Device-Independent Conference Keys from Parity-Extended Games
Abstract
Device-independent conference key agreement (DI-CKA) lets a group of parties establish a shared secret key from untrusted quantum devices, with security certified by non-locality. Existing DI-CKA protocols are each built around a single Bell inequality, typically a multiparty variant of the CHSH game. DI-QKD protocols, in contrast, have been built from a much richer landscape of non-local games, and it has remained unclear how to carry this landscape over to the conference setting. We introduce Parity−G$ games}$, which extend any two-player game G to N players, for every N, provided G has an optimal strategy in which one player measures Pauli observables. The extension preserves the quantum and classical values of G, and the security of the resulting N-party protocol follows from an analysis of the two-player game alone. Our framework recovers the Parity-CHSH game of Ribeiro, Murta and Wehner (Phys. Rev. A, 2018) as a special case. Applied to the Mermin--Peres Magic Square Game, it yields a new N-player pseudo-telepathy game, the Parity Magic Square Game, which ideal devices win in every round. We use it to construct the first DI-CKA protocol based on a pseudo-telepathy game. We prove the protocol secure against coherent attacks. It produces up to two key bits per round, and at low noise its key rate exceeds that of the DI-CKA protocol based on the Parity-CHSH game.
Related
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- Device-independent conference key agreement from two-body correlators with balanced Dicke states
- Improving the Loss Tolerance of Heralded Photonic GHZ States for Long-Distance Device-Independent Conference Key Agreement
- Randomness can be certified in energy-constrained semi-device-independent scenarios
- Computing key rates for one-sided device-independent quantum key distribution
BibTeX
@misc{chakraborty2026deviceindependent,
title = {{Device-Independent Conference Keys from Parity-Extended Games}},
author = {Suvradip Chakraborty and Ronak Ramachandran and Aniruddha Sen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.01025},
eprint = {2610.01025},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.01025},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Device-Independent Conference Keys from Parity-Extended Games
AU - Suvradip Chakraborty
AU - Ronak Ramachandran
AU - Aniruddha Sen
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.01025
UR - https://arxiv.org/abs/2610.01025
AB - Device-independent conference key agreement (DI-CKA) lets a group of parties establish a shared secret key from untrusted quantum devices, with security certified by non-locality. Existing DI-CKA protocols are each built around a single Bell inequality, typically a multiparty variant of the CHSH game. DI-QKD protocols, in contrast, have been built from a much richer landscape of non-local games, and it has remained unclear how to carry this landscape over to the conference setting. We introduce Parity−G$ games}$, which extend any two-player game G to N players, for every N, provided G has an optimal strategy in which one player measures Pauli observables. The extension preserves the quantum and classical values of G, and the security of the resulting N-party protocol follows from an analysis of the two-player game alone. Our framework recovers the Parity-CHSH game of Ribeiro, Murta and Wehner (Phys. Rev. A, 2018) as a special case. Applied to the Mermin--Peres Magic Square Game, it yields a new N-player pseudo-telepathy game, the Parity Magic Square Game, which ideal devices win in every round. We use it to construct the first DI-CKA protocol based on a pseudo-telepathy game. We prove the protocol secure against coherent attacks. It produces up to two key bits per round, and at low noise its key rate exceeds that of the DI-CKA protocol based on the Parity-CHSH game.
ER -