Semiconductor manufacturing has been outsourced to un-trusted regions due to globalization. The complex multistep fabrication of micro-scale integrated circuits (ICs) and the tedious assembly of macro-scale Printed Circuit Boards (PCBs) are vulnerable to malicious attacks from design to final delivery. PCBs provide the functional connections of Integrated Circuits (ICs), sensors, power supplies, etc. of many critical electronic systems for consumers, corporations, and governments. The feature sizes of PCB signal traces in 2D and vias in 3D are an order of magnitude larger than IC devices, and are thereby more vulnerable to non-destructive attacks such as X-ray or probing. Active and passive countermeasures have been successfully developed for IC devices, however PCBs devices are difficult to wholly secure from all attacks. Passive countermeasures for X-ray attacks using high-z materials to block and scatter X-rays are effective, but there is a lack of active and passive countermeasures for PCB. In this paper, a framework for passively obfuscating a PCB's critical connections between components, such as ICs, from non-destructive attacks is demonstrated. This framework can be further extended to incorporate active countermeasures in future work. A proof of concept for a PCB electronic design automation (EDA) tool which combines the small features of micro electro-mechanical systems (MEMS), simulation of X-ray, and 3D PCB Manufacturing to iteratively optimize PCB design to thwart reverse engineering and probing attacks.

Index Terms—Additive Manufacturing, MEMS, Hardware Assurance, Physical Inspection, Non-Destructive Technology

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