Making the decoy state measurement device independent quantum key distribution practically useful
The relatively low key rate seems to be the major barrier to its practical use for the decoy state measurement device independent quantum key distribution (MDI QKD) We present a four intensity protocol for the decoy state MDI QKD that hugely raises the key rate, especially in the case in which the total data size is not large. Also, calculations show that our method makes it possible for secure private communication with fresh keys generated from MDI QKD with a delay time of only a few seconds.