It is possible to steal intellectual property by recording and processing sounds emitted by a 3-D printer.
A device as ordinary and ubiquitous as a smartphone can end up placed next to a machine and capture acoustic signals that carry information about the precise movements of the printer’s nozzle, said Mohammad Al Faruque, director of University of California, Irvine’s (UCI) Advanced Integrated Cyber-Physical Systems Lab.
It is possible to then reverse engineer the recording of the object undergoing printing and re-create it elsewhere. Detailed processes may end up deciphered through this cyber attack, presenting significant security risks.
“In many manufacturing plants, people who work on a shift basis don’t get monitored for their smartphones, for example,” Al Faruque said. “If process and product information is stolen during the prototyping phases, companies stand to incur large financial losses. There’s no way to protect these systems from such an attack today, but possibly there will be in the future.”
Al Faruque’s team achieved nearly 90 percent accuracy using the sound copying process to duplicate a key-shaped object in the lab.
State-of-the-art 3-D printing systems convert digital information embedded in source code to build layer upon layer of material until a solid object takes shape. That source file, referred to as G-code, can end up protected from cyber theft with strong encryption, but once the creation process starts up, the printer emits sounds that can give up the secrets buried in the software.
“My group basically stumbled upon this finding last summer as we were doing work to try to understand the relationship between information and energy flows,” said Al Faruque, an electrical engineer and computer scientist. “According to the fundamental laws of physics, energy is not consumed; it’s converted from one form to another – electromagnetic to kinetic, for example. Some forms of energy are translated in meaningful and useful ways; others become emissions, which may unintentionally disclose secret information.”
The emissions produced by 3-D printers are acoustic signals that contain a lot of information, he said.
“Initially, we weren’t interested in the security angle, but we realized we were onto something, and we’re seeing interest from other departments at UCI and from various U.S. government agencies,” he said.
“President Obama has spoken about returning manufacturing to the United States, and I think 3-D printing will play a major role because of the creation of highly intellectual objects, in many cases in our homes,” Al Faruque said. But he cautioned with the convenience of these new technologies come opportunities for industrial espionage.
He suggested engineers begin to think about ways to jam the acoustic signals emanating from 3-D printers, possibly via a white-noise device to introduce intentional acoustic randomness or by deploying algorithmic solutions.
At a minimum, a fundamental precaution would be to prevent people from carrying smartphones near the rapid prototyping areas when sensitive objects are being printed, Al Faruque said. Today’s smartphones have sensors that can capture a range of analog emissions.