Summary
– Blockstream CEO Adam Back endorses optional, opt-in quantum-resistant upgrades and opposes freezing quantum-vulnerable wallets.
– His view conflicts with BIP‑361, a three-phase plan that would invalidate legacy signatures and freeze unmigrated coins, including Satoshi’s holdings.
– The debate underscores a trade-off between intergenerational security and limits on property rights and censorship resistance.
Bitcoin’s debate over the quantum computing threat reignited after Blockstream CEO Adam Back, speaking at Paris Blockchain Week, argued for optional, opt-in upgrades rather than forcibly freezing old wallets. Back said “preparation is much safer than hasty responses in a crisis,” urging the network to build quantum-resistant paths now while preserving user choice and property rights.
Describing today’s quantum computers as “essentially lab experiments,” Back noted incremental progress over more than 25 years but warned Bitcoin must not wait for a successful attack. He pushed back on locking coins by protocol fiat, saying the community can coordinate under pressure and has fixed urgent bugs within hours in past emergencies.
BIP‑361 would freeze 1.7 million BTC if users fail to move
Back’s stance contrasts with BIP‑361, “Post‑Quantum Migration and Legacy Signature Sunset,” a proposal from Jameson Lopp and co‑authors that would phase out quantum-vulnerable outputs and ultimately freeze unmigrated coins. Building on BIP‑360’s soft‑fork framework, it introduces a quantum‑resistant output type and targets early formats like pay‑to‑public‑key (P2PK) addresses that reveal public keys on‑chain.
Estimates put roughly 1.7 million BTC — about 34% of supply, including Satoshi Nakamoto’s early holdings worth tens of billions — in quantum-exposed address types. Under BIP‑361’s schedule, Phase A would begin three years after activation and ban new payments to legacy addresses while still allowing spending from them. Five years after activation, Phase B would render old ECDSA and Schnorr signatures invalid, freezing any coins not migrated to quantum‑resistant outputs.
Lopp and co‑authors argue this is needed to prevent “intergenerational theft” by future quantum adversaries and to avoid attackers seizing dormant wallets, undermining confidence in Bitcoin’s fixed supply. Critics like Back counter that deliberately freezing coins violates decentralization and censorship resistance, amounting to protocol-level expropriation even if framed as security.
They say Bitcoin’s history favors social consensus and voluntary upgrades, and that efforts should focus on offering robust quantum-safe options, education, and incentives so users migrate voluntarily rather than under threat of losing access to funds.
This clash echoes past protocol governance disputes — from block-size wars to taproot activation — framing the quantum question as the next major test of how far Bitcoiners will go to protect the network without undermining the principles that made it attractive.