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.
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.
The emergence of large-scale quantum computing presents an imminent threat to contemporary public-key cryptosystems, with quantum algorithms such as Shor’s algorithm capable of efficiently breaking RSA and elliptic curve cryptography (ECC). This vulnerability has catalyzed accelerated standardization efforts for post-quantum cryptography (PQC) by the U.S. National Institute of Standards and Technology (NIST) and global security stakeholders. While theoretical security analysis of these quantum-resistant algorithms has advanced considerably, comprehensive real-world performance benchmarks spanning diverse computing environments—from high-performance cloud infrastructure to severely resource-constrained IoT devices—remain insufficient for informed deployment planning. This paper presents the most extensive cross-platform empirical evaluation to date of NIST-selected PQC algorithms, including CRYSTALS-Kyber and NTRU for key encapsulation mechanisms (KEMs), alongside BIKE as a code-based alternative, and CRYSTALS-Dilithium and Falcon for digital signatures. Our systematic benchmarking framework measures computational latency, memory utilization, key sizes, and protocol overhead across multiple security levels (NIST Levels 1, 3, and 5) in three distinct hardware environments and various network conditions. Results demonstrate that contemporary server architectures can implement these algorithms with negligible performance impact (<5% additional latency), making immediate adoption feasible for cloud services. In contrast, resource-constrained devices experience more significant overhead, with computational demands varying by up to 12× between algorithms at equivalent security levels, highlighting the importance of algorithm selection for edge deployments. Beyond standalone algorithm performance, we analyze integration challenges within existing security protocols, revealing that naive implementation of PQC in TLS 1.3 can increase handshake size by up to 7× compared to classical approaches. To address this, we propose and evaluate three optimization strategies that reduce bandwidth requirements by 40–60% without compromising security guarantees. Our investigation further encompasses memory-constrained implementation techniques, side-channel resistance measures, and hybrid classical-quantum approaches for transitional deployments. Based on these comprehensive findings, we present a risk-based migration framework and algorithm selection guidelines tailored to specific use cases, including financial transactions, secure firmware updates, vehicle-to-infrastructure communications, and IoT fleet management. This practical roadmap enables organizations to strategically prioritize systems for quantum-resistant upgrades based on data sensitivity, resource constraints, and technical feasibility. Our results conclusively demonstrate that PQC is deployment-ready for most applications, provided that implementations are carefully optimized for the specific performance characteristics and security requirements of target environments. We also identify several remaining research challenges for the community, including further optimization for ultra-constrained devices, standardization of hybrid schemes, and hardware acceleration opportunities.
The migration of remote-access and industrial communication systems from classical public-key cryptography to post-quantum cryptography (PQC) requires careful evaluation at both the protocol and system levels. This paper presents PQC-E2E-CA, a system-level evaluation framework for reviewing post-quantum and hybrid cryptographic configurations in Secure Shell (SSH). The framework integrates OQS-enabled OpenSSH and OpenSSL with Linux netem network emulation, automated experiment execution, SCP integrity verification, and statistical post-processing. The evaluation separates key exchange behavior from host key authentication. Specifically, it measures ML-KEM and hybrid ML-KEM as SSH key exchange mechanisms, and ML-DSA as a host-key signature mechanism. Experiments are conducted under controlled RTT and packet-loss conditions using a gateway virtualised client-server testbed. The results show that ML-KEM and hybrid ML-KEM can be integrated into SSH without prohibitive application-level session setup overhead in the evaluated environment. Among the evaluated configurations, ML-KEM-768 demonstrates comparatively lower SSH session establishment latency at 50 ms RTT with 0% packet loss. ML-DSA-44 achieves the lowest host-key authentication latency under the same conditions and maintains relatively stable performance at 150 ms RTT with 5% packet loss. SCP throughput results for 100 MB and 200 MB transfers indicate that sustained transfer performance is mainly influenced by RTT and transport-layer dynamics using a single dominant key exchange configuration. These findings support migration toward standardized post-quantum mechanisms in SSH-based gateway and remote-access environments, provided that algorithm choice and system configuration are validated under representative workloads and network conditions.
As quantum computing advances, widely deployed public-key cryptosystems face a credible long-term risk, motivating a transition to post-quantum cryptography (PQC). Building on NIST’s standardization, this paper evaluates the practical performance of CRYSTALS-Kyber and CRYSTALS-Dilithium through both microbenchmarks and TLS 1.3 deployments, with the expectation that compute costs remain competitive while deployment overhead is dominated by larger handshake messages. At the algorithm level, we measure key generation, encapsulation/decapsulation, signing, and verification for reference and AVX2-optimized implementations using a consistent toolchain and runtime configuration, and compare them against classical baselines (RSA, ECDH, and ECDSA). Across tested parameter sets, AVX2 delivers multifold speedups and keeps operations in the sub-millisecond range, with Kyber and Dilithium execution times that are competitive with or better than security-aligned classical counterparts. At the protocol level, we integrate ML-KEM and ML-DSA into TLS 1.3 and extract handshake latency (ClientHello→ServerHello and ClientHello→END) and handshake message sizes from captured traces in a low-RTT setting. PQC handshakes incur only a modest latency increase at the 128-bit level relative to P-256, while at 192- and 256-bit security they complete substantially faster than P-384 and P-521 configurations. The main cost is bandwidth: server-to-client handshake traffic increases from a few kilobytes in classical TLS to roughly 8–15 kB under PQC. Overall, the results indicate that deployment challenges are driven less by computation than by larger handshake footprints, especially on bandwidth- or RTT-constrained links.
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.
The development of quantum computing technology is progressing very quickly, which poses a great threat to classical cryptographic algorithms like RSA and ECC, as they are based on mathematical problems that can be easily solved using quantum computing technology. To overcome the threat of quantum computing technology, the need for PQC algorithms like CRYSTALS Kyber, CRYSTALS Dilithium, Falcon, and SPHINCS+, which are standardized or recommended by NIST, has become essential in the era of cybersecurity. The feasibility of these algorithms in real time applications is the main focus of this thesis. A mixed approach is adopted for this purpose. Benchmark experiments were performed using the Open Quantum Safe library and PQC enabled OpenSSL for key generation, encryption, decryption, signature generation, signature verification, and TLS handshakes. Simulated environment and cloud environment were used for this purpose. Moreover, case studies were also conducted for cloud computing, financial sector, and IoT applications. Additionally, threat modeling is also performed for assessing the migration risks, i.e., “harvest now decrypt later.” The results indicate that the lattice-based methods, like Kyber and Dilithium, offer a robust trade off in terms of performance and security, albeit with increased key and signature sizes compared to classical methods. Hash based methods, like SPHINCS+, offer robust security, albeit with significant performance and size overheads, indicating that they are best used in specific circumstances. Hybrid approaches, using classical as well as quantum methods, were indicated as viable in the transition from classical to quantum methods, especially in circumstances that require backward compatibility. The paper concludes that NIST standardized PQC algorithms are technically viable for contemporary applications, especially in cloud computing and high-performance computing. However, for large-scale implementation, proper engineering and monitoring of developments in crypt analysis need to be performed. Future research should be directed towards implementation optimization, migration frameworks, and further studies in real-world implementations, especially for resource-constrained IoT and legacy system applications.
The advent of quantum computing has precipitated an estimated attack resistant cryptography system necessitating quantum attacks. The classical asymmetric algorithms, i.e., RSA and ECC are susceptible to Shor algorithm and a transition should be made to Post-Quantum Cryptography (PQC) anymore. The novelty of this work lies in providing a unified comparative framework that analyzes PQC families through security assumptions, concrete key/ciphertext sizes, and implementation complexity an aspect not addressed collectively in prior surveys. This survey gives a general picture of the status of the design process and general evaluation of PQC accounting its application within the paradigm of the diversified networks including the IoT and 5G/6G and in the cyber-physical environment. Furthermore, this review uniquely synthesizes practical hybrid‑deployment strategies, including protocol layering, coexistence models, and backward‑compatibility mechanisms, offering actionable guidance for real‑world migration. Additionally, the manuscript contributes a prioritized list of open problems across IoT, 5G/6G, blockchain, and cyber‑physical systems, highlighting domains facing the most urgent quantum‑resilience challenges. In this paper, the authors will evaluate the most popular PQC schemes, including schemes based on lattice, code, hash, and isogeny, depending on their performance, scalability, and interoperability (with reference to the recent research). It also examines the problems of integration as implemented with respect to the computational overhead, latency and adoption of hybrid with classical cryptography. This is expounded more to the standardization of PQC by NISTs and with a focus on such algorithms as CRYSTALS-Kyber and Dilithium. The findings suggest that, hybrid PQC protocols are able to control quantum resistance and actual performance in numerous infrastructures in computing systems.