Quantum communication networks and their use for protocols beyond just QKD

Joshi SK, Zixin Huang, Fletcher A +28 more

Anoop Kumar Pandey

Zixin Huang, Siddarth Koduru Joshi, Djeylan Aktas +12 more

Abstract Anonymity in networked communication is vital for many privacy-preserving tasks. Secure key distribution alone is insufficient for high-security communications. Often, knowing who transmits a message to whom and when must also be kept hidden from an adversary. Here, we experimentally demonstrate five information-theoretically secure anonymity protocols on an eight user city-wide quantum network using polarisation entangled photon pairs. At the heart of these protocols is anonymous broadcasting, which is a cryptographic primitive that allows one user to reveal one bit of information while keeping their identity anonymous. For a network of n users, the protocols retain anonymity for the sender, given that no more than n − 2 users are colluding. This is an implementation of genuine multi-user cryptographic protocols beyond standard QKD. Our anonymous protocols enhance the functionality of any fully-connected Quantum Key Distribution network without trusted nodes.

Christopher Battarbee, Suchetana Goswami, Elham Kashefi +1 more

In this review, we survey the cryptographic task of authentication from the perspective of quantum communication. We review three main flavours of authentication that are often conflated in the literature: authentication of classical messages, authentication of quantum messages, and entity authentication, also covering recent hardware-assisted approaches. We compare representative protocols for each functionality in terms of their security assumptions, set-up requirements, composability, and scalability in large or dynamic networks, and use these criteria to identify and recommend suitable candidates. Finally, applications are surveyed: we provide a detailed case study of authentication and quantum key distribution (QKD), then extend the discussion to protocols beyond QKD, where the role of authentication is more complex. Our take-home message is that an authentication requirement is not an intrinsic limitation of quantum networks: as with all secure communication, each protocol relies on a particular authentication resource, and the security claim of that protocol is meaningful only once the authentication resource and its deployment assumptions are made explicit. At the same time, the existing classical and quantum literature already offers a range of quantum-secure authentication schemes, which can support different applications when carefully matched to the required functionality, assumptions, and security guarantees.

Ramanathan Udayakumar, A Haja Alaudeen, Ульмас Ибрагимов +2 more

Sixth-generation (6G) networks offer unprecedented ultra-reliability, capacity, and low-latency communication. Nevertheless, the same developments also pose security threats to complex communication infrastructures that may be resistant to traditional cryptographic tools, especially in the context of quantum computing. Quantum Key Distribution (QKD) is an innovative technique for achieving unconditional security that leverages quantum-mechanical principles to share cryptographic keys securely. This paper discusses how QKD can be integrated into 6G and beyond networks and used to ensure the confidentiality and integrity of data across applications such as autonomous systems, the Internet of Things (IoT), and smart city infrastructure. This paper explores the architecture of QKD-based 6G communication, key-generation systems, and quantum-resistant network layers. It also examines scalability, synchronization, and hardware implementation, and suggests possible hybrid approaches for integrating classical and quantum security protocols. The results imply that the idea of QKD may become the foundation of safeguarded communication systems in the future, ensuring resilience against attacks in the quantum era and enabling individuals to trust the next generation of wireless.

Riccardo Bassoli, Holger Boche, Christian Deppe +4 more