CaSTL: Towards cyber-physical authentication of additively manufactured components

Abstract

The use of Additive Manufacturing (AM) has rapidly accelerated in many domains ranging from avionics to rockets. Because AM produces physical components by interpreting digital design files, techniques must be developed to bridge the cyber and physical domains to establish a verifiable connection between the digital identity of a component (e.g. STL file, G-code) and the physical manifestation of the component instance (i.e. the 3D printed object). This work introduces a cyber-physical approach to hide cyber-information in AM part designs that enables unique identification of printed components using steganography and computer vision. We describe CASTL (“castle”) which stands for Cyber-physical Authentication of STL file, and allows for unique association between digital information describing a component instance and the printed component itself. The main contribution of CASTL is the combination of generative steganography and image processing to embed component metadata into a CAD image and recover this same metadata from an image of the manufactured component, creating a coupling between a component’s digital identity and its physical manifestation, which we term Cyber-physical Authentication (CPA). CASTL facilitates CPA of additively manufactured objects, fostering increased transparency and enhanced cyber-physical security guarantees for additively manufactured components.