At Paris Blockchain Week on Wednesday, Blockstream CEO Adam Back proposed optional updates to make Bitcoin resistant to quantum computing threats. This comes a day after Bitcoin developers advocated for a mandatory freeze on quantum-vulnerable coins.
“Proactive measures are crucial. Controlled changes are far safer than crisis-driven reactions,” stated Back at the conference. He highlighted Bitcoin’s effective emergency coordination, noting that “bugs have been swiftly identified and fixed within hours. Urgency brings focus and fosters consensus.”
His stance contrasts with BIP-361, a proposal by Jameson Lopp and five other developers advocating for phasing out quantum-vulnerable addresses over five years. The plan, updated on April 15 in Bitcoin’s official repository as “Post Quantum Migration and Legacy Signature Sunset,” involves a phased soft fork to freeze coins that do not migrate, affecting even the holdings of Satoshi Nakamoto.
This debate underscores a growing divide among Bitcoin developers regarding how to address “Q-Day”—the anticipated emergence of quantum computers powerful enough to break Bitcoin’s encryption. Research from Google and Caltech indicates such computers might appear within years, not decades.
The discussion has intensified with rapid advancements in quantum computing. Recent research from Google Quantum AI suggests that quantum machines could compromise elliptic curve cryptography with fewer than 1,200 logical qubits. According to the study, a system using superconducting qubits would require under 500,000 physical qubits to break Bitcoin’s security in minutes, a significant reduction from earlier estimates.
Approximately 6.9 million BTC are at risk, including about 1.7 million in Satoshi-era mining rewards, as per the researchers’ findings.
Other stakeholders in the Bitcoin ecosystem propose varied solutions to mitigate quantum computing threats. BitMEX Research suggested creating a “canary fund” of quantum-vulnerable coins, freezing them only if spent from the address. Meanwhile, some researchers are exploring ways to create quantum-resistant Bitcoin transactions without a network fork, and other networks like Ethereum, Solana, Naoris Protocol, and Circle’s Arc Network are investigating quantum resistance.