Regensburg 2022 – wissenschaftliches Programm

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QI: Fachverband Quanteninformation

QI 7: Quantum Communication and Networks

QI 7.3: Vortrag

Mittwoch, 7. September 2022, 15:30–15:45, H8

Prepare-and-measure conference key agreement protocol based on single-photon interference — •Giacomo Carrara, Federico Grasselli, Gláucia Murta, Hermann Kampermann, and Dagmar Bruß — Institut für Theoretische Physik III, Heinrich-Heine-Universität Düsseldorf, Germany

Quantum Key Distribution (QKD) and its multipartite counterpart, Conference Key Agreement, (CKA) are fundamental cryptographic tasks, where two or more parties try to establish a common, secret key. The so-called Twin-Field Quantum Key Distribution (TF-QKD) setup recently received great attention as it only requires lasers and linear optical devices. TF-QKD has been generalized to many parties, where a CKA protocol based on single-photon interference has been proposed [F. Grasselli et al, 2019, New J. Phys., 21 123002]. This multipartite protocol, however, has a big drawback: it does not have a prepare-and-measure formulation and thus lacks a simple, practical implementation. In this work we propose a CKA protocol that allows for a prepare-and-measure implementation, where the parties are required only to produce weak coherent pulses. We provide for this protocol a security analysis based on the decoy state method and analyze how the protocol performs compared to the well-known repeaterless bound, considering different network architectures.