Abstract With the increasing demand for quantum hardware, shared and multi-tenant environments have been proposed to optimize resource utilization. However, the multi-tenancy paradigm in quantum computing inherently introduces security threats. This paper examines crosstalk-mediated attacks targeting three-qubit Grover’s search algorithm and explores two fundamental mitigation strategies: gate-based dynamical decoupling and the use of a buffer qubit. We evaluate the effectiveness of each method individually and in combination, finding that while both strategies offer some level of attack mitigation, their combined application yields the most significant performance improvement. Beyond security vulnerabilities, our work also has implications for unintentional circuit interference that can occur when multiple quantum circuits are executed in close proximity.
Abstract With the increasing demand for quantum hardware, shared and multi-tenant environments have been proposed to optimize resource utilization. However, the multi-tenancy paradigm in quantum computing inherently introduces security threats. This paper examines crosstalk-mediated attacks targeting three-qubit Grover’s search algorithm and explores two fundamental mitigation strategies: gate-based dynamical decoupling and the use of a buffer qubit. We evaluate the effectiveness of each method individually and in combination, finding that while both strategies offer some level of attack mitigation, their combined application yields the most significant performance improvement. Beyond security vulnerabilities, our work also has implications for unintentional circuit interference that can occur when multiple quantum circuits are executed in close proximity.
Researchers are today exploring models for cloud-based usage of quantum computers where multi-tenancy can be used to share quantum computer hard-ware among multiple users. Multi-tenancy has a promise of allowing better utilization of the quantum computer hardware, but also opens up the quantum computer to new types of security attacks. As this and other recent research shows, it is possible to perform a fault injection attack using crosstalk on quantum computers when a victim and attacker circuits are instantiated as co-tenants on the same quantum computer. To ensure such attacks do not happen, this paper proposes that new techniques should be developed to help catch malicious circuits before they are loaded onto quantum computer hardware. Following ideas from classical computers, a compile-time technique can be designed to scan quantum computer programs for mali-cious or suspicious code patterns before they are compiled into quantum circuits that run on a quantum computer. This paper presents ongoing work which demonstrates how crosstalk can affect Grover's algorithm, and then presents suggestions of how quantum programs could be analyzed to catch circuits that generate large amounts of crosstalk with malicious intent.
Hardware crosstalk in multi-tenant superconducting quantum computers poses a severe security threat, allowing adversaries to induce targeted errors across tenant boundaries by injecting carefully engineered pulses. We present a simulation-based study of active crosstalk attacks at the pulse level, analyzing how adversarial control of pulse timing, shape, amplitude, and coupling can disrupt a victim's computation. Our framework models the time-dependent dynamics of a three-qubit system in the rotating frame, capturing both always-on couplings and injected drive pulses. We examine two attack strategies: attacker-first (pulse before victim operation) and victim-first (pulse after), and systematically identify the pulse and coupling configurations that cause the largest logical errors. Protocol-level experiments on quantum coin flip and XOR classification circuits show that some protocols are highly vulnerable to these attacks, while others remain robust. Based on these findings, we discuss practical methods for detection and mitigation to improve security in quantum cloud platforms.
As quantum computing rapidly advances, its nearterm applications are becoming increasingly evident.However, the high cost and under-utilization of quantum resources are prompting a shift from single-user to multi-user access models.In a multi-tenant environment, where multiple users share one quantum computer, protecting user confidentiality becomes crucial.The varied uses of quantum computers increase the risk that sensitive data encoded by one user could be compromised by others, rendering the protection of data integrity and confidentiality essential.In the evolving quantum computing landscape, it is imperative to study these security challenges within the scope of realistic threat model assumptions, wherein an adversarial user can mount practical attacks without relying on any heightened privileges afforded by physical access to a quantum computer or rogue cloud services.In this paper, we demonstrate the potential of crosstalk as an attack vector for the first time on a Noisy Intermediate Scale Quantum (NISQ) machine, that an adversarial user can exploit within a multi-tenant quantum computing model.The proposed side-channel attack is conducted with minimal and realistic adversarial privileges, with the overarching aim of uncovering the quantum algorithm being executed by a victim.Crosstalk signatures are used to estimate the presence of CNOT gates in the victim circuit, and subsequently, this information is encoded and classified by a graph-based learning model to identify the victim quantum algorithm.When evaluated on up to 336 benchmark circuits, our attack framework is found to be able to unveil the victim's quantum algorithm with up to 85.7% accuracy.
The rapid advancement of quantum computing has spurred widespread adoption, with cloud-based quantum devices gaining traction in academia and industry. This shift raises critical concerns about the privacy and security of computations on shared, multi-tenant quantum platforms accessed remotely. Recent studies have shown that crosstalk on shared quantum devices allows adversaries to interfere with victim circuits within a neighborhood. While insightful, these works left unresolved questions regarding the root cause of crosstalk, effective countermeasures, and replicability across circuits. We revisit the crosstalk effect, tracing its origins to the SWAP path between qubits and demonstrating its impact even over long distances. Our results significantly improve the understanding of this phenomenon beyond prior works. The proposed SWAP-based side-channel attack operates in both active and passive modes, as verified on real IBM quantum devices. In the active attack, an attacker executing a single CNOT gate can perturb victim circuits running Grover's Algorithm, reducing expected output accuracy by 81.62% through strategic qubit placement. Moreover, this effect can be modeled to identify qubits more susceptible to attack. The passive attack, leveraging a stealthy circuit as small as 6.25% of the victim's, achieves 100% accuracy in predicting the victim's circuit size when running Simon's Algorithm. These findings challenge the existing defense strategy of maximizing topological distance between circuits, showing that attackers can still extract sensitive information or manipulate results remotely. Our work highlights the urgent need for robust security measures to safeguard quantum computations against emerging threats.
This work presents a novel security attack based on CNOT gate induced crosstalk in superconducting qubit systems. Compared to previous work, this work introduces a double-sided crosstalk attack where attacker's circuits are located on either side of the victim circuit executing in a multi-tenant cloud-based quantum computer. The attacker, a malicious tenant or user, can interfere with, or disrupt, the state of neighboring qubits in the victim tenant or user without direct access to victim's qubits, by taking advantage of interference and crosstalk among the otherwise logically isolated qubits. New aspect of this attack is the location of the attacker's circuits on both sides of the victim. Experimental validation on cloud-based Rigetti quantum devices demonstrates that these attacks can compromise data integrity and cause the victim's circuit's outputs to change. Magnitude of the change is evaluated using total variational distance and tested on number of common benchmarks that can execute on today's quantum computers. This work underscores the need for improved isolation mechanisms and secure scheduling in multitenant quantum computing cloud environments.
Abstract Quantum computing has the potential to provide solutions to problems that are intractable on classical computers, but the accuracy of the current generation of quantum computers suffer from the impact of noise or errors such as leakage, crosstalk, dephasing, and amplitude damping among others. As the access to quantum computers is almost exclusively in a shared environment through cloud‐based services, it is possible that an adversary can exploit crosstalk noise to disrupt quantum computations on nearby qubits, even carefully designing quantum circuits to purposely lead to wrong answers. In this study, the extent and characteristics of crosstalk noise are studied through tomography conducted on IBM Quantum computers, leading to an enhanced crosstalk simulation model. These results indicate that crosstalk noise is a significant source of errors on IBM quantum hardware, making crosstalk based attack a viable threat to quantum computing in a shared environment. Based on the crosstalk simulator benchmarked against IBM hardware, the impact of crosstalk attacks and develop strategies are assessed for mitigating crosstalk effects. Through a systematic set of simulations, the effectiveness of three crosstalk attack mitigation strategies is assessed, namely circuit separation, qubit allocation optimization via reinforcement learning, and the use of spectator qubits, and show that they all overcome crosstalk attack risk with varying degrees of success and help to secure quantum computing in a shared platform.