Reverse engineering of electronic hardware has been performed for decades for two broad purposes: (1) honest and legal means for failure analysis and trust verification; and (2) dishonest and illegal means of cloning, counterfeiting, and development of attacks on hardware to gain competitive edge in a market. Destructive methods have been typically considered most effective to reverse engineer Printed Circuit Boards (PCBs) – a platform used in nearly all electronic systems to mechanically support and electrically connect all hardware components. However, the advent of advanced characterization and imaging tools such as X-ray tomography has shifted the reverse engineering of electronics toward non-destructive methods. These methods considerably lower the associated time and cost to reverse engineer a complex multi-layer PCB. In this paper, we introduce a new anti–reverse engineering method to protect PCBs from non-destructive reverse engineering. We add high-Z materials inside PCBs and develop advanced layout algorithms, which create inevitable imaging artifacts during tomography, thereby making it practically infeasible for an adversary to extract correct design information with X-ray tomography.