Fig. 3: Composable SKF results.
From: Practical continuous-variable quantum key distribution with composable security
a Pseudo-temporal evolution of the composable SKF with the time parameter calculated as the ratio of the cumulative number N of complex symbols available for the classical steps of the protocol and the rate B = 100 MHz at which these symbols are modulated. b Variation of untrusted noise ξu measured in the experiment (lower point) and its worst-case estimator (upper point), and the noise threshold to beat to get a positive composable SKF. The deviation of the simulation traces in (a) from the experimental data between 1 and 5 s is due to the slight increase in ξu. c, d Comparison of confidence intervals derived in this manuscript (Beta; solid-red trace and Gaussian; dotted-green trace) with those derived in the original composable security proof (ref. 10; dashed-blue trace) as a function of N. Using the confidence intervals from ref. 10 leads to no key generation until almost the end (filled-blue square in (a) at N/B ≈ 10).
