Quantum Key Distribution with Multiple Pairs of States Based on BB84

To improve BB84's ability against eavesdropping,quantum key distribution(QKD)with M(M=3,4,5…)pairs of quantum states was proposed here.To test its security,the quantum key distribution process was eavesdropped by intercepting and retransmitting photons.The eavesdropper took two methods to measure every photon's state:to measure with a randomly selected base from M bases,and to measure with Breidbart base.Under each eavesdropping methods,the relationship between M and safety was explored.The simulation result indicated:quantum key distribution with multiple pairs of states had the same perfomance with BB84 in detecting the eavesdropper,but it had better perfomance than BB84 in letting the eavesdropper get less information.