SAQ1 – Quantum Technologies and Applications
Thursday, 4 June 2026, 11:00-12:30, room Sala 6 (1st floor)
Session Chair: Diego Lopez (Telefonica, ES)
Empowering Mobile Networks Security Resilience by Using Post-Quantum Cryptography
Ricardo Alves Faval (Federal University of Uberlândia (UFU), Brazil); Rodrigo Moreira (Federal University of Viçosa, Brazil); Flavio de Oliveira Silva (University of Minho, Portugal & Federal University of Uberlândia, Brazil)
The transition to a cloud-native 5G Service-Based Architecture (SBA) improves scalability but exposes control-plane signaling to emerging quantum threats, including Harvest-Now, Decrypt-Later (HNDL) attacks. While NIST has standardized post-quantum cryptography (PQC), practical, deployable integration in operational 5G cores remains underexplored. This work experimentally integrates NIST-standardized ML-KEM-768 and ML-DSA into an open-source 5G core (free5GC) using a sidecar proxy pattern that preserves unmodified network functions (NFs). Implemented on free5GC, we compare three deployments: (i) native HTTPS/TLS, (ii) TLS sidecar, and (iii) PQC-enabled sidecar. Measurements at the HTTP/2 request-response boundary over repeated independent runs show that PQC increases end-to-end Service-Based Interface (SBI) latency to ~54 ms, adding a deterministic 48-49 ms overhead relative to the classical baseline, while maintaining tightly bounded variance (IQR ≤ 0.2 ms, CV < 0.4%). We also quantify the impact of Certification Authority (CA) security levels, identifying certificate validation as a tunable contributor to overall delay. Overall, the results demonstrate that sidecar-based PQC insertion enables a non-disruptive and operationally predictable migration path for quantum-resilient 5G signaling.
Future Generation Wireless Quantum Optical Communications with Transmission of Thermal States
Peter Jung and Kushtrim Dini (Universität Duisburg-Essen, Germany)
Recent research has shown that radio applications operating above 300 GHz demand a labor-intensive analog design that must account for the frequency-dependent behavior of ohmic resistance at these frequencies. This challenge has brought optical communication solutions, well suited for the sixth generation (6G) terahertz (THz) band spanning 300 GHz to 10 THz, into focus. In particular, laser based wireless quantum optical communication concepts replacing radio frequency (RF) transceivers traditionally used in channel coded wireless systems have emerged. Light emitting diodes (LEDs) to be deployed at the required quantum transmitters are easy to implement alternatives to the said lasers. However, since LEDs likely emit incoherent thermal states instead of coherent states generated by lasers, the transmission of such thermal states via wireless multipath thermal noise quantum communication channels leading to received radiation fields lacking coherence has to be studied. It will be illustrated in this manuscript that the uncoded transmission quality suffers considerably in this case. Thus, the authors propose the inclusion of sophisticated channel coding such as the 5G/NR polar coding in wireless quantum optical communications employing LEDs. In this manuscript, it will be demonstrated that this approach is capable of achieving the desired robust transmission performance.
How Many Qubits Can Be Teleported? Scalability of Fidelity-Constrained Quantum Applications
Oscar Adamuz-Hinojosa, Jonathan Prados-Garzon, Sara Vaquero-Gil and Juan M. Lopez-Soler (University of Granada, Spain)
Quantum networks (QNs) enable the transfer of qubits between distant nodes using quantum teleportation, which reproduces a qubit state at a remote location by consuming a shared Bell pair. After teleportation, qubits are stored in quantum memories, where decoherence progressively degrades their quantum states. This degradation is quantified by the fidelity, defined as the overlap between the stored quantum state and the ideal target state. Some quantum applications (QApps) require the teleportation of multiple qubits and can only operate if all teleported qubits simultaneously maintain a fidelity above a given threshold. In this paper, we study how many qubits can be teleported under such fidelity-constrained operation in a two-node QN. To that end, we define a QApp-level reliability metric as the probability that all end-to-end Bell pairs satisfy the target fidelity upon completion of the multi-qubit teleportation stage. We design a Monte Carlo-based simulator that captures stochastic Bell-pair generation, Quantum Repeater (QR)-assisted entanglement distribution, and fidelity degradation. Fiber-based and terrestrial free-space optical (FSO) quantum links and representative NV-center- and trapped-ion-based quantum memories are considered. Results show that memory coherence is the main scalability bottleneck under stringent fidelity targets, while parallel entanglement generation is essential for multi-qubit teleportation.
An Efficient Progressive Swapping to the Middle Distribution Protocol Adapted to Imperfect Quantum Memories in Quantum Networks
Claire Mesny (Orange Labs, France & INSA Lyon, France); Fabrice M. Guillemin (Orange Labs, France); Claire Goursaud (INSA-Lyon, France)
The distribution of entangled pairs of photons on the links composing a quantum network, combined with Bell state measurements and teleportation, is the basic apparatus to transfer quantum bits (qubits) over long distances. Entanglement distribution establishes an end-to-end entangled pair while consuming intermediate pairs on links and holding them for a certain time period. The technical literature identifies two main kinds of protocols, parallel and sequential ones, the latter having an advantage in resource consumption over the former. In this paper, we introduce an efficient swapping protocol called Progressive Swapping to the Middle (PSM) as it combines the existing Progressive Swapping (PS) protocol from both extremities of a path that meet in the middle where the received pairs are swapped. We compare PSM with two parallel protocols and PS; in our evaluation, we take into account imperfect memories and fidelity degradation. We demonstrate that PSM yields a much better link probability than PS while keeping a reasonable link fidelity, and shows an advantage in resource consumption over other protocols.
A Post-Quantum Cryptographic Framework for High-Level Security Protocols in 6G
Pasindu Udugahapattuwa (University College Dublin, Ireland & General Sir John Kotelawala Defence University, Sri Lanka); Chamitha De Alwis (University of Bedfordshire, United Kingdom (Great Britain)); Engin Zeydan (CTTC, Spain); Uditha L. Wijewardhana (University of Sri Jayewardenepura & Faculty of Engineering, Sri Lanka); Madhusanka Liyanage (University College Dublin, Ireland)
Sixth-generation (6G) networks will underpin highly critical, latency-sensitive, and massive-scale services, making them a prime target for emerging quantum-capable adversaries. Existing high-level security protocols, including authentication, key exchange, and end-to-end protection mechanisms, are not yet systematically engineered for post-quantum cryptography (PQC) and must be redesigned to remain secure in the quantum era. This paper proposes a conceptual post-quantum cryptographic framework for high-level security protocols in 6G networks, such as TLS 1.3, IKEV2, SSH, MQTT, CoAP, and so on. The framework integrates security-by-design principles, hybrid classical-post-quantum migration strategies, and optimization techniques tailored to resource-constrained devices and heterogeneous 6G environments. A conceptual security analysis is conducted to assess the impact of embedding PQC algorithms into protocol flows, revealing new risks related to hybrid protocol complexity, side-channel exposure, and implementation-induced vulnerabilities. To enable rigorous evaluation and comparison of candidate designs, the paper defines a set of key performance and security metrics, including handshake latency, computational and memory overhead, energy consumption, interoperability with legacy systems, and robustness against quantum and classical attacks. The work outlines practical migration pathways and Key Performance Indicators (KPIs) to guide standardization efforts and deployment decisions. By providing an integrated requirements analysis and design framework, this study advances quantum-safe 6G infrastructures and strengthens the resilience and competitiveness of future networked systems. Finally, it should be aligned with the architectural impacts, KPIs, further testing, and evaluation in the development of this framework for the future. Then it will be ensured that its scalability, reliability, and long-term efficacy.
