Quantum Threat to Blockchain Exposes $586 Billion in Bitcoin

European financial regulators have issued a warning about the potential threat of quantum computing to blockchain security. According to the Joint Committee of the European Supervisory Authorities, advanced quantum computers could break the encryption protecting blockchains before they become commercially viable.

The regulators estimate that around 6.9 million Bitcoin, worth approximately $586 billion, are stored in legacy or reused wallets that could be vulnerable to a future quantum attack. This is because their public keys are already visible on the blockchain, which a powerful enough quantum computer could theoretically use to derive the private key and seize control of the coins.

Bitcoin's decentralized structure means that upgrading to quantum-resistant signatures would require network-wide consensus among developers, miners, and users, a process that has historically taken years. Furthermore, holders of exposed coins would need to move them into safer wallet formats before an attack becomes feasible.