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arXiv · 2506.01296

Long-Distance Device-Independent Conference Key Agreement

Makoto Ishihara·Anders J. E. Bjerrum·Wojciech Roga·Jonatan B. Brask·Ulrik L. Andersen·Masahiro Takeoka
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Abstract

Device-independent quantum key distribution (DI-QKD) enables two remote parties to share an information-theoretically secure key without any assumptions on the inner workings of the devices used. Device-independent conference key agreement (DI-CKA) is multipartite DI-QKD where more than two parties share a common secure key. The performance of DI-CKA, however, is strictly limited because of its susceptibility to losses due e.g. to imperfect detection efficiency and channel transmission. Here, we propose a DI-CKA protocol which reduces this limitation by using a heralding scheme to distribute multipartite entanglement. We analyze key rates of our protocol for two different measurement scenarios and we show that our protocol outperforms a previous DI-CKA protocol even with an experimentally feasible measurement.

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Makoto Ishihara, Anders J. E. Bjerrum, Wojciech Roga, Jonatan B. Brask, Ulrik L. Andersen, Masahiro Takeoka. 2025-06-02. Long-Distance Device-Independent Conference Key Agreement. https://doi.org/10.1103/2qyl-3rk1

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