CoinDesk
Coinbase says Bitcoin should begin preparing for quantum computers now, before a machine capable of deriving private keys from exposed public keys could put vulnerable wallets at risk. The exchange recommends flexible transaction formats, staged adoption of post-quantum signatures and reliable implementations that work for both individual users and institutions.
Why it matters
Bitcoin currently uses ECDSA and Schnorr signatures. A sufficiently powerful quantum computer could, in theory, use a public key to derive its private key and spend the bitcoin it protects. No such machine exists today, but Coinbase argues preparation cannot wait for a confirmed threat: Bitcoin consensus changes and ecosystem migrations can take years. Google researchers have suggested a capable machine could arrive by 2029, though that remains a projection.
Coinbase favors transaction formats that can accommodate new signature types without rebuilding the system. It points to P2MR (BIP-360) and P2TRv2 as proposals that could offer flexibility. A staged transition could let users adopt hybrid signatures, where either a traditional ECDSA or Schnorr key, or a post-quantum key, can authorize a spend. The exchange also urges careful evaluation of stateful signature schemes, which require wallets to track one-time keys, alongside stateless alternatives.
Market impact
For exchanges and custodians, post-quantum security also needs to work with multiparty computation, which can distribute key protection rather than rely on one person or device. Coinbase says implementations should be dependable across platforms and avoid risks such as secret leakage or unsafe key reuse.
The dispute over dormant or late-migrating wallets is separate. Coinbase does not prescribe what should happen to forgotten coins, but says that debate should not delay protections for active wallets. Any proposed rescue mechanism would itself need to be quantum-safe.
Frequently asked questions
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How could a quantum computer put Bitcoin wallets at risk?
A sufficiently powerful quantum computer could derive a private key from an exposed public key, then use it to spend the bitcoin in a vulnerable wallet.
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What does Coinbase mean by staged post-quantum protection?
It describes allowing wallets to adopt hybrid signatures before a broader transition is finalized. One possible setup would authorize spending with either a traditional ECDSA or Schnorr key, or a post-quantum key.
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Why does Coinbase support flexible Bitcoin transaction formats?
Flexible formats could support new post-quantum signature types without requiring the whole transaction system to be rebuilt. Coinbase points to P2MR (BIP-360) and P2TRv2 as proposals.
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Why are stateful post-quantum signatures a concern for wallets?
They require wallets to track one-time signing keys and avoid reusing them. Coinbase says stateless alternatives should also be supported to reduce risks from lost records or key reuse.
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How does Coinbase suggest handling dormant Bitcoin wallets?
Coinbase says the question of dormant or late-migrating wallets should be debated separately so it does not delay broader protections. Any rescue method should itself be quantum-safe.
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