Analysis of the Trusted‐Device Scenario in Continuous‐Variable Quantum Key Distribution. Issue 11 (29th August 2019) - Laudenbach, Fabian
Abstract: The assumption that detection and/or state preparation devices used for continuous‐variable quantum key distribution are beyond influence of potential eavesdroppers leads to a significant performance enhancement in terms of achievable key rate and transmission distance. A detailed and comprehensible derivation of the Holevo bound in this so‐called trusted‐device scenario is provided. Modeling an entangling‐cloner attack and using some basic algebraic matrix transformations, it is shown 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, a numerical evaluation of our results is provided, illustrating the counter‐intuitive fact that an appropriate amount of trusted‐receiver loss and noise can even be beneficial for the key rate. Abstract : Continuous‐variable quantum key distribution (CV‐QKD) is a straightforward way to achieve information‐theoretic communication security using standard components provided by the optical‐telecommunication industry. Achievable secure‐key rates and transmission lengths can be significantly improved by declaring certain noise sources as trusted devices. This article provides a detailed analytical and numerical security analysis of CV‐QKD in the trusted‐device scenario.