Hardware Trojans in superconducting electronic circuits

Abstract Hardware Trojans that exploit the unique characteristics of superconducting electronic (SCE) circuits are explored in this paper. Two types of hardware Trojan circuits are proposed: a magnetically-coupled data transmission Trojan embedded in single flux quantum full adder circuit and a pulse-interleaved Trojan implemented within a frequency divider. The working principles of how these Trojan circuits exploit the frequency-sensitive nature of SCE circuits are explained. The proposed Trojan circuits stay hidden during typical low-frequency testing, and only triggered and become active (and potentially dangerous) at higher frequencies. Extensive analysis demonstrate that these Trojans have a high chance of staying stealthy during testing, underscoring the need for more comprehensive security measures that account for the full range of operating frequencies for the protection of both classical superconducting systems and future quantum technologies.