Quantum Key Distribution (QKD) promises information-theoretic security, yet integrating QKD into existing protocols like TLS remains challenging due to its fundamentally different operational model. In this paper, we propose a hybrid QKD-KEM protocol with two distinct integration approaches: a client-initiated flow compatible with both ETSI 004 and 014 specifications, and a server-initiated flow similar to existing work but limited to stateless ETSI 014 APIs. Unlike previous implementations, our work specifically addresses the integration of stateful QKD key exchange protocols (ETSI 004) which is essential for production QKD networks but has remained largely unexplored. By adapting OpenSSL’s provider infrastructure to accommodate QKD’s pre-distributed key model, we maintain compatibility with current TLS implementations while offering dual layers of security. Performance evaluations demonstrate the feasibility of our hybrid scheme with acceptable overhead, showing that robust security against quantum threats is achievable while addressing the unique requirements of different QKD API specifications.
Quantum Key Distribution (QKD) promises information-theoretic security, yet integrating QKD into existing protocols like TLS remains challenging due to its fundamentally different operational model. In this paper, we propose a hybrid QKD-KEM protocol with two distinct integration approaches: a client-initiated flow compatible with both ETSI 004 and 014 specifications, and a server-initiated flow similar to existing work but limited to stateless ETSI 014 APIs. Unlike previous implementations, our work specifically addresses the integration of stateful QKD key exchange protocols (ETSI 004) which is essential for production QKD networks but has remained largely unexplored. By adapting OpenSSL’s provider infrastructure to accommodate QKD’s pre-distributed key model, we maintain compatibility with current TLS implementations while offering dual layers of security. Performance evaluations demonstrate the feasibility of our hybrid scheme with acceptable overhead, showing that robust security against quantum threats is achievable while addressing the unique requirements of different QKD API specifications.
The emergence of large-scale quantum computers poses a significant threat to current cryptographic protocols, particularly Transport Layer Security (TLS), which relies on RSA and elliptic curve cryptography vulnerable to Shor's algorithm. This paper presents a hybrid framework for quantum-resistant TLS handshakes that integrates post-quantum cryptography (PQC), quantum key distribution (QKD) and classical cryptography to provide comprehensive protection against both classical and quantum attacks. The approach employs three QKD protocols; BB84, E91, and Measurement-Device-Independent QKD (MDI-QKD) alongside NIST-standardized PQC algorithms as well as alternative candidates such as HQC and BIKE. A key innovation is the QKD key management module, which addresses performance bottlenecks through periodic key generation and secure reuse within predefined retention periods, significantly reducing QKD overhead in TLS handshakes. The experimental implementation using the quantum network simulator evaluated 144 distinct cryptographic protocol combinations. Results demonstrate that ML-KEM combined with ML-DSA provides optimal PQC performance, while QKD protocol selection is distance-dependent: BB84 for short-range and MDI-QKD for long-distance communication. The framework includes various attack mitigation mechanisms and ensure security as long as at least one cryptographic method remains uncompromised. Consistent with current global quantum network usage, the proposed TLS approach is designed primarily for MAN and WAN environments rather than the Internet, providing a balanced solution that combines theoretical security guarantees with computational efficiency.
With the advent of quantum computing, classical cryptographic techniques—such as those underpinning Transport Layer Security (TLS)—are becoming increasingly vulnerable. Although post-quantum cryptographic algorithms are being developed, their long-term security remains uncertain. Quantum Key Distribution (QKD) offers a fundamentally different approach to key exchange and secure communication, as it bases security on the physics of quantum information rather than computational difficulty. This paper presents a practical simulation framework that integrates QKD-derived keys into the TLS protocol using the Pre-Shared Key (PSK) mode. The system employs a layered QKD architecture, implemented using QuNetSim, to generate and manage quantum keys, which are then distributed through a centralized Key Management Server (KMS). The proposed approach demonstrates how quantum-generated keys can be seamlessly integrated into the TLS protocol to enhance resilience against quantum attacks, providing a viable pathway toward post-quantum-secure communication.
Quantum-Safe Networks (QSNs) use quantum key distribution (QKD) to deliver keys generated using a Quantum Random Number Generator (QRNG) to consumers at scale. In practice, prevailing Quantum-Key-as-a-Service (QKaaS) offerings still assume that each consumer site deploys on-premise QKD hardware, creating cost and feasibility barriers that limit adoption. Although ETSI GS QKD 014 standardizes APIs for key retrieval between Secure Application Entities (SAEs) and Key Management Entities (KMEs), it does not address key delivery across untrusted classical networks to consumers without local QKD devices. We close this gap with a gateway architecture that transparently secures ETSI-compliant QKD APIs using Post-Quantum Cryptography (PQC)—applying PQC signatures and key-encapsulation mechanisms end-to-end—without requiring changes to existing devices or software. The design supports cryptographic agility, enabling runtime selection and rotation among standardized PQC schemes. Evaluations on both simulated QKD environments and production-grade hardware show minimal overhead (≈1.3×–1.5× versus baseline) and robust scaling across concurrent connections and multiple consumer sites, extending the reach of QSNs beyond premises equipped with QKD while preserving end-to-end quantum-safe guarantees. Overall, this paper equips practitioners with a systematized view of PQC–QKD integration in QSNs, with an actionable gateway blueprint for extending QSNs without the need for on-premise QKD deployments.
Post-quantum cryptography (PQC) and quantum key distribution (QKD) address the quantum threat from opposite directions: PQC replaces vulnerable public-key algorithms with schemes believed to resist quantum cryptanalysis, while QKD derives keys whose secrecy rests on physical assumptions rather than computational ones. Because each approach has a distinct failure mode, a growing body of work combines them so that a session key remains secure if either component holds. We first establish the deployed baseline, hybrid classical-plus-PQC key exchange, against which QKD-augmented designs must be judged. We then propose a taxonomy of hybrid PQC-QKD designs along eight dimensions (integration layer, combiner construction, authentication scope and source, QKD topology, trusted entities, key-delivery interface, classical component, and evidence type), and use it to compare published protocols, including Muckle and its successors, MACsec and TLS integrations, and IKEv2 mechanisms standardised in RFCs 8784, 9370, and 9867. We examine key-combiner constructions in light of the KEM-combiner literature and of NIST, ETSI, and ITU-T guidance, and map the security arguments for hybrid PQC-QKD protocols onto a common grid of security model, assumptions, permitted compromise, established guarantee, and limitations. We synthesise deployment evidence from metropolitan and national QKD networks, distinguishing the few testbeds that have run PQC in the key path from pure-QKD deployments, and summarise the standards and policy landscape, including the positions of national security agencies that recommend against relying on QKD alone. We close with open problems: authentication of the QKD classical channel, shared-infrastructure threat models, device certification versus formal proofs, formal verification of hybrid handshakes, and the lack of peer-reviewed deployment economics.
Quantum Cryptography or Quantum Key Distribution (QKD) solves the key distribution problem by allowing the exchange of a cryptographic key between two remote parties with absolute security, guaranteed by the laws of quantum physics.Extensive studies have been undertaken on QKD since it was noted that quantum computers could break public key cryptosystems based on number theory.Actually, the progress of research in this field allows the implementation of QKD outside of laboratories.Efforts are made to exploit this technology in the existing communication networks and to improve the performance and reliability of the implemented technologies.Some research is in progress for the integration of QKD with the protocols in different layers of OSI model.The examples of such research effort are the integration of QKD in point-to-point protocol (PPP) OSI layer 2 and the integration of QKD with IPSEC at OSI layer-3.All these works are moving towards the utilization of QKD technology for enhancing the security of modern computing applications on the internet.In this paper, we present a novel extension of the TLS protocol based on QKD.We introduce a scheme for integrating Quantum Cryptography in this protocol.Our approach improves the security of the process of authentication and data encryption.Also, we describe an example to illustrate the feasibility of our scheme's implementation.
The emergence of quantum computing poses a threat to classical cryptography algorithms, necessitating a shift to quantum secure cryptography. Hybrid protocols combining at least one classical and one quantum-resistant cryptographic algorithm are becoming the standard for securing communications. In this work, we present our novel solution for integrating three different cryptographic assumptions (two of them quantumresistant) into hybrid network security protocols, ensuring that three different cryptographic assumptions must be broken before the protocol becomes vulnerable. Our solution allows for a seamless integration of classical and post-quantum (PQ) cryptography, and quantum key distribution (QKD) into existing network security protocols (e.g., TLS, IPsec) without any major modifications to the protocols themselves. This crypto-agility ensures the mitigation of some of the most well known challenges of both PQ cryptography and QKD. Our findings demonstrate the feasibility of such triple-hybrid network security protocols, showing non-substantial decrease in performance and almost no added packet overhead compared to state of the art protocols. In exchange, we pave the way towards next generation networks where the potential of new quantum-resistant cryptographic schemes can be leveraged in a dynamic and agile fashion, thus fostering a new era of unbreakable communication systems.