Mutual semi-quantum key agreement protocol using Bell states

Quantum key agreement (QKA) can generate a shared secret key which is equally negotiated by all the participants in the protocol. In most of the QKA protocols, all the participants require quantum capabilities. But the quantum devices are too expensive for participants. This paper proposes a mutual semi-quantum key agreement protocol which allows two parties (Alice and Bob) to negotiate a shared secret key equally. In the protocol, Alice can perform any quantum operation, but Bob is a classical participant which can only perform reflection, measurement and reorder operation. Even though Bob has fewer quantum resources, Alice and Bob have an equal contribution to the shared final key, no one can determine the shared key alone. In addition, we demonstrate the security of the proposed protocol. The analysis results show that the proposed protocol not only resists against some common attacks but also assures the fairness property. It is significant for communication participant without enough quantum devices to achieve quantum communication. The proposed protocol can be implemented with present quantum technologies.