TL; DR
- from Coinbase The Quantum Advisory Council says post-quantum migration planning must begin before quantum attacks become practical.
- The report estimates that approximately 7 million BTC are quantum vulnerable because public keys are exposed or reused via legacy formats.
- About 1.7 million BTC are said to be in old Pay-to-Public-Key addresses, including early mined and possibly abandoned coins.
- The council views the issue as a long-term governance challenge, rather than an immediate emergency.
Coinbase’s Quantum Advisory Council has warned that Bitcoin and other crypto networks should start planning for post-quantum migration well before quantum computers can realistically break current public-key cryptography.
In a June 11 report titled “Post-Quantum Migration and Abandoned Coins,” the council described the issue as both a technical migration problem and a governance dilemma. The key question is not only how to move users to quantum-safe addresses, but also what the network should do with coins that are never migrated.
The report says that no current quantum computer can break the cryptography that protects crypto assets today. However, it is argued that the risk is strategic because in decentralized ecosystems, major upgrades can take years to coordinate, especially when there are user funds, abandoned wallets and ownership rights involved.
Why Some Bitcoin Is More Visible
The Coinbase report estimates that approximately 7 million BTC are currently quantum vulnerable. That figure includes coins in address types where public keys are already exposed, as well as coins associated with address reuse, where a public key is made public after a transaction is broadcast.
A particularly sensitive category are outdated Pay-to-Public-Key addresses. According to the report, approximately 1.7 million BTC are located on these P2PK addresses, where public keys are directly visible. That bucket contains early mined coins, including coins related to Bitcoin’s earliest history, as well as funds that could be lost or abandoned.
The problem is different than with a regular software upgrade. Active users can be told to move funds to quantum-safe addresses once suitable signature schemes are ready. Abandoned coins, lost wallets and dormant early addresses are more difficult because there may be no one available to move them.
The governance dilemma
The council outlined several broad paths. One option is a hard migration deadline, after which unmigrated vulnerable funds could be frozen or burned to prevent future quantum theft. This approach prioritizes network security, but raises serious questions about property rights.
A second option is to retain the rights and do nothing, leaving vulnerable coins untouched. That avoids forced intervention, but could allow future attackers to steal exposed funds if quantum capabilities eventually become strong enough.
The report also discusses middle ground ideas. These include limiting the rate of how much can be moved from older addresses in a block-like time interval, sometimes described as an hourglass mechanism, and using zero-knowledge proofs such as BIP-361 to let users prove ownership of old keys without revealing sensitive information.
Planning before the crisis
The practical recommendation of the council is to separate the technical activities from the administrative battle. In other words, the industry can start building and testing quantum-safe signatures now, while still debating how to handle abandoned or vulnerable coins later.
That distinction is important. Waiting until quantum attacks are imminent would strain networks trying to coordinate technical upgrades, wallet migrations, exchange support, and community governance. Starting early gives developers and users more room to test systems and avoid hasty decisions.
For Bitcoin holders, it’s not like coins are suddenly unsafe these days. It is that long-lived digital assets need long-lived security planning. The more value there is in crypto networks in recent decades, the more important it becomes to plan cryptographic transitions before they become an emergency.
Coinbase’s report adds another important voice to that conversation. The debate over abandoned coins won’t be easy, but the council’s message is clear: the post-quantum migration issue is no longer theoretical enough to ignore.