Meaning that recovering sanded serial numbers is not new, but this particular way of doing it is.
    • by Anonymous Coward

      I am not even really sure what use the serial number is. A serial number will get you the original manufacturer data, the original distributor, the DoR (Dealer of Record) and the police report stating when it was first stolen. Thats pretty much it. Even all of that assumes that it is a firearm manufactured in the last 50 years only. I suppose if a firearm is serially stolen, or a cache of firearms was stolen you could link them together, but normally a cache is broken up and distributed.

      Now the rifling and

      • by felrom ( 2923513 )

        The problem is that most people have watched too much CSI and think that a serial number on a gun is equivalent to a magical beacon that instantly homes in on the person who committed the crime. Just look at all the hysteria in the last few years over 3d printed guns and 80% firearms: it all revolves around the line of reasoning of, "if a criminal used this in a crime, we couldn't trace it back to them." The whole breathless panic never stops long enough to understand that criminals aren't going out and b

        • I'd be interested to see the life of a gun. From first initial theft(or undocumented sale) to how many hands one firearm passes thru. It would be interesting to see how much separator there is from the original documented owner.

          • Re: Is this new? (Score:3, Insightful)

            by BlueTrin ( 683373 )
            The problem is that if you base yourself on declared data you will have a massive bias as criminals are unlikely to provide information. Therefore your data will be about legally owned guns which is not the data you would need for crimes. I still agree with you that it would be interesting.
        • by Anonymous Coward

          You deserve more insightful points that you know.

          I would like to know what the serial number does for an investigation beyond knowing which purchaser the gun was stolen from. It doesn't tie the gun to other crimes, unless criminals are in the habit of stating, "and then I pulled out my gun, with the filed off serial number of ACQJ3235235 and shot the guy." "Where's the gun, then?" "I don't know".

          I mean you would practically have to have a confession, at which point the gun _and the gun's serial number_ i

        • It's even less clear than an IP address.

    • by dbIII ( 701233 )
      Yes. The usual method uses acid to preferentially attack the stamped areas that are more stressed than the surrounding metal. That needs a bit more damage than the SEM could pick up with this alternative.
  • by He Who Has No Name ( 768306 ) on Saturday February 21, 2015 @05:07AM (#49099581)

    Defeated by a $59 Dremel tool that completely removes the metal from that area of the frame...

    • I was wondering when this would be brought up. Once the word on the street gets around that you need to remove a millimeter of metal under the serial number for it to be really obliterated, Dremel tool sales will go through the roof.
  • by Anonymous Coward

    140 micrometers is 0.0055 inches

    which is about 6 thousandths of an inch

    which is about 3 head hairs stacked

    which is why I need more crystal to stay ahead of this blue persuasion that has been following me

  • by jcr ( 53032 )

    All you need is a spot welder.

    -jcr

  • by hankwang ( 413283 ) on Saturday February 21, 2015 @05:41AM (#49099639) Homepage

    It has been possible for decades to recover serial numbers by chemical etching [csitechblog.com], which is sensitive to changes in the crystal structure. All you need is a polishing implement and a bottle of etching gel. What is the added value of this EBSD technique? I can see a big disadvantage: you need equipment (a scanning electron microscope) worth a few hundred kEUR and the object with the erased serial number needs to fit into the vacuum chamber of said equipment.

    The article mentions that etching techniques don't always work, but they don't state that their technique does work on samples for which the etching method doesn't work...

  • there is techniques to read pulished-out stamped numbers (eg. on car frames) since ages.

  • by wierd_w ( 1375923 ) on Saturday February 21, 2015 @07:23AM (#49099777)

    Metal grain boundries change if you heat the metal up. This also removes the temper, but rapid heating followed by rapid cooling (Such as by very high speed friction sanding, then submersion in water or oil) will change the crystal grain structure of the metal pretty deeply if done right.

    Failing that, sanding off the top layer, then applying heat with a heat gun for a few minutes, then clenching with a cold oil pour will have the same effect, but more reliably.

    Seriously, this is how heat treatment of steels works. Steels and other metal alloys go through various phases of crystal growth types under different temperature and pressure environments. They grow when hot (but not molten) which is why the metal weakens. If you heat it up hot enough, this processes changes into annealing where the crystals break down from thermal forces and the metal becomes amorphous. Flash cooling results in a densely packed matrix of tiny metal grains, which strengthens the metal.

    Seriously-- all you have to do is alter the crystal growth pattern under where the serial number was. Heat treatment will do exactly that.

  • by CanHasDIY ( 1672858 ) on Saturday February 21, 2015 @11:04AM (#49100381) Homepage Journal

    This could actually be useful for gun shops, since we have to meticulously catalog the serial numbers of all firearms that come in and go out. We often get older (like, 150 year older), used firearms where the serials are worn down and difficult to read, even with a jewelers loupe.

    Or rather it would be useful for gun shops, if the process isn't as cost-prohibitive as I presume it will be.

    • I own several guns < 150 years old which never had a serial number - prior to 1968 it wasn't required on most firearms. Of course most guns did get serial numbers just for inventory purposes, but things like cheap .22 rifles or cheap shotguns sometimes didn't.
      • by ihtoit ( 3393327 )

        yeah, it's a requirement in England now and retroactive to firearms made after 1968. That said I have a Webley Junior Mk.II from 1949 with a serial on it (pretty much all Webleys have serial numbers, they've been going since 1925 - my two Stingrays also have serials).

    • The last time I heard of a gun with an obfuscated serial number it involved a cop "throw down". Really, it's pretty rare when somebody buys a gun legally and then removes the serial number before committing a crime. It's so much easier to just buy a stolen gun.

  • by codeButcher ( 223668 ) on Saturday February 21, 2015 @03:29PM (#49101637)

    ... how to recover serial numbers obliterated from metal surfaces such as firearms and automobiles ... In the NIST experiments... researchers hammered the letter 'X' into a polished stainless steel plate.

    Just had a look at the few automobiles and firearms I own. None are made out of polished stainless steel plate.

    Also, while my oldtimers are stamped, I recall seeing a few items of more recent manufacture that had the s/n milled into the substrate.

    • None are made out of polished stainless steel plate

      It works exactly the same way with plain carbon steel with a rough surface or even mill scale still on it. They just used polished plate to reduce the variables. Stainless is also a bit of a bastard to etch so the usual method of just acid etching to recover serial numbers is less likely to work on stainless than with your carbon steel automobile and firearm parts.

      s/n milled into the substrate

      That will still distort the metal underneath though probably

  • Banksters can loot trillions at will sans steenking serial numbers. Let's see some Magical Chrystal Pattern Matching to put a stop to that.
  • Who erases serial numbers, and doesn't anneal the base material? Idiots.
  • Why is it that cops ever recover murder weapons at all? Seems to me that if you have a gun that could incriminate you, the obvious thing to do is get a bench grinder and turn it into a pile of filings.

    -jcr

    • Dumping a gun in a trash can or river is fast. Grinding it to filings is not fast.
      Now I don't know how fast the cops often gets the perpetrator but I imagine some crooks are afraid they'd get caught before grinding it down.
      Also, grinding it down is a lot of work. People are lazy.
      The serial number can be filed down before the crime.

      • by jcr ( 53032 )

        Grinding it to filings is not fast.

        Less than fifteen minutes to totally destroy it, I would say.

        -jcr

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