Horizon 03
Quantum Technologies
Usually discussed as one machine. It is really several capabilities, maturing at different rates, with different consequences.
Some technologies change the assumptions beneath the system.
The shift
The field is usually discussed as though it were a single thing: a computer that will eventually break encryption. That framing is convenient and misleading. Quantum computing is the least mature of at least four capability lines, and it is not the one already in service.
Each line changes a different assumption. Computing changes what is expensive to calculate. Communication changes what can be intercepted without the interception being detectable. Sensing changes what can be measured — gravity, magnetic fields, inertial position — sometimes where satellite navigation cannot reach. Timing changes how precisely distributed systems can agree on when something happened, and a surprising amount of infrastructure is built on shared time it does not own.
The consequences therefore do not wait for the hardest machine. Precision timing and sensing are being deployed now. Cryptographic migration is an engineering and lifecycle problem today, whatever the arrival date of a cryptanalytically relevant computer turns out to be.
The horizon moves. So must the assumptions built around it.
What we ask
- Which of our assumptions rest on something being expensive to compute?
- What here depends on precise shared time, and what happens when it drifts?
- Where would a measurement we cannot currently take change a decision?
- Which information stays sensitive long enough for capture-now-decrypt-later to be rational?
- What in the estate cannot have its cryptography changed without replacing hardware?
Lines of inquiry
- 01
Computing and the cryptographic transition
The migration begins with knowing where public-key cryptography is actually used — the least glamorous part of the work and the one most often deferred. The durable outcome is not one completed migration but the ability to complete the next one, because the algorithms will change again.
- 02
Communication and detectable interception
Quantum key distribution offers a narrow and genuine property: interception that cannot go unnoticed. It is also frequently oversold, constrained by distance, trusted nodes, and cost, and it solves a smaller part of the problem than the marketing suggests. We are interested in where that property is worth the constraints and where conventional cryptography is the better answer.
- 03
Sensing and measurement
Quantum gravimeters, magnetometers, and inertial sensors change what is observable — subsurface structure, magnetic signatures, position without satellites. The interesting question is rarely the instrument. It is what becomes decidable once a measurement that was previously unavailable becomes routine, and who else can now take it.
- 04
Timing and synchronisation
Finance, telecommunications, power distribution, and navigation depend on precise time, most of it derived from a small number of satellite constellations. Better clocks change both the resilience of that dependence and the precision available to anyone who holds one.
- 05
Long-lived systems
Industrial control, embedded devices, vehicles, and physical infrastructure outlive their assumptions. Where the upgrade path is a site visit, the decision point is not the arrival of the technology — it is the next procurement, and that requirement is written now.
Not one machine. Several capabilities.
If you are trying to establish which of these actually touch your systems, and on what timescale, that is a tractable question and a good place to start.