Novel Nonclassical-light-assisted Protocols for Quantum Key Distribution.

摘要

During our Phase I period of performance, we have investigated a competing technology to the decoy-state protocol for QKD (quantum key distribution) based on the use of entangled light pulses randomly mixed with Weak Laser Pulses (WLP), the so-named NCBB84 protocols, where the WLP are used exactly as in the standard BB84 (Bennett & Brassard 1984) protocol. Our theoretical work has identified a number of promising NCBB84 candidates, among which is the entangled decoy state protocol, which at this moment appears optimal. The entangled decoy state approach is especially promising from a practical standpoint because it allows a homodyne detection scheme to be used as opposed to photon-number-counting detectors needed by the standard decoy- state approach. Consequently, detectors with much higher efficiencies and lower dark-count rates can be used with our new scheme, increasing the key generation rate.