Entanglement-secured single-qubit quantum secret-sharing

TL;DR

This paper introduces a secure single-qubit quantum secret sharing protocol utilizing polarization-entangled photon pairs, demonstrating enhanced security and high fidelity under realistic experimental conditions.

Contribution

The paper presents a novel entanglement-based protocol for single-qubit quantum secret sharing, improving security against eavesdropping compared to correlation-based methods.

Findings

Achieved 87% secret-sharing fidelity with current apparatus.

Entanglement-based protocol resists photon-number splitting eavesdropping.

Demonstrated robustness of entanglement security under lossy and imperfect conditions.

Abstract

In single-qubit quantum secret sharing, a secret is shared between N parties via manipulation and measurement of one qubit at a time. Each qubit is sent to all N parties in sequence; the secret is encoded in the first participant's preparation of the qubit state and the subsequent participants' choices of state rotation or measurement basis. We present a protocol for single-qubit quantum secret sharing using polarization entanglement of photon pairs produced in type-I spontaneous parametric downconversion. We investigate the protocol's security against eavesdropping attack under common experimental conditions: a lossy channel for photon transmission, and imperfect preparation of the initial qubit state. A protocol which exploits entanglement between photons, rather than simply polarization correlation, is more robustly secure. We implement the entanglement-based secret-sharing protocol with 87% secret-sharing fidelity, limited by the purity of the entangled state produced by our present apparatus. We demonstrate a photon-number splitting eavesdropping attack, which achieves no success against the entanglement-based protocol while showing the predicted rate of success against a correlation-based protocol.