Foresight Briefing · 005

Executive summary

• Quantum risk is often treated as distant “tech to monitor”. The harvest‑now, decrypt‑later (HNDL) model means the most consequential phase of the risk is already underway.
  

• New research from Google and others has cut estimated quantum resources for breaking mainstream encryption by around an order of magnitude, prompting major providers like Cloudflare to pull their post‑quantum migration timelines forward to 2029.
  

• At the same time, the World Economic Forum, the G7 financial roadmap and national cyber agencies are formalising expectations that boards treat quantum cryptography as a strategic and systemic risk, not just a technical one.
  

• For senior leaders, the key question is no longer “when will quantum computers break encryption?” but “what long‑lived data has already been harvested, and how will its eventual exposure cascade across our financial, regulatory and strategic position?”

1. From future crypto risk to present‑day data exposure

For most boards, quantum computing has sat somewhere between distant horizon and science fiction – filed under “technology to monitor” and revisited periodically. That framing is becoming a liability. Standards bodies have selected post‑quantum algorithms, and national cybersecurity agencies have issued migration timelines, but the key change in the last six months is the speed of the credible threat and recognition that the critical phase is the silent data harvesting already underway.

The mechanism is known as harvest now, decrypt later. In this model, adversaries collect and store encrypted data today so that it can be decrypted once quantum computers can break current public‑key cryptography. Long‑lived data – financial records, intellectual property, strategic plans, sensitive contracts and client archives – is valuable enough to target now, because decryption in five or ten years can still cause major harm. The collection is invisible to boards and, once done, cannot be reversed.

Confidence assessment: High confidence that HNDL harvesting is occurring today by state and criminal actors; medium confidence on the specific volume of data harvested from any one sector or firm.

Board implications this quarter

• Reframe quantum risk as a current confidentiality and governance problem, not a distant technical issue.

• Ask which categories of data would still matter if exposed 3-4 years from now, and how they are encrypted today.

• Recognise that any sensitive data already intercepted under vulnerable schemes is effectively “pre‑breached,” even if decryption is not yet possible.

2. Where the risk is moving: three shifts since early 2026

The governance foundations were laid with NIST and national guidance in 2024–2025. What has moved this into active board territory are three developments since the start of 2026.

2.1 Algorithmic advances: Q‑Day just moved closer

In March 2026, Google published an analysis indicating that the quantum resources required to break widely used elliptic‑curve cryptography are roughly 20 times lower than earlier estimates, cutting the number of physical qubits needed from several million to well under a million in some scenarios. Independent work summarised in a March 2026 technical review shows similar reductions for RSA‑2048, with estimates falling from around 20 million qubits in 2025 to potentially under 100,000 under newer architectures.

These advances have led major industry players to revise their migration timelines. Cloudflare, for example, has publicly accelerated its roadmap and now targets full post‑quantum security across its platform by 2029, with staged milestones through 2026–2028.

Confidence assessment: High confidence that credible technical estimates of “Q‑Day” capability have moved meaningfully closer; medium confidence on exact dates, but low confidence in the “10+ years away” comfort once common in boardrooms.

Board implications this quarter

• Treat a 2–3 year migration window for critical systems as prudent planning, not alarmism.

• Ask whether internal plans still assume a decade‑long runway, and if so, why.

• Expect vendors and financial‑market actors to use 2029 as a reference date for “full post‑quantum readiness.”
  

2.2 Regulatory convergence: from guidance to roadmaps

In February 2026, the World Economic Forum framed quantum security as a question leaders cannot ignore, warning that the harvest‑now, decrypt‑later model “transforms a future computing problem into an immediate crisis” for organisations with long‑lived data. The article calls explicitly for boards to assign responsibility for quantum risk, understand where cryptography is used, and assess reliance on vulnerable algorithms.

That same period saw publication of the G7 strategic roadmap for post‑quantum cryptography in the financial sector, setting out overlapping phases from executive awareness and inventory through to migration and validation, with a target of completing transitions to quantum‑safe standards by the early‑to‑mid 2030s. The UK’s National Cyber Security Centre has also indicated that large organisations may need 2–3 years just to discover cryptographic assets, plan and begin migration, with a goal of full PQC adoption by around 2035.

Confidence assessment: High confidence that finance ministries, supervisors and cyber agencies now treat PQC as a systemic issue that boards must own; medium confidence on the precise regulatory timelines country by country.

Board implications this quarter

• Assume quantum risk will move from guidance to sector‑specific requirements in financial services and critical infrastructure.

• Expect scrutiny not only of internal systems but of third‑party and supply‑chain exposure.

• Treat 2026–2028 as the window to be ahead of mandates, not responding under enforcement pressure.

  
  

2.3 HNDL as a cross‑domain cascade, not a pure cyber issue

Industry and policy analysis now emphasise that HNDL is simultaneously a technical, financial, regulatory, reputational and strategic risk, with different cascade paths depending on sector and data estate. Palo Alto Networks and others stress the need for cryptographic asset inventories, prioritisation of long‑lived data, crypto‑agility and engagement with regulators and vendors as part of a broader quantum‑resilience strategy.

Confidence assessment: High confidence that HNDL will manifest across multiple domains; medium confidence on which cascade channel will dominate for any given firm.

Board implications this quarter

• Stop treating PQC solely as a “CISO topic” and start viewing it as a cross‑domain strategic risk.

• Ask for a first‑cut map of cyber, financial, legal, reputational and strategic exposures tied to long‑lived encrypted data.

• Build quantum‑risk awareness into existing governance and resilience structures.

3. The cascade across your risk landscape

Most internal teams track quantum as a technology or cyber risk. That is too narrow for HNDL. As the threat develops, five distinct exposure channels intersect.

• Cyber and operational disruption The present‑day risk is strategic harvesting of encrypted data. When Q‑Day arrives for particular algorithms, operational impacts – from payments infrastructure to cloud integrations – will depend on what was collected and when.

• Financial and market confidence For financial institutions, the G7 roadmap signals that quantum cryptography is viewed as a systemic vulnerability, not just a firm‑specific issue. For corporates, compromised long‑term contracts, IP or proprietary models can undermine valuations and competitive position without a “classic breach” narrative.

• Regulatory and legal exposure

  Entities unable to show structured assessment, planning and progress as mandates arrive will face governance and compliance questions on top of technical remediation.

• Reputational risk A Q‑Day‑adjacent incident – credible evidence that long‑held encrypted data from a known organisation has been decrypted and misused – would be simultaneously a regulatory, client confidence and media event. There will be little warning in conventional incident data.

• Strategic risk For sectors such as pharmaceuticals, defence, advanced manufacturing and technology, the highest‑value HNDL targets are precisely the long‑horizon assets that define competitive advantage – R&D records, design files, deal histories and long‑term customer information. By the time decryption is achieved, the strategic window to protect that information has closed.
  

Confidence assessment: High confidence that HNDL will generate multi‑channel cascades; medium confidence on which combination will dominate per sector and firm.

Board implications this quarter

• Insist on cross‑functional analysis of HNDL impacts, not just a technology migration plan.

• Ask for a short list of “crown‑jewel” data sets that must remain confidential for 10+ years and how they are protected today.

• Consider how a future HNDL‑related disclosure would play with regulators, investors and key customers.

4. Why the next 6–12 months are the critical window

Two forces converge in this period.

• Technical acceleration compresses the migration runway The March 2026 algorithmic advances have shortened realistic planning horizons from “sometime in the 2030s” to “credible pressure by late this decade” for high‑value targets. Large organisations may need 2–3 years just to inventory cryptographic assets and launch early migrations.

• Regulation and expectations are crystallising The G7 roadmap and national guidance translate NIST standards into sectoral expectations, especially for finance and critical infrastructure. The window to move proactively – rather than under supervisory or market pressure – is open now but narrowing.
  

Together, these create a plausible 12‑month scenario in which a major regulatory mandate, a credible Q‑Day‑adjacent disclosure or a visible HNDL‑related incident triggers simultaneous regulatory, reputational and financial consequences.

Confidence assessment: High confidence that 2026–2027 will define whether firms are ahead or behind on PQC; medium confidence on the exact timing of trigger events.

Board implications this quarter

• Treat this planning cycle as the point to move from “monitoring” to active programme design.

• Ask whether cryptographic inventory and vendor engagement have even started.

• Decide now whether the organisation intends to be an early mover or a reluctant follower.

5. Why this matters for business

Three practical points for boards and executive teams.

• The active risk phase has already begun HNDL means the first and irreversible phase – data collection – is happening now; waiting for Q‑Day is waiting until the breach is manifest, not until it begins.

• The supply chain is the hidden exposure Many organisations lack visibility into the cryptographic standards used by critical vendors, cloud providers and software dependencies. A firm can advance its own migration while remaining exposed through third parties, and regulators are starting to ask for supply‑chain mapping.

• Reputational and strategic risk compound silently Unlike conventional breaches, HNDL offers no clear detection moment, notification duty or remediation window. By the time decrypted data is weaponised, reputational and strategic damage will have accumulated silently.
  

Confidence assessment: High confidence that boards under‑estimate supply‑chain and silent‑accumulation aspects of HNDL; medium confidence on how fast market expectations will adjust.

Board implications this quarter

• Elevate quantum risk formally to the board or a named committee.

• Require an initial map of internal and third‑party cryptographic dependencies.

• Integrate quantum risk into strategic and reputational resilience discussions, not only cyber dashboards.

6. Where the HORIZON Futures Engine adds value

Most organisations already have technical teams watching NIST, standards and vendor roadmaps. The gap is cross‑domain: how a quantum‑related trigger ripples across markets, regulation, supply chains and reputation – and what that means for the specific organisation.

The HORIZON Futures Engine addresses that gap by:

• Cross‑domain cascade mapping Linking HNDL and PQC developments to existing credit, market, regulatory, ESG and supply‑chain risks, rather than treating them as isolated cyber signals.

• Alternative futures analysis Building structured scenarios around the pace of quantum capability and speed of regulatory formalisation, and stress‑testing current plans against each plausible future.

• Velocity‑aware early warning Scoring signals for likelihood, impact and velocity, and tracking concrete triggers such as major algorithm disclosures, regulatory consultations, vendor migrations and insurance‑pricing shifts.

7. Signals to watch over the next 12 months

• Further quantum‑algorithm disclosures from major technology firms, national labs and standards bodies that compress credible Q‑Day timelines.

• Sector‑specific regulatory mandates building on the G7 roadmap, especially in finance and critical infrastructure.

• Vendor and cloud‑provider PQC milestones indicating how quickly the cryptographic environment in key supply chains is changing.

• Insurance‑market moves to incorporate post‑quantum readiness into pricing and terms.

8. Questions for your next executive or risk committee meeting

• What categories of data must remain confidential for 5–10 years, and how are those data protected today (algorithms, key lengths, locations)?

• Have we mapped our cryptographic surface area across third‑party vendors, cloud providers, payments infrastructure and software dependencies?

• How would a Q‑Day‑adjacent incident in our sector – a credible disclosure that previously harvested data has been decrypted – cascade across our regulatory, market and reputational exposure?

• Are current business plans and strategic commitments stress‑tested against different quantum‑risk futures, or is this still treated as an IT migration item to tackle “later”?
  

The emerging question for senior leaders is no longer whether quantum computing will eventually threaten today’s encryption; that point is settled. It is whether the organisation understands how this risk is already cascading through its specific landscape – and whether it will respond in a managed way, or in conditions it did not anticipate.