The advent of quantum computing poses a significant threat to classical cryptographic systems, necessitating the development of quantum-resistant alternatives. This thesis explores a hybrid key exchange framework combining Quantum Key Distribution (QKD) with Post-Quantum Cryptography (PQC) to secure classical post-processing steps such as information reconciliation and privacy amplification. Specifically, CRYSTALS-Kyber is used for key encapsulation, while CRYSTALS-Dilithium and SPHINCS+ provide digital signatures for authentication. While the mathematical security foundations of these algorithms are assumed, their integration is evaluated through performance benchmarking and system-level analysis. The results show that incorporating PQC-based authentication into QKD post-processing significantly improves resilience against quantum adversaries, while introducing only a reasonable computational and bandwidth overhead. This work contributes to the development of robust hybrid cryptographic systems capable of with standing both classical and quantum-era threats.
The advent of quantum computing poses a significant threat to classical cryptographic systems, necessitating the development of quantum-resistant alternatives. This thesis explores a hybrid key exchange framework combining Quantum Key Distribution (QKD) with Post-Quantum Cryptography (PQC) to secure classical post-processing steps such as information reconciliation and privacy amplification. Specifically, CRYSTALS-Kyber is used for key encapsulation, while CRYSTALS-Dilithium and SPHINCS+ provide digital signatures for authentication. While the mathematical security foundations of these algorithms are assumed, their integration is evaluated through performance benchmarking and system-level analysis. The results show that incorporating PQC-based authentication into QKD post-processing significantly improves resilience against quantum adversaries, while introducing only a reasonable computational and bandwidth overhead. This work contributes to the development of robust hybrid cryptographic systems capable of with standing both classical and quantum-era threats.
As the advent of quantum computing threatens traditional cryptographic protocols, hybrid classical-quantum secure communication infrastructures have emerged as a critical frontier in cybersecurity. This paper explores the integration of post-quantum cryptographic algorithms—specifically CRYSTALS-Kyber for key encapsulation and CRYSTALS-Dilithium for digital signatures—into hybrid communication architectures designed to resist quantum-level attacks. Leveraging lattice-based cryptographic primitives, both algorithms have been selected for standardization by NIST due to their robust security and performance characteristics. This study evaluates their implementation in real-world communication stacks, assesses latency and throughput under hybrid channel configurations, and proposes a layered security architecture combining classical and quantum-resilient mechanisms. Furthermore, it examines key management, digital trust, and infrastructure scalability in a post-quantum context. Simulation results and hardware-based validations are used to determine practical deployment feasibility in critical sectors such as finance, defense, and healthcare. The findings offer a comprehensive framework for securing data in transitional computing eras, ensuring forward secrecy, and maintaining operational integrity against future adversarial quantum threats.
This research aims to establish a secure system for key exchange by using post-quantum cryptography (PQC) schemes in the classic channel of quantum key distribution (QKD). Modern cryptography faces significant threats from quantum computers, which can solve classical problems rapidly. PQC schemes address critical security challenges in QKD, particularly in authentication and encryption, to ensure the reliable communication across quantum and classical channels. The other objective of this study is to balance security and communication speed among various PQC algorithms in different security levels, specifically CRYSTALS-Kyber, CRYSTALS-Dilithium, and Falcon, which are finalists in the National Institute of Standards and Technology (NIST) Post-Quantum Cryptography Standardization project. The quantum channel of QKD is simulated with Qiskit, which is a comprehensive and well-supported tool in the field of quantum computing. By providing a detailed analysis of the performance of these three algorithms with Rivest–Shamir–Adleman (RSA), the results will guide companies and organizations in selecting an optimal combination for their QKD systems to achieve a reliable balance between efficiency and security. Our findings demonstrate that the implemented PQC schemes effectively address security challenges posed by quantum computers, while keeping the the performance similar to RSA.
The Hybrid approach in Quantum Cryptography creates adaptable security model which provides the safest Communication in the emerging quantum era. The development of quantum computing raise questions about the long-term security. Traditional algorithms, such as RSA, ECC, and Diffie-Hellman, which is seemed computationally secure but it can be effectively solved by quantum algorithms such as Shor's and Grover's. This problem leads to the origination of two key trends in current studies, namely Post-Quantum Cryptography (PQC), designing mathematical approaches to encryption resistant to quantum attacks; Quantum Key Distribution (QKD) using the principles of quantum mechanics to assure security in communications. Accordingly, this research proposes a hybrid security framework including reliable data encryption and authentication using PQC, combined with the safe key- exchange method of QKD. The model is implemented in Python, Qiskit, and PQClean's Kyber and Dilithium algorithms to show how these two paradigms can cooperate toward quantum- resilient communication. To present the system performance, key exchange efficiency, computational overhead, and security strength have been considered. According to the results, this hybrid approach gives superior defense against quantum threats while maintaining practical effectiveness for real-world applications such as cloud security, 6G networks, and the Internet of Things.
The emergence of quantum computers poses a significant threat to classical cryptographic systems. Post-quantum cryptography (PQC) aims to develop cryptographic protocols resistant to quantum attacks. This study explores the enhancement of post-quantum cryptographic protocols by integrating quantum-resistant key exchange mechanisms. We propose the Quantum-Lattice Resilient Exchange Framework (Q-LREF), utilizing lattice dimensions 256, 512, and 1024) with Gaussian noise distribution 3.2. Through experimental evaluation, we demonstrate that our approach outperforms traditional RSA and ECC schemes while achieving comparable efficiency to CRYSTALS-Kyber with robust security margins. By reviewing existing literature, implementing our novel framework, and analyzing results, we demonstrate the efficacy of our approach against both classical and quantum adversaries. We also provide a comprehensive analysis of potential challenges and future directions in PQC, including detailed examination of various quantum-resistant algorithms and their applications.
Large quantum computers will be able to break the cryptographic algorithms on which current secure communications rely on. Post-Quantum Cryptography (PQC) and Quantum key distribution (QKD) are two security technologies that show protection capabilities against the latent quantum threat. While PQC relies on different hard mathematical problems to develop a wide variety of cryptographic operations, QKD is based on quantum physics laws to generate and distribute symmetric cryptographic keys through different QKD protocols. These keys can be used by different applications to perform security transformations. QKD still requires authentication to prevent man-in-the-middle attacks. The hybridization of PQC and QKD is an important step for future secure infrastructures, being able to provide long-term security. In this work we propose authenticated QKD approaches that rely on pre-shared keys and hybrid PQC/QKD alternatives and which are able to securely exchange secret QKD keys through authenticated channels. We identify the different configuration alternatives and their parameters, as well as we develop a wide performance evaluation. Results show that pre-shared keys and PQC-based authentication through Dilithium algorithm are the fastest alternatives. Also, we show the potential of the T12 QKD protocol.
The advent of quantum computing poses significant challenges to traditional cryptographic systems, threatening the confidentiality, integrity and authenticity of digital communications. This thesis investigates the integration of Post-Quantum Cryptography (PQC) algorithms into mobile communication systems to address these challenges. The study focuses on evaluating key PQC algorithms shortlisted by the National Institute of Standards and Technology (NIST), including CRYSTALS-Kyber, CRYSTALS-Dilithium, Falcon and SPHINCS+, within the context of 5G and future mobile network architectures. The research encompasses the design and implementation of an experimental framework involving mobile devices, servers, and cloud-based infrastructure to simulate real-world communication scenarios. Performance metrics such as key generation time, signature generation, encryption and decryption speed, and resource consumption were analysed across various devices to identify algorithms suitable for mobile environments. The findings reveal that lattice-based algorithms, such as Kyber and Dilithium, offer a promising balance between security and efficiency, making them ideal for resourceconstrained devices. In contrast, hash-based algorithms like SPHINCS+ exhibit higher computational demands, limiting their practicality in certain applications. This work highlights the importance of algorithm selection and hardware optimization in ensuring secure and efficient communications in the quantum era. xi By integrating theoretical advancements in PQC with practical applications, this research lays the foundation for quantum-resistant security in mobile networks, ensuring secure and futureready digital communications.