Privacy Enhanced QKD Networks: Zero Trust Relay Architecture based on Homomorphic Encryption

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Brazaola-Vicario, Aitor, Lage, Oscar, Bernabé-Rodríguez, Julen, Jacob, Eduardo, Astorga, Jasone
Format: Preprint
Publié: 2025
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866914376863186944
author Brazaola-Vicario, Aitor
Lage, Oscar
Bernabé-Rodríguez, Julen
Jacob, Eduardo
Astorga, Jasone
author_facet Brazaola-Vicario, Aitor
Lage, Oscar
Bernabé-Rodríguez, Julen
Jacob, Eduardo
Astorga, Jasone
contents Quantum key distribution (QKD) enables unconditionally secure symmetric key exchange between parties. However, terrestrial fibre-optic links face inherent distance constraints due to quantum signal degradation. Traditional solutions to overcome these limits rely on trusted relay nodes, which perform intermediate re-encryption of keys using one-time pad (OTP) encryption. This approach, however, exposes keys as plaintext at each relay, requiring significant trust and stringent security controls at every intermediate node. These "trusted" relays become a security liability if compromised. To address this issue, we propose a zero-trust relay design that applies fully homomorphic encryption (FHE) to perform intermediate OTP re-encryption without exposing plaintext keys, effectively mitigating the risks associated with potentially compromised or malicious relay nodes. Additionally, the architecture enhances crypto-agility by incorporating external quantum random number generators, thus decoupling key generation from specific QKD hardware and reducing vulnerabilities tied to embedded key-generation modules. The solution is designed with the existing European Telecommunication Standards Institute (ETSI) QKD standards in mind, enabling straightforward integration into current infrastructures. Its feasibility has been successfully demonstrated through a hybrid network setup combining simulated and commercially available QKD equipment. The proposed zero-trust architecture thus significantly advances the scalability and practical security of large-scale QKD networks, greatly reducing reliance on fully trusted infrastructure.
format Preprint
id arxiv_https___arxiv_org_abs_2503_17011
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Privacy Enhanced QKD Networks: Zero Trust Relay Architecture based on Homomorphic Encryption
Brazaola-Vicario, Aitor
Lage, Oscar
Bernabé-Rodríguez, Julen
Jacob, Eduardo
Astorga, Jasone
Cryptography and Security
Quantum key distribution (QKD) enables unconditionally secure symmetric key exchange between parties. However, terrestrial fibre-optic links face inherent distance constraints due to quantum signal degradation. Traditional solutions to overcome these limits rely on trusted relay nodes, which perform intermediate re-encryption of keys using one-time pad (OTP) encryption. This approach, however, exposes keys as plaintext at each relay, requiring significant trust and stringent security controls at every intermediate node. These "trusted" relays become a security liability if compromised. To address this issue, we propose a zero-trust relay design that applies fully homomorphic encryption (FHE) to perform intermediate OTP re-encryption without exposing plaintext keys, effectively mitigating the risks associated with potentially compromised or malicious relay nodes. Additionally, the architecture enhances crypto-agility by incorporating external quantum random number generators, thus decoupling key generation from specific QKD hardware and reducing vulnerabilities tied to embedded key-generation modules. The solution is designed with the existing European Telecommunication Standards Institute (ETSI) QKD standards in mind, enabling straightforward integration into current infrastructures. Its feasibility has been successfully demonstrated through a hybrid network setup combining simulated and commercially available QKD equipment. The proposed zero-trust architecture thus significantly advances the scalability and practical security of large-scale QKD networks, greatly reducing reliance on fully trusted infrastructure.
title Privacy Enhanced QKD Networks: Zero Trust Relay Architecture based on Homomorphic Encryption
topic Cryptography and Security
url https://arxiv.org/abs/2503.17011