Coinbase advisory warns Ethereum, Solana face quantum risk

Coinbase’s Independent Advisory Board on Quantum Computing and Blockchain released a report Tuesday warning that proof-of-stake blockchains such as Ethereum and Solana could be exposed to future quantum attacks. The board said the risk comes from the cryptographic signature schemes that validators and wallets use to secure transactions and reach consensus.

Ethereum validators use BLS signatures, while Solana uses Ed25519 for validators and many users. The report explains that a quantum computer capable of breaking those algorithms could allow attackers to forge validator signatures and disrupt consensus. The board noted that fixing the problem may require changes to core consensus code as well as to wallet software.

A board spokesperson said: “The right time to prepare for a cryptographic transition is before it becomes urgent. Our view is that customer assets are safe today, but the industry should not confuse ‘not imminent’ with ‘not important.'”

The report flagged wallet cryptography as a long-term vulnerability. Wallet signatures prove ownership and authorize transactions; if they were broken, attackers could impersonate owners and move funds. Wallets with public keys visible on-chain are most exposed. The advisory estimated roughly 6.9 million Bitcoin have public keys visible on the blockchain. The report raised questions about how networks should treat accounts that never upgrade, including lost keys, inactive accounts and abandoned wallets.

The advisory noted that quantum computers capable of breaking modern digital-signature algorithms do not yet exist and would require a major leap in capability. It added that Bitcoin’s core infrastructure — including mining, hash functions and the historical ledger — is not considered meaningfully vulnerable under current understanding. The report also said that theoretical quantum advantages, such as those from Grover’s algorithm, do not translate to practical wins for current proof-of-work puzzles because of large overheads.

The report described technical challenges in moving to quantum-resistant cryptography. Quantum-safe signature schemes are much larger than today’s signatures, which could slow transaction processing, increase storage needs and raise costs. The advisory pointed to work in the Ethereum community, including a February proposal by co-founder Vitalik Buterin to replace BLS validator signatures, KZG commitments and ECDSA wallet signatures with quantum-resistant alternatives.

Coinbase formed the advisory board in January and assembled academic and industry experts to study these risks and outline long-term options. The council includes researchers from multiple universities and organizations. The report aims to ground the discussion in technical detail and to encourage practical migration planning so custodians, exchanges and users have time to adopt quantum-ready formats without rushed changes.

The board did not predict an imminent threat but emphasized that preparation will take years. Networks, custodians and wallet providers will need to evaluate protocol changes, user migrations and the handling of dormant accounts as part of any transition to cryptography that can withstand future quantum computers.