QKD parameter estimation by two-universal hashing
This work addresses a key bottleneck in practical QKD implementations by enhancing security and efficiency for small data blocks, which is crucial for real-world quantum communication systems.
The paper tackles the problem of improving finite-key performance in quantum key distribution (QKD) by proposing a protocol that uses two-universal hashing instead of random sampling for error estimation, resulting in a dramatic performance boost for small block sizes and a faster convergence rate to the asymptotic key rate.
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 than $c'n^{-1/3}$ for an optimized protocol that uses random sampling and has the same asymptotic rate, where $c'$ depends on the security parameter and the error rate.