Software developed to disguise
3D printing files shared online


London designer Matthew Plummer-Fernandez has developed a piece of software that allows users to visually corrupt 3D-print files so they can't be recognised on file-sharing sites.

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

Matthew Plummer-Fernandez's Disarming Corruptor algorithm can be used to transform and disguise STL (STereoLithography) files - which record the outer shape of an object to be printed - in a way that can be only reversed by trusted recipients with the relevant key.

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

"Thingiverse lets you share 3D files - these get rendered, tagged, and exposed to the whole internet, and you don’t know who might be looking at them in the near future," Plummer-Fernandez told Dezeen. "Patent trolls frighten me, and so do mysterious law enforcement agencies and their web-crawling technologies."

"In a time of prolific online espionage, crackdowns on file-sharing, and a growing concern for the 3D-printing of illegal items and copyright-protected artefacts, Disarming Corruptor is a free software application that helps people to circumvent these issues," he said, adding that the project was inspired by devices such as the Enigma Machine used to encrypt and decode messages during the Second World War.

"People could alternatively just email each other encrypted files if necessary, but I wanted to devise a system where people could utilise the benefits of a sharing site and maintain a level of privacy and personal control."

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

After downloading Disarming Corruptor, users open the file they want to distort then use slide bars to set seven values that are displayed as an encryption key at the top of the screen.

Pressing Corrupt transforms the shape according to these settings and saves the new file plus an image of the encryption key in the same location as the original. The disguised object can then be uploaded to a public file-sharing site like Thingiverse and the decoding key distributed to a few trusted people.

The last slider controls how much the form is corrupted, so the result can retain some recognisable elements. "This could be useful for instances where you might want simply make functional object inoperative until keys are shared," the designer suggests.

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

To restore the file to its original form, the recipient needs both the application and the unique seven-digit settings used by the sender. They simply open the corrupted version in the Disarming Corruptor program, move the sliders to generate the correct key in the top bar and click Repair. Entering the incorrect settings to decode the file would just damage it further.

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

"I know there are a lot of harmless copyright infringements already on Thingiverse," Plummer-Fernandez continued. "Think of all the Yoda Heads out there. These are exposed to all the patent and copyright trolls to dive in and pick out victims, and I'm sure the small print on these sharing services leaves their communities hanging out to dry when they come for them."

"When patent trolls and law enforcement agencies find these files on sharing sites they will only see abstract contortions, but within the trusting community these files will still represent the objects they are looking for, purposely in need of repair," he said.

Disarming Corruptor for disguising 3D print files by Matthew Plummer Fernandez

The software is free and available for Mac OSX, and Plummer-Fernandez is working on exports for Linux and Windows.

Plummer-Fernandez was born in Colombia and now lives in London, where he graduated from the Royal College of Art's Design Products MA in 2009, and creates his own 3D-editing tools for design projects like the 3D-printed vessels made by scanning and manipulating everyday objects that he presented this time last year.

  • spot

    Serious question: Are there any benefits over packing the file in a password protected rar or zip file? Like it is done with illegal copies of music or movies when they are uploaded to file sharing websites. And give the password to the people you trust. This looks just more complicated to me.

    • Tanuki

      I think there are brute-force cracking methods for password encrypted zip files. I found that out when I protected a file and forgot the password!. Not sure how secure this guy’s system is. I guess we’ll have to wait until there is actually a valuable stl file actually created :P

    • Xela C

      Isn’t the benefit that you can freely share a partially encrypted version of the file and then supply the decryption keys only with certain people?

      • tanuki

        Maybe, but then wouldn’t the file sharing be even easier? i.e sharing a 2kb password vs sharing an actual file?

    • yarrmepantsbelongsaysI

      Yeah, or just use a private BT tracker.

  • sign

    Did the NSA already offer you money to build a back door into your software?

  • Tom

    “Patent trolls” I wish this guy would learn the correct meaning of the word troll, and not just think it means hackers and nasty people on the internet.

    Not to mention that this, like any encryption or protection software, can and will be circumvented, so whilst it may be a good way to restrict content to only paid users of a website, it won’t be foolproof and is certainly not going to result in secret 3D-printed gun plans circulating the internet for a few people to share.

  • Daniel brown

    I hate to sound so negative, but:

    1. This software seems to have been invented just to cash in on publicity surrounding the 3D printing hype-bubble. I agree with other commentators that simply using an encrypted .zip file would be more secure (this doesn’t look like true public-private key encryption), and not to mention would be less obvious (a screwed up .stl file is obviously hiding something, whereas no-one knows what is in a .zip file).

    2. As Tom says, the author doesn’t seem to understand the correct definition of a ‘patent troll’, A troll is someone who patents something (or buys a patent) with no intention of using that patent except to gain money from other people via licensing. In the above case, Lucasfilm etc own the rights to Yoda imagery, and they most certainly are using it (they made a few films you might have heard about, not to mention the merchandise you probably owned as a kid).

    Honestly, I appreciate the super-hype about 3D-printing. I too yearn for the day a machine can print a lifelike, full-size model of Kate Moss made out of ice cream, but things like this are just making a mockery of the media.

    • Tom

      Actually I meant the classic description of a troll, which is someone who deliberately posts or says something they know will cause an inflammatory reaction purely for the enjoyment of watching people argue, and it’s mostly a harmless bit of fun on messageboards – the media seem to understand the term as outright bullying these days. I don’t even see how “trolling” can apply to the patent world really.

  • beatrice

    Ooh. Lots of negative comments. I think it’s pretty clever. Maybe the application is not quite there yet, but the possibility to publish a distorted but recoverable file is clever, and I hate to say it, more fun than a password locked zip folder.

    Maybe security is not the why for this one, maybe it’s just cool and there’s other applications. Gets my vote.

    n.b. “just because it’s about 3d printing, doesn’t mean it’s crap”

  • Anon

    Has anyone seen the new Autodesk Project Shapesifter I’m guessing it was built of the back of this?

  • Dmitry Trofimov

    Cloud services allow you to set sharing permissions in such a way your file will be available only for specific groups of people. That is another valid method of limiting content exposure.

    There are applications that utilise such capabilities already, for example 3DView Chrome app that allows sharing 3D content (STL) through your Google Drive account.