Source-linked AI summary
Security Proof for Quantum Key Distribution Using Qudit Systems
Lana Sheridan, Valerio Scarani
TL;DR
The paper addresses the lack of full security proofs for higher-dimensional QKD by deriving finite-key security bounds against coherent attacks. It finds that higher-dimensional protocols outperform qubit protocols in asymptotic key rate and noise robustness, while finite-key corrections vary little with dimension.
Problem
Full security proofs for higher-dimensional QKD protocols were still lacking despite indications of greater information transmission and noise resistance.
Method
The authors derive security bounds against coherent attacks for two higher-dimensional QKD protocol families, including finite-key effects and mutually unbiased basis choices.
Results
Higher-dimensional protocols perform better than corresponding qubit protocols for secret key rate and noise robustness, while finite-key effects vary little with d.
Takeaways & Limitations
The study supports using higher-dimensional alphabets for QKD when secret key rate or noise robustness is the figure of merit.
Takeaways & Limitations
The finite-key bound contains a dimension-dependent correction whose previously misstated form can significantly affect higher-dimensional results.
Abstract
from arXiv · showhide
We provide security bounds against coherent attacks for two families of quantum key distribution protocols that use $d$-dimensional quantum systems. In the asymptotic regime, both the secret key rate for fixed noise and the robustness to noise increase with $d$. The finite-key corrections are found to be almost insensitive to $d\lesssim 20$.