Coinbase says Bitcoin should begin preparing for quantum computing threats before a machine capable of breaking its cryptography is announced.
The cryptocurrency exchange and custodian said in a blog post that protecting Bitcoin will require more than choosing a new digital signature system. Developers must also consider how users will move their funds, how exchanges will safeguard assets and what happens to coins whose owners have lost access.
Coinbase described the transition as a complex, multiyear process. Changes to Bitcoin’s shared rules and the migration of funds can take years, the company said, making early preparation necessary.
The company said it holds about 5% of all bitcoin in existence. It is preparing its own systems, working with developers and researchers, and supporting open-source efforts through engineering resources and participation in the Bitcoin Security Consortium.
The post presents considerations for community discussion rather than a final Coinbase position. It does not announce an agreed upgrade or establish a migration deadline.
Digital signatures allow Bitcoin’s network to verify that the holder of a secret key authorized a transaction. A sufficiently powerful quantum computer could threaten the cryptography behind existing signatures, potentially putting funds with exposed public keys at risk.
Coinbase wants developers to evaluate designs that can accommodate different quantum-resistant signature systems over time. That flexibility would allow protections to be replaced or supplemented without redesigning the entire structure used to set spending conditions.
The company also called for testing tailored to Bitcoin. New signatures must fit limited transaction space and remain practical for the computers that independently verify the blockchain.
Evaluations should examine transaction size, fees, verification speed and the time needed to migrate vulnerable funds, Coinbase said. Performance in general cryptography tests may not reflect the costs of using a system across Bitcoin.
Another concern is whether a signature system requires users to maintain a record of previous signing steps. Such systems, known as stateful signatures, can offer smaller signatures and faster verification, but mistakes in recordkeeping can enable forgery.
An outdated backup or failed update could cause a wallet to reuse signing information, the company warned. Exchanges would face additional challenges coordinating servers across locations. Coinbase wants clear operating guidance and an option that does not require maintaining signing history.
For institutional custody, the company also favors compatibility with multiparty computation, which allows several participants to cooperate in signing without concentrating all signing authority in one place.
Coinbase suggested evaluating a staged transition that gives funds alternative spending routes using either an existing signature or a quantum-resistant one. This could allow active wallets to prepare while broader rules remain under discussion.
Dormant and inaccessible coins pose harder questions. Potential responses include restrictions on older signatures, spending limits, freezes and rescue mechanisms, although Coinbase did not endorse a final policy.
Any rescue mechanism must resist quantum attacks and prevent an attacker from claiming funds merely by knowing an exposed public key, the company said.
Coinbase urged the community to continue that debate alongside technical preparations so disputes over abandoned funds do not delay work on quantum-resistant signatures.
