TL;DR
- Coinbase The Quantum Advisory Board says planning for post-quantum migration must begin before quantum attacks become practical.
- The report estimates that about 7 million bitcoins are at risk because public keys are exposed through outdated formats or address reuse.
- About 1.7 million bitcoins are said to be held in legacy public key payment addresses, including early mined coins that are likely abandoned.
- The council portrays the issue as a long-term challenge to governance, rather than an immediate emergency.
Coinbase’s Quantum Advisory Board has warned that Bitcoin and other crypto networks need to start planning for a post-quantum migration long before quantum computers can realistically crack public key encryption today.
In a June 11 report titled “Post-Quantum Migration and Migration Coins,” the council framed the issue as a technical migration problem and governance dilemma. The key question is not just how to move users to quantum-secure addresses, but what the network should do about coins that are never migrated.
The report says that no current quantum computer can break the cryptography that secures crypto assets today. However, he sees the risk as strategically important because decentralized ecosystems can take years to coordinate major upgrades, especially when it comes to user funds, abandoned wallets and equity.
Why are some Bitcoins more vulnerable?
A Coinbase report estimates that approximately 7 million BTC are currently at risk from quantum risk. This number includes coins in address types where public keys are already visible, as well as coins associated with address reuse, where the public key becomes exposed after the transaction is broadcast.
One particularly sensitive category is legacy public key payment addresses. The report says that about 1.7 million bitcoins are held in these P2PK addresses, where the public keys are directly visible. This bucket includes early mined coins, including coins associated with Bitcoin’s earliest history, as well as funds that may have been lost or abandoned.
The issue is different from a regular software upgrade. Active users can be told to move funds to quantum-secure addresses once appropriate signing schemes are ready. Abandoned coins, lost wallets, and dormant early addresses are more difficult because there may be no one available to transfer them.
Governance dilemma
The Council identified several broad paths. One option is to set a hard deadline for migration, after which non-migrating vulnerable funds can be frozen or burned to prevent future quantum theft. This approach prioritizes network integrity but raises serious questions regarding property rights.
The second option is to maintain the rights and do nothing, leaving the vulnerable coins untouched. This avoids coercive intervention but may allow future attackers to steal exposed funds if quantum capabilities eventually become strong enough.
The report also discusses centrist ideas. This includes limiting the rate at which legacy addresses can be transferred in any block-like period of time, sometimes described as an hourglass mechanism, and using zero-knowledge proofs such as BIP-361 to allow users to prove ownership of legacy keys without revealing sensitive information.
Planning before the crisis
The Council’s practical recommendation is to separate engineering work from the governance battle. In other words, the industry can start building and testing quantum-secure signatures now while continuing to discuss how to deal with abandoned or weak coins later.
This distinction is important. Waiting until quantum attacks are imminent would leave networks trying to coordinate technology upgrades, wallet migration, exchange support, and community governance under pressure. Starting early gives developers and users more room to test systems and avoid hasty decisions.
For Bitcoin holders, the point is not that currencies suddenly become unsafe today. The problem is that long-term digital assets need long-term security planning. The more crypto networks increase in value over decades, the more important it is to plan crypto transitions before they become emergencies.
The Coinbase report adds another key voice to that conversation. The debate over cryptocurrencies will not be easy, but the council’s message is clear: the question of post-quantum migration is no longer theoretical enough to be ignored.
