Metadata in Micro-manufactured Products
3D printing creates physical objects as though they were units of digital data. It takes instructions from software to render physical objects by successively adding small points or layers of substance, one after the next.
3D printing will be a bonanza for digital forensics investigators, just as other digital technologies have been.
Digital artifacts -- like spreadsheet documents or digital photographs -- often contain metadata, such as timestamps and information about the source of the artifact (e.g., what software was used to create the artifact). Metadata is often hidden from view. Users are often surprised the metadata exists.
Metadata can be a treasure trove to a forensic investigator who inspects an artifact like a photograph. The investigator might, for instance, determine the time the photo was created, the type of camera that was used, its GPS location, the photo manipulation techniques employed and so on.
Metadata Surprises in History
History tells many stories of forensic investigators surprising the subjects of investigation with metadata. The more sensational stories involve technology that was new at the time, when the existence of metadata in the technology was little known.
* In the mid-1980s Col. Oliver North was surprised to learn that after he deleted e-mails, his deleted records were recoverable. In addition, the e-mail system he was using kept metadata indicating that he tried to delete relevant records while an investigation was pending.
* When product developers at one employer switched to a competitor, they took a Microsoft Word document with them. While working for the competitor, they claimed they invented new product ideas from scratch. But metadata in the Word document betrayed them. They recorded their “new” ideas in the very Word document they took from the first employer. The metadata in that document contained a code showing the document had been printed on a printer owned by the first employer. That code was the smoking gun; it showed that the plans were not created from scratch after the developers left the first employer. John H. Jessen, “Special Issues Involving Electronic Discovery,” 9 Kansas Journal of Law and Policy 425, 441 (2000).
* More recently, some Twitter users are surprised that sometimes Twitter associates GPS metadata with each tweet to show where the user was when the tweet was sent. The GPS data might be taken from the user’s smartphone. A forensic investigator could use that GPS metadata to show, for example, that a spouse was at the home of a paramour.
Metadata in 3D Printed Objects
It is into this historical context that 3D printing emerges. 3D printing technologies are diverse. But in principle a 3D printer can incorporate words, codes and numbers into the objects they create.
This web site demonstrates the incorporation of a unique serial number into each 3D printed object: http://www.gomboc.eu/site.php?inc=0&menuId=20 In that example, the serial number is visible to the eye. But serial numbers and other metadata could be hidden from view inside the object, or could be microscopic.
It is natural that the makers of 3D printer technology would embed serial numbers, time stamps, GPS markers and many other codes into objects. The codes can help with billing, shipping, quality control, inventory management and other operations.
3D printing is growing in popularity, and its growth will continue. 3D technology will make it easier and less expensive for anyone to design and print a custom object.
Metadata as Legal Evidence
Eventually, 3D printed objects will be evidence in official investigations, just as spreadsheets and digital photographs are today. When that happens, I anticipate that forensic investigators will be able to harvest metadata from those objects.
For example, suppose a California tax auditor wants to know whether an aircraft part was either designed or manufactured in the state of California. Clues to answer those questions might be embedded as metadata in the aircraft part itself.
What do you think, dear reader?
–Benjamin Wright
Mr. Wright teaches the law of data security and investigations at the SANS Institute.
Related Article: 3D Printing and Copyright Compliance
