Experimental anonymous conference key agreement using linear cluster states

Abstract

Multipartite entanglement enables secure and anonymous key exchange between multiple parties in a network. In particular Greenberger-Horne-Zeilinger (GHZ) states have been introduced as resource states for anonymous key exchange protocols, in which an anonymous subset of parties within a larger network establishes a secret key. However, the use of other types of multipartite entanglement for such protocols remains relatively unexplored. Here we demonstrate that linear cluster states can serve as a versatile and potentially scalable resource in such applications. We implemented an anonymous key exchange protocol with four photons in a linear cluster state and established a shared key between three parties in our network. We show how to optimize the protocol parameters to account for noise and to maximize the finite key rate under realistic conditions. As cluster states have been established as a flexible resource in quantum computation, we expect that our demonstration provides a first step towards their hybrid use for networked computing and communication.

References in corpus (5)

• Resource-efficient linear optical quantum computation
• Ultrafast Fault-Tolerant Long-Distance Quantum Communication with Static Linear Optics
• Conference key agreement in a quantum network
• Secure Anonymous Conferencing in Quantum Networks
• Anonymous conference key agreement in linear quantum networks

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• Quantum cryptography beyond key distribution: theory and experiment
• Experimental anonymous quantum conferencing
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• Anonymous and private parameter estimation in networks of quantum sensors
• Graph state extraction from two-dimensional cluster states
• Distinguishing Graph States by the Properties of Their Marginals