A Distributed Quantum Blind Millionaire Protocol Based on Quantum Walks
TL;DR
This paper applies the one‐directional quantum walks on a circle (ODQWC) to the QBM problem for the first time and develops a new distributed QBM protocol that achieves higher qubit efficiency and can serve as a building block for broader multi‐party collaborative computation tasks.
Abstract
The quantum blind millionaire (QBM) problem is a fundamental primitive in quantum secure multi‐party computation. It enables two groups to compare aggregated private sums while protecting individual data, and is widely adopted in privacy‐preserving collaborative decision‐making. However, most existing QBM protocols either rely on semi‐honest third parties or adopt sophisticated quantum states. These approaches lead to high resource overhead and operational complexity, which restricts practical deployment. In this paper, we apply the one‐directional quantum walks on a circle (ODQWC) to the QBM problem for the first time and develop a new distributed QBM protocol. This scheme employs only a single quantum walker and requires no trusted third party. Moreover, the proposed protocol achieves higher qubit efficiency than most existing mainstream QBM protocols, with an efficiency exceeding 1/(2n)$1/(2n)$ . According to our analysis, the protocol passes the verification of both correctness and security, and its feasibility is confirmed via IBM Qiskit simulations. The proposed scheme solves the QBM problem efficiently and can serve as a building block for broader multi‐party collaborative computation tasks.