Post‑Quantum Cryptography: Inevitable Preparation or Premature Bet?
News and information from the Advent IM team.
- by Olivia Lawlor-Blackburn
- Advent IM Blog
Post‑quantum cryptography (PQC) has rapidly moved from academic research to a topic of board‑level concern. Two recent articles capture the debate clearly. Computer Weekly’s “Shrinking PQC timeline highlights immediate risk to data security” argues that organisations must act now to mitigate growing cryptographic risk. In contrast, The Register’s “Cryptographers place $5,000 bet whether quantum will matter” highlights scepticism within the cryptographic community about whether quantum computers will threaten real‑world encryption any time soon.
For UK organisations, this is not simply a technical disagreement. It is a question of governance, regulatory defensibility, and long‑term data protection. Whether quantum computing arrives sooner or later, organisations are increasingly expected to demonstrate that they have understood the risk landscape and taken proportionate steps to address it.
The argument for urgency: why PQC is being treated as a current risk
The most compelling arguments in favour of preparing for PQC do not come from vendors but from government guidance and risk authorities. The UK National Cyber Security Centre (NCSC) has formally stated that migration to PQC is a national‑scale transformation that must already be underway, with key milestones in 2028, 2031 and full transition by 2035.
From a governance and compliance perspective, this is significant. Once national technical guidance exists, failure to plan becomes a conscious risk decision rather than an oversight. Regulators, auditors, and courts increasingly expect organisations to align with authoritative best practice where it exists, particularly where sensitive or long‑lived data is concerned.
A central concept highlighted by Computer Weekly is “harvest now, decrypt later”. Threat actors do not need quantum computers today to create risk. They simply need to collect and store encrypted data now, with the intention of decrypting it in the future once cryptographic barriers fall. For data that must remain confidential for decades, such as health records, identity data, defence or critical infrastructure information, this fundamentally changes the timeline of exposure.
From a UK GDPR standpoint, this matters. Article 32 requires security measures appropriate to the risk, and risk is no longer defined only by present‑day technical capability, but by foreseeable future compromise. Organisations that rely solely on legacy cryptography without considering its future lifespan may struggle to evidence accountability if data confidentiality is later compromised.
The accelerating behaviour of large technology providers further reinforces this point. Google’s decision to move its PQC migration target forward to 2029 reflects internal risk assessments that assume timelines are tightening. These decisions influence the wider ecosystem: browsers, operating systems and cloud services are already introducing hybrid cryptographic approaches that reshape expected security baselines across the UK economy.
The sceptical view: why some experts urge caution
The Register article highlights a legitimate and important counter‑argument. Several respected cryptographers argue that quantum computing remains far from being practically capable of breaking real‑world encryption. Error correction, scale and stability remain significant technical barriers. To date, no quantum system has demonstrated anything approaching the capability required to compromise modern elliptic curve cryptography in operational settings.
This scepticism raises valid governance questions. If the threat timeline remains highly uncertain, is there a risk of organisations investing prematurely in complex and immature solutions? Post‑quantum algorithms are newer and more complicated, often involving larger keys and greater computational overhead. Poorly implemented cryptographic change can introduce vulnerabilities of its own.
There is also a governance risk around “security hype”. Boards may feel pressured to act decisively in response to headlines, rather than proportionately in response to data‑driven risk assessment. Over‑investment in speculative threats may divert attention from more immediate and demonstrable control weaknesses, such as asset visibility, access management, or supply‑chain assurance.
Importantly, even UK guidance recognises that PQC migration must be phased, risk‑based and aligned to organisational context. A rushed, universal replacement of cryptographic controls today would be neither necessary nor advisable for most organisations.
Framing the issue correctly: this is a governance challenge, not a technology race
The apparent tension between these two viewpoints is largely resolved when PQC is understood not as a binary technical upgrade, but as a long‑term governance and data protection programme.
The NCSC does not call for immediate wholesale cryptographic replacement. Instead, it advocates foundational activities that most organisations should arguably have in place already: understanding where cryptography is used, which data depends on it, how long that data must remain confidential, and how reliant the organisation is on third‑party suppliers for cryptographic controls.
From a compliance and information risk perspective, these activities deliver value regardless of how quantum technology evolves. They support GDPR accountability, strengthen supplier governance, reduce cryptographic technical debt, and improve organisational resilience. They also enable boards to evidence informed decision‑making — a critical factor in regulatory scrutiny following data incidents.
In this sense, PQC preparation is far less about predicting quantum breakthroughs and far more about demonstrating mature risk management.
Preparing is no longer optional
Whether one aligns more closely with the urgency expressed in Computer Weekly or the scepticism captured by The Register, the practical conclusion for UK organisations is the same: preparation must begin regardless.
The UK’s National Cyber Security Centre has been explicit that post‑quantum migration is a long‑duration change that cannot be compressed into a late or reactive response. Cryptographic risk touches data protection, procurement, system lifecycles, contracts and governance structures. Leaving it until certainty arrives is incompatible with how modern risk management and regulatory accountability operate.
Preparing does not mean replacing cryptography today. It means understanding your data, your dependencies and your exposure. It means assessing which information has long‑term confidentiality requirements, identifying where legacy cryptography underpins critical services, and ensuring suppliers can support future change. It also means equipping boards and senior leaders with clear visibility of cryptographic risk ownership.
Crucially, these actions strengthen organisational security even if quantum timelines slip. They improve control maturity, support compliance with UK GDPR and NIS obligations, and demonstrate that foreseeable risks are being managed responsibly.
Quantum computing may remain uncertain. Governance expectations are not. Organisations that prepare now; proportionately, pragmatically and transparently. Placing themselves in a far stronger position whatever the future holds.
In short, post‑quantum readiness is no longer about predicting when quantum will matter. It is about being able to show that you were prepared, regardless.