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Bitcoin Researchers Propose BIP-361 to Freeze Quantum-Vulnerable Coins

Bitcoin Researchers Propose BIP-361 to Freeze Quantum-Vulnerable Coins

At Paris Blockchain Week, Adam Back called for an optional post-quantum Bitcoin upgrade, while the updated BIP-361 draft would phase out vulnerable addresses over five years, highlighting a sharper split over how to address quantum risk.

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Fact Check
The core substance of the claim is strongly supported by the primary source, BIP 361: Post Quantum Migration and Legacy Signature Sunset at https://bips.xyz/361. That document explicitly describes a phased migration plan: Phase A disallows sending funds to quantum-vulnerable addresses after about 160,000 blocks (~3 years), and Phase B occurs 2 years after Phase A, meaning about 5 years after activation, when nodes reject ECDSA/Schnorr spends and vulnerable coins become frozen. CoinDesk’s article 'Bitcoin developers are trying to build quantum defenses. Your coins could pay the price.' corroborates that this proposal was updated on April 15 and summarizes the same three-stage structure. PANews independently repeats the same timeline. The only slight caveat is that the exact 'updated on April 15' detail comes from corroborating reporting rather than from a fetched changelog page, but the main claim about the three-stage plan, increasing restrictions on legacy address use, and freezing older wallets after five years is well supported.
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Summary

Debate over draft BIP-361 expanded after Blockstream CEO Adam Back said at Paris Blockchain Week that Bitcoin should pursue an optional quantum-resistant upgrade rather than freezing unmigrated holdings. The latest report says about 6.9 million BTC could be at risk, including roughly 1 million BTC linked to Satoshi Nakamoto and 5.6 million long-dormant BTC. This contrasts with BIP-361, a soft fork proposal updated on April 15 that would phase out quantum-vulnerable addresses over five years and freeze coins that are not migrated. The dispute centers on whether Bitcoin should mitigate potential future quantum threats through voluntary migration or enforce stricter protocol-level restrictions on older address types.

Terms & Concepts
  • BIP-361: A draft Bitcoin Improvement Proposal aimed at reducing quantum-related risk by transitioning Bitcoin away from vulnerable legacy cryptographic schemes.
  • Soft fork: A backward-compatible Bitcoin protocol upgrade that tightens rules without requiring all nodes to leave the existing network.
  • Quantum-resistant: Describes cryptographic methods designed to remain secure against attacks from quantum computers.