Repeatable part authentication using impedance based analysis for side-channel monitoring

The rise of the interconnected manufacturing enterprise has extended its vulnerability space to malicious cyber-physical attacks. To improve the resilience of a manufacturing enterprise to cyber-to-physical attacks, a robust set of quality tools for part and process authentication and verification are needed. However, current Non-Destructive Evaluation (NDE) methodologies, which focus on verifying a small subset of geometric features of a part such as its length, width or depth among others, are easier to circumvent by an attacker. This work presents a novel approach to improve the resilience of a manufacturing enterprise via side channels, specifically using electromechanical impedance signatures measured by piezoelectric transducers (PZTs) to verify if a part conforms to its design intent. Since electromechanical impedance signatures take into account all geometric features and material characteristics in a holistic manner, they can provide a new class of robust quality metrics that can be used in tandem with traditional NDE methodologies to verify a part or a process. Two major contributions of this work include (1) demonstrate the feasibility of using a PZT mounted to a fixture to facilitate side channel analysis for part authentication and compare its performance to other PZT mounting methods, and (2) develop a new damage metric that properly distinguishes between nominal parts and various altered groups. The results of our study show that using PZTs as a side channel has the potential for part and process authentication in a manufacturing setting. Furthermore, we show that a PZT mounted to a secondary device, such as a fixture, can be used for NDE in a manufacturing setting.