Post-quantum cryptography: what comes next?
This month, a major milestone in post-quantum cryptography (PQC) has been reached: 3 algorithm standards (ML-KEM, ML-DSA, SLH-DSA) have been published by NIST, the US national standards organisation.
The NCSC have updated our PQC white paper to reflect this milestone. While the core technical messages of the paper remain unchanged, we know that many of you want to understand the next steps in the national migration to PQC.
What are the key early activities?
Standardisation of algorithms is just the start of the work for the international cryptography community as we move towards full migration to PQC. We need robust implementations of those algorithms, and we need the services and protocols that use current public-key algorithms to be modified to incorporate PQC. For example, there are broader international standards efforts on updating major internet protocols such as TLS.
This means that migration to PQC is a multi-year activity. For some sectors, we expect it to take more than a decade. However, the scale of the effort means that work to prepare is a priority now. Larger organisations (and those that have bespoke IT or operational technology) should be planning for a future migration to PQC. This ‘initial discovery’ work includes:
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ensuring the organisation has a clear view of the data it holds, the value that data has to the organisation (and its likely adversaries), and how long it expects particular data holdings to last
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building a record of what systems data is processed and stored on
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understanding how data is protected across those systems, focussing on where public key cryptography is used
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understanding how each organisation’s supply chain is approaching their own PQC migration
The highest priority systems for migration will be:
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systems that carry data that will be valuable for a long time
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systems where changes can only be made infrequently, perhaps because of a dependence on very long-lived (or hard-to-upgrade) hardware
What comes next?
There are a number of ways in which the NCSC will support the PQC migration planning process, and subsequently migration itself.
1. Support to regulation
Many larger organisations work within regulated sectors. The NCSC will support regulators in setting the right guidelines and policies for their sectors, and will consult with major industry bodies to understand their challenges, partnering with DSIT and other lead government departments as needed.
We know that some sectors (for example, finance and telecoms) have already put significant thought into what integrating PQC into their complex networks will mean. Where there is best practice that we can point others towards, we will highlight it, but we will also offer direct advice where there are hard problems unique to particular sectors.
2. Support to central government
Within government, the NCSC will primarily work with Cabinet Office and DSIT to determine policy for other departments’ migrations, and provide bespoke consultancy required (for example, where systems process data that’s related to national security).
We intend to work with one or two departments over the coming year to explore in more detail what building a ‘whole-department PQC migration plan’ will involve. If there are principles from this that have wider application, we will share them.
3. Helping all organisations get good advice.
There are already a number of specialist companies offering services related to post-quantum cryptography, and we want to see excellent consultancy offered in a wide range of areas, from deep expertise in post-quantum cryptography, to discovery activities and migration planning, through to large-scale system integration.
Longer term, we plan to be able to accredit suitable consultants and consultancies through our existing schemes. In the nearer term, we will be exploring efficient ways to connect organisations with the expertise they need, in a way that scales to a UK-wide migration.
Future publications
We are planning a few more pieces of guidance in the coming months. These will include a set of FAQs offering thoughts on some aspects of migration that may be more difficult. We’ll also expand on how the NCSC can help industry, including more details on assuring consultancies. Further into the future, we will update guidance on particular cryptographic technologies incorporating PQC as their implementation matures, and offer more regular reflections on the national migration as we learn from various sectors' experiences.
Jeremy B
Principal Technical Director for Crypt and High Threat Technologies, NCSC
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