Ailsa Robertson | Searcharxiv

arXiv2026

Integrity from Algebraic Manipulation Detection in Trusted-Repeater QKD Networks

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.

quant-ph↗

arXiv2025

Irrelevant carrots and non-existent sticks: trust, governance, and security in the transition to quantum-safe systems

Quantum computing poses an urgent and widely recognised threat to global cybersecurity, enabling encrypted government, financial, and healthcare data harvested today to be decrypted in the near future. Transitioning to quantum-safe cryptography is therefore essential, demanding coordinated action across a complex, multi-actor innovation system. Drawing on insights from an expert workshop in Amsterdam, this study develops a socially informed vision for a quantum-safe future and analyses the current innovation landscape to identify critical gaps and the actions needed to address them. We map twelve key actor groups involved in the migration process, finding that regulators exert the strongest direct influence, while standardisation bodies play a crucial indirect role. This research provides one of the first system-level mappings of actors, influence pathways and governance responsibilities shaping the quantum-safe transition, revealing several responsibilities with unclear ownership. Although centred on the Netherlands, our findings are applicable to other national contexts navigating quantum-safe transitions.

physics.soc-ph↗