By the same authors

From the same journal

Continuous-variable quantum cryptography using two-way quantum communication

Research output: Contribution to journalArticle



Publication details

JournalNature Physics
DateE-pub ahead of print - 11 Jul 2008
DatePublished (current) - Sep 2008
Issue numbern/a
Number of pages5
Pages (from-to)726-730
Early online date11/07/08
Original languageEnglish


Quantum cryptography has recently been extended to continuous-variable systems, such as the bosonic modes of the electromagnetic field possessing continuous degrees of freedom. In particular, several cryptographic protocols have been proposed and experimentally implemented using bosonic modes with Gaussian statistics. These protocols have shown the possibility of reaching very high secret key rates, even in the presence of strong losses in the quantum communication channel. Despite this robustness to loss, their security can be affected by more general attacks where extra Gaussian noise is introduced by the eavesdropper. Here, we show a 'hardware solution' for enhancing the security thresholds of these protocols. This is possible by extending themto two-way quantum communication where subsequent uses of the quantum channel are suitably combined. In the resulting two-way schemes, one of the honest parties assists the secret encoding of the other, with the chance of a non-trivial superadditive enhancement of the security thresholds. These results should enable the extension of quantum cryptography to more complex quantum communications.

Bibliographical note

© 2008 Nature Publishing Group. This is an author produced version of a paper published in Nature Physics. Uploaded in accordance with the publisher's self archiving policy.

    Research areas

  • Quantum Cryptography, quantum communication, Security, Uncertainty principle, Unconditional security

Discover related content

Find related publications, people, projects, datasets and more using interactive charts.

View graph of relations