Multi-party quantum key agreement with four-qubit cluster states

Based on four-qubit cluster states, we present a new multi-party quantum key agreement (QKA) protocol. The proposed protocol makes full use of four-qubit cluster states as quantum resources and performs the X operation to generate a shared key. In addition, our multi-party QKA protocol ensures each participant to contribute equally to the final key. Compared with other existed multi-party QKA protocols, our protocol has high efficiency. Furthermore, the security analysis shows that our protocol can resist the outsider and participant attacks.