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arXiv · 2506.09772

Device Independent Quantum Key Activation

Bora Ulu·Nicolas Brunner·Mirjam Weilenmann
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Abstract

Device-independent quantum key distribution (DIQKD) allows two distant parties to establish a secret key, based only on the observed Bell nonlocal distribution. It remains however, unclear what the minimal resources for enabling DIQKD are and how to maximize the key rate from a given distribution. In the present work, we consider a scenario where several copies of a given quantum distribution are jointly processed via a local and classical wiring operation. We find that, under few assumptions, it is possible to activate device-independent key. That is, starting from a distribution that is useless in a DIQKD protocol, we obtain a positive key rate by wiring several copies together. We coin this effect device-independent key activation. Our analysis focuses on the standard DIQKD protocol with one-way post-processing, and we resort to semi-definite programming techniques for computing lower bounds on the key rate.

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Bora Ulu, Nicolas Brunner, Mirjam Weilenmann. 2025-06-11. Device Independent Quantum Key Activation. https://doi.org/10.1103/f8jc-q1kg

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