The transition to quantum-resistant cybersecurity is no longer just a question for the future. Although quantum computers capable of breaking today’s widely used encryption are not yet available at the necessary scale, sensitive information intercepted today could already be at risk. For organisations responsible for protecting data over many years, preparing for this possibility is becoming increasingly urgent.
But what does preparing for the quantum era actually involve? Which technologies can help organisations protect their systems without disrupting existing operations, and where should they begin?
Q-FENCE, a Horizon Europe project bringing together 15 partners across 10 countries, is working to answer these questions. Coordinated by Walton Institute at South East Technological University in Ireland, the project combines academic cryptography research with industrial expertise to develop quantum-resistant solutions that can be integrated into existing digital infrastructures.
We spoke with Indrakshi Dey, Q-FENCE project coordinator, about the quantum threat, the role of hybrid cryptography and the practical steps organisations can take to prepare.
Understanding the quantum threat
For those who are new to Q-FENCE, could you briefly introduce the project?
Q-FENCE, or Securing Tomorrow’s Digital Infrastructure with Quantum-Resistant Cryptography, is a three-year Horizon Europe project that began in November 2025, coordinated by Walton Institute at South East Technological University in Ireland. It brings together fifteen partners across ten countries, combining academic cryptography groups with industry players including Toshiba Europe, Red Hat, Telespazio and Fraunhofer IPMS, with a budget of approximately €5.3 million. Our aim is twofold. First, to build a hybrid cryptographic framework that protects sensitive data against quantum attack. Second, and just as important, to give organisations a realistic route from the encryption they use today to post-quantum alternatives, without switching off the systems they depend on. Technically, Q-FENCE is built on a dual-core design. A “soft” core provides lattice-based post-quantum cryptography, specifically Ring-LWE and Module-LWE, seeded by quantum random number generation for genuinely high-entropy keys, together with homomorphic encryption so that data can be processed while it stays encrypted. A “hard” core anchors trust in the silicon itself, using Physically Unclonable Functions for device identity, post-quantum secure boot, and a dedicated hardware accelerator so that the cryptography remains fast enough to be practical on constrained devices. We then validate the whole framework in five real-world pilots and turn what we learn into deployment guides, benchmarks and contributions to standardisation.
The project’s ambition reflects a wider challenge facing organisations across Europe: the security mechanisms underpinning today’s digital infrastructure may not remain reliable indefinitely. Understanding the nature of that risk is the first step towards preparing for it.
What risks does quantum computing create, and what does it mean to become “quantum-ready”?
Almost everything we trust online rests on a small number of mathematical problems that classical computers cannot solve quickly. This is what RSA and elliptic-curve cryptography are built on. Shor’s algorithm, running on a sufficiently powerful quantum computer, solves precisely those problems. The Global Risk Institute puts the probability that quantum machines will be capable of breaking today’s standards by 2030 somewhere between 11% and 31%. What many people miss is that the risk is not purely in the future. An adversary does not need a quantum computer today to cause harm tomorrow. They only need to capture encrypted traffic now and store it until the capability arrives. Cryptographers call this “harvest now, decrypt later”. It reframes the question entirely. Rather than asking when quantum computers will be strong enough, organisations should ask what they are transmitting today that still needs to be confidential in fifteen or twenty years. For hospitals, banks, government departments and infrastructure operators, the honest answer is usually: most of it. Becoming quantum-ready is less about buying a product and more about running a programme. It means knowing where cryptography actually sits in your estate, which is harder than it sounds; identifying which data has a long confidentiality lifetime; becoming crypto-agile, so that algorithms can be replaced without rebuilding applications from scratch; and having a phased migration plan with a realistic timeline. Gartner has reported that more than 70% of organisations feel unprepared to deploy post-quantum cryptography at scale, and the bottleneck is rarely the mathematics. It is engineering, compatibility and trust.
This makes quantum readiness a practical challenge as much as a technological one. Organisations need to protect sensitive information while keeping essential services running, often across systems that have been built over many years. For Q-FENCE, this is one reason to explore approaches that combine existing cybersecurity technologies with quantum-resistant alternatives.
Making the transition without rebuilding everything
How does combining existing cybersecurity technologies with quantum-resistant solutions help organisations?
No bank, hospital or satellite operator can pause operations for a cryptographic rebuild. That constraint shapes our whole approach. Q-FENCE uses hybrid cryptography: a well-understood classical algorithm and a post-quantum algorithm run alongside each other, so that a connection is only compromised if both are broken. This gives immediate protection against the harvest-now-decrypt-later threat while preserving the assurance that comes from decades of scrutiny of classical schemes. The practical benefit is backward compatibility. Systems that have not yet migrated continue to work, so migration can proceed department by department rather than as a single high-risk cutover. We are targeting at least 95% compatibility with legacy systems during transition, and our components are deliberately modular so they can be dropped into existing stacks rather than requiring new ones. We also work hard on the overhead, because post-quantum algorithms generally use larger keys and more computation than what they replace. Techniques such as the Number Theoretic Transform and Barrett reduction, combined with hardware acceleration, keep performance within workable limits even on embedded and battery-powered devices. The economics matter too. McKinsey’s analysis suggests hybrid approaches can reduce migration costs by up to 40% compared with wholesale cryptographic replacement. Acting early and incrementally is considerably cheaper than acting late and all at once.
Hybrid cryptography offers a possible route forward, but adopting new algorithms is not as simple as switching them on. Organisations must also consider performance, compatibility and the maturity of the technologies they introduce. This raises a broader question about the relationship between cryptographic standards and their deployment in operational environments.
NIST has already standardised post-quantum algorithms. Why isn’t it enough simply to adopt them?
Standardising an algorithm and deploying it across a working estate are very different problems. NIST’s selection process took six years, and broad deployment is expected to take another five to ten. The reasons are practical rather than mathematical. Post-quantum algorithms generally use larger keys and signatures than the schemes they replace, and they place different demands on memory, bandwidth and power. That is a genuine obstacle for IoT devices, embedded systems and satellite payloads, where every byte and every milliwatt is accounted for. Beyond the algorithm itself, protocols, libraries, certificate infrastructure, hardware and supply chains all have to change together, and none of that is specified by a standards document. There is also a maturity argument. These algorithms are new and have not had the decades of sustained cryptanalysis that RSA and elliptic-curve cryptography have endured. SIKE, an alternate candidate in the NIST process, was broken shortly after selection. Running a classical and a post-quantum algorithm side by side hedges against exactly that risk. Finally, a standard tells you what to use, not how to migrate a twenty-year-old infrastructure without downtime. That gap between the standard and the deployment is where Q-FENCE does its work.
The challenge, then, is to bridge the gap between recognising the need for quantum-resistant security and putting a realistic transition plan in place. For organisations wondering how to move from awareness to action, that process can begin with a few concrete decisions.
Where should organisations begin?
If an organisation reads this and wants to act, what are the first three things they should do before the end of the year?
First, build a cryptographic inventory. Find out where cryptography actually sits in your estate: not just the obvious places like TLS and VPNs, but code signing, hardware security modules, embedded devices, backups and the systems your suppliers run on your behalf. Most organisations cannot answer this question today, and finding out takes months rather than weeks, which is exactly why it should start now. Second, classify your data by confidentiality lifetime. Ask which information still needs to be secret in 2040. That subset is your harvest-now-decrypt-later exposure, and it tells you the order in which to migrate rather than leaving you facing the whole estate at once. Third, build crypto-agility into the decisions you are making anyway. Anything procured or architected this year will still be running when migration becomes urgent, so ask vendors for their post-quantum roadmap and require that algorithms can be replaced without rebuilding the application. If there is capacity for a fourth step, name a single accountable owner. Migrations that belong to everybody tend to belong to nobody.
Preparing for quantum-resistant security does not require every organisation to solve every technical challenge immediately. It does require them to understand where they are exposed, prioritise the data that needs long-term protection and make decisions today that will leave room for change tomorrow.
For Q-FENCE, the next step is to test whether the technologies and approaches being developed can meet the demands of real operational environments. That means looking beyond algorithms alone to the devices, networks, sectors and organisations that will ultimately need to rely on them.