Most quantum computing coverage asks businesses to prepare for something that will not affect them for a decade, if at all. Drug discovery, portfolio optimisation, climate modelling — genuinely important, genuinely not your problem unless you are in one of those industries.
There is one exception, and it is the part that gets buried under the rest. It concerns encryption, it has already started, and it applies to anyone storing data that must stay secret for years.
The short version of the technology
Classical computers work in bits, which are one or zero. Quantum computers use qubits, which hold a superposition of both and can be entangled with each other, so certain calculations explore many possibilities at once rather than one at a time.
This only helps for particular problem shapes. A quantum computer is not a faster computer. It is a machine that is dramatically better at a narrow class of problems and no better at everything else.
Unfortunately, one of those problems is the mathematics protecting most of the internet.
Why encryption is the urgent part
RSA and elliptic-curve cryptography rest on problems classical computers cannot solve in reasonable time — factoring large numbers, computing discrete logarithms. Shor's algorithm solves both efficiently on a sufficiently large quantum computer.
Nobody has built one of those yet. The machines that exist have too few stable qubits and too high an error rate. Estimates for when that changes range from a decade to never, and anyone quoting a precise date is guessing.
So why act now?
Harvest now, decrypt later. An adversary does not need a quantum computer today to benefit from one tomorrow. Capture encrypted traffic now, store it, decrypt when the hardware arrives. Anything that must stay confidential into the 2030s and beyond is already exposed, because the interception can happen at any point before the capability exists.
That reframes the deadline entirely. The question is not when quantum computers arrive. It is how long your data needs to stay secret, and whether that window overlaps.
What that means in practice
For most businesses, very little needs doing this year. Two things are worth the time.
Know where your cryptography lives. Which systems use RSA or ECC, in what form, and where are the keys? Most organisations cannot answer this quickly, and the answer is a prerequisite for any migration. It is also useful for reasons that have nothing to do with quantum computing.
Prefer crypto agility over specific algorithms. Design systems so the algorithm can be swapped without rewriting the application. Standards bodies have selected post-quantum algorithms and implementations are maturing; the systems that will migrate cheaply are the ones that never hard-coded the choice.
Everything else — buying quantum access, hiring quantum specialists, running experiments — is only worth it if quantum simulation is central to what your company does. For nearly everyone it is not.
The blockchain angle
This lands harder on chains than on most systems. Wallet security rests on elliptic-curve signatures, and a public address exposes a public key. Ledgers are permanent by design, so a signature recorded today is still sitting there when the mathematics protecting it fails.
Several networks are researching quantum-resistant signature schemes, and none of the major ones has migrated. For anything being built now with a long expected life, the design question is whether the signature scheme can be changed later, and what happens to assets held at addresses using the old one.
That question belongs in the architecture review, not the risk register.
What to do this quarter
Inventory where RSA and ECC are used, and note the key rotation story for each.
Identify data that must stay confidential beyond roughly 2035, and treat its transport and storage as the migration priority.
For anything being designed now, keep the algorithm choice swappable.
Ignore the rest. It will still be there when it starts to matter, and the coverage between now and then will mostly be selling something.
We build the cryptographic layer for blockchain and smart contract systems. If you are designing something intended to last, it is worth an hour of conversation now rather than a migration later.
