Information-theoretic security proof of differential-phase-shift quantum key distribution protocol based on complementarity

摘要

We show the information-theoretic security proof of thedifferential-phase-shift (DPS) quantum key distribution (QKD) protocol based onthe complementarity approach [arXiv:0704.3661 (2007)]. Our security proofprovides a slightly better key generation rate compared to the one derived inthe previous security proof in [arXiv:1208.1995 (2012)] that is based on theShor-Preskill approach [Phys. Rev. Lett. ${\bf 85}$, 441 (2000)]. Thisimprovement is obtained because the complementarity approach can employ moredetailed information on Alice's sending state in estimating the leakedinformation to an eavesdropper. Moreover, we remove the necessity of thenumerical calculation that was needed in the previous analysis to estimate theleaked information. This leads to an advantage that our security proof enablesus to evaluate the security of the DPS protocol with any block size. This paperhighlights one of the fundamental differences between the Shor-Preskill and thecomplementarity approaches.