Secure Quantum Dialogue Under the Collective Noise Targeting to Improve Efficiency

In quantum secure dialogue, or bidirectional quantum secure direct communication, the users exchange information simultaneously and bidirectionally. In this paper, a secure quantum dialogue which is immune to collective noise has been proposed. In this schema, the data of two users is divided into three-bit sets and is transmitted using two GHZ states simultaneously. This scheme uses the entanglement swapping to produce the initial state. In this method, the eavesdropper attacks are disclosed and it has no information loss. The performance of this protocol has increased compared to previous protocols. The best efficiency of the previous protocols was 25%, but the proposed protocol reached 42.85%