Enhancing noise robustness in device-independent conference key agreement with asymmetric parity-CHSH inequalities
Abstract
Conference key agreement allows multiple remote parties to establish a shared secret key with information-theoretical security. In device-independent conference key agreement, security can be guaranteed with minimal assumptions on the devices used, provided that a violation of a Bell inequality is observed. However, implementations are extremely challenging because high detection efficiency is required to observe loophole-free Bell violations. Here, we enhance the robustness of device-independent conference key agreement by introducing a new family of multipartite Bell inequalities called the asymmetric parity-Clauser-Horne-Shimony-Holt (CHSH) inequalities. We derive a tight analytical lower bound on the conditional von Neumann entropy of the outcomes of one of the parties in a protocol based on this inequality, including noisy preprocessing. Using this bound, we analyze robustness to detection inefficiencies as well as local and global depolarizing noise. We show that the combination of the asymmetric parity-CHSH inequality and noisy preprocessing can significantly improve the robustness to imperfections.
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BibTeX
@misc{ishihara2026enhancing,
title = {{Enhancing noise robustness in device-independent conference key agreement with asymmetric parity-CHSH inequalities}},
author = {Makoto Ishihara and Wojciech Roga and Jonatan Bohr Brask and Masahiro Takeoka},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03551},
eprint = {2609.03551},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03551},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Enhancing noise robustness in device-independent conference key agreement with asymmetric parity-CHSH inequalities
AU - Makoto Ishihara
AU - Wojciech Roga
AU - Jonatan Bohr Brask
AU - Masahiro Takeoka
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03551
UR - https://arxiv.org/abs/2609.03551
AB - Conference key agreement allows multiple remote parties to establish a shared secret key with information-theoretical security. In device-independent conference key agreement, security can be guaranteed with minimal assumptions on the devices used, provided that a violation of a Bell inequality is observed. However, implementations are extremely challenging because high detection efficiency is required to observe loophole-free Bell violations. Here, we enhance the robustness of device-independent conference key agreement by introducing a new family of multipartite Bell inequalities called the asymmetric parity-Clauser-Horne-Shimony-Holt (CHSH) inequalities. We derive a tight analytical lower bound on the conditional von Neumann entropy of the outcomes of one of the parties in a protocol based on this inequality, including noisy preprocessing. Using this bound, we analyze robustness to detection inefficiencies as well as local and global depolarizing noise. We show that the combination of the asymmetric parity-CHSH inequality and noisy preprocessing can significantly improve the robustness to imperfections.
ER -