EU regulators warn quantum computers may threaten $586B in bitcoin

September 24, 2026 at 02:32 PM2 min

This digest was compiled by AI from multiple sources — links to the originals are below.

European financial regulators warned that advanced quantum computers could break blockchain cryptography, putting about 6.9 million bitcoin worth roughly $586 billion at risk. The Joint Committee of the European Supervisory Authorities said the threat could emerge before quantum computing has a viable commercial application. The warning renews debate over whether to freeze bitcoin in legacy addresses with exposed public keys.

Key Facts

European financial regulators warned that advanced quantum computers could break blockchain cryptography, putting about 6.9 million bitcoin worth roughly $586 billion at risk.
The Joint Committee of the European Supervisory Authorities includes the European Banking Authority, European Securities and Markets Authority, and European Insurance and Occupational Pensions Authority.
Older or reused Bitcoin addresses are especially vulnerable because their public keys may already be visible on the blockchain.
The European Commission has urged member states to begin post-quantum transitions by the end of 2026.
A recent IBM report says quantum computing will be in use in four years or less.

Quantum Threat Assessment

European financial regulators warned that advanced quantum computers could eventually break cryptography protecting blockchains, potentially putting about 6.9 million Bitcoin, worth roughly $586 billion, at risk. The warning from the Joint Committee of the European Supervisory Authorities brings fresh urgency to a long-running question for bitcoin of whether to freeze or not freeze the BTC in legacy wallets. In the event that quantum computers one day do become capable of breaking bitcoin’s cryptography, roughly 6.9 million bitcoin, worth roughly $586 billion, are currently vulnerable, according to Cryptoquant. “Threats could materialize earlier than any viable commercial application,” the authorities said in their Autumn 2026 Risk and Vulnerabilities report released Wednesday. An advanced quantum computer “could undermine some cryptography systems widely used to secure communications, transactions, databases and blockchains,” according to the report.

Vulnerable Addresses

Older or reused Bitcoin addresses are especially vulnerable because their public keys may already be visible on the blockchain, allowing a sufficiently powerful quantum computer to derive their private keys. The Satoshi-era bitcoin held in older, legacy addresses or reused addresses could face greater risk if quantum computing advances. In those cases, the public key may already be visible on the blockchain. A sufficiently powerful quantum computer could use it to derive the private key and take control of the coins. Many unspent bitcoin outputs still hide the public key behind a cryptographic hash, leaving them less exposed for now.

Regulatory Response

Bitcoin’s shift to quantum-resistant security would require networkwide consensus and the transfer of exposed coins. The European Commission has urged member states to begin post-quantum transitions by the end of 2026. Although the report does not mention timelines for quantum computing becoming commercially viable, a recent IBM report says it will be in use in four years or less. The European Union warning does not say that a quantum computer capable of breaking bitcoin’s cryptography exists today.