Nine crypto companies launched the Quantum Alliance on Thursday to build common security standards for bitcoin, Ethereum and other blockchains, amid warnings that 6.4 million bitcoin — 30.2% of the supply — have already-exposed public keys that a future quantum computer could exploit.

The alliance's members include blockchain security firm Hacken, Charles Hoskinson's Midnight Foundation, layer-1 blockchain Quantus and Postquant Labs. Its initial output will be common security tests and guidance for migrating existing networks to quantum-resistant systems.

The threat model is specific. A sufficiently powerful quantum computer could reverse-engineer a wallet's publicly visible key to derive its secret key and steal the funds. The alliance itself clarified that no existing machine can do this today — but the exposed-key surface is large, and the estimate includes roughly 1.1 million bitcoin attributed to Satoshi Nakamoto.

When does the threat arrive?

That's where the experts split. Richard Carback, chief technology officer of Postquant Labs, says he considers 2028 a realistic date for a cryptographically relevant quantum computer (CRQC) capable of breaking today's cryptography. Bryn Bennett, chief revenue officer at The Vault, disagrees with pinning any date at all.

"Nobody knows the date, but the estimates keep falling, and the risk is one we can already plan for," Bennett told CoinDesk. "The question for custodians isn't whether the date is 2028 or 2035; it's whether you can migrate in time if it arrives early."

Recent research has lowered estimates of the computing power needed to attack bitcoin and Ethereum, but no existing machine can break their cryptography, and predictions remain disputed.

Who takes the vulnerable coins?

Christopher Smith, CEO of Quantus, believes the first mover with a working CRQC — likely state-backed — could simply seize the exposed coins.

"The most likely scenario is that whoever gets the first CRQC will take them, probably with the blessing of whichever national government," Smith told CoinDesk. "Hopefully it's a government that likes bitcoin."

That scenario frames the alliance's urgency. If billions in bitcoin sit behind keys a quantum machine could crack, the question is not just technical but geopolitical.

Should vulnerable bitcoin be frozen?

The industry has no consensus. Binance founder Changpeng Zhao has suggested freezing Satoshi's estimated 1.1 million bitcoin if they remain untouched as quantum technology advances. Bitcoin developer Jameson Lopp has also proposed restrictions on vulnerable coins to prevent theft. Critics counter that freezing someone's bitcoin violates the network's core promise that no one can confiscate it.

Carback prefers moving vulnerable coins to a trust structure, letting owners who can prove ownership recover their funds. Bennett argues the governance question has no natural owner.

"Nobody owns that issue, and that's the problem," Bennett said. "A custodian protects its clients' assets, not abandoned ones. Freezing coins is a governance decision for the Bitcoin network, not for the industry."

"Any freeze would trade quantum risk for a precedent on property rights and neutrality," he added.

What would migration actually cost?

Making bitcoin quantum-resistant means replacing the digital signatures that authorize transactions. That requires coordination among developers, miners, wallet providers, exchanges and users — and Bennett says coordination, not cryptography, is the real expense.

"Nobody has a credible single number, and anyone offering one is guessing," Bennett said of the cost. "The real cost isn't the cryptography; it's coordinating wallets, exchanges, custodians and protocol developers."

There's an engineering trade-off too. Replacement signatures could take up more block space, raising fees or reducing bitcoin's transaction throughput. Researchers are already working on ways to limit that impact.

For now, the alliance's standards work gives the industry a shared baseline rather than a mandate — any actual protocol change on Bitcoin would still need the ecosystem's broad consent. The unresolved question is whether the network can harden itself against quantum theft without rewriting the rules that made it succeed.

By Daniel Okafor