Catenaa, Sunday, January 11, 2026-A senior Coinbase executive has cautioned that advances in quantum computing could threaten roughly 33% of Bitcoin’s supply, reigniting debate over the network’s long-term cryptographic security.
David Duong, Global Head of Investment Research at Coinbase, highlighted that Bitcoin’s reliance on elliptic curve cryptography and SHA-256 makes certain addresses vulnerable to future quantum attacks.
Based on data through block 900,000, Duong estimates that 6.51 million BTC, including legacy Pay-to-Public-Key outputs, bare multisig scripts, and some Taproot addresses, could be compromised if a quantum computer capable of running Shor’s algorithm becomes available.
Satoshi-era coins make up a notable portion of this at-risk supply.
Duong emphasized that every transaction temporarily exposes public keys, creating a short-term attack window even before “Q-day,” when quantum machines could break current cryptography.
The warning follows growing institutional attention, including BlackRock flagging quantum risks in its iShares Bitcoin Trust ETF prospectus, and US and EU authorities urging migration to post-quantum cryptography by 2035.
Industry opinions diverge on the immediacy of the threat. Blockstream CEO Adam Back stressed that protections are already being developed, while investors like Nic Carter argue that more attention is needed given potential government and adversary activity.
Capriole Investments founder Charles Edwards warned that a decade could be sufficient for a breakthrough, whereas Michael Saylor noted that quantum advances could ultimately strengthen Bitcoin as active coins migrate to updated standards.
Developers have discussed implementing post-quantum signature schemes, but widespread adoption would likely require a hard fork complicated by dormant wallets and decentralized governance.
Analysts continue to monitor on-chain patterns, highlighting that coins untouched for years could be primary targets if quantum capabilities materialize.
