Optimal Experimental Scheme for Practical BB84 Quantum Key Distribution Protocol with Weak Coherent Sources, Noisy and Lossy Channel

It is the first scheme which allows the detection apparatus to achieve the photon number of arriving signals. Moreover, quantum bit error rates (QBERs) of multiphoton pulses can also be achieved precisely. Thus, our method is sensitive to the photon number splitting and resending (PNSR) attack, i.e., the eavesdropper (Eve) replaces one photon of the multiphoton pulse by a false one and forwards the pulse to the receiver, while the decoy-state protocols are not. In our scheme, Eve’s whatever attacks will be limited by using the improved decoy-state protocols and by checking the QBERs. Based on our multiphoton pulses detection apparatus, a quasi-single-photon protocol is presented to improve the security of the communication and the rate of the final key. We analyze that our scheme is optimal under today’s technology.