Components that are produced using additive manufacturing can be marked for unique identification and secure authentication. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (like e.g. those in a digital product passport) to real-life parts. Our work aims to provide a new methodology for the identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. We use non-destructive X-ray computed microtomography (XCT) to image the microstructural features of Al-based 3D-printed parts and, based on size and geometry, select the most prominent features to create a unique digital authenticator.