That format works similarly to Bitcoin's existing Taproot addresses but with the quantum-vulnerable key path removed, protecting new coins going forward.
Bitcoin News
Cypherpunk Jameson Lopp and five co-authors have proposed a three-phase plan to freeze BTC held in quantum-vulnerable addresses on the Bitcoin network, including an estimated $74 billion stash linked to an early Bitcoin pioneer. The proposal, called the Post Quantum Migration and Legacy Signature Sunset, was posted as a draft under BIP-361 to GitHub on Tuesday.
The proposal addresses a known risk to the Bitcoin network: approximately 1.7 million BTC locked in early pay-to-public-key addresses that are not protected against quantum computing attacks. If quantum computers advance to the point where they can break these address types, the coins could be stolen and the resulting sell pressure could significantly damage network value and trust.
BIP-361 is the second stage of a broader effort that began with BIP-360, released in February, which proposed a soft fork introducing a new output type called pay-to-Merkle-root. That format works similarly to Bitcoin's existing Taproot addresses but with the quantum-vulnerable key path removed, protecting new coins going forward. Roughly 34% of the current BTC supply remains in address types that BIP-360 alone would not protect.
Under BIP-361's first phase, three years after activation, no new Bitcoin could be sent to old-style addresses. All users would be expected to have migrated to quantumresistant address types by that point.
The second phase, five years after activation, would invalidate old-style signatures entirely, effectively freezing any Bitcoin still held in vulnerable addresses. A third phase provides a potential recovery mechanism using zero-knowledge proofs, allowing holders who missed the deadline but still possess their seed phrase to reclaim frozen funds.
The authors described the freeze mechanism as a private incentive to upgrade, arguing that coins lost or frozen make the remaining supply slightly more valuable, while coins recovered through a quantum attack would reduce the value held by all other participants. Lopp told Cointelegraph on Wednesday that BIP-361 is not currently positioned for adoption and described it as a rough sketch of one possible approach, with various aspects expected to evolve as research continues.
The proposal drew pushback from portions of the Bitcoin community. Several prominent figures rejected it publicly, with critics describing the plan as authoritarian and a philosophical departure from Bitcoin's core principles, given that it would render existing holdings unspendable for any holder who fails to migrate in time.
Supporters of the proposal framed the freeze as a defensive measure, arguing the network has an interest in preventing a malicious actor from exploiting quantum capabilities to extract large amounts of BTC and undermine both value and trust.
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