# Security of quantum-key-distribution protocols using two-way classical communication or weak coherent pulses

 Authors: B Kraus, C Branciard, R Renner Physical Review A 75, 012316 (2007) http://dx.doi.org/10.1103/PhysRevA.75.012316 We apply the techniques introduced by Kraus [Phys. Rev. Lett. 95, 080501 (2005)] to prove security of quantum-key-distribution (QKD) schemes using two-way classical post-processing as well as QKD schemes based on weak coherent pulses instead of single-photon pulses. As a result, we obtain improved bounds on the secret-key rate of these schemes. For instance, for the six-state protocol using two-way classical post-processing we recover the known threshold for the maximum tolerated bit error rate of the channel, 0.276, but demonstrate that the secret-key rate can be substantially higher than previously shown. Moreover, we provide a detailed analysis of the Bennett-Brassard 1984 (BB84) and the SARG protocol using weak coherent pulses (with and without decoy states) in the so-called untrusted-device scenario, where the adversary might influence the detector efficiencies. We evaluate lower bounds on the secret-key rate for realistic channel parameters and show that, for channels with low noise level, the bounds for the SARG protocol are superior to those for the BB84 protocol, whereas this advantage disappears with increasing noise level. secu_crypto_2way_wcp.pdf

# BibTeX Source

@ARTICLE{Kraus2007,
author = {Kraus, B. and Branciard, C. and Renner, R.},
title = {Security of quantum-key-distribution protocols using two-way classical
communication or weak coherent pulses},
journal = {Physical Review A},
year = {2007},
volume = {75},
pages = {012316},
abstract = {We apply the techniques introduced by Kraus [Phys. Rev. Lett. 95,
080501 (2005)] to prove security of quantum-key-distribution (QKD)
schemes using two-way classical post-processing as well as QKD schemes
based on weak coherent pulses instead of single-photon pulses. As
a result, we obtain improved bounds on the secret-key rate of these
schemes. For instance, for the six-state protocol using two-way classical
post-processing we recover the known threshold for the maximum tolerated
bit error rate of the channel, 0.276, but demonstrate that the secret-key
rate can be substantially higher than previously shown. Moreover,
we provide a detailed analysis of the Bennett-Brassard 1984 (BB84)
and the SARG protocol using weak coherent pulses (with and without
decoy states) in the so-called untrusted-device scenario, where the
adversary might influence the detector efficiencies. We evaluate
lower bounds on the secret-key rate for realistic channel parameters
and show that, for channels with low noise level, the bounds for
the SARG protocol are superior to those for the BB84 protocol, whereas
this advantage disappears with increasing noise level. },
doi = {10.1103/PhysRevA.75.012316},
owner = {cc},
sn = {1050-2947},
timestamp = {2010.08.20},
ut = {WOS:000243894100043}
}