Growing awareness of the impact of quantum threat on classical cryptography directly translates into a growing demand for accurate network simulation tools capable of estimating the integration effects of quantum-safe cryptography in current systems. In particular, the adoption of Post-Quantum Cryptography (PQC) has a direct impact on the performance of network endpoints and transmission overhead. This also affects the scalability of widely adopted security protocols such as TLS and SSH. In this paper, we present a throughput-oriented analytical model that provides a tight upper bound on the maximum sustainable rate of post-quantum secure connection establishment in TLS and SSH. This model takes into account both endpoint and network capacity constraints, decomposing the handshake process into dominant cryptographic operation time and network transmission time. Identifying the bottleneck allows us to derive the achievable throughput in terms of handshakes per second. The experimental results provided show the accuracy of the model against the data obtained from an experimental testbed using, among others, NIST standard primitives from FIPS 203, 204, and 205, including ML-KEM and ML-DSA. Finally, we integrate our model into a network environment and demonstrate how it can be leveraged to enable efficient resource allocation among multiple endpoints, optimizing PQC traffic in multiple-unicast scenarios.
Growing awareness of the impact of quantum threat on classical cryptography directly translates into a growing demand for accurate network simulation tools capable of estimating the integration effects of quantum-safe cryptography in current systems. In particular, the adoption of Post-Quantum Cryptography (PQC) has a direct impact on the performance of network endpoints and transmission overhead. This also affects the scalability of widely adopted security protocols such as TLS and SSH. In this paper, we present a throughput-oriented analytical model that provides a tight upper bound on the maximum sustainable rate of post-quantum secure connection establishment in TLS and SSH. This model takes into account both endpoint and network capacity constraints, decomposing the handshake process into dominant cryptographic operation time and network transmission time. Identifying the bottleneck allows us to derive the achievable throughput in terms of handshakes per second. The experimental results provided show the accuracy of the model against the data obtained from an experimental testbed using, among others, NIST standard primitives from FIPS 203, 204, and 205, including ML-KEM and ML-DSA. Finally, we integrate our model into a network environment and demonstrate how it can be leveraged to enable efficient resource allocation among multiple endpoints, optimizing PQC traffic in multiple-unicast scenarios.
The advances in quantum computing present a threat to public key primitives due to their ability to solve hard cryptographic problems in polynomial time. To address this threat to critical Internet security protocols like the Transfer Layer Security (TLS), and Secure Shell (SSH), the National Institute of Standards and Technology (NIST) is currently working on the new generation of quantum-resistant key encapsulation and authentication schemes. In this paper, we evaluate protocol handshake performance when both post-quantum key exchange and authentication are integrated into TLS and SSH. Our experiments consider realistic network conditions and reveal that the introduced handshake latency ranges between 1-300% for TLS and 0.5-50% for SSH depending on the post-quantum algorithms used. In addition, we examine how the initial TCP window size affects post-quantum TLS and SSH performance, and show that even a small size increase can reduce the observed post-quantum slowdown by 50%. Finally, we discuss alternatives that can encourage the early adoption of post-quantum cryptography with minimum protocol performance degradation.
We benchmark the TLS 1.3 handshake using post-quantum cryptographic algorithms, including both key encapsulation mechanisms and digital signature schemes, and compare them against traditional, non-quantum-safe counterparts. Our evaluation covers all FIPS-approved post-quantum standards (ML-KEM, ML-DSA, and SLH-DSA), as well as a selection of digital signature schemes from second-round candidates of the NIST PQC competition that are available in the liboqs library from the Open Quantum Safe project. To assess real-world performance, we simulate various network conditions (rate, delay, and losses) and analyze the impact of post-quantum cryptography on TLS connection latency.
The prospect of a cryptographically relevant quantum computer (CRQC) undermines the public-key primitives that secure virtually every layer of modern communication networks, from subscriber authentication in cellular cores to transport-layer key exchange. Adversaries already following a harvest-now, decrypt-later (HNDL) strategy make this threat actionable today for any traffic whose confidentiality must outlast a decade. Following NIST’s finalisation of the first post-quantum cryptography (PQC) standards, ML-KEM (FIPS 203), ML-DSA (FIPS 204), and SLH-DSA (FIPS 205) in August 2024, and the selection of HQC as a fourth key-encapsulation candidate in March 2025, research has shifted from algorithm design to network-level integration. This paper reports a PRISMA-2020-compliant systematic literature review of PQC migration in communication networks, structured around five research questions covering protocol and scenario coverage, quantitative performance impact, hybrid cryptography strategies, transition barriers, and open research gaps. Six databases (IEEE Xplore, Scopus, Web of Science, ACM Digital Library, SpringerLink, and MDPI) were searched (3229 records identified); after deduplication, title-keyword screening, full-text eligibility assessment, and a pre-specified quality appraisal (Q1–Q6, threshold ≥3/6) applied to 310 eligible studies, a final synthesis corpus of 141 studies (68 journal articles, 68 conference papers, 4 conference-derived book chapters, 1 workshop paper) was screened, quality-appraised, and synthesised narratively with supporting evidence tables. The review finds that transport-layer protocols (TLS 1.3, QUIC, DTLS 1.3) dominate the literature, that lattice-based ML-KEM/ML-DSA offer the most favourable latency–bandwidth–energy trade-off among standardised families, and that classical–PQC hybrid schemes are the de facto transition strategy across 5G/6G, IoT, VPN, and automotive scenarios, at the cost of 10–100× larger keys/signatures and 8–40% handshake latency overhead. Persistent barriers include constrained-device resource limits, immature hardware acceleration, incomplete IETF/3GPP standardisation, and public-key-infrastructure scaling. We propose a five-level PQC transition-readiness maturity model and identify large-scale field validation, PQC–QKD integration, and lightweight signature schemes as priority directions for future work.
Abstract—The advent of fault-tolerant Cryptanalytically Relevant Quantum Computers (CRQCs) presents an existential threat to modern information security. Shor's polynomial-time quantum algorithm renders widely deployed public-key cryptographic primitives—including RSA, Diffie-Hellman (DH), and Elliptic Curve Cryptography (ECDH/ECDSA)—completely vulnerable to private key derivation. Furthermore, 'Harvest Now, Decrypt Later' (HNDL) adversarial campaigns actively intercept and store encrypted enterprise telemetry today, anticipating future quantum decryption capabilities. In response, the National Institute of Standards and Technology (NIST) finalized its primary Post-Quantum Cryptography (PQC) standards in FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), and FIPS 205 (SLH-DSA). However, transitioning complex enterprise IT ecosystems to quantum-resistant primitives introduces severe architectural and computational disruptions: public key and signature sizes increase by several orders of magnitude, cryptographic handshake latencies escalate, network packets experience Maximum Transmission Unit (MTU) fragmentation, and legacy Hardware Security Modules (HSMs) lack microarchitectural support for lattice-based polynomial arithmetic. This paper provides an exhaustive, mathematically grounded technical survey and architectural roadmap for enterprise PQC migration. We formalize the Module Learning with Errors (M-LWE) and Module Short Integer Solution (M-SIS) hardness foundations, evaluate hybrid classical/post-quantum cryptographic transition models across standard transport protocols (TLS 1.3, IKEv2/IPsec, SSH), and formulate an enterprise Crypto-Agility Maturity Model. Furthermore, we construct an empirical enterprise testbed measuring throughput, connection establishment latency, memory footprints, and packet fragmentation across legacy and quantum-resistant suites. Our results show that while ML-KEM-768 achieves microsecond-level encapsulation, its 1,088-byte ciphertext expands TLS ClientHello payloads into multiple TCP segments under constrained networks. Finally, we establish open research directions in post-quantum identity federations, stateful hash signature tracking, and hardware-accelerated polynomial arithmetic. Index Terms—Post-Quantum Cryptography (PQC), FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), Crypto-Agility, TLS 1.3, Lattice-Based Cryptography, Harvest Now Decrypt Later, Hardware Security Modules (HSM), Enterprise Migration.
This thesis investigates the current state of Post-quantum cryptography (PQC) in the industry, with a particular focus on its practical deployment, integration challenges, and performance implications.The study combines a structured analysis of academic literature, standardization efforts, and industry guidance with an experimental evaluation of PQC integration in widely used security protocols. The analysis shows that, while significant progress has been made in the standardization of quantum-resistant algorithms such as ML-KEM, ML-DSA, and SLH-DSA, real-world adoption remains in an early and transitional phase. Organizations primarily focus on evaluation and pilot implementations, as deployment is constrained by interoperability issues, implementation maturity, and the complexity of migrating existing cryptographic infrastructures.To complement the conceptual analysis, experimental measurements were conducted for TLS, SSH, and IPsec to evaluate the performance impact of hybrid post-quantum cryptographic mechanisms. The results indicate that performance overhead is not uniform across components. In particular, post-quantum signature schemes introduce significant computational and network overhead, mainly due to increased key and certificate sizes. In contrast, hybrid key exchange mechanisms show only moderate performance impact across all evaluated protocols.The findings highlight that the primary challenge of PQC adoption lies not in algorithm design but in practical integration and large-scale migration. Hybrid cryptographic approaches emerge as the most viable strategy for enabling a gradual transition, balancing improved security against quantum threats with operational feasibility.Overall, this thesis demonstrates that PQC is transitioning from a theoretical research field to a practical engineering challenge, with significant implications for the future design of secure communication systems.
Quantum computing poses a critical threat to classical public-key cryptography, driving the adoption of post-quantum cryptography (PQC).While PQC performance has been extensively benchmarked in TLS, empirical studies on the Secure Shell (SSH) protocol remain limited.This paper evaluates the integration of PQC and hybrid (classical+PQC) mechanisms into SSH using an OQS-OpenSSH 8.9 prototype with liboqs support.We measured handshake latency, session size, and Secure Copy Protocol (SCP) transfer performance across standardized algorithms (CRYSTALS-Kyber, CRYSTALS Dilithium, Sphincs+), Falcon, and hybrid configurations.Experiments on heterogeneous legacy hardware under realistic LAN conditions were validated through Wireshark captures and protocol checklists.The results show that Falcon yields the smallest handshake sizes, Dilithium offers balanced and stable performance, Kyber scales predictably with NIST security levels, and Sphincs+ incurs significant overhead.Hybrid modes add limited cost while retaining classical trust anchors.These findings extend SSH PQC research beyond handshake analysis, offering deployment-oriented guidance for quantum-safe migration.