Integrity from Algebraic Manipulation Detection in Trusted-Repeater QKD Networks

TL;DR

This paper introduces a novel protocol for trusted-repeater QKD networks that guarantees both confidentiality and integrity using Algebraic Manipulation Detection codes, achieving information-theoretic security against manipulation.

Contribution

It is the first to provide a provably secure protocol combining AMD codes with multi-path relaying for integrity in trusted-repeater QKD networks.

Findings

Protocol achieves information-theoretic security against manipulation.

Formal proof of integrity guarantees using game-based analysis.

Enhances security of long-distance quantum communication networks.

Abstract

Quantum Key Distribution (QKD) allows secure communication without relying on computational assumptions, but can currently only be deployed over relatively short distances due to hardware constraints. To extend QKD over long distances, networks of trusted repeater nodes can be used, wherein QKD is executed between neighbouring nodes and messages between non-neighbouring nodes are forwarded using a relay protocol. Although these networks are being deployed worldwide, no protocol exists which provides provable guarantees of integrity against manipulation from both external adversaries and corrupted intermediates. In this work, we present the first protocol that provably provides both confidentiality and integrity. Our protocol combines an existing cryptographic technique, Algebraic Manipulation Detection (AMD) codes, with multi-path relaying over trusted repeater networks. This protocol achieves Information Theoretic Security (ITS) against the detection of manipulation, which we prove formally through a sequence of games.