title: Simple and efficient quantum key distribution with parametric down-conversion.
abstract: We propose an efficient quantum key distribution protocol based on the photon-pair generation from parametric down-conversion (PDC). It uses the same experimental setup as the conventional protocol, but a refined data analysis enables detection of photon-number splitting attacks by utilizing information from a built-in decoy state. Assuming the use of practical detectors, we analyze the unconditional security of the new scheme and show that it improves the secure key generation rate by several orders of magnitude at long distances, using a high intensity PDC source.
authors.affiliation: Division of Materials Physics, Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan. adachi@qi.mp.es.osaka-u.ac.jp
authors.forename: Yoritoshi
authors.initials: Y
authors.lastname: Adachi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Koashi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Imoto