2013/12/31 by Stefano Pirandola, Carlo Ottaviani, Gaetana Spedalieri +6 · 5 citations
Computer Science · Mathematics · Physics and Astronomy · #Computer network #Computer science #Computer security #Cryptography #Distributed computing #Encryption #Key (lock) #Key distribution #Physics #Public-key cryptography #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum computer #Quantum cryptography #Quantum information #Quantum key distribution #Quantum mechanics #Quantum network #Qubit #Relay #Scalability #Shared secret #math-ph #math.MP #physics.data-an #physics.optics #quant-ph
paper · pdf · doi:10.1038/nphoton.2015.83
published as Nature Photonics 9, 397-402 (2015) · Theory and Experiment. Main article (6 pages) plus Supplementary Information (additional 13 pages)
arxiv created 2014/08/01 · openalex publication_date 2015/05/25 · arxiv updated 2015/06/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We extend the field of continuous-variable quantum cryptography to a network formulation where two honest parties connect to an untrusted relay by insecure quantum links. To generate secret correlations, they transmit coherent states to the relay where a continuous-variable Bell detection is performed and the outcome broadcast. Even though the detection could be fully corrupted and the links subject to optimal coherent attacks, the honest parties can still extract a secret key, achieving high rates when the relay is proximal to one party, as typical in public networks with access points or proxy servers. Our theory is confirmed by an experiment generating key-rates which are orders of magnitude higher than those achievable with discrete-variable protocols. Thus, using the cheapest possible quantum resources, we experimentally show the possibility of high-rate quantum key distribution in network topologies where direct links are missing between end-users and intermediate relays cannot be trusted.