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arXiv · 2603.20395

Security of Binary-Modulated Optical Key Distribution Against Quantum-Enhanced Coherent Eavesdropping

Karol Łukanowski·Michał Wójcik·Stefano Olivares·Konrad Banaszek·Marcin Jarzyna
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Abstract

Optical key distribution (OKD) protects the physical layer of communication links by taking advantage of the inherent noise present in the photodetection process. It allows for efficient generation of a shared random key between two distant users that is secure against passive eavesdropping and can be subsequently used for cryptographic purposes. Moreover, it can be straightforwardly implemented over standard intensity modulation and direct detection links, making it an attractive alternative to quantum key distribution. Here we present a comprehensive security analysis against more powerful eavesdroppers possessing the ability to perform either coherent detection, or even quantum-optimal measurements on the intercepted transmission.

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Karol Łukanowski, Michał Wójcik, Stefano Olivares, Konrad Banaszek, Marcin Jarzyna. 2026-03-20. Security of Binary-Modulated Optical Key Distribution Against Quantum-Enhanced Coherent Eavesdropping. https://doi.org/10.1088/1367-2630%2Fae8a75

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