UK NCSC issues updated TLS guidance for post-quantum cryptography migration
The UK National Cyber Security Centre recommends migrating to TLS 1.3 with post-quantum configurations now, aligning with new IETF standards.
Key points
- The NCSC updated its TLS guidance to include post-quantum cryptography configurations for general and government OFFICIAL use.
- Organizations using TLS 1.2 or older must migrate to TLS 1.3, as earlier versions do not support post-quantum updates.
- The agency advises prioritizing this migration by 2031, suggesting organizations begin the process immediately.
The UK National Cyber Security Centre (NCSC) published updated guidance on configuring post-quantum cryptography (PQC) in TLS. This release follows the Internet Engineering Task Force (IETF) publication of RFC 10024, which defines post-quantum traditional hybrid key agreement mechanisms for TLS 1.3.
The new recommendations provide specific configurations for both hybrid post-quantum/traditional and pure post-quantum cipher choices. The NCSC states these settings are suitable for general use and for protecting government OFFICIAL information. Hybrid options are currently the most widely deployed in common libraries, but the agency also supports pure PQC configurations to prepare for a future where traditional cryptography may no longer be sufficient.
Context and Technical Background
Some procedural delays mean the final RFC for pure PQC options has not yet been published as a standard. However, the NCSC notes that stable pure PQC options already exist in several major libraries and are available for use. The agency emphasizes that TLS 1.3 is the only version that supports PQC; earlier versions will not be upgraded to include these capabilities.
Consequently, any organization currently using TLS 1.2 or older versions must move to TLS 1.3 as soon as possible. This migration is necessary not only for quantum resilience but also to access the broader set of security benefits offered by TLS 1.3. The NCSC plans to continue updating its technical guidance as PQC support is introduced into other protocols and product types.
In the coming months, the NCSC intends to update its IPsec guidance as those RFCs are finalized. The agency also plans to include post-quantum authentication recommendations for TLS in future updates. This guidance supports the NCSC’s published timelines, which recommend that high-priority migration activities be carried out by 2031.
Who Is Affected
For many organizations, protecting the confidentiality of data in transit falls into the high-priority category for migration. The NCSC argues that the availability of standardized post-quantum TLS configurations, combined with implementations in well-studied libraries, means organizations should aim to make this move now. The guidance includes recommended profiles for securely configuring TLS for the most common versions and scenarios.
The agency also provides additional guidance for managing older versions of TLS during the transition period. A recent PQC migration workshop report highlights that no organization can navigate this migration alone, offering key takeaways for those undertaking the process. The NCSC views the current moment as the appropriate time to begin migrating to post-quantum standards.
What should you do?
Organizations should review their current TLS configurations to determine if they are using TLS 1.2 or older versions. Those still on legacy versions should plan an immediate migration to TLS 1.3 to ensure compatibility with future post-quantum updates. Security teams should evaluate the hybrid and pure PQC cipher choices recommended by the NCSC to determine which fits their current library support and risk profile.
What to do and how to stay safe: NCSC
- Audit current TLS versions across all systems to identify any instances of TLS 1.2 or older that require immediate upgrade to TLS 1.3.
- Review the NCSC’s recommended TLS profiles to configure hybrid or pure post-quantum cipher suites suitable for your data classification.
- Monitor IETF and NCSC channels for the finalization of pure PQC RFCs and subsequent updates to IPsec and authentication guidance.
- Assess library compatibility to ensure your cryptographic implementations support the stable pure PQC options currently available.
Step-by-step guide: Mobile Device Security: How to Protect Data Beyond Passwords
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Does TLS 1.2 support post-quantum cryptography?
No, the NCSC states that TLS 1.3 is the only version that supports PQC, and earlier versions will not be upgraded.
When should organizations complete their migration to post-quantum TLS?
The NCSC recommends that high-priority migration activities, including protecting data in transit, be carried out by 2031, but advises starting now.
Are pure post-quantum options ready for use?
Yes, stable pure PQC options exist in major libraries and are available for use, even though the final RFC standard is still pending publication.
