PQC Tracker

NCSC Guidance: Post-Quantum Cryptography Migration

ActiveUKGuidance
Effective date
Aug 1, 2023
Published date
Aug 1, 2023

Summary

The UK National Cyber Security Centre (NCSC) provides guidance on migrating to post-quantum cryptography, urging UK organisations to begin planning immediately. The NCSC recommends following NIST-standardised PQC algorithms and adopting a hybrid approach during transition. Aligned with the UK Government Cyber Security Strategy 2022–2030, the guidance targets government departments, critical national infrastructure operators, and large enterprises.

PKI impact

Medium riskTLS/SSLCode SigningEmail/S-MIME

NCSC guidance targets UK government and critical national infrastructure operators whose certificate-dependent services face long-term quantum risk. Deadlines are advisory, but long PKI migration lead times — particularly Root CA re-keying — mean organizations that delay past 2025 will face compressed timelines.

Migration hints

  • Complete a cryptographic asset register covering all TLS/SSL certificates, code-signing certificates, and client authentication certificates used in CNI and government systems.
  • Adopt NCSC's recommended hybrid approach for TLS/SSL: deploy ML-KEM alongside ECDH key exchange to protect against both classical and quantum adversaries during transition.
  • When renewing CAs or procuring HSMs, require vendor roadmaps for ML-DSA (FIPS 204) and ML-KEM (FIPS 203) support in hardware before committing to a platform.
  • Use NCSC's Board Toolkit framing to communicate PKI migration cost and urgency to senior leadership for budget allocation.

Milestones (2)

DeadlineLabelTypeHardNotes
Dec 31, 2025Begin cryptographic inventory and PQC readiness assessmentInventoryNCSC urges organisations to complete cryptographic asset inventories and identify quantum-vulnerable systems. This is a recommendation, not a statutory deadline.
Dec 31, 2027Implement cryptographic agility in new and updated systemsCrypto AgilityNCSC recommends organisations embed cryptographic agility into procurement and development practices by 2027.

Algorithm references (3)

  • ML-KEMFIPS 203Recommended

    Replaces: RSA, ECDH

    NCSC recommends ML-KEM (FIPS 203) as the primary post-quantum key encapsulation mechanism for UK organisations.

  • ML-DSAFIPS 204Recommended

    Replaces: RSA, ECDSA

    NCSC recommends ML-DSA (FIPS 204) for post-quantum digital signatures in UK systems.

  • SLH-DSAFIPS 205Noted

    Replaces: RSA, ECDSA

    SLH-DSA (FIPS 205) noted as an alternative signature scheme with conservative security assumptions.

Changelog (2)

DateTypeDescription
Jul 1, 2025ClarificationNCSC updated PQC migration guidance to incorporate FIPS 206 (FN-DSA) and align with final NIST IR 8547 deprecation timelines, reinforcing the hybrid approach for UK government and CNI systems.
Aug 1, 2023NewNCSC published updated post-quantum cryptography migration guidance, recommending NIST FIPS 203/204/205 and hybrid approaches for UK organisations.

Issuer

National Cyber Security CentreNCSC

Type: GOVERNMENT

Region: UK

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