BIP 361’s Post-Quantum Migration Plan Sparks Debate Over Bitcoin Freezing

Bitcoin developers have ignited fierce debate with a new proposal aimed at shielding the network from future quantum computer attacks that could crack its cryptography. 

On Tuesday, cypherpunk Jameson Lopp and five co-authors published BIP 361, titled “Post Quantum Migration and Legacy Signature Sunset.” The draft, posted to the Bitcoin BIPs GitHub repository, outlines a three-phase plan to push users toward quantum-resistant addresses and eventually disable old signature schemes vulnerable to quantum threats.

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The concern stems from how Bitcoin handles public keys. Early addresses, including many from Satoshi Nakamoto’s era, expose keys directly on the blockchain. A sufficiently powerful quantum computer could theoretically derive private keys from them, putting an estimated 6.7 million BTC—worth tens of billions—at risk of theft.

BIP 361 builds on the earlier BIP 360, which introduced post-quantum output types. Once activated via soft fork:

• Phase A, roughly three years later, would block new sends to legacy addresses, nudging adoption of safer formats.
• Phase B, five years after activation on a fixed “flag day,” would invalidate ECDSA and Schnorr signatures entirely, freezing any unmigrated quantum-vulnerable UTXOs.
• Phase C, still under discussion, could offer a recovery path for some frozen funds using zero-knowledge proofs to verify ownership, such as via BIP-39 seed phrases.

Proponents argue the structured timeline creates clear incentives for migration without waiting for a crisis. Many supporters asked to hurry up with the plan, pointing to the slow pace of ecosystem-wide upgrades across wallets, exchanges, and services, while overall reaction on X was swift and overwhelmingly negative. 

Critics called the plan “authoritarian” and “confiscatory,” accusing it of violating Bitcoin’s core promise of immutable property rights. 

“This quantum proposal is highly authoritarian and confiscatory,” commented a user, “There is no good rationale for forcing the upgrade and rendering old spends invalid. Upgrade should be 100% voluntary.” 

Many rejected Phase B outright, insisting upgrades must remain voluntary and that inactive or lost coins—including potential Satoshi holdings—should not face forced freezes. Others labeled it central planning that treats Bitcoin like an HOA rather than decentralized money.

Developers behind the BIP, including Bitcoin Stack Exchange contributor Mark “Murch” Erhardt who announced it, framed the move as a pragmatic defense. Yet the backlash highlights deep tensions over balancing long-term security against the protocol’s resistance to retroactive rule changes. 

Given Bitcoin’s consensus-driven process means any soft fork requires broad miner and node support, the proposal is currently testing the community’s tolerance for enforced upgrades. 

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