Encrypted-State Compilation with Circuit Obfuscation Protects Cloud-Based Quantum Circuits

Quantum compilation, the process of translating complex algorithms into instructions for quantum hardware, presents a growing security challenge, particularly as cloud-based quantum computing becomes more prevalent. Chenyi Zhang, Tao Shang, and Xueyi Guo from Beihang University and the Beijing Academy of Quantum Information Sciences, address this vulnerability with a novel compilation scheme that prioritises data protection. Their research introduces a framework which encrypts the quantum state throughout the compilation process and deliberately obscures the circuit’s underlying structure, safeguarding both the algorithm’s function and its design. This innovative approach, based on established encryption and obfuscation techniques, demonstrably enhances security at the compilation stage, achieving significant improvements in key metrics while maintaining practical performance and minimising any reduction in the accuracy of quantum computations

Cloud computing presents challenges for quantum circuit security, as compilation often occurs on the cloud provider’s systems, potentially exposing user circuits to risks like structural leakage and predictable outputs. To address these concerns, researchers propose a new compilation scheme, ECQCO, which represents the first secure compilation framework designed for environments where compilers and quantum hardware co-exist. The method conceals quantum information using quantum homomorphic encryption to hide output states and quantum indistinguishability obfuscation to disguise the circuit’s internal structure, effectively preventing reverse engineering or tampering. This innovative approach also incorporates an adaptive decoupling obfuscation algorithm to further enhance security and optimise performance.

Quantum Circuit Obfuscation for Intellectual Property Protection

This research details a novel approach to securing quantum circuits against intellectual property theft and malicious manipulation. Quantum computers, as they become more powerful and accessible via cloud platforms, require robust security measures. Traditional security methods are insufficient for quantum circuits due to their unique properties and susceptibility to quantum attacks, making obfuscation a crucial technique. Obfuscation transforms a circuit into a functionally equivalent but structurally different form, making it difficult to understand, reverse engineer, or tamper with. The core contribution is a new framework for obfuscating quantum circuits, leveraging quantum indistinguishability obfuscation (QIO) to create circuits indistinguishable from the original in terms of input/output behaviour.

The obfuscation process relies on establishing and verifying equivalence between the original and obfuscated circuits, a challenging task in the quantum domain. Quantum homomorphic encryption (QHE) is used to encrypt quantum data and operations, adding another layer of security, while matrix decomposition techniques transform circuits while preserving functionality. This comprehensive framework combines multiple techniques to achieve a high level of security, providing a practical implementation of QIO and methods for verifying circuit equivalence.

Quantum Circuit Obfuscation via Encryption and Indistinguishability

Researchers have developed a new compilation scheme for quantum computers that addresses a critical security vulnerability arising from cloud-based access. As quantum computing advances, users increasingly rely on remote quantum processors, requiring the transmission of sensitive quantum program designs to potentially untrusted environments. This new approach, ECQCO, protects quantum circuits during the compilation process, safeguarding both functionality and underlying structure. It achieves this protection by concealing quantum information using quantum homomorphic encryption to hide output states and quantum indistinguishability obfuscation to disguise the circuit’s internal structure, effectively preventing reverse engineering or tampering.

This differs from previous methods that often assumed a separation between the compiler and the quantum hardware, which doesn’t reflect the reality of cloud-based systems. Rigorous testing demonstrates the scheme’s effectiveness, showing a significant enhancement in security metrics, with evaluations revealing strong performance in protecting circuit integrity. Importantly, ECQCO achieves this security without significantly impacting performance, with minimal increases in circuit depth and negligible changes in fidelity. This balance between security and efficiency is crucial for practical implementation.

Circuit Privacy Through Encrypted Compilation

This research introduces an encrypted-state compilation scheme designed to protect quantum circuits during the compilation process, particularly in cloud computing environments. The method addresses vulnerabilities that could expose user circuits to risks such as structural leakage and output predictability by combining quantum indistinguishability obfuscation and quantum homomorphic encryption. This effectively safeguards both the functionality and the internal structure of quantum circuits, ensuring privacy during compilation. The team demonstrates a strong balance between security and efficiency, achieving notable results on benchmark datasets with only modest increases in circuit complexity and minimal impact on fidelity.

The method is well-suited for near-term quantum devices and scenarios where quantum program privacy is paramount. Future work should also address the verifiability of results on the user side and explore engineering mechanisms to further optimise performance. This research represents a significant step towards building trust in quantum computing platforms and unlocking their full potential.