Demonstration of Blind Quantum Computing

TLDR

Quantum computers promise not only computational speedups but also the possibility of preserving the privacy of a computation. This work demonstrates the first experimental realization of blind quantum computation, keeping the input, computation, and output hidden from the server. The protocol employs measurement‑based quantum computation, enabling a client who can prepare and transmit single photonic qubits to delegate computations to a quantum server. The demonstration successfully performs blind delegated one‑ and two‑qubit gates, as well as the Deutsch and Grover algorithms, underscoring its importance for future unconditionally secure quantum cloud computing.

Abstract

Quantum computers, besides offering substantial computational speedups, are also expected to provide the possibility of preserving the privacy of a computation. Here we show the first such experimental demonstration of blind quantum computation where the input, computation, and output all remain unknown to the computer. We exploit the conceptual framework of measurement-based quantum computation that enables a client to delegate a computation to a quantum server. We demonstrate various blind delegated computations, including one- and two-qubit gates and the Deutsch and Grover algorithms. Remarkably, the client only needs to be able to prepare and transmit individual photonic qubits. Our demonstration is crucial for future unconditionally secure quantum cloud computing and might become a key ingredient for real-life applications, especially when considering the challenges of making powerful quantum computers widely available.