Quantum Neural Networks (QNNs) have shown significant value across domains, with well-trained QNNs representing critical intellectual property often deployed via cloud-based QNN-as-a-Service (QNNaaS) platforms.
Existing approaches for QNN model extraction attacks have largely overlooked the impact of varying quantum noise inherent in noisy intermediate-scale quantum (NISQ) computers, limiting their effectiveness in real-world settings.
The CopyQNN framework proposes a three-step data cleaning method to eliminate noisy data based on its noise sensitivity, followed by the integration of contrastive and transfer learning within the quantum domain.
Experimental results on NISQ computers demonstrate that the practical implementation of CopyQNN outperforms state-of-the-art QNN extraction attacks, achieving an average performance improvement of 8.73% while reducing the number of required queries by 90x.