Finite-key analysis for measurement-device-independent quantum key distribution.
Quantum key distribution promises unconditionally secure communications. However, as practical devices tend to deviate from their specifications, the security of some practical systems is no longer valid. In particular, an adversary can exploit imperfect detectors to learn a large part of the secret key, even though the security proof claims otherwise. Recently, a practical approach--measurement-device-independent quantum key distribution--has been proposed to solve this problem. However, so far its security has only been fully proven under the assumption that the legitimate users of the system have unlimited resources. Here we fill this gap and provide a rigorous security proof against general attacks in the finite-key regime. This is obtained by applying large deviation theory, specifically the Chernoff bound, to perform parameter estimation. For the first time we demonstrate the feasibility of long-distance implementations of measurement-device-independent quantum key distribution within a reasonable time frame of signal transmission.
EI Telecomunicación, Department of Signal Theory and Communications, University of Vigo, Vigo E-36310, Spain.
Marcos
M
Curty
Center for Quantum Information and Quantum Control, Department of Physics and Department of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G4.
Feihu
F
Xu
Center for Quantum Information and Quantum Control, Department of Physics and Department of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G4.
Wei
W
Cui
Group of Applied Physics, University of Geneva, Geneva CH-1211, Switzerland.
Charles Ci Wen
CC
Lim
NTT Basic Research Laboratories, NTT Corporation, 3-1, Morinosato Wakamiya Atsugi-Shi, Kanagawa 243-0198, Japan.
Kiyoshi
K
Tamaki
Center for Quantum Information and Quantum Control, Department of Physics and Department of Electrical & Computer Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G4.
Hoi-Kwong
HK
Lo
D016494:Computer Security; D008962:Models, Theoretical; D011789:Quantum Theory; D013685:Telecommunications