title: Tomographic quantum cryptography: equivalence of quantum and classical key distillation.
abstract: The security of a cryptographic key that is generated by communication through a noisy quantum channel relies on the ability to distill a shorter secure key sequence from a longer insecure one. For an important class of protocols, which exploit tomographically complete measurements on entangled pairs of any dimension, we show that the noise threshold for classical advantage distillation is identical with the threshold for quantum entanglement distillation. As a consequence, the two distillation procedures are equivalent: neither offers a security advantage over the other.
authors.affiliation: Institut für Theoretische Physik, Universität Hannover, 30167 Hannover, Germany.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Bruss
authors.forename: Matthias
authors.initials: M
authors.lastname: Christandl
authors.forename: Artur
authors.initials: A
authors.lastname: Ekert
authors.forename: Berthold-Georg
authors.initials: BG
authors.lastname: Englert
authors.forename: Dagomir
authors.initials: D
authors.lastname: Kaszlikowski
authors.forename: Chiara
authors.initials: C
authors.lastname: Macchiavello