Why Is Quantum Risk Becoming A Bitcoin Governance Issue? Coinbase’s Independent Advisory Board on Quantum Computing and Blockchain has estimated that roughly 7 million bitcoin sit in addresses exposed to a future quantum attack, turning a long-running technical concern into a larger governance question for the bitcoin community. The report does not argue that bitcoin cryptography can be broken today. It instead says the migration process could take years, meaning the network cannot wait until a cryptographically relevant quantum computer exists before deciding how vulnerable coins should be handled. The exposure is divided into two main groups. About 1.7 million bitcoin are held in roughly 20,000 legacy pay-to-public-key addresses, where the public key itself is visible onchain. Those coins are directly exposed if quantum computers become capable of deriving private keys from public keys. Many of them are believed to be early-era coins, including coins assumed to belong to bitcoin’s pseudonymous creator or owners who may have lost access long ago. The larger risk comes from address reuse. Citing estimates from quantum-security firm Project Eleven, the board said about 5 million bitcoin are vulnerable because their public keys have already been revealed. Unlike the older legacy coins, much of this bucket appears to involve active users, including large cold wallets held by known exchanges and wallets showing recent activity. Why Does Address Reuse Matter? Bitcoin addresses are safest when public keys are not exposed until coins are spent. When users reuse addresses, or when older address formats reveal public keys more directly, that protection weakens in a future quantum scenario. That distinction matters because the governance debate is not only about abandoned coins. If all vulnerable bitcoin belonged to owners who lost their keys years ago, the policy question would be narrower. The board’s report says the more difficult issue