Efficient mediated semi-quantum key distribution

Abstract

Mediated semi-quantum key distribution (MSQKD) allows two “classical” participants to establish a secret key with the help of an untrusted quantum third party (TP). In all existing MSQKD protocols, the quantum capability required by TP is high and thus it needs much cost in a real implementation. In this paper, we propose an efficient MSQKD protocol, where TP only needs to prepare and measure qubits in the X basis and two “classical” participants just have the ability to prepare and measure qubits in the Z basis. Compared with other similar MSQKD protocols, the proposed protocol reduces the capability requirements of TP without sacrificing the qubit efficiency.