Abstract: The coding efficiency of classical network coding is inefficient during transmission and easy to be bugged.Although Hayashi’s proposal of sharing EPR at the transmitter improves the coding efficiency for information transmission,it can not rea-lize the complete recovery of transmitted information,and the information is not safely disposed,so it is easy to be bugged.To this end,based on the three-particle maximally entangled GHZ state,a quantum network coding scheme is proposed to prevent information being eavesdropped by using the quantum no-cloning theorem and teleportation.Starting from the classical butterfly network coding,the direct product operation is carried out on particles to be sent and the GHZ state particles at the sending end.Then bell measurement is performed on the calculated particles,and the precoding information can be obtained according to the measurement results.The precoding information is transmitted to intermediate nodes,and auxiliary particles used for measurement are introduced at the receiving end.Then,quantum entanglement computation is performed on the received particles,and joint unitary operation is performed on particle clusters.Finally,based on the coding information,corresponding unitary matrix is selected to restore particle clusters.Experimental data shows that the single transmission success rate of GHZ-based quantum network coding has been significantly improved,in terms of encoding efficiency,the cross transmission of quantum information in the butterfly network can be completed with only 6 qubits.In terms of security,the probability of detecting whether the information is bugged has improved.It proves that the proposed scheme improves the coding efficiency of the network coding system and effectively solves the bugging problem of information transmission.

Key words: Eavesdropping attack, Network coding, No-cloning, Quantum network coding, Teleportation