Bitcoin’s quantum fight pits Adam Back against coin-freeze proposal

• Blockstream CEO Adam Back backs “optional” quantum-resistant upgrades and rejects freezing quantum‑vulnerable wallets.
• His stance clashes with BIP‑361, a three‑phase plan that would eventually invalidate legacy signatures and freeze unmigrated coins, including Satoshis stash.
• The debate highlights how Bitcoin must balance intergenerational security against hard limits on property rights and censorship resistance.

Bitcoins (BTC) long‑running debate over the quantum computing threat has flared again after Blockstream CEO Adam Back used Paris Blockchain Week to argue for optional, opt‑in upgrades instead of forcibly freezing old wallets. “Preparation is much safer than hasty responses in a crisis,” Back said, insisting that the network should build quantum‑resistant paths now while preserving user choice and property rights.

Back described todays quantum computers as “essentially lab experiments” and noted he has followed the field for more than 25 years, during which progress has been “incremental,” but warned that Bitcoin cannot afford to wait until a real‑world break occurs. He also pushed back on calls to lock down coins by protocol fiat, arguing that the Bitcoin community has shown it can coordinate under pressure and that “bugs have been identified and fixed within hours” in past emergencies.

Back‘s comments directly contrast with BIP‑361, “Post‑Quantum Migration and Legacy Signature Sunset,” a proposal from Jameson Lopp and five co‑authors that would gradually phase out quantum‑vulnerable outputs and ultimately freeze unmigrated coins. The draft, which builds on BIP‑360’s soft‑fork framework, introduces a quantum‑resistant output type and targets early formats such as pay‑to‑public‑key (P2PK) addresses that expose public keys on‑chain.

Estimates cited by CoinMarketCap and other publications say roughly 1.7 million BTC — about 34% of total supply, including Satoshi Nakamoto‘s early holdings valued around $70–$80 billion at current prices — still sit in quantum‑exposed address types. Under BIP‑361’s three‑phase 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 go further by rendering old ECDSA and Schnorr signatures invalid, meaning any coins that had not been migrated to quantum‑resistant outputs would be effectively frozen on the network. Lopp and co‑authors frame this as necessary to prevent “intergenerational theft” by a future quantum adversary and to avoid a scenario where an attacker can seize dormant wallets and crash trust in Bitcoins fixed‑supply narrative.

Back and other critics counter that deliberately freezing coins crosses a red line for decentralization and censorship resistance, amounting to protocol‑level expropriation even if done in the name of security. They argue that Bitcoin has historically relied on social consensus and voluntary upgrades, and that the community should instead focus on offering robust quantum‑safe options, education and incentives so users migrate out of genuine self‑interest rather than under threat of losing control over their funds.

In previous crypto.news coverage of protocol‑level governance battles and hard‑fork debates, similar tensions have surfaced between risk‑mitigation schemes and the movement‘s founding principles, from block‑size wars to taproot activation. The quantum fight, now centered on BIP‑361 and Back’s rival vision of optional defenses, is shaping up as the next major test of how far Bitcoiners are willing to go to “save” the network without breaking what made it attractive in the first place.