Open AccessSecurity bound of continuous-variable quantum key distribution with discrete modulation
Author(s) -
Yong Shen,
Zou H
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.1473
Subject(s) - quantum key distribution , computer science , quantum cryptography , modulation (music) , coherent states , alice and bob , key (lock) , noise (video) , gaussian noise , topology (electrical circuits) , telecommunications , algorithm , physics , mathematics , quantum , quantum information , quantum mechanics , computer security , alice (programming language) , combinatorics , artificial intelligence , acoustics , image (mathematics) , programming language
Security of continuous-variable quantum key distribution with four-state protocol based on discrete modulation of noisy coherent states is analyzed. Combing discrete modulation and reverse reconciliation, this protocol can be used for long distance cryptography. There is a small difference between the state Alice sends in the discrete modulation protocol and the Gaussian modulation protocol, and it can be treated as excess noise and loss in the channel. As Alice cannot do a precise modulation, she will induce noise to the coherent state. We look this noise as the source noise and derive a lower bound to the secure key rate assuming the eavesdropper cannot benefit from the noise in the source. For avoiding the fast and random phase locking between the signal and local oscillator in experiment, we also analyze the security of four-state protocol using no-switching scheme.