Semi-Quantum Signature Protocol Using EPR Steering and Single Photons

This study tackles critical issues in semi-quantum signature (SQS) protocols to enhance security and efficiency. It revisits Xia et al.'s SQS protocol, which uses EPR steering for security but introduces inconsistencies in a semi-quantum environment. Xia et al. assume that both the signatory and arbitrator have full quantum capabilities, while the verifier only has partial capabilities, making them a classical participant. However, their protocol requires the verifier to perform eavesdropping checks, necessitating quantum storage, which is not aligned with a semi-quantum environment. The study proposes a novel SQS protocol using EPR steering and single photons, with pre-shared keys to determine photon arrangements to address this. This ensures that only the communicating parties know the inspection and message transmission locations, solving the quantum storage issue and enabling efficient eavesdropper detection and identity authentication. This new protocol adheres to semi-quantum principles and sets a foundation for future advancements in quantum cryptography and secure communication.