Nine blockchain firms have formed the Quantum Alliance, an open standards body that aims to define what “quantum-resistant” actually means and how networks, wallets and infrastructure can prove it. The timing matters: the group estimates that roughly 30% of all bitcoin already has an exposed public key on-chain, leaving those coins theoretically vulnerable to a future quantum attack.
🔑 Key takeaways
- Nine firms, including Quantus, Postquant Labs and The Vault, launched the alliance on October 15 in Lisbon.
- An estimated 6.04 to 6.4 million BTC, about 30% of supply, have public keys exposed on-chain.
- The group’s “Quantum Doomsday Clock” sets a threshold of about 856,000 physical qubits, with March 2028 flagged as an early possible window.
- Google Quantum AI has cut its estimate to fewer than 500,000 qubits needed to break Bitcoin’s cryptography.
- Whether to freeze, move or leave vulnerable coins untouched remains an open governance question.
An open alliance modeled on the IETF
The nine founding members are Quantus, American Fortress, Intmax, Keystone, Midnight Foundation, Postquant Labs, Abelian, The Vault and Hacken. The alliance was formed on October 15 in Lisbon. Their activities span base-layer protocols, privacy networks, rollups, hardware wallets and security auditing, giving the group a cross-sector view of the ecosystem.
The governance model draws on the Internet Engineering Task Force (IETF), the body that develops internet standards. Proposals will advance based on public evidence and working implementations, not on the size of member companies or how many tokens they hold. All work will be published as open source.
The alliance will not launch a new blockchain. Instead, it will publish open guidelines on testing and migration, modeled on IETF practice. Its starting point is a gap: in August 2024, the U.S. National Institute of Standards and Technology (NIST) approved the first post-quantum cryptography standards, yet the crypto industry still lacks a unified approach to implementing them.
6 Million BTC With an Exposed Public Key
The alliance estimates that between 6.04 and 6.4 million BTC, roughly 30% of total supply, have public keys exposed on the blockchain and are therefore potentially vulnerable to a quantum computer attack. Of that amount, about 1.1 million BTC is attributed to Satoshi Nakamoto’s old addresses. The group stressed that no existing quantum computer can carry out such an attack today.
The technical problem lies in how most blockchains secure accounts: with elliptic curve signatures. Once an account’s public key is recorded on the ledger, a sufficiently powerful quantum computer running Shor’s algorithm could, in theory, reverse-engineer the matching private key and seize the funds.
This cryptography does not only protect individual holdings. It also secures the minting keys of stablecoins, cross-chain bridges, oracles and governance contracts. A compromised privileged key could therefore trigger cascading effects across several platforms at once.
| Indicator | Estimate |
|---|---|
| BTC with exposed public keys | 6.04 to 6.4 million |
| Share of total supply | about 30% |
| Of which Satoshi-era addresses | about 1.1 million |
| Doomsday Clock physical qubit threshold | about 856,000 |
| Qubits needed to break Bitcoin cryptography (Google Quantum AI) | fewer than 500,000 |
A Timeline That Keeps Shrinking
Estimates are converging on a shorter horizon. The alliance cites several recent forecasts pointing to the late 2020s. Its “Quantum Doomsday Clock” sets a threshold of about 856,000 physical qubits and flags March 2028 as a possible early window.
Richard Carback, chief technology officer of Postquant Labs, told CoinDesk he considers 2028 a realistic timeline for a machine capable of breaking today’s cryptography. Separately, a Google Quantum AI study reduced the number of qubits needed to break Bitcoin’s cryptography to fewer than 500,000. No machine can do it yet, but Google continues to chip away at the major quantum bottlenecks.
“Nobody knows the exact date, but the estimates keep coming down, and this is a risk we can already plan for. The question for custodians isn’t whether the date is 2028 or 2035. It’s whether you can migrate in time if it comes sooner.”
Bryn Bennett, Chief Revenue Officer, The Vault
Christopher Smith, founder and CEO of Quantus, put it more bluntly: “In the future, ‘post-quantum cryptography’ will simply be called ‘cryptography’, and everything else will be in a museum.” He also warned that the first party to build a cryptographically relevant quantum computer (CRQC) could likely take “billions of dollars” in bitcoin, probably with the blessing of a national government.
Four Workstreams and the Dilemma of Vulnerable Coins
The alliance’s work is organized around four groups:
- migrating blockchains to quantum-resistant algorithms, including accounts whose public keys are already exposed;
- post-quantum zero-knowledge proof systems used by rollups and privacy networks;
- wallet security for generating, storing and recovering post-quantum keys;
- interoperability across blockchains, bridges and wallets after the transition.
The hardest question concerns the vulnerable coins themselves. Carback prefers that they be moved rather than frozen, and proposes placing them in a trust that would let owners reclaim their funds after proving ownership. Bryn Bennett takes a firm position on the principle:
“Nobody owns this problem, and that is the problem. A custodian protects its clients’ assets, not abandoned ones. Freezing coins is a governance decision for the Bitcoin network, not for the industry.”
Bryn Bennett, Chief Revenue Officer, The Vault
He added that “any freeze would trade quantum risk for a precedent on property rights and network neutrality.” Earlier proposals already exist. Changpeng Zhao, founder of Binance, suggested freezing the roughly 1.1 million BTC attributed to Satoshi if those coins remain untouched as quantum technology advances. Bitcoin developer Jameson Lopp has also proposed restrictions on vulnerable coins. Critics argue that freezing someone’s bitcoin contradicts the promise that no one can confiscate them.
Replacing digital signatures would require agreement among developers, miners, wallet providers, exchanges and users. Post-quantum signatures are larger, which could push up fees or reduce the number of transactions a block can process. Research is under way to limit that impact.
In parallel, a consortium backed by Strategy, BlackRock and Coinbase launched the Bitcoin Security Consortium in July, pledging $15 million over three years to fund Bitcoin security research, including preparations for quantum threats. Coinbase has urged Bitcoin developers to begin the quantum migration now, noting that preparations could take years.
Outlook: Prepare Early, Decide Carefully
The central scenario is a gradual migration driven by open standards and public testing. If the estimates of 856,000 or 500,000 qubits prove accurate sooner than expected, pressure on custodians and developers would rise sharply, and the March 2028 window would become a concrete horizon.
If quantum progress slows, the main risk becomes inertia, with exposed accounts left unchanged for lack of consensus on how to handle them. The freeze debate goes beyond technology, since it touches network neutrality and property rights. The date matters less than the ability to migrate on time.
Sources
Cet article est publié à titre informatif et éducatif. Il ne constitue en aucun cas un conseil en investissement. Faites vos propres recherches (DYOR) avant toute décision.
