Adam Back Proposes Bitcoin's Quantum Resistance Upgrade Should be Optional, Not Mandatory

April 16 — Blockstream CEO Adam Back advocated for an opt-in upgrade to add quantum resistance to Bitcoin during Paris Blockchain Week on Wednesday, diverging from a previously proposed mandatory freeze solution. “Being prepared in advance is critical to driving changes in a controlled manner, rather than reacting hastily to security issues in a crisis,” Back said. He also highlighted Bitcoin’s existing emergency coordination capabilities: “Vulnerabilities have been identified and fixed within hours in the past. When things become urgent, focus will shift, and consensus will form.” Back’s stance contrasts with BIP-361, a proposal co-drafted by Jameson Lopp and five other developers. Updated April 15 in Bitcoin’s official codebase under the theme “Post-Quantum Migration and Legacy Signature Deprecation,” the plan calls for phasing out quantum-vulnerable addresses over five years via a soft fork—ultimately freezing assets (including Satoshi Nakamoto’s bitcoins) that haven’t completed the migration. Advances in quantum computing have accelerated the debate. Last month, Google Quantum AI released a study stating a quantum computer could break elliptic curve encryption with fewer than 1,200 logical qubits. Its superconducting qubit system would need fewer than 500,000 physical qubits to crack Bitcoin’s encryption in minutes—down roughly 20x from prior estimates. Researchers peg ~6.9 million BTC at risk of quantum attacks, including ~1.7 million from Satoshi-era mining rewards. On the same day, BitMEX Research proposed an alternative mitigation: creating a “canary fund” of quantum-vulnerable addresses, with a full freeze triggered only if a transfer occurs from any address in the fund.