Bitcoin Must Prepare for Quantum Threat Now, Coinbase Says

Coinbase’s quantum advisory council is urging blockchain developers to begin preparing for a post-quantum future now, arguing that the technical work of upgrading Bitcoin, Ethereum, and other networks shouldn’t wait for consensus on what to do with vulnerable or abandoned coins.

In a new report released Thursday, the council identified one of the most contentious questions facing the industry of what happens to the cryptocurrency whose owners never migrate to quantum-safe addresses.

“No quantum computer can break blockchain cryptography right now,” the council wrote. “But timelines are uncertain, and the crypto community needs to start preparing now rather than debating exactly when the threat will arrive.”

Launched in January, Coinbase’s Independent Advisory Board on Quantum Computing and Blockchain brings together researchers from academia and industry, including representatives from Stanford University, the University of Texas at Austin, the Ethereum Foundation, Eigen Labs, Bar-Ilan University, and UC Santa Barbara, to study quantum risks to blockchain networks.

The report comes as researchers warn that a “cryptographically relevant quantum computer”—one powerful enough to crack the elliptic curve digital signatures protecting Bitcoin, Ethereum, and other major blockchains—is more likely than not to exist as early as 2030.

According to the advisory council, the issue could affect millions of Bitcoin sitting in legacy addresses where public keys are already exposed, making them directly vulnerable to a future quantum attack.

“Many of these are believed to be Satoshi’s coins or funds whose owners have long since lost their keys,” they wrote. “Factor in address reuse across other address types, and approximately 7 million Bitcoin total are currently considered quantum-vulnerable.”

The report outlines three options for coins that don’t migrate to quantum-safe addresses. First, permanently freeze (or burn) them after a deadline. Second, do nothing and let users decide, adding that “forcing coins to be burned overrides property rights and sets a precedent for network-level interference that conflicts with Bitcoin’s core principles.” Third, use middle-ground steps like limiting how many vulnerable coins can move per block or accepting special cryptographic proofs in place of legacy signatures, and let users “pre-commit to migrations without publicly moving funds yet.”

“We stress that the above proposals are compatible with each other; there is no reason to not adopt more than one or all of them, since each has its own advantages,” they wrote.

The debate comes as major blockchain networks begin preparing for a post-quantum future.

In January, the Ethereum Foundation formed a team to coordinate Ethereum’s transition to post-quantum security and has explored replacing validator and wallet signatures with quantum-resistant alternatives. This was followed in February by Ethereum co-founder Vitalik Buterin mapping out a quantum upgrade roadmap.

In April, the Coinbase advisory council warned that proof-of-stake networks, including Ethereum and Solana, may be particularly vulnerable to future quantum attacks because the validator signatures used to secure those blockchains rely on cryptography that quantum computers could eventually break.

On Tuesday, the Stellar Development Foundation unveiled a roadmap for migrating users to quantum-safe cryptography. Bitcoin developers, meanwhile, continue to debate how vulnerable coins should be migrated—and what should happen to those that never move.

“The right time to prepare for a cryptographic transition is before it becomes urgent,” a Coinbase Advisory Board spokesperson previously told Decrypt. “Our view is that customer assets are safe today, but the industry should not confuse ‘not imminent’ with ‘not important.’”