Quantum risk for Irish healthcare data

Short answer: Healthcare data has long retention periods, so it is exposed to "harvest now, decrypt later" attacks even though no quantum computer can break today's encryption. A 2025 npj Digital Medicine commentary says the date of "Q-Day" is hypothetical, but that medical devices and patient records need a plan to move to post-quantum cryptography.

What Q-Day means

"Q-Day", also called Y2Q, is the hypothetical point when a quantum computer can break the widely used cryptography behind digital services. The authors of a 2025 News & Views piece in npj Digital Medicine, Freyer, Ostermann, Minssen and Gilbert, stress that its timing is unknown. Prototypes have gained qubits, but they are described as far from fully functional, and quantum algorithms remain largely a theoretical field.

The piece cites expert estimates that put the likelihood of functional quantum computers at between 19% and 34% within 10 years, and between 60% and 82% within 20 years. It also notes that such dates have been pushed back several times. The honest summary is that nobody knows, and that is part of the planning problem.

Why healthcare is exposed

The authors give two reasons Q-Day is debated. Infrastructure should be ready and switched to quantum-safe schemes before then, to avoid failures in authentication, key exchange and secure communication. And there is an immediate "harvest now, decrypt later" risk, where adversaries store encrypted data until a quantum computer can read it.

Healthcare makes the second risk worse. Retention periods are long and health data keeps its value over a lifetime, so a record encrypted today may still be sensitive in decades. The commentary also points to femtech and other sensitive applications as areas of particular concern.

Medical devices

The same piece says medical devices and healthcare systems are critical infrastructure. If the cryptographic protections on them were compromised, the consequences could be immediate and potentially life-threatening. Devices are also hard to update: they can stay in service for years, and changing firmware and communication protocols takes planning and, in many cases, regulatory work.

The authors call for rapid adoption of post-quantum cryptography, time-phased and scalable technology rollout strategies, and revised regulatory frameworks to protect patient safety, privacy and trust.

Possible consequences of decrypted data

The commentary lists harms beyond an ordinary privacy breach. Access to previously secure medical data could, if actors were willing to act criminally, change risk assessment in insurance and lead to discrimination in coverage and pricing. Records of public figures or vulnerable groups could also be targeted for political or social reasons.

The standards that exist

NIST approved FIPS 203 (ML-KEM), FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA) on 13 August 2024. Falcon was selected for standardization as FN-DSA, and FIPS 206 is still in development. These are the algorithms vendors are expected to build into products over the coming years.

A practical first step

A health provider or device maker can start with an inventory of where cryptography is used, how long each data set must stay confidential, and which devices cannot easily be updated. Then ask suppliers about their plans for the NIST post-quantum standards. Our posts on harvest now, decrypt later and on crypto inventories cover the method.

This article is an independent explainer based on published research. It is not medical, legal or compliance advice.

FAQ

Can quantum computers break healthcare encryption today?

No. The date of Q-Day is hypothetical, and current prototypes are described as far from fully functional.

What is "harvest now, decrypt later" in healthcare?

Adversaries store encrypted data now and wait until a quantum computer can decrypt it. Health data keeps its value for a lifetime, so the exposure lasts a long time.

Why are medical devices a special concern?

They are part of critical infrastructure, and a compromise of their cryptography could have immediate and potentially life-threatening effects. Updating devices takes planning.

How likely is a functional quantum computer in the next decade?

The commentary cites expert estimates of 19% to 34% within 10 years and 60% to 82% within 20 years, and notes that such dates have been pushed back before.

What should a healthcare organisation do first?

Inventory where cryptography is used, rank data by how long it must stay confidential, flag devices that are hard to update, and ask vendors about NIST post-quantum support.