Quantum-Augmented Multi-party Computation: Boosting Efficiency and Security Through Masking

Multi-party computation (MPC) allows several parties to jointly compute a function while preserving input confidentiality and avoiding single points of failure. The study presents a hybrid architecture for Quantum-Augmented MPC (QAMPC) that combines Shamir secret sharing (SSS) with a quantum masking and rebuild stage. The masking operation involves adding a random number to the shadow share. The protocol classically generates player shares and reusable shadow shares, and employs quantum processes such as entanglement with the Quantum Fourier Transform (QFT) or X gates for masking. The quantum masking step enables safe reuse of shadow shares even in the presence of an eavesdropper. In simulations, compared to an equivalent classical masking technique, the QAMPC protocol achieves 10.9× lower verification overhead to authenticate a 20-bit secret with 9 parties (as classical-only masking suffers from substantive message passing overheads); it also delivers up to 4.66× higher transaction throughput (since masking permits multiple authentication runs without re-executing the full 'classical MPC'). The security analysis of the QAMPC protocols shows that the eavesdropper’s effort to recover the secret grows exponentially with the secret size and the number of players. The protocols were also tested in a noisy environment. For instance, X gate-based masking holds well in the presence of noise, providing a \((99%)\) success rate with an error rate of \((0.1%)\). These results indicate that quantum masking can substantially reduce verification overhead and increase throughput in SSS-based MPC while strengthening resilience to eavesdropping.