Improved Data Post-Processing in Quantum Key Distribution and Application to Loss Thresholds in device independent QKD

摘要

Security proofs of quantum key distribution (QKD) often requirepost-processing schemes to simplify the data structure, and hence the securityproof. We show a generic method to improve resulting secure key rates bypartially reversing the simplifying post-processing for error correctionpurposes. We apply our method to the security analysis of device-independentQKD schemes and of detection-device-independent QKD schemes, where in bothcases one is typically required to assign binary values even to lost signals.In the device-independent case, the loss tolerance threshold is cut down by ourmethod from 92.4% to 90.9%.The lowest tolerable transmittance of thedetector-device-independent scheme can be improved from 78.0% to 65.9%.