Implementation of classical client universal blind quantum computation with 8-state RSP in current architecture

TL;DR

The paper addresses secure delegated quantum computation for clients with limited quantum capabilities by making UBQC non-interactive through 8-state remote state preparation. It combines a QFactory-based non-interactive RSP with UBQC to blind the initial cluster state, enabling a fully classical client to delegate computations to a quantum server on current architectures. The authors implement and validate the approach on IBMQ simulators with Bell, GHZ, and MWIP examples, and they discuss the resulting security model, overhead, and a key constraint that the randomization parameter $r$ be set to zero. The work advances the practicality of UBQC on near-term hardware while acknowledging trade-offs in circuit depth, runtime, and game-based security assumptions. It lays groundwork for further refinements to restore stronger blindness while preserving compatibility with existing quantum platforms.

Abstract

The future of quantum computing architecture is most likely the one in which a large number of clients are either fully classical or have a very limited quantum capability while a very small number of servers having the capability to perform quantum computations and most quantum computational tasks are delegated to these quantum servers. In this architecture, it becomes very crucial that a classical/semi-classical client is able to keep the delegated data/ computation secure against eavesdroppers as well as the server itself, known as the blindness feature. In 2009, A. Broadbent et. al proposed a universal blind quantum computation (UBQC) protocol based on measurement-based quantum computation (MBQC) that enables a semi-classical client to delegate universal quantum computation to a quantum server, interactively and fetch the results while the computation itself remains blind to the server. In this work, we propose an implementation (with examples) of UBQC in the current quantum computing architecture, a fully classical client, a quantum server (IBM Quantum) and the computation does not proceed interactively (projective measurement basis is not decided by previous measurement outcome). We combined UBQC with the 8-state remote state preparation (RSP) protocol, to blindly prepare the initial cluster state, which is an initial resource state in UBQC protocol, to allow a completely classical client to perform delegated blind quantum computation. Such an implementation has already been shown to be secure in a game-based security setting, which is the weakest security model.

Figures (6)

• Figure 1: \ref{['MBQC_fig']} shows an MBQC model based 2D cluster state computation and \ref{['UBQC_fig']} is an equivalent cluster state in UBQC model.
• Figure 4: This is an example implementation of delegated private bell state preparation using the given methodology. The Fig.\ref{['bell_b']} is what was sent to the IBMQ server.
• Figure 5: This is an example implementation of delegated private GHZ state preparation using the given methodology. The quantum circuit corresponding to Fig.\ref{['ghz_b']} was sent to the IBMQ server.
• Figure 6: This is an example implementation of delegated MWIP problem using the given methodology. The Fig.\ref{['mwip_result']} shows the results which were obtained by delegating the 'BQC model' to IBMQ server and running the 'classical' and 'circuit model' solution at the local system. Upon comparison the results from all the three executions match.
• Figure 7: MBQC equivalent of universal single qubit gates