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arXiv · 1904.01970

Analysis of the trusted-device scenario in continuous-variable quantum key distribution

Fabian Laudenbach·Christoph Pacher
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Abstract

The assumption that detection and/or state-preparation devices used for continuous-variable quantum key distribution (CV-QKD) are beyond influence of potential eavesdroppers leads to a significant performance enhancement in terms of achievable key rate and transmission distance. We provide a detailed and comprehensible derivation of the Holevo bound in this so-called trusted-device scenario. Modelling an entangling-cloner attack and using some basic algebraic matrix transformations, we show that the computation of the Holevo bound can be reduced to the solution of a quadratic equation. As an advantage of our derivation, the mathematical complexity of our solution does not increase with the number of trusted-noise sources. Finally, we provide a numerical evaluation of our results, illustrating the counter-intuitive fact that an appropriate amount of trusted receiver loss and noise can even be beneficial for the key rate.

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Fabian Laudenbach, Christoph Pacher. 2019-04-03. Analysis of the trusted-device scenario in continuous-variable quantum key distribution. https://doi.org/10.1002/qute.201900055

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