The emergence of quantum computing threatens classical cryptographic systems, motivating the development of cryptographic solutions based on Post-Quantum Cryptography (PQC) and Quantum Key Distribution (QKD). This paper surveys hybrid key-establishment techniques combining PQC and QKD, including XOR/concatenation, KEM combiners, split usage, and cascade approaches, and evaluates their applicability to protocols such as TLS and IPsec. It further compares positions of major standardization bodies (ANSSI, BSI, NCSC, NIST, ETSI) and identifies key challenges in standardization, performance, scalability, and complexity. While not a universal solution, hybridization remains relevant for high-assurance environments.
The emergence of quantum computing threatens classical cryptographic systems, motivating the development of cryptographic solutions based on Post-Quantum Cryptography (PQC) and Quantum Key Distribution (QKD). This paper surveys hybrid key-establishment techniques combining PQC and QKD, including XOR/concatenation, KEM combiners, split usage, and cascade approaches, and evaluates their applicability to protocols such as TLS and IPsec. It further compares positions of major standardization bodies (ANSSI, BSI, NCSC, NIST, ETSI) and identifies key challenges in standardization, performance, scalability, and complexity. While not a universal solution, hybridization remains relevant for high-assurance environments.
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.
As quantum computing advances toward practical use, classical cryptography is at a serious risk of being compromised, especially with the use of quantum algorithms like the Shor algorithm, which can break RSA in polynomial time, as well as Elliptic Curve Cryptography (ECC). This research paper highlights the urgent need to protect electronic communications against quantum attacks by leveraging two novel approaches: Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC). The study aims to evaluate the effectiveness, scalability, and integration possibility of these technologies separately and in mixed combinations, to achieve long-term resilient cybersecurity. This research is a mixed-methods study that combines literature analysis, expert surveys, and performance benchmarking to determine the strength of encryption, compatibility with the network, and feasibility in the real world. First-hand information was gathered through structured surveys among cybersecurity professionals and scholars. In contrast, second-hand information was retrieved from peer-reviewed journals and official standards of institutions, such as NIST. It has been found that QKD offers unparalleled information-theoretic security, founded on quantum mechanics, yet has limitations in terms of scale and cost. PQC algorithms, however, especially lattice-based cryptography, are simpler to integrate into a classical infrastructure but present a performance issue on hardware with limited capabilities. Based on the study, a hybridized cryptographic model appears to be the best solution to the current approach of implementing the secure key exchange properties of QKD and the universal properties of PQC, without compromising either.
Quantum computing is posing a serious risk to classical cryptographic tools such as RSA and ECC as sophisticated quantum algorithms are able to crack their mathematical foundation in a time bound that is a a polynomial in the number of repetitions. In this paper, we will describe the process of integrating Post-Quantum Cryptography (PQC) and Quantum Key Distribution (QKD) into a hybrid approach to secure communications in the post-quantum world. The suggested methodology is a combination of the computational efficiency and scalability of PQC and the information-theoretic security and eavesdropping detection abilities of QKD. Simulation observations indicate that PQC-only systems are both faster in generating keys and scalable, but do not have a strong eavesdropping detection. On the other hand, non-conditional security is only a feature of systems based on QKD, but it is also highly overhead and slows down key rate. The hybrid PQC-Q KD model provides a balanced performance, high resilience, high authentication, high confidentiality, and realistic deployability. On balance, this discussion demonstrates that the hybrid approach is better than standalone methods and can provide a strong solution to protect against new quantum threats. The large-scale network protocol can be optimized, resources and further integration with other emerging technologies, such as 5G/6G, IoT or cloud computing, can be directed in future research.
The accelerated advancements in quantum computing substantially threaten classical cryptographic systems, particularly those that rely on RSA, ECC, and other public key encryption methods. Particularly Shor's method shows how easily conventional cryptographic techniques might be broken; therefore quick development of quantum resistant substitutes is necessary. Rising as a potential answer with cryptographic algorithms meant to resist quantum attacks is post quantum cryptography (PQC). Nonetheless, performance trade-offs, compatibility problems, and the absence of standardized implementations make the shift to completely quantum-safe cryptographic systems very difficult. Hybrid PQC systems that combine conventional and quantum resistant cryptographic mechanisms have been suggested as a workable method for tackling these difficulties so guaranteeing security in the post quantum future. Emphasizing their security, performance, and practical implementations, this review article offers a thorough study of hybrid PQC methods. The resistance of many hybrid cryptographic models including lattice-based, code-based, and multivariate cryptographic techniques against quantum attacks is comprehensively investigated in this work methodologically, we review current PQC hybrid models, evaluate their computing efficiency, and examine security criteria grounded on recent research and standardizing initiatives like those under NIST. Our results show that hybrid PQC models create difficulties in terms of key management, computational overhead, and implementation complexity even if they improve security by reducing risks related with both conventional and quantum attacks. A comparative study shows among several hybrid systems the trade-offs in terms of encryption speed, key sizes, and resource use. Moreover showing the feasibility of PQC hybridizing in IoT, cloud computing, and block chain security are pragmatic uses of PQC hybridizing in which case appropriate protocols are needed for broad acceptance. At last, our work emphasizes the significant contribution hybrid PQC models provide in the transitional period producing a quantum secure environment. To enable basic integration into the present digital infrastructure, future research should focus on improving the efficiency of hybrid cryptosystems, optimizing key exchange mechanisms, and regulating standardization concerns. The findings of this study support the present discussion on post quantum security and provide data for academics and corporate leaders aiming for the next generation of cryptographic solutions. https://doi.org/10.5281/zenodo.17873992
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.
Quantum computing provides the pathway to dismantle the security provided by cryptography especially classical public-key systems due to the emergence of Shor’s algorithm. This emerging threat necessitates the development of new security paradigms that are quantum-resistant. Consequently, two new approaches have emerged as prominent solutions, namely Quantum Key Distribution (QKD), which relies on quantum mechanical principles for security, and Post-Quantum Cryptography (PQC), which relies on classical cryptography for quantum resistance. This paper presents an extensive analysis of the global research trends in quantum cryptography and post-quantum cryptographic algorithms by incorporating the use of both bibliometric analysis and comparative analysis. The paper relies on a dataset collected from the Web of Science database from 2010 to 2025. The findings of the paper demonstrate an increase in scientific production in the field of quantum cryptography, with post-quantum cryptography emerging as a new dominant area coinciding with standardization by NIST, whereas quantum key distribution continues to evolve with new developments in quantum communication.