QKD parameter estimation by two-universal hashing leads to faster convergence to the asymptotic rate. (arXiv:2109.06709v2 [quant-ph] UPDATED)

This paper proposes and proves security of a QKD protocol which uses
two-universal hashing instead of random sampling to estimate the number of bit
flip and phase flip errors. This protocol dramatically outperforms previous QKD
protocols for small block sizes. More generally, for the two-universal hashing
QKD protocol, the difference between asymptotic and finite key rate decreases
with the number $n$ of qubits as $cn^{-1}$, where $c$ depends on the security
parameter. For comparison, the same difference decreases no faster …

convergence hashing parameter rate