Quantum cryptography with an ideal local relay

Gaetana Spedalieri, Carlo Ottaviani, Samuel L. Braunstein, Tobias Gehring, Christian S. Jacobsen, Ulrik L. Andersen, Stefano Pirandola

Research output: Contribution to conferencePaperpeer-review


We consider two remote parties connected to a relay by two quantum channels. To generate a secret key, they transmit coherent states to the relay, where the states are subject to a continuous-variable (CV) Bell detection. We study the ideal case where Alice's channel is lossless, i.e., the relay is locally situated in her lab and the Bell detection is performed with unit efficiency. This configuration allows us to explore the optimal performances achievable by CV measurement-device-independent (MDI) quantum key distribution (QKD). This corresponds to the limit of a trusted local relay, where the detection loss can be re-scaled. Our theoretical analysis is confirmed by an experimental simulation where 10^-4 secret bits per use can potentially be distributed at 170km assuming ideal reconciliation.
Original languageEnglish
Publication statusPublished - 3 Sept 2015

Bibliographical note

in Proceedings of the SPIE Security + Defence 2015 conference on Quantum Information Science and Technology, Toulouse, France (21-24 September 2015) - Paper 9648-47


  • quant-ph

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