Coinbase Urges Early Move to Quantum-Resistant Bitcoin Security

Coinbase, which holds approximately 5% of all Bitcoin on behalf of clients such as banks, asset managers, and hedge funds, is urging the network to start preparing for quantum-resistant security. Although the threat remains a future possibility, the key challenge is whether Bitcoin can coordinate a gradual transition to stronger cryptography before quantum computing becomes a serious risk.

Bitcoin transactions use digital signatures to verify that someone attempting to spend funds has control over them. The network currently relies on Elliptic Curve Digital Signature Algorithm (ECDSA) and Schnorr signatures, both of which remain secure against existing computing capabilities.

However, a sufficiently advanced quantum computer could potentially derive a private key from an exposed public key, creating a way for attackers to spend vulnerable Bitcoin without authorization.

A quantum machine capable of breaking widely used cryptographic systems is known as a cryptographically relevant quantum computer (CRQC). The source report references a projection from Google researchers suggesting that such a machine could emerge as early as 2029.

Preparing for this possibility presents a coordination challenge. Bitcoin operates through a decentralized network, meaning significant protocol changes require broad agreement among participants. Wallet providers, custodians, exchanges, and other infrastructure operators would also need time to develop, test, and deploy new security measures.

Coinbase argues that preparation should begin well before a CRQC becomes available, rather than allowing a potential emergency to dictate the migration timeline.

Although there is currently no evidence that quantum computers are breaking Bitcoin’s digital signatures, transitioning to new cryptographic standards could take years. Early preparation would give developers time to evaluate potential solutions and upgrade infrastructure without implying that an immediate quantum attack is underway.

Coinbase’s Bitcoin Quantum Strategy Leaves Room for Multiple Designs

Coinbase wants Bitcoin transaction outputs, which establish the conditions under which funds can be spent, to support post-quantum cryptography without requiring a complete redesign of the transaction system whenever signature technology changes.

A more flexible output structure could make it easier to introduce, replace, or combine quantum-resistant signature schemes as research progresses and security requirements evolve. Coinbase identifies P2MR, associated with BIP-360, and P2TRv2 as potential approaches worth examining.

The company also supports a gradual migration rather than an immediate, network-wide switch. One possible solution would use a hybrid arrangement that allows the same funds to be spent through either a conventional ECDSA or Schnorr key or a post-quantum key.

Such a model could enable Bitcoin holders to adopt stronger protection before a complete transition takes place. However, Coinbase has not finalized the preferred technical design or established how and when older signature schemes should eventually be phased out.

Wallets that depend on tracking signing-key states require particular attention. If a wallet loses, corrupts, or incorrectly manages records of previously used signing keys, key reuse could create opportunities for forged signatures.

For this reason, Coinbase recommends considering stateless cryptographic alternatives alongside stateful designs. This would give wallet developers more options and reduce dependence on systems that require perfectly maintained records.

Software Security and Wallet Reliability Remain Essential

Coinbase also emphasizes that the quality of implementation will be crucial to any quantum-resistant upgrade. Introducing stronger cryptography alone will not guarantee security if the surrounding software contains exploitable weaknesses.

The company calls for consistent signature verification across different platforms, safeguards against timing-based information leaks, straightforward security settings, and protection against failures in the random-number generators used during signing.

These measures are intended to prevent a transition to quantum-resistant cryptography from introducing new vulnerabilities into Bitcoin wallets and related infrastructure. Careful implementation and testing will therefore be as important as selecting the underlying cryptographic algorithms.

Institutional compatibility presents another major consideration. Coinbase wants post-quantum Bitcoin solutions to support multiparty computation (MPC), a technology that distributes key-related operations among multiple participants rather than relying on a single person or device.

This capability matters for exchanges, custodians, and financial institutions that manage substantial amounts of Bitcoin. If a new security scheme works effectively only for individual wallets, larger organizations could face additional technical barriers and a slower migration process.

Dormant Bitcoin and Exposed Public Keys Complicate the Transition

Eventually restricting or retiring ECDSA and Schnorr spending could create challenges for Bitcoin held in older address formats. Some dormant wallets may belong to people who have lost access to their private keys, while certain legacy address types have already exposed their public keys.

Coinbase warns that an attacker with access to a sufficiently powerful quantum computer could potentially target vulnerable holdings before the broader public becomes aware of that capability.

However, the company has not endorsed a specific policy for Bitcoin that is dormant, quantum-exposed, or believed to be permanently lost. Instead, it argues that the treatment of these holdings should be debated separately so disagreements over legacy funds do not prevent developers from advancing protections for users who can upgrade.

Any proposed mechanism for recovering or otherwise addressing vulnerable legacy Bitcoin would also need to account for quantum security.

For now, the immediate priority is not to select a single transaction format or signature scheme as the definitive solution. Coinbase’s position is that developers should evaluate flexible cryptographic designs, implementation risks, and institutional requirements while addressing the politically sensitive question of legacy Bitcoin separately.

Starting this work early could give the Bitcoin ecosystem more time to prepare for potential quantum threats without suggesting that the network faces a confirmed attack today.

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