Overcoming fundamental bounds on quantum conference key agreement

Abstract

Twin-Field Quantum Key Distribution (TF-QKD) enables two distant parties to establish a shared secret key, by interfering weak coherent pulses (WCPs) in an intermediate measuring station. This allows TF-QKD to reach greater distances than traditional QKD schemes and makes it the only scheme capable of beating the repeaterless bound on the bipartite private capacity. Here, we generalize TF-QKD to the multipartite scenario. Specifically, we propose a practical conference key agreement (CKA) protocol that only uses WCPs and linear optics and prove its security with a multiparty decoy-state method. Our protocol allows an arbitrary number of parties to establish a secret conference key by single-photon interference, enabling it to overcome recent bounds on the rate at which conference keys can be established in quantum networks without a repeater.

10 + 26 pages, 5 figures

References in corpus (10)

• Sending-or-Not-Sending with Independent Lasers: Secure Twin-Field Quantum Key Distribution Over 509 km
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• Quantum key distribution over 658 km fiber with distributed vibration sensing
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• Secure Anonymous Conferencing in Quantum Networks
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Cited by in corpus (9)

• Repeater-like asynchronous measurement-device-independent quantum conference key agreement
• Multi-field quantum conferencing overcomes the network capacity limit
• Experimental Measurement-Device-Independent Quantum Cryptographic Conferencing
• Simple loss-tolerant protocol for GHZ-state distribution in a quantum network
• Efficient source-independent quantum conference key agreement
• Quantum state estimation of multi-partite single photon path entanglement via local measurements
• Genuine multipartite entanglement is not necessary for standard device-independent conference key agreement
• Experimental Phase-Matching Quantum Cryptographic Conferencing in Symmetric and Asymmetric Fiber Channels
• Spanning-tree-packing protocol for conference key propagation in quantum networks