title: Noisy processing and distillation of private quantum States.
abstract: We provide a simple security proof for prepare and measure quantum key distribution protocols employing noisy processing and one-way postprocessing of the key. This is achieved by showing that the security of such a protocol is equivalent to that of an associated key distribution protocol in which, instead of the usual maximally entangled states, a more general private state is distilled. In addition to a more general target state, the usual entanglement distillation tools are employed (in particular, Calderbank-Shor-Steane-like codes), with the crucial difference that noisy processing allows some phase errors to be left uncorrected without compromising the privacy of the key.
authors.affiliation: Institut für Angewandte Physik, Technische Universität Darmstadt, D-64289 Darmstadt, Germany.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Renes
authors.forename: Graeme
authors.initials: G
authors.lastname: Smith