GCRI · Cybersecurity and Digital Resilience

Post quantum migration

A sufficiently powerful quantum computer would break the public-key cryptography that protects most internet traffic, digital signatures and identities today. Data captured now could be decrypted later. Standard post-quantum algorithms now exist, and migration will take many years across software, hardware, protocols and certificates. This page sets out why migration matters now, how it is planned and measured, and what evidence serves the organisations and agencies that must carry it out.

01Register

Post quantum migration on the record.

02The question

Post quantum migration: how the risk develops.

Cryptographic transition requirements. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mechanism

Quantum algorithms break public-key schemes

Shor's algorithm, run on a large fault-tolerant quantum computer, would break RSA and elliptic-curve cryptography. Symmetric encryption is less affected and can be strengthened with longer keys.

Mechanism

Harvest now, decrypt later

Adversaries can store encrypted data today and decrypt it once quantum capability exists. Data that must stay secret for many years is already at risk.

Mechanism

Cryptography is everywhere

Public-key cryptography is embedded in protocols, devices, smart cards, firmware and certificates. Organisations rarely have an inventory of where it is used.

Mechanism

Migration takes years

Replacing algorithms requires standards, product updates, testing, interoperability and replacing long-lived hardware. Agencies plan migration over a decade or more.

03Geography

Connected activity in Europe.

Night lights, population density, land cover and true-colour imagery over Europe, from NASA GIBS. Each layer carries its own date.

The interactive map needs JavaScript; the layer list and sources are below.

Layers 4

Connected activity, for this page

Latest available

NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth

Loading the latest NASA imagery.

Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.

Connected activity, framed on Europe.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.

Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · NASA HLS S30Sources and licences

  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). doi:10.7927/H49C6VHW. CC BY 4.0
  • MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
  • Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
  • © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
  • Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
  • Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
  • Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
  • Observed (EO): NASA HLS S30 (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
  • NASA GIBS: We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
  • Optional layers (5 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.

Layers and dates

  • Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
  • Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
  • Vegetation greenness (NDVI), rolling 8 days: MODIS Terra NDVI, NASA LANCE · 13 Oct 2026
  • True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
  • Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
  • Enhanced vegetation index, rolling 8 days: MODIS Terra EVI, NASA LANCE · 13 Oct 2026

04Across the domains

Post-quantum migration is due in every domain that keeps long-lived secrets.

Migration planning is designed for the Foresight Outlook series. NIST published FIPS 203, 204 and 205 in 2024; national agencies have set transition timelines, which organisations should check at source.

  • Cryptographic inventory lessons.
  • Migration project records.
05Monitor

Security posture and third parties.

The screen a team would use to follow this subject: its measures, states and decisions. Names are examples and values are illustrative.

Security posture and third parties

Post quantum migration · Enterprise network · Quarter 1

Two critical suppliers unassessedGCRI · Cybersecurity and Digital Resilience

CSF profile, current vs target

tier 1 to 4

Critical suppliers

Supplier ACloud hostingYesMedium
Supplier BPayroll SaaSNoUnknown
Supplier CManaged SOCYesLow
Supplier DIdentity providerNoUnknown

Critical vulnerabilities open

Security posture and third parties: the screen's structure, terms and states for Post quantum migration.Example names and illustrative values; a design, not a record or a live system.
06Indicators

What is measured, and how well.

Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.

IndicatorUnitCadenceSource typeLabel
Systems with cryptographic inventorypercent of critical systemsper assessmentCryptographic discovery and inventoryDECLARED
Connections using post-quantum or hybrid key exchangepercent of connectionsmonthlyNetwork measurementsOBSERVED
Products supporting standard post-quantum algorithmscountper assessmentVendor disclosuresDECLARED
Data with long confidentiality requirementscount of data classesper assessmentData classificationDECLARED
Migration milestones metpercent of planned milestonesannualMigration programme recordsREPORTED
Expert estimates of cryptographically relevant quantum computer timingprobability by periodannualExpert surveysESTIMATED
07Twin and cascade simulator

Model post quantum migration as a system. Run the cascade.

Assembled from the Nexus Standards area profile Cyber and digital resilience law alignment: the hazards it names, the systems and sectors that carry the loss, the controls that dampen it and the data that observe it. Choose the components, pick an initiating hazard and step through the cascade. The Map view places the run on an example geography with open data. Every coupling weight is a stated assumption you can change. A teaching model, not a forecast, an assessment or a certification. To model a place of your own choosing, open the full System Builder.

Hazards

  • Dam failure
  • Sea-ice loss
  • Coastal erosion (set off downstream)
  • River flood (set off downstream)
  • Flash flood (set off downstream)
  • Mass displacement (set off downstream)
  • Biodiversity loss (set off downstream)
  • Widespread power outage (set off downstream)
  • Water supply shortfall (set off downstream)
  • Arctic winter sea-ice collapse (set off downstream)
  • Polar vortex disruption (set off downstream)

Controls

  • NS-10 Policies and clauses (machine-readable obligations: definition, binding, evaluation and enforcement)
  • NS-11 Verification and monitoring (evidence, attestations, zero-trust conformance observation)
  • NS-9 Contextual UNIs (deployments, instances, programme instances)
  • NRS-X6 Cyber and digital security risk
  • NRS-H93 Hazard family: Identity, trust and cryptographic failure (NHS-1 cyber.identity)
  • NRS-K31 Domain pack profile: Cyber national resilience (DOMAIN-031)
  • NRS-H54 Hazard family: Signal and platform disruption (NHS-1 cyber.platform)
  • NRS-H86 Hazard family: Telecom and data-centre failure (NHS-1 infra.digital)
  • NRS-H94 Hazard family: Systemic cyber events (NHS-1 cyber.systemic-cyber)

Observation

  • NIST National Vulnerability Database APIs (listed for reference)
  • CISA Known Exploited Vulnerabilities catalogue (listed for reference)
  • EUR-Lex Cellar (EU legal acts and delegated acts) (listed for reference)
  • Cybersecurity Supply Chain Risk Management
  • Legal measures pillar of the Global Cybersecurity Index

Example geography

  • North America: 243 hexagonal cells
  • Night lights tonight, outages (VIIRS Day/Night Band), NASA GIBS
  • Surface water through cloud, 30 m (OPERA DSWx-S1 radar), NASA GIBS
  • Rain rate, last half hour (IMERG), NASA GIBS
  • Vegetation disturbance alerts, 30 m (OPERA DIST-ALERT), NASA GIBS
08Sources

Where the evidence comes from.

Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.

SourceWhat it givesLicence class
NIST FIPS 203, 204 and 205 and the NIST post-quantum projectStandard post-quantum algorithms and transition guidancePublic domain, US government
National cyber agency migration guidance, such as UK NCSC and German BSITimelines and practices for migrationPublic, terms per agency
IETF drafts and standards for post-quantum and hybrid protocolsProtocol integration of new algorithmsOpen, IETF Trust terms
Cloudflare Radar post-quantum adoption dataShare of web traffic using post-quantum key agreementPublic, terms per provider (to check)
Expert surveys on quantum threat timelinesDistribution of expert expectationsPublic reports, licence to check
09Methods and evidence

How post quantum migration is modelled, measured and tested.

The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.

System model

The couplings between the systems in post quantum migration: signs of influence, a reinforcing and a balancing loop, and cross-links where stress jumps.

++−+CyberCritical infrastructureCommunitiesEconomyR reinforcingB balancing
Causal loop diagram from the page's systems; signs show the direction of influence. Illustrative structure for a system dynamics or network model, not estimated couplings.
FAIR guiding principles · GO FAIR and FORCE11W3C PROV · World Wide Web ConsortiumGuidance on consistent treatment of uncertainties · IPCCCEOS Analysis Ready Data · Committee on Earth Observation Satellites
10Decisions

Who decides, and what the evidence serves.

Cybersecurity and Digital Resilience prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Who decidesThe questionEvidence this page serves
Organisations and their security teamsWhich systems to migrate first and whenInventories; prioritisation by data lifetime
National cyber agenciesWhat timelines and requirements to setReadiness reviews; adoption data
Vendors and standards bodiesHow to implement and test new algorithmsProtocol and product readiness

Outputs this topic produces

  • Cryptographic inventory methods
  • Migration prioritisation by data lifetime and system exposure
  • Readiness reviews for products and protocols
  • Evidence notes on migration timelines
11Core questions

What experts ask.

The timing of a cryptographically relevant quantum computer is uncertain, but the migration cannot wait for certainty. Data encrypted today could be recorded and decrypted later, a risk often called harvest now, decrypt later. Systems with long lifetimes, such as infrastructure controls, vehicles and identity documents, may still be in service when the threat arrives. Past cryptographic transitions have taken many years, which is why experts recommend starting now.

  • Where does an organisation use public-key cryptography, in which protocols, products and devices?
  • Which data must remain confidential long enough to be at risk from future decryption?
  • Which systems can be updated easily, and which will need replacement or special measures?
  • How can systems be designed for cryptographic agility, so that algorithms can be changed again in future?
12Mechanisms

Drivers and processes.

The transition is driven by a future threat, current standards and long system lifetimes.

Threat

Quantum attack

A large fault-tolerant quantum computer could break widely used public-key schemes. Symmetric encryption is less affected and can be strengthened with longer keys. See Quantum Technologies.

Standards

New algorithms

Post-quantum algorithms for key establishment and digital signatures have been standardised and are being built into protocols and products.

Systems

Inventory and agility

Organisations often do not know where cryptography is used. Hard-coded algorithms in devices and software make change slow.

The hardest part of the migration is usually not the mathematics but the inventory. Cryptography is embedded in protocols, libraries, hardware security modules, smart cards and devices, often without documentation. Organisations that treat the transition as an opportunity to build cryptographic agility, the ability to change algorithms without redesigning systems, will be better placed for future changes as well.

13Methods and data

How the evidence is built, and its limits.

  1. 01

    Cryptographic inventory

    Discovery of algorithms, keys and certificates in use. Automated tools help but miss embedded and legacy systems.

  2. 02

    Risk prioritisation

    Ranking systems by data sensitivity, lifetime and exposure. It depends on assumptions about when the threat arrives.

  3. 03

    Hybrid deployment

    Combining classical and post-quantum algorithms during transition, applying cybersecurity and cryptography. It adds overhead but guards against flaws in new schemes.

  4. 04

    Testing

    Performance and interoperability testing of new algorithms, which have larger keys or signatures and can affect constrained devices.

15Where this page's references

Where this page's references lead.

The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.

16Questions

Questions and answers.

What is post-quantum cryptography?
Cryptographic algorithms run on ordinary computers that are designed to resist attack by both classical and quantum computers, such as those standardised by NIST in FIPS 203, 204 and 205.
When will quantum computers break encryption?
No one knows. Expert estimates vary widely. Agencies recommend migrating now because migration takes years and data can be harvested today.
What is hybrid key exchange?
Combining a classical and a post-quantum algorithm so that a connection remains secure if either one holds, used during the transition.
When will quantum computers break current encryption?
No one knows. Expert estimates vary widely. The case for starting migration now rests on long transition times and the harvest now, decrypt later risk, not on a specific date.
Is quantum key distribution the answer?
Quantum key distribution is a different technology with specific uses and limits. Most national authorities recommend post-quantum algorithms as the primary migration path.
Does symmetric encryption need to change?
Less urgently. Symmetric algorithms are weakened but not broken by known quantum attacks, and longer keys restore their margin.
What should an organisation do first?
Build an inventory of where public-key cryptography is used, identify data and systems with long confidentiality needs or lifetimes, and ask suppliers about their post-quantum plans.
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