MULTISS: un protocole de stockage confidentiel {\`a} long terme sur plusieurs r{\'e}seaux QKD

TL;DR

This paper introduces MULTISS, a secure long-term distributed storage protocol across multiple QKD networks, enhancing security over previous single-network protocols by using hierarchical secret sharing and update capabilities.

Contribution

It extends LINCOS by enabling multi-network secret sharing with hierarchical secret sharing, improving security and allowing updates without full secret reconstruction.

Findings

MULTISS provides perfect security across multiple QKD networks.

It allows secret updates without reconstructing the entire secret.

MULTISS is proven to be more secure than LINCOS.

Abstract

This paper presents MULTISS, a new protocol for long-term storage distributed across multiple Quantum Key Distribution (QKD) networks. This protocol is an extension of LINCOS, a secure storage protocol that uses Shamir secret sharing for secret storage on a single QKD network. Our protocol uses hierarchical secret sharing to distribute a secret across multiple QKD networks while ensuring perfect security. Our protocol further allows for sharing updates without having to reconstruct the entire secret. We also prove that MULTISS is strictly more secure than LINCOS, which remains vulnerable when its QKD network is compromised.