No abstract

Additive manufacturing (AM, or 3D printing) is a novel manufacturing technology that has been adopted in industrial and consumer settings. However, the reliance of this technology on computerization has raised various security concerns. In this paper, we address issues associated with sabotage via tampering during the 3D printing process by presenting an approach that can verify the integrity of a 3D printed object. Our approach operates on acoustic side-channel emanations generated by the 3D printer's stepper motors, which results in a non-intrusive and real-time validation process that is difficult to compromise. The proposed approach constitutes two algorithms. The first algorithm is used to generate a master audio fingerprint for the verifiable unaltered printing process. The second algorithm is applied when the same 3D object is printed again, and this algorithm validates the monitored 3D printing process by assessing the similarity of its audio signature with the master audio fingerprint. To evaluate the quality of the proposed thresholds, we identify the detectability thresholds for the following minimal tampering primitives: insertion, deletion, replacement, and modification of a single tool path command. By detecting the deviation at the time of occurrence, we can stop the printing process for compromised objects, thus saving time and preventing material waste. We discuss various factors that impact the method, such as background noise, audio device changes, and different audio recorder positions.

No abstract

Additive manufacturing involves a new class of cyber-physical systems that manufacture 3D objects incrementally by depositing and fusing together thin layers of source material. In 2015, the global additive manufacturing industry had°5.165 billion in revenue, with 32.5% of all manufactured objects used as functional parts. Because of their reliance on computerization, additive manufacturing devices (or 3D printers) are susceptible to a broad range of attacks. The rapid adoption of additive manufacturing in aerospace, automotive and other industries makes it an attractive attack target and a critical asset to be protected. This chapter compares emerging additive manufacturing and traditional subtractive manufacturing from the security perspective. While the discussion compares the two manufacturing technologies, the emphasis is on additive manufacturing due to its expected dominance as the manufacturing technology of the future. The chapter outlines the additive and subtractive manufacturing workflows, proposes a framework for analyzing attacks on or using additive manufacturing systems and presents the major threat categories. In order to compare the two manufacturing paradigms from the security perspective, the differences between the two workflows are identified and the attack analysis framework is applied to demonstrate how the differences translate into threats. The analysis reveals that, while there is significant overlap with regard to security, fundamental differences in the two manufacturing paradigms require a separate investigation of additive manufacturing security.

Additive manufacturing (AM), a.k.a. 3D printing is increasingly used to manufacture functional parts of safety-critical systems. The AM's dependence on computerization raises the concern that the AM process can be tampered with, and a part's mechanical properties sabotaged. To address this threat, we propose a novel approach for detecting sabotage attacks based on trusted monitoring of the current delivered to each printer motor. The proposed approach offers numerous advantages: 1) it is non-invasive in a time-critical process, 2) it can be retrofitted in legacy systems, and 3) it can be air-gapped from the computerized components of the AM process, making simultaneous compromise more difficult. We evaluated the approach on five categories of toolpath command-level manipulations that impact the geometry of the 3D printed object. Our evaluation showed that all but one tested category of attacks can be reliably detected, even if a single toolpath command is modified. INDEX TERMS Three-dimensional printing, security, side-channel attacks, power system security, intrusion detection.