Efficient multiparty quantum key agreement protocol based on commutative encryption

A secure multiparty quantum key agreement protocol using single-qubit states is proposed. The agreement key is computed by performing exclusive-OR operation on all the participants’ secret keys. Based on the commutative property of the commutative encryption, the exclusive-OR operation can be performed on the plaintext in the encrypted state without decrypting it. Thus, it not only protects the final shared key, but also reduces the complexity of the computation. The efficiency of the proposed protocol, compared with previous multiparty QKA protocols, is also improved. In the presented protocol, entanglement states, joint measurement and even the unitary operations are not needed, and only rotation operations and single-state measurement are required, which are easier to be realized with current technology.