LAUSR

As we know, if a quantum communication protocol has the information leakage problem, it is an insecure protocol, so we should carefully design the protocol to avoid the information leakage problem. Unfortunately, we find this problem exists in the “secure quantum dialogue (QD) protocol based on four-qubit cluster state”. It is found that half of the exchanged information leaks out. To make up this problem, two ways to improve it is given. It shows that the improved QD protocols successfully avoid the information leakage problem. Especially, the further improved QD protocol only needs the single particle measurement instead of Bell-basis measurement and doesn’t need any unitary operation to be performed. In addition, the communication efficiency is improved to 1.33 times of the original QD protocol.