Continuous-variable measurement-device-independent quantum key distribution: Composable security against coherent attacks

Cosmo Lupo, Carlo Ottaviani, Panagiotis Papanastasiou, Stefano Pirandola

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We present a rigorous security analysis of continuous-variable measurement-device-independent quantum key distribution (CVMDI QKD) in a finite-size scenario. The security proof is obtained in two steps: by first assessing the security against collective Gaussian attacks, and then extending to the most general class of coherent attacks via the Gaussian de Finetti reduction. Our result combines recent state-of-the-art security proofs for CVQKD with findings about min-entropy calculus and parameter estimation. In doing so, we improve the finite-size estimate of the secret key rate. Our conclusions confirm that CV MDI protocols allow for high rates on the metropolitan scale, and may achieve a nonzero secret key rate against the most general class of coherent attacks after 10^7–10^9 quantum signal transmissions, depending on loss and noise, and on the required level of security.
Original languageEnglish
Article number052327
Pages (from-to)1-10
Number of pages10
JournalPhysical Review A
Issue number5
Publication statusPublished - 29 May 2018

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