The most consequential device in cryptography does not exist yet. Quantum memory, an Oxford lecturer argues, will decide whether Bitcoin (BTC) breaks or gets replaced by something better.

Stefano Gogioso published that argument on Tuesday. He says the promise of quantum cryptography now rests on building a single piece of hardware.

“The development of portable long-term quantum memory will be one of the most consequential milestones of quantum technology. These devices will power an entirely new class of applications, such as quantum money, the ultimate incarnation of a digital store of value.”

Gogioso, a quantum computing lecturer at the University of Oxford and co-founder of quantum security firm Spooqy, told BeInCrypto.

The Bottleneck Quantum Money Never Cleared

An earlier report from the BeInCrypto Experts Council ended on an unsolved problem. Quantum money cannot be forged, because quantum states cannot be copied.

Nobody, however, can hold those states for long. The best laboratory systems keep one alive for seconds, which is why the case for quantum money has stayed theoretical.

Gogioso’s post sets out what a usable device would actually need. Stability measured in months, or ideally forever. Portability, first inside a shipping crate and later inside a pocket. Capacity running to billions of separate states.

He also rules out the more familiar idea of quantum RAM. Nothing in his design needs random access or in-place editing. States are drawn in order and spent once.

The distance between seconds and months is the entire problem.

Why Gogioso Calls Quantum Memory Inevitable

His answer arrives in two steps, and the first one is categorical.

A fault-tolerant quantum computer must keep fragile states alive at scale, against noise, for as long as a calculation runs. That requirement is what fault tolerance means.

Remove the computing, Gogioso argues, and a quantum memory device is what remains. Denying one therefore means denying the other.

The reframing matters commercially. Billions of dollars are already committed to fault-tolerant machines. The memory sits inside those roadmaps as an unavoidable step.

His second step concerns portability. Machines running at cryogenic temperatures will keep their states at the bottom of a refrigerator for years to come.

Atom-based designs are different. They store information in properties that nature already keeps isolated. That turns the problem into hard engineering rather than physics.

Gogioso also lowers the bar in a way the debate has mostly ignored. A memory does not have to survive decades. A sealed single-use cartridge, filled at a facility and spent state by state, would serve every application he describes.

The Same Machine Breaks Bitcoin and Builds Its Replacement

Follow that argument into crypto and it produces an awkward symmetry.

In March, Google Quantum AI worked with the Ethereum Foundation and Stanford on the cost of attacking Bitcoin. The team put the requirement at fewer than 500,000 physical qubits.

Such a machine only works if it is fault tolerant. And fault tolerance, by Gogioso’s own definition, is quantum memory.

The conclusion is uncomfortable for both camps. The hardware that would expose Bitcoin’s signatures would also fuel quantum money.

Every dollar chasing fault tolerance therefore funds both futures at once. No version of this story exists where quantum computers break Bitcoin and the alternative stays impossible.

Gogioso and Daniela Herrmann, chief executive of quantum firm Dynex, made the wider case on the panel above.

Why a Stolen Shipment Would Not Matter

The security model behind all of this inverts an old assumption.

Classical key material is dangerous in transit. Whoever copies it owns it, and leaves no trace of having done so.

An entangled pair carries no information at all while it sits in storage. The randomness that becomes a key appears only at the moment of measurement.

A hijacked crate would therefore cost a supplier its stock rather than its secrets. Gogioso writes that the worst a corrupt supplier can deliver is a tank of useless gas.

A second consequence is stranger. These resources burn. A key consumes entangled pairs, and a banknote gets spent across its own verifications.

Gogioso calls the effect cryptography by combustion. Money built this way would arrive with a fuel gauge.

Q-Day Has a Calendar. Quantum Money Does Not.

The two halves of this story move at very different speeds.

The attack side is full of dates. IBM expects quantum computing to move its earnings by 2028 or 2029. Hong Kong has set its banks a quantum readiness deadline of 2030.

The National Institute of Standards and Technology plans to retire current elliptic-curve signatures by 2030. It would disallow them outright by 2035.

The replacement side has no calendar whatsoever. Gogioso declines to supply one. His post argues for the inevitability of the resource, not the imminence of a product.

He was more forward-looking on the panel, suggesting provably impossible applications within five to seven years. That estimate covered quantum resources broadly, not a memory small enough for a wallet.

Herrmann drew the same boundary during the discussion.

“Quantum money is the vision, once this all plays out. Right now, quantum money as such isn’t available yet. But as soon as the chips advance, these things have to be handled with real responsibility.”

What the Argument Leaves Open

Two questions survive it.

Somebody still has to fill the memories. That leaves an issuer inside a system advertised as having no custodian.

A bearer instrument with no ledger also has no recovery. A note that is lost, stolen, or simply left to decay takes its value with it.

The industry is building the machine regardless. It has not yet decided which of the two things it wants.

Source: BeInCrypto