# Information-theoretic security proof for quantum-key-distribution protocols

 Authors: R Renner, N Gisin, B Kraus Physical Review A 72, 012332 (2005) http://dx.doi.org/10.1103/PhysRevA.72.012332 We present a technique for proving the security of quantum-key-distribution (QKD) protocols. It is based on direct information-theoretic arguments and thus also applies if no equivalent entanglement purification scheme can be found. Using this technique, we investigate a general class of QKD protocols with one-way classical post-processing. We show that, in order to analyze the full security of these protocols, it suffices to consider collective attacks. Indeed, we give new lower and upper bounds on the secret-key rate which only involve entropies of two-qubit density operators and which are thus easy to compute. As an illustration of our results, we analyze the Bennett-Brassard 1984, the six-state, and the Bennett 1992 protocols with one-way error correction and privacy amplification. Surprisingly, the performance of these protocols is increased if one of the parties adds noise to the measurement data before the error correction. In particular, this additional noise makes the protocols more robust against noise in the quantum channel. infothsecurityqc.pdf

# BibTeX Source

@ARTICLE{Renner2005,
author = {Renner, R. and Gisin, N. and Kraus, B.},
title = {Information-theoretic security proof for quantum-key-distribution
protocols},
journal = {Physical Review A},
year = {2005},
volume = {72},
pages = {012332},
number = {1},
abstract = {We present a technique for proving the security of quantum-key-distribution
(QKD) protocols. It is based on direct information-theoretic arguments
and thus also applies if no equivalent entanglement purification
scheme can be found. Using this technique, we investigate a general
class of QKD protocols with one-way classical post-processing. We
show that, in order to analyze the full security of these protocols,
it suffices to consider collective attacks. Indeed, we give new lower
and upper bounds on the secret-key rate which only involve entropies
of two-qubit density operators and which are thus easy to compute.
As an illustration of our results, we analyze the Bennett-Brassard
1984, the six-state, and the Bennett 1992 protocols with one-way
error correction and privacy amplification. Surprisingly, the performance
of these protocols is increased if one of the parties adds noise
to the measurement data before the error correction. In particular,
this additional noise makes the protocols more robust against noise
in the quantum channel. },
doi = {10.1103/PhysRevA.72.012332},
owner = {cc},
sn = {1050-2947},
timestamp = {2010.08.20},
ut = {WOS:000230887300062}
}