An improved semi-quantum secret sharing protocol with enhanced verification to counter man-in-the-middle attacks

Semi-quantum secret sharing (SQSS) is an essential branch of semi-quantum cryptography. Unlike conventional quantum cryptographic protocols, SQSS does not require all participants to possess quantum capabilities, thereby simplifying implementation. This paper identifies a critical vulnerability in Li et al.’s SQSS protocol, which makes it susceptible to man-in-the-middle attacks during eavesdropping. To address this issue, we propose a secure SQSS protocol incorporating an enhanced verification mechanism performed by the dealer. This additional step enables the sender to verify the integrity of transmitted particles and detect potential eavesdropping. As a result, the protocol effectively mitigates the risk of man-in-the-middle attacks and ensures the security and completeness of secret message exchange.