Multiparty semi-quantum key agreement protocol without participant measurement

The semi-quantum key agreement (SQKA) protocol enables classical participants to complete key agreement with limited quantum capabilities. The previous semi-quantum key agreement protocols required the classical party to have the ability to measure qubits, and share a key before the protocol began. This paper proposes a SQKA protocol that allows semi-quantum participants to use single photons for key negotiation with the help of a semi-honest third party (TP). Unlike previous approaches, this protocol further reduces the quantum capability requirements for participants and eliminates the need for prior key sharing. Furthermore, through security analysis and multi-party expansion, the protocol can resist external attacks such as the intercept-resend attack, measure-resend attack, entangle-measure attack. Additionally, it can be applied to scenarios involving different numbers of participants.