Single-Round Deterministic Quantum Anonymous Veto Using Bell States

Abstract: Quantum Anonymous Veto (QAV) protocols enable secure and anonymous decision-making by allowing participants to detect the presence of a veto without revealing individual choices. While existing QAV schemes offer strong theoretical guarantees, they face significant limitations in practical implementation due to resource requirements, scalability issues, and the need for multipartite entanglement. In this work, we propose a novel deterministic QAV protocol that leverages only bipartite entanglement in the form of Bell states and achieves conclusive veto detection in a single round. Our approach eliminates the need for multi-qubit entangled states and iterative rounds, thereby significantly reducing experimental overhead and enhancing scalability. The protocol preserves critical properties such as voter anonymity, correctness, and verifiability, making it well-suited for implementation on near-term quantum devices. Furthermore, we outline a practical photonic realization based on polarization-path encoding and discrete-time quantum walks, demonstrating its feasibility within current quantum optical platforms. This work contributes a resource-efficient and experimentally viable alternative to existing QAV schemes, advancing the prospects of secure quantum decision-making in distributed systems.