Europol Warns Quantum Computers Threaten Exposed Wallet Keys, Not Blockchains

Europol’s European Cybercrime Centre concluded Wednesday that cryptocurrency wallets, rather than the blockchains they operate on, are the primary point of exposure to future quantum-computing attacks. In a report published October 7, the European Union’s law-enforcement agency urged developers, exchanges, miners, and users to begin a phased shift to post-quantum security now, even though machines capable of carrying out such attacks do not yet exist.

The report draws a distinction that earlier warnings often blurred: the hash functions that secure a blockchain’s history, including Bitcoin mining, remain far more resistant to quantum attack than the public-key cryptography used to control wallets. A sufficiently powerful quantum computer could derive a private key from a public key and spend the associated funds. “Cryptocurrencies will not collapse due to quantum computing,” Europol said, and “proactive adaptation, rather than systemic collapse, is the most likely outcome.”

Why Wallets, Not Blockchains, Are the Exposure

The distinction turns on where keys become visible. When a Bitcoin address moves funds, its public key is recorded onchain, which would let a future quantum computer work backward toward the private key. Bitcoin’s Elliptic Curve Digital Signature Algorithm, or ECDSA, is the vulnerable element, not the SHA-256 hash function that underpins mining and the ledger. Europol estimates roughly 6.9 million bitcoin sit in addresses with exposed public keys, including early pay-to-public-key outputs and long-dormant holdings from the network’s earliest days, the population at the center of the debate over whether quantum computers can break Bitcoin.