BIP-361 proposes freezing quantum-vulnerable Bitcoin within five years

Jameson Lopp and five co-authors had BIP-361 merged into the Bitcoin BIPs repository on April 14, 2026. The initial merge version proposed a three-phase plan to phase out quantum-vulnerable cryptographic signatures and freeze any unmigrated bitcoin within five years. The proposal could affect approximately 5.6 million dormant bitcoin worth roughly $420 billion, including an estimated 1.1 million BTC attributed to Satoshi Nakamoto. Lopp describes it as a contingency plan to prevent quantum computers from enabling attackers to steal lost coins, warning that credible quantum threats could trigger immediate market panic. The proposal has sparked fierce debate, with critics like Mati Greenspan and Leo Fan arguing it violates Bitcoin's core principles of immutable, censorship-resistant ownership by making property rights conditional on migration activity.

BIP-361 proposal to freeze quantum-vulnerable Bitcoin

• ▪Any change from BIP-361 would require consensus across the decentralized Bitcoin network
• ▪BIP-361 was merged into the Bitcoin BIPs repository on Tuesday, April 14, 2026
• ▪BIP-361 proposes invalidating transactions from quantum-vulnerable wallets over time
• ▪Jameson Lopp described BIP-361 as a rough idea for a contingency plan rather than a finalized specification
• ▪BIP-361 is a proposal from Jameson Lopp and others that explores phasing out bitcoin's current cryptographic signatures
• ▪BIP-361 could potentially freeze assets that fail to migrate from quantum-vulnerable wallets

Quantum computing threat to dormant Bitcoin holdings

• ▪Bitcoin was trading at $73,725.85 as of the article publication date
• ▪The 5.6 million dormant bitcoin was worth roughly $420 billion at April 2026 prices
• ▪Approximately 5.6 million bitcoin has not moved in over a decade
• ▪Jameson Lopp and other analysts consider the 5.6 million dormant bitcoin likely lost
• ▪Jameson Lopp believes dormant coins could pose systemic risk if quantum computing gives attackers the ability to grab them

Community debate over freezing versus Bitcoin's core principles

• ▪BIP-361 has sparked fierce debate within the Bitcoin community

Perspective of BIP-361 proponents (Jameson Lopp and co-authors)

• ▪BIP-361 represents a contingency plan to prevent quantum computers from enabling attackers to steal dormant bitcoin
• ▪BIP-361 would require unmigrated coins to be frozen within five years of implementation
• ▪BIP-361 could affect approximately 1.1 million BTC attributed to Satoshi Nakamoto if those coins remain unmigrated
• ▪BIP-361 aims to phase out legacy cryptographic signatures vulnerable to quantum attacks through a three-phase implementation

Perspective of Bitcoin immutability advocates (including Mati Greenspan and Leo Fan)

• ▪BIP-361 would transform Bitcoin ownership from absolute to conditional based on migration activity
• ▪Freezing dormant bitcoin through BIP-361 would violate Bitcoin's core principle of immutable ownership
• ▪Implementing BIP-361 would undermine Bitcoin's promise as unstoppable money that cannot be seized or frozen
• ▪The debate over BIP-361 centers on philosophical questions about Bitcoin's identity rather than purely technical considerations