An efficient lightweight mediated semi-quantum key distribution with single-particle states

Abstract In this paper, we propose an efficient lightweight mediated semi-quantum key distribution (LM-SQKD) protocol, which enables two lightweight participants to securely establish a shared key with the help of an untrusted third party (TP). Compared with existing M-SQKD protocols, our protocol significantly reduces the overall quantum burden and improves the qubit efficiency, where TP only needs to prepare and measure qubits in the X basis and two lightweight participants are just required to execute three unitary operations and reflect qubits. Furthermore, the detailed security analysis verifies that the proposed protocol can against three well-known attacks.