TY - JOUR
T1 - Line-of-sight quantum key distribution with differential phase shift keying
AU - Endo, Hiroyuki
AU - Sasaki, Toshihiko
AU - Takeoka, Masahiro
AU - Fujiwara, Mikio
AU - Koashi, Masato
AU - Sasaki, Masahide
N1 - Funding Information:
The authors thank Professor R Matsumoto for the theoretical discussion. This work was partly supported by ‘Research and Development of the Quantum Cryptography Technology for Satellite Communications (JPJ007462)’ in ‘Research and Development of Information and Communications Technology (JPMI00316)’ of Ministry of Internal Affairs and Communication (MIC), Japan. This work was also funded in part by JSPS KAKENHI Grant No. 21K14163.
Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd on behalf of the Institute of Physics and Deutsche Physikalische Gesellschaft.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Free-space optical (FSO) links offer a practical approach to realize quantum key distribution (QKD) in a global scale. However, when one wants to further extend the distance from the geostationary orbit to the ground, currently known QKD schemes cannot realize practical key rates mainly due to the diffraction losses of a laser beam. If the facts that the FSO links are highly directional and must be used in the line-of-sight (LoS) condition are taken into account, one may impose some physical restrictions on an eavesdropping model to explore longer-distance QKD. In this paper, we propose a novel FSO secret key agreement scheme, line-of-sight QKD (LoS-QKD), based on a quantum wiretap channel. In our model, an eavesdropper can tap only a limited fraction of the FSO signal beam but perform any physically allowable operations on the tapped signals. Fading effects which are significant in the FSO links are fully taken into account. We provide a security proof for the differential phase shift (DPS) keying scheme in terms of the metric which meets the composability. We investigate numerically the performances of LoS-QKD with DPS keying, including finite-length analysis, showing that our proposed scheme can realize high-speed and long-distance secret key agreement with information-theoretic security.
AB - Free-space optical (FSO) links offer a practical approach to realize quantum key distribution (QKD) in a global scale. However, when one wants to further extend the distance from the geostationary orbit to the ground, currently known QKD schemes cannot realize practical key rates mainly due to the diffraction losses of a laser beam. If the facts that the FSO links are highly directional and must be used in the line-of-sight (LoS) condition are taken into account, one may impose some physical restrictions on an eavesdropping model to explore longer-distance QKD. In this paper, we propose a novel FSO secret key agreement scheme, line-of-sight QKD (LoS-QKD), based on a quantum wiretap channel. In our model, an eavesdropper can tap only a limited fraction of the FSO signal beam but perform any physically allowable operations on the tapped signals. Fading effects which are significant in the FSO links are fully taken into account. We provide a security proof for the differential phase shift (DPS) keying scheme in terms of the metric which meets the composability. We investigate numerically the performances of LoS-QKD with DPS keying, including finite-length analysis, showing that our proposed scheme can realize high-speed and long-distance secret key agreement with information-theoretic security.
KW - free-space optical communications
KW - physical-layer cryptography
KW - quantum key distribution
KW - satellite communications
UR - http://www.scopus.com/inward/record.url?scp=85126138647&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85126138647&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/ac5056
DO - 10.1088/1367-2630/ac5056
M3 - Article
AN - SCOPUS:85126138647
SN - 1367-2630
VL - 24
JO - New Journal of Physics
JF - New Journal of Physics
IS - 2
M1 - 025008
ER -