title: Unconditional security of a three state quantum key distribution protocol.
abstract: Quantum key distribution (QKD) protocols are cryptographic techniques with security based only on the laws of quantum mechanics. Two prominent QKD schemes are the Bennett-Brassard 1984 and Bennett 1992 protocols that use four and two quantum states, respectively. In 2000, Phoenix et al. proposed a new family of three-state protocols that offers advantages over the previous schemes. Until now, an error rate threshold for security of the symmetric trine spherical code QKD protocol has been shown only for the trivial intercept-resend eavesdropping strategy. In this Letter, we prove the unconditional security of the trine spherical code QKD protocol, demonstrating its security up to a bit error rate of 9.81%. We also discuss how this proof applies to a version of the trine spherical code QKD protocol where the error rate is evaluated from the number of inconclusive events.
authors.affiliation: Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: J-C
authors.initials: JC
authors.lastname: Boileau
authors.forename: K
authors.initials: K
authors.lastname: Tamaki
authors.forename: J
authors.initials: J
authors.lastname: Batuwantudawe
authors.forename: R
authors.initials: R
authors.lastname: Laflamme
authors.forename: J M
authors.initials: JM
authors.lastname: Renes