Saved in:
Bibliographic Details
Main Authors: Matsuura, Takaya, Yamano, Shinichiro, Kuramochi, Yui, Sasaki, Toshihiko, Koashi, Masato
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2504.07356
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917494734716928
author Matsuura, Takaya
Yamano, Shinichiro
Kuramochi, Yui
Sasaki, Toshihiko
Koashi, Masato
author_facet Matsuura, Takaya
Yamano, Shinichiro
Kuramochi, Yui
Sasaki, Toshihiko
Koashi, Masato
contents Practical quantum key distribution (QKD) protocols require a finite-size security proof. The phase error correction (PEC) approach is one of the general strategies for security analyses that has successfully proved finite-size security for many protocols. However, the conventional PEC approach cannot achieve the asymptotically optimal key rate in general, as long as the failure probability of PEC is estimated through the phase error rate. In this work, we propose a new PEC-type strategy that can provably achieve the asymptotically optimal key rate. The key piece for this is a virtual protocol based on universal source compression with quantum side information, which is of independent interest. A universal source compression with quantum side information protocol is first constructed for fixed-length independent and identically distributed (i.i.d.)~setups and then extended to adaptive-length setups with the restrictions on possible states imposed by joint random variables. Combined with the reduction method to collective attacks, this enables us to tightly evaluate the failure probability of PEC for permutation-symmetric QKD protocols, and thus leads to asymptotically tight analyses. As a result, the security of any permutation-symmetrizable QKD protocol gets reduced to the estimation problem of a single conditional Rényi entropy, which can be efficiently solved by a convex optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2504_07356
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Asymptotically tight security analysis of quantum key distribution based on universal source compression
Matsuura, Takaya
Yamano, Shinichiro
Kuramochi, Yui
Sasaki, Toshihiko
Koashi, Masato
Quantum Physics
Practical quantum key distribution (QKD) protocols require a finite-size security proof. The phase error correction (PEC) approach is one of the general strategies for security analyses that has successfully proved finite-size security for many protocols. However, the conventional PEC approach cannot achieve the asymptotically optimal key rate in general, as long as the failure probability of PEC is estimated through the phase error rate. In this work, we propose a new PEC-type strategy that can provably achieve the asymptotically optimal key rate. The key piece for this is a virtual protocol based on universal source compression with quantum side information, which is of independent interest. A universal source compression with quantum side information protocol is first constructed for fixed-length independent and identically distributed (i.i.d.)~setups and then extended to adaptive-length setups with the restrictions on possible states imposed by joint random variables. Combined with the reduction method to collective attacks, this enables us to tightly evaluate the failure probability of PEC for permutation-symmetric QKD protocols, and thus leads to asymptotically tight analyses. As a result, the security of any permutation-symmetrizable QKD protocol gets reduced to the estimation problem of a single conditional Rényi entropy, which can be efficiently solved by a convex optimization.
title Asymptotically tight security analysis of quantum key distribution based on universal source compression
topic Quantum Physics
url https://arxiv.org/abs/2504.07356