The United Kingdom’s National Cyber Security Centre is now directing a timeline for organizations to adopt post-quantum cryptography, moving beyond warnings about the future threat of quantum computers. This guidance is for large organizations, operators of critical national infrastructure systems, and companies with bespoke IT, recognizing their complex cryptographic needs. The NCSC outlines a migration process beginning with an assessment of cryptographic dependencies, emphasizing detailed planning before technical implementation. These key target dates are intended to guide investment decisions and broader cyber security planning as the nation prepares for a mass technology change.
NCSC Timelines for Post-Quantum Cryptography Migration
The National Cyber Security Centre anticipates most organizations will complete migration to post-quantum cryptography by 2035, establishing a firm end-date for a widespread technological shift and signaling a move beyond simply warning about the quantum threat. This target date, detailed in recently released guidance, assumes a decade is sufficient for the development of robust post-quantum standards and the creation of a supporting product ecosystem, allowing for the eventual phasing out of vulnerable traditional public key cryptography. Understanding the full scope of an organization’s cryptographic footprint is the first step to effectively plan and execute a transition to post-quantum algorithms.
The NCSC recognizes that legacy protocols within industrial control systems present a particular challenge, often lacking modern cryptographic standards, and that their replacement will require architectural evolution alongside algorithm updates to support modern key management solutions. Initial migration plans, therefore, should incorporate flexibility to adapt to evolving developments within the broader PQC ecosystem.
The NCSC is also preparing to launch a pilot scheme to assure consultancy companies offering support for the discovery, assessment, and planning activities related to PQC migration, ensuring that skilled expertise is readily available within the United Kingdom. This initiative aims to address a potential skills gap and facilitate organizations’ access to the necessary support for managing the complexities of the migration process.
This targeted approach reflects the understanding that these entities face the most complex cryptographic needs and the highest risk profiles, requiring tailored guidance and prioritization. The agency’s focus on these specific sectors differentiates this guidance from broader cybersecurity recommendations, acknowledging the unique challenges faced by organizations with sophisticated IT environments.
The NCSC’s guidance builds upon a white paper published in November 2023, with subsequent updates in August 2024 to reflect the publication of three algorithm standards by the National Institute of Standards and Technology. The 2023 paper signaled that organizations should be beginning or continuing their preparation for PQC migration as part of a broader uplift in cyber security as systems are replaced.
The agency cautions against organizations attempting to develop their own implementations of post-quantum cryptography, instead recommending reliance on certified implementations and trusted libraries incorporating PQC into protocols. “Other than a very small number of companies who hire cryptography specialists, your plan should not involve you (nor most of your suppliers) producing your own implementations of post-quantum cryptography,” the NCSC advises.
The agency encourages organizations to develop a statement of intent outlining their recognition of the quantum threat, proposed responses, level of ambition, timelines, and desired end-state, to help suppliers understand the demand for PQC migration and accelerate the availability of post-quantum secure products. This proactive approach aims to stimulate the market and ensure that organizations have access to the tools and technologies needed to successfully complete the migration process.
The NCSC believes that a proactive approach to PQC migration is a matter of cyber security and a critical component of building broader cyber resilience into systems. “The activities described in planning your migration are substantial, and are critical to reducing cyber risks,” the NCSC asserts.
The NCSC’s commitment to establishing clear timelines and providing targeted guidance represents a step towards proactively addressing the long-term threat posed by quantum computers to current cryptographic systems, and will shape the direction of cyber security practices for years to come. The agency’s pilot scheme for assuring consultancy companies, coupled with its emphasis on a comprehensive discovery exercise, highlights the importance of preparation and expertise in navigating this complex technological transition.
NIST Standards and the 2023/2024 NCSC Guidance
The NCSC recognizes that migrating to post-quantum cryptography is not simply a matter of swapping algorithms, but requires a broader assessment of existing systems and protocols. The agency’s guidance, building on a 2023 white paper with updates in August 2024 reflecting NIST’s algorithm publications, emphasizes that organizations should be actively preparing for PQC migration now. This preparation, however, is most effective when integrated with routine system replacements and upgrades, minimizing disruption and maximizing efficiency. This initial phase is critical for understanding the scope of the undertaking and identifying potential challenges.
PQC Migration Timelines for Critical National Infrastructure
The NCSC specifically calls for organizations to simultaneously communicate their cryptographic needs to suppliers during this initial phase, acknowledging the interconnectedness of the migration process and the need for collaborative planning. Identifying dependencies on suppliers and physical infrastructure is a key element of the initial assessment, and the NCSC emphasizes its importance for accurate planning and resource allocation.
The agency also highlights the importance of evaluating any investment needed to implement PQC, including addressing long-lived hardware roots of trust that may require replacement or upgrade. The NCSC’s long-term target for full migration to PQC is 2035, a date intended to allow sufficient time for the maturation of PQC standards and the development of trusted implementations.
However, the agency acknowledges that migration will be an iterative process, involving multiple deployment and testing cycles, and that plans must account for this reality. The availability of services protecting confidentiality of key assets will precede the wider adoption of PQC in areas like certificate-based Public Key Infrastructure (PKI), as well as IoT and industrial control systems protocols. As suppliers refine their own plans, organizations are expected to adapt their strategies accordingly, and as the broader PQC ecosystem matures, greater precision can be added to later stages of migration.
The agency stresses that thorough testing and validation must be embedded throughout the migration process, mirroring best practices for any major IT or operational technology upgrade. This emphasis on rigorous testing reflects the understanding that PQC implementation is a fundamental shift in cryptographic infrastructure, not a simple algorithm swap.
The guidance advises organizations to prioritize systems processing business and personally sensitive data, or those managing critical communications and systems, ensuring that the most valuable assets are protected first. The NCSC’s approach is not solely focused on technical implementation. It also prioritizes supporting regulated sectors, central government, and ensuring the UK has access to the necessary skills to enable future migration. This coordinated effort recognizes that successful PQC adoption requires collaboration across government, industry and academia.
The agency anticipates that the total financial cost of PQC migration could be significant, and therefore emphasizes the importance of organizations budgeting accordingly, including for preparatory activities as well as the actual migration itself. “Although the core timelines are relevant to all organisations,” the NCSC states, the guidance is “primarily aimed at technical decision-makers and risk owners of large organizations, operators of critical national infrastructure (CNI) systems including industrial control systems (ICS), and companies that have bespoke IT.” The agency’s timeline is designed to be flexible, acknowledging that a tail of technologies may require longer to migrate, but expects all organizations to focus on the 2035 target. This long-term vision allows for the evolution of the PQC landscape and the emergence of robust standards, while still providing a clear deadline for action.
The NCSC’s guidance is intended to provide a roadmap for organizations navigating this complex transition, ensuring that the UK remains resilient in the face of the evolving quantum threat. The agency’s commitment to supporting industry and government emphasises the importance of a collaborative approach to PQC migration, recognizing that a collective effort is essential to safeguarding critical infrastructure and data in the quantum era.
Sector-Specific Approaches to PQC Migration Readiness
Organizations should now be actively preparing for migration as part of broader cybersecurity improvements, particularly as systems undergo scheduled replacement cycles, according to guidance released by the agency. This approach acknowledges that a full shift to PQC is not a singular event, but rather an extended period of co-existence between traditional public key cryptography and post-quantum algorithms. Migration plans must account for the complexities of maintaining interoperability during this transition, as the introduction of PQC necessitates compatibility-breaking changes to encryption methods.
The NCSC suggests that organizations may need to support both traditional and PQC algorithms concurrently, allowing for a phased rollout and minimizing disruption to existing services. This is particularly relevant for enterprise Public Key Infrastructure, or PKI, where establishing a new PQC root-of-trust and issuing updated certificates to all network entities will be a significant undertaking, potentially requiring physical access to some devices for certificate updates.
The agency outlines options such as cross-signing old and new roots to maintain backwards compatibility, but stresses the need to assess the security implications of each approach. The agency’s guidance details that a system will not achieve quantum-secure authentication until the PKI migration is complete and traditional certificates are either expired or revoked. Successful migration relies on the availability of robust, standards-compliant implementations of PQC algorithms and protocols, and organizations should factor this into their timelines.
The NCSC expects confidentiality-protecting services to be available sooner than certificate-based PKI and protocols used in Industrial Control Systems and the Internet of Things, indicating a tiered rollout based on technological maturity and risk profiles. “It will take a number of years for all protocols and global cryptographic infrastructure to be fully PQC-ready, and for there to be trusted implementations of everything you will need,” the agency states.
Organizations should anticipate iterative deployment and testing cycles, refining their plans as suppliers evolve their own strategies and the broader PQC ecosystem matures. The availability of commercial PQC infrastructure will allow for greater precision in the later stages of migration, but the initial focus should be on identifying priority services, those processing the most valuable or long-lived data, and dependencies on long-lived hardware. A thorough assessment of supply chains and service providers is also important, alongside the identification of risks associated with legacy systems.
“There will be a small set of more rarely used technologies for which migration by 2035 may be more difficult,” the NCSC notes, suggesting that long-term planning must consider the potential for persistent vulnerabilities. As with any major IT migration, a robust testing framework is essential to ensure the security and reliability of PQC deployments.
The NCSC’s approach is not simply about replacing algorithms. It’s about building a resilient cryptographic infrastructure that can withstand the evolving threat landscape. The agency’s guidance acknowledges that migration activities are substantial and critical to reducing cyber risks, and that organizations should begin or continue their preparation now.
The agency’s blog post from March 2025, setting direction for the UK’s migration to PQC, highlights the importance of integrating PQC migration into broader cyber security practices. A later post from July 2026, detailing guidance on responding to and recovering from cyberattacks, emphasises the need for a comprehensive approach to cyber resilience.
See today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals.
