Just over 10,000 bitcoins — out of the roughly 20 million in circulation — are sitting in wallets that have actually suffered a quantum attack.
This figure comes from CoinShares, a crypto asset management company, which found in February that only 10,230 coins were both vulnerable to quantum computing and linked to wallet addresses with publicly visible cryptographic keys.
At current prices, that’s about $730 million, which the company likens to normal business rather than a market crisis.
A steel frame takes shape in Chicago
The discovery comes at an inauspicious moment. This week, PsiQuantum co-founder Peter Shadbolt posted a photo to X showing the Chicago construction site where his company is building what it calls the world’s first commercially useful quantum computer.
Workers made 500 tons of steel in six days. The structure will house a machine capable of processing 1 million qubits – a unit of quantum computing power.
Scientists say that capacity, in theory, is enough to break the type of encryption protecting Bitcoin wallets.
Time to build big quantum computers. Five hundred tons of steel in six days. Delivery date Cryoplant breathing down our neck. Thanks to the hundreds of people who have joined this mission pic.twitter.com/eqSwsESusK
— Pete Shadbolt (@PeteShadbolt) March 5, 2026
The company raised $1 billion for the project, which was announced in September, with chipmaker Nvidia as a key partner.
PsiQuantum says the facility is designed to support fault-tolerant quantum computing and serve as infrastructure for next-generation AI systems.
For context, the largest quantum computer currently operating at the California Institute of Technology operates at 6,100 qubits. The jump to 1 million represents a scale that is unprecedented in the industry.
What would really be at stake
Bitcoin encryption relies on 256-bit cryptographic keys. A previously published paper published last month put the number of qubits needed to crack a 2,048-bit key at around 100,000 – suggesting that a 1 million-qubit machine could mathematically do the job.
But experts have long noted that the raw qubit count is only part of the equation. Error rate and system stability are just as important.
BTCUSD trading at $68,470 on the 24-hour chart: TradingView
Not all Bitcoin wallets face equal exposure. Coins held at addresses that have never been transacted, known as Unspent Transaction Outcomes or UTXOs, are at risk, especially those whose public keys have been exposed on the blockchain. Many of these wallets date back to the early days of Bitcoin.
Developers are already working on a fix
Bitcoin developers debated how to respond. One option on the table is a hard fork – a fundamental change to the network’s code – to introduce post-quantum cryptography.
The co-author of BIP-360, a proposal aimed at making Bitcoin quantum resilient, said the upgrade could take up to seven years.
PsiQuantum, for its part, has said it has no intention of using its technology to attack Bitcoin. Founder Terry Rudolph made this point publicly at the Bitcoin Quantum Summit last July.
Experts in the field say that the real quantum threat to Bitcoin is still at least a decade away.
Construction is currently underway in Chicago – 500 tons of steel and counting.
Featured image from Unsplash+/Alex Shuper, chart from TradingView
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