Quantum multi-party fair exchange protocol based on three-particle GHZ states.

To address the risk of spoofing the information exchanged by users and reduce the trustworthiness of third party, we propose a quantum information fair exchange protocol based on three-particle GHZ states. This protocol achieves quantum multi-party fair exchange of secret information through the utilization of three-particle GHZ states, Pauli matrix, a semi-trusted third party, and polarization state of a single photon. By leveraging the unique physical properties of the GHZ state, this protocol achieves fair exchange of secret information with experimental results that align with theoretical derivation, thus demonstrating its feasibility. Additionally, it provides superdense coding which enhances transmission efficiency while also being resistant to false signal attacks, interception retransmission attacks, and entanglement attacks, ultimately improving security. Furthermore, compared with the classic fair exchange protocol, which requires a trusted third party, it only requires a semi-trusted third party, which raises the security from "computational security" to "unconditional security". The implementation of this protocol resolves the risk of users who hand over information first, presenting a novel solution for digital currency trading, information swapping, and multi-party secure computing. [ABSTRACT FROM AUTHOR]