Europol warns quantum computers could threaten exposed wallet keys

Europol warned that future quantum computers could threaten cryptocurrency funds when attackers can see a wallet’s public key, potentially deriving the private key needed to authorize transfers. The agency said current quantum machines cannot carry out the attacks and did not predict when capable systems might emerge. Its reports describe a prospective risk to wallet security, not an imminent breakdown of blockchain networks. The distinction is between the cryptographic keys that authorize transactions and the hash functions used in important parts of blockchains. Europol said public-key cryptography is the main point of exposure: a sufficiently powerful quantum computer could theoretically calculate a corresponding private key from an exposed public key, allowing an attacker to move the funds without permission. By contrast, the agency characterized blockchain hash functions as comparatively resistant to quantum attacks. Bitcoin holdings are not equally exposed. Public keys may remain hidden until an address is used to send a transaction, while some address types reveal them by default.