The prospect of cryptographically relevant quantum computers threatens public-key primitives underpinning modern digital infrastructure, including RSA, Diffie-Hellman, and elliptic-curve cryptography. Post-quantum cryptography (PQC) responds with algorithms believed to be hard for both classical and quantum adversaries. In August 2024, the U.S. National Institute of Standards and Technology (NIST) finalised the first three PQC standards: FIPS 203 (ML-KEM, based on Kyber), FIPS 204 (ML-DSA, based on Dilithium), and FIPS 205 (SLH-DSA, based on SPHINCS+). This paper surveys the algorithmic families behind these standards, the harvest-now-decrypt-later threat model, hybrid migration strategies, performance trade-offs, and the engineering challenges of transitioning the global cryptographic stack. We examine deployment progress in TLS, SSH, X.509, and constrained devices, and outline open research questions on side-channel security, falcon-style signatures, and the long-term replacement schedule for classical asymmetric cryptography.
The prospect of cryptographically relevant quantum computers threatens public-key primitives underpinning modern digital infrastructure, including RSA, Diffie-Hellman, and elliptic-curve cryptography. Post-quantum cryptography (PQC) responds with algorithms believed to be hard for both classical and quantum adversaries. In August 2024, the U.S. National Institute of Standards and Technology (NIST) finalised the first three PQC standards: FIPS 203 (ML-KEM, based on Kyber), FIPS 204 (ML-DSA, based on Dilithium), and FIPS 205 (SLH-DSA, based on SPHINCS+). This paper surveys the algorithmic families behind these standards, the harvest-now-decrypt-later threat model, hybrid migration strategies, performance trade-offs, and the engineering challenges of transitioning the global cryptographic stack. We examine deployment progress in TLS, SSH, X.509, and constrained devices, and outline open research questions on side-channel security, falcon-style signatures, and the long-term replacement schedule for classical asymmetric cryptography.
Large-scale quantum computers threaten the public-key cryptography that protects enterprise data, communications, and digital identity. Shor's algorithm solves integer factorization and discrete logarithms in polynomial time, which would break RSA, Diffie-Hellman, and elliptic-curve schemes once a cryptographically relevant quantum computer exists. The danger is not only future. Adversaries can record encrypted traffic today and decrypt it later, a tactic known as harvest-now-decrypt-later. In August 2024 the U.S. National Institute of Standards and Technology published its first post-quantum standards: FIPS 203 (ML-KEM, derived from CRYSTALS-Kyber), FIPS 204 (ML-DSA, from CRYSTALS-Dilithium), and FIPS 205 (SLH-DSA, from SPHINCS+). This paper presents a practical migration framework for enterprises. It reviews the quantum threat and Mosca's inequality for timing the transition, summarizes the new standards with their key and signature sizes, and proposes a five-phase roadmap built on crypto-agility: discovery and inventory, risk prioritization, agility engineering, hybrid deployment, and validation. Performance trade-offs are analyzed using documented parameter sizes and illustrative TLS handshake figures. ML-KEM-768 carries a 1,184-byte public key against 64 bytes for an elliptic-curve key, while SPHINCS+ signatures can exceed 17 kilobytes. The work does not report a real deployment. It consolidates published parameters and field guidance into an actionable plan, and it highlights open challenges in certificate sizing, hardware support, and long-lived embedded systems.
Large-scale quantum computers threaten the public-key cryptography that protects enterprise data, communications, and digital identity. Shor's algorithm solves integer factorization and discrete logarithms in polynomial time, which would break RSA, Diffie-Hellman, and elliptic-curve schemes once a cryptographically relevant quantum computer exists. The danger is not only future. Adversaries can record encrypted traffic today and decrypt it later, a tactic known as harvest-now-decrypt-later. In August 2024 the U.S. National Institute of Standards and Technology published its first post-quantum standards: FIPS 203 (ML-KEM, derived from CRYSTALS-Kyber), FIPS 204 (ML-DSA, from CRYSTALS-Dilithium), and FIPS 205 (SLH-DSA, from SPHINCS+). This paper presents a practical migration framework for enterprises. It reviews the quantum threat and Mosca's inequality for timing the transition, summarizes the new standards with their key and signature sizes, and proposes a five-phase roadmap built on crypto-agility: discovery and inventory, risk prioritization, agility engineering, hybrid deployment, and validation. Performance trade-offs are analyzed using documented parameter sizes and illustrative TLS handshake figures. ML-KEM-768 carries a 1,184-byte public key against 64 bytes for an elliptic-curve key, while SPHINCS+ signatures can exceed 17 kilobytes. The work does not report a real deployment. It consolidates published parameters and field guidance into an actionable plan, and it highlights open challenges in certificate sizing, hardware support, and long-lived embedded systems.
The impressively fast development of quantum computing is a serious threat to classical public-key cryptography, and algorithms such as Shor's and Grover's will render RSA and elliptic curve systems essentially useless as soon as a cryptanalytically relevant quantum computer becomes available. Although it is still some way off before such machines are available, the harvest-now-encrypt-later threat highlights the need for proactive defense. In response, the National Institute of Standards and Technology (NIST) published the first post-quantum cryptography standards in 2024, including ML-KEM (Kyber) for key establishment, ML-DSA (Dilithium) for digital signatures and SLH-DSA (SPHINCS+) as a stateless hash-based alternative. This paper is a summary of the evolving post-quantum landscape, starting with the standards and their underlying security and then moving on to migration policies such as CNSA 2.0 and CISA, NSA and NIST guidance. It also looks at integration patterns for important protocols such as TLS, IPsec, SSH, and code signing. A performance, interoperability and overhead evaluation methodology is presented with results showing that hybrid deployment and crypto-agile architectures make PQC adoption a viable option. The paper concludes by providing a governance-oriented roadmap, where inventory, prioritization and pilot deployments are identified as near-term actions, with open questions remaining on performance optimization, implementation security and algorithm resilience over time.
This paper examines the technical, operational, and governance challenges of migrating modern enterprise and cloud architectures to post-quantum cryptography (PQC). Following the National Institute of Standards and Technology's (NIST) release of finalized standards—including FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), and FIPS 205 (SLH-DSA)—organizations face significant friction regarding key and signature size inflation, protocol interoperability, and legacy infrastructure constraints. By analyzing these barriers, the study outlines practical transition strategies, emphasizing automated cryptographic discovery, hybrid deployment architectures, crypto-agility, and a phased, risk-based rollout program.
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.
Quantum computing poses an existential threat to classical public-key cryptography, particularly RSA and elliptic-curve systems, which form the backbone of secure communication, authentication, and digital trust. Once scalable quantum computers emerge, algorithms such as Shor’s will be capable of breaking these schemes, jeopardizing confidentiality and integrity across the internet and enterprise systems. Post-quantum cryptography (PQC) offers a viable defense, providing quantum-resistant algorithms that can be implemented on today’s hardware and protocols. Recent standardization milestones—including NIST’s approval of ML-KEM (Kyber) for key establishment, ML-DSA (Dilithium) and SLH-DSA (SPHINCS+) for signatures, and the selection of HQC as a complementary KEM—mark a turning point for practical adoption. This paper surveys the quantum threat model, algorithm families, performance trade-offs, and integration patterns such as hybrid modes and crypto-agile architectures. It further outlines a phased migration roadmap for enterprises, emphasizing harvest-now-decrypt-later risks and compliance imperatives. By bridging technical, operational, and policy perspectives, the study provides actionable guidance to prepare organizations for a secure and quantum-resilient future.