Side-channel Attacks on Quantum Controllers for Extracting Quantum Circuit Information and Countermeasures

With the growing deployment of quantum computing, side-channel attacks have emerged as one of the most serious security threats for cloud quantum service providers. This study investigates whether it is possible to infer the execution order and start times of quantum gates—and ultimately reconstruct the victim circuit—solely from measurements of the power consumption of quantum controllers. While most previous research has focused on reconstructing quantum circuits composed of standard basis gates, the possibility of reconstructing users’ custom quantum circuits from the power leakage of quantum controllers has received little attention. Our approach is evaluated under two observation models: per-channel power and total power. In the per-channel setting, the power trace of each channel is analyzed separately and compared with simulated pulse templates for different gates, in order to identify the most likely gate type and its start time. In this setting, template-based power comparison accurately determines both the gate and its onset time, and simple decision rules reduce misclassification between similar gates. In the total-power setting, an optimization model is employed to recover the logical ordering of the circuit with good accuracy, without requiring access to individual channel traces. The results show that even with a single measurement, circuit reconstruction is feasible provided that the pulse shapes and the device topology are known.