Analogously to classical computers, quantum processors exhibit side channels that may give attackers access to potentially proprietary algorithms. We identify and exploit a previously unexplored side channel in trapped-ion quantum processors that arises from the radio-frequency (RF) signals used to modulate lasers for ion cooling, gate execution, and readout. In these quantum processors, acousto-optical modulators (AOMs) imprint phase and frequency modulations onto laser fields interacting with the ions to implement individual and collective unitaries. The AOMs are driven by strong RF signals, a fraction of which leaks out of the device. We discuss general strategies to exploit this side channel and demonstrate how to detect RF leakage from a state-of-the-art qudit-based quantum processor using off-the-shelf components. From this data, we extract pulse characteristics of single-ion and entangling gates, thereby implementing a proof-of-principle exploitation of the novel attack vector. Finally, we outline ways to mitigate the information leakage through the presented side channel.

翻译：与经典计算机类似，量子处理器同样存在侧信道，可能使攻击者获取潜在的专有算法。我们在囚禁离子量子处理器中发现并利用了一个先前未被探索的侧信道，该信道源于用于调制离子冷却、门操作和读取的激光的射频信号。在这些量子处理器中，声光调制器将相位和频率调制施加到与离子相互作用的激光场上，以实现个体和集体的幺正操作。声光调制器由强射频信号驱动，其中一部分信号会从设备中泄漏。我们讨论了利用该侧信道的一般策略，并演示了如何使用现成组件检测基于最先进qudit量子处理器的射频泄漏。从这些数据中，我们提取了单离子门和纠缠门的脉冲特性，从而实现了对这一新型攻击向度的原理性验证利用。最后，我们概述了通过该侧信道缓解信息泄漏的方法。