High-rate measurement-device independent quantum cryptography

Stefano Pirandola, Carlo Ottaviani, Gae Spedalieri, Christian Weedbrook, Samuel Leon Braunstein, Seth Lloyd, T Gehring, C. S. Jacobsen, U. L. Andersen

Research output: Contribution to journalArticlepeer-review


Quantum cryptography achieves a formidable task—the remote distribution of secret keys by exploiting the fundamental laws of physics. Quantum cryptography is now headed towards solving the practical problem of constructing scalable and secure quantum networks. A significant step in this direction has been the introduction of measurement-device independence, where the secret key between two parties is established by the measurement of an untrusted relay. Unfortunately, although qubit-implemented protocols can reach long distances, their key rates are typically very low, unsuitable for the demands of a metropolitan network. Here we show, theoretically and experimentally, that a solution can come from the use of continuous-variable systems. We design a coherent-state network protocol able to achieve remarkably high key rates at metropolitan distances, in fact three orders of magnitude higher than those currently achieved. Our protocol could be employed to build high-rate quantum networks where devices securely connect to nearby access points or proxy servers.
Original languageEnglish
Pages (from-to)397-402
JournalNature photonics
Issue number6
Early online date25 May 2015
Publication statusPublished - Jun 2015

Bibliographical note

Main text plus appendix. 13 pages. 9 figures


  • quant-ph
  • math-ph
  • math.MP
  • physics.data-an
  • physics.optics

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