3D Printing Secured Using Three-Layer System That Ensures Components Aren’t Compromised

A research team has developed a security system for additive manufacturing processes to help protect them against possible cyberattacks, as well as to ensure the overall integrity of the components produced by 3D-printing methods.

Scientists at the Georgia Institute of Technology and Rutgers University have developed a three-layer method combining acoustic, spatial, and material techniques that “enable real-time and post-production detection of a defective print,” Raheem Beyah, professor and associate chair in Georgia Tech’s School of Electrical and Computer Engineering, told Design News.

The system—the first of its kind—uses a validation technique that’s independent of printer firmware or software in the controlling computer to ensure that components produced using additive manufacturing have not been compromised.

Dedicated security processes are commonplace among business IT systems due to the high risk of intrusion, data breaches, and cyber attacks. However, until now they haven’t specifically secured additive manufacturing systems present on computers and hardware attached to those networks. These systems are becoming more prevalent to replace conventional fabrication processes in areas ranging from aerospace components to medical implants, making the software that controls them also vulnerable.

Each of the three layers of the system Beyah and his team developed has its specific form and function, and for each researcher’s require a “golden, or trusted” copy of the print and the corresponding signature, he said. For the acoustic layer, the team used an inexpensive microphone to record the sounds from various actuators and fans, which generate an acoustic pattern.

“This pattern should be identical for every identical object that is printed,” he explained. “Thus, we can compare the audio from the golden copy to that from subsequent prints. Deviations indicate some sort of problem—either malicious or benign.”

The spatial layer is comprised of a linear potentiometer and gyroscopic sensor attached to each other to construct a set of spherical coordinates to describe the printer’s motion, Beyah said. “Similar to the acoustic layer approach, we obtain data—this time from the linear potentiometer and gyroscopic sensor— from the printing of the golden copy and compare it with the data generated from subsequent prints,” he said.

The materials layer uses contrast agents embedded into the printed object during the printing process to act as signature markers for particular prints without compromising the structural integrity of the original model, Beyah said. 

“We embed nanoparticles [gold nanorods] at different points in the printed model to generate a pattern specific to the model,” he said. “This can be accomplished by using a machine that has dual extruders with one containing filament with embedded nanorods. This pattern is only known to us—thus if the print is modified the nanorods will be out of place or missing.”

The researchers tested their technique on three different types of 3D printers and a computer numerical control machine using a polyethylene tibial knee prosthesis as a test case, they said. Beyond detecting malicious activity or quality problems, the technique also could stop inadvertent production problems, which has the potential to reduce materials waste, researchers said.

The team—which also includes Mehdi Javanmard, assistant professor in the Department of Electrical and Computer Engineering at Rutgers University—presented their research in mid-August at the USENIX Security Symposium in Vancouver.

Beyah said he believes the technique can be used to secure the additive manufacturing process across many industries, including for the production of aircraft parts, automobile parts, and artificial limbs. The team plans to continue their work to improve the system so it functions without limitations in various environments, he added.

“We’re now working to ensure that the technique is robust,” Beyah said. “For example, we did not consider the acoustic technique in a noisy environment. We’re looking at various signal-processing techniques to enable it to work in large print centers.”

Elizabeth Montalbano is a freelance writer who has written about technology and culture for more than 15 years. She currently resides in a village on the southwest coast of Portugal.