We present a rigorous security analysis of Continuous-Variable Measurement-Device Independent Quantum Key Distribution (CV MDI 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 CV QKD with new 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.
@article{arxiv.1704.07924,
title = {Continuous-variable measurement-device-independent quantum key distribution: Composable security against coherent attacks},
author = {Cosmo Lupo and Carlo Ottaviani and Panagiotis Papanastasiou and Stefano Pirandola},
journal= {arXiv preprint arXiv:1704.07924},
year = {2018}
}
Comments
v4: close to the published version (which is shorter than previous arXiv versions)