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arXiv · 2606.20346

Effective discrete-modulated continuous variable QKD under general attacks using dimension reduction

Mariana Navarro·Mateus Araújo·Antonio Acín·Carlos Pascual-García
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Abstract

Continuous variable quantum key distribution via discrete modulations ensures information-theoretic security using standard telecom technologies, providing affordable and scalable quantum communications with simplified classical postprocessing. However, existing security proofs against general attacks often rely on restrictive assumptions, such as a bounded dimension for coherent states, or require impractically large block sizes. In this work, we develop a finite-size security analysis that removes these limitations while incorporating realistic experimental features. Our approach combines an optimization under infinite dimensions, a security proof against general attacks, a trusted detector model accounting for the receiver imperfections, and postselection strategies to reuse discarded measurement outcomes. We report positive key rates in the finite-size regime for relevant block sizes of the order of $10^7$. These results contribute to narrowing the gap between theoretical security proofs and practical implementations of discrete-modulated continuous variable quantum key distribution protocols.

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Mariana Navarro, Mateus Araújo, Antonio Acín, Carlos Pascual-García. 2026-06-18. Effective discrete-modulated continuous variable QKD under general attacks using dimension reduction. https://arxiv.org/abs/2606.20346

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