Anonymous quantum conference key agreement (AQCKA) allows a group of users within a network to establish a shared cryptographic key without revealing their participation. Although this can be achieved using bi-partite primitives alone, it is costly in the number of network rounds required. By allowing the use of multi-partite entanglement, there is a substantial efficiency improvement. We experimentally implement the AQCKA task in a six-user quantum network using Greenberger-Horne-Zeilinger (GHZ)-state entanglement and obtain a significant resource cost reduction in line with theory when compared to a bi-partite-only approach. We also demonstrate that the protocol retains an advantage in a four-user scenario with finite key effects taken into account.
@article{arxiv.2311.14158,
title = {Experimental anonymous quantum conferencing},
author = {Jonathan W. Webb and Joseph Ho and Federico Grasselli and Gláucia Murta and Alexander Pickston and Andrés Ulibarrena and Alessandro Fedrizzi},
journal= {arXiv preprint arXiv:2311.14158},
year = {2024}
}