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arXiv · 2111.02467

Fundamental limitations on the device-independent quantum conference key agreement

Karol Horodecki·Marek Winczewski·Siddhartha Das
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Abstract

We provide several general upper bounds on the rate of a key secure against a quantum adversary in the device-independent conference key agreement (DI-CKA) scenario. They include bounds by reduced entanglement measures and those based on multipartite secrecy monotones such as a multipartite squashed entanglement-based measure, which we refer to as reduced c-squashed entanglement. We compare the latter bound with the known lower bound for the protocol of conference key distillation based on the parity Clauser-Horne-Shimony-Holt game. We also show that the gap between the DI-CKA rate and the device-dependent rate is inherited from the bipartite gap between device-independent and device-dependent key rates, giving examples that exhibit the strict gap.

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Karol Horodecki, Marek Winczewski, Siddhartha Das. 2021-11-03. Fundamental limitations on the device-independent quantum conference key agreement. https://doi.org/10.1103/physreva.105.022604

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