Overview
- Coinbase research chief David Duong estimates about 6.51 million BTC, or roughly 32.7% of supply, could be vulnerable to future quantum attacks, citing Project 11 data.
- Most exposure stems from address reuse, accounting for nearly 70% of the vulnerable coins, along with script types such as Pay-to-Public-Key, bare multisig, and Taproot.
- Analysts outline two vectors: long‑range attacks against outputs with already exposed public keys and short‑range windows during spending when keys are revealed.
- Developers are drafting and testing quantum‑resistant signature upgrades, while NIST guides critical systems toward post‑quantum cryptography by 2035 and BlackRock has disclosed quantum risk in its iShares filing.
- Timelines remain contested among experts, but Coinbase emphasizes that migrating signature security is the near‑term priority and regards quantum mining as a lower concern given current hardware limits.