Bitcoin's BIP-361 Quantum Fix Splits Community Over Address Freezing

A proposed Bitcoin improvement to address quantum vulnerability has divided the cryptocurrency community over whether to freeze legacy addresses, including those attributed to Satoshi Nakamoto. The BIP-361 proposal, which went live on April 14, has sparked debate between prominent figures including software engineer Jameson Lopp, who supports the measure, and Adam Back, who opposes it.

The BIP-361 Proposal and Community Divide

BIP-361 introduces a “post quantum migration and legacy signature sunset” mechanism to protect Bitcoin from potential quantum computing attacks. The proposal remains in draft phase with no deadline for signaling support.

The proposal works in two stages. In phase A, new transactions to quantum-vulnerable addresses would be frozen, forcing the network to shift to post-quantum (PQ) address types. Phase B would block all spending to vulnerable addresses, potentially with a five-year grace period. According to the proposal, responsibility for quantum-proof holding will rest with individual wallet holders, each required to upgrade their addresses.

Rough estimates suggest approximately 6.7M BTC may be at risk due to being held in early, less secure addresses. The argument for freezing is that hacked funds could be sold, undermining Bitcoin’s price and eroding trust in the network.

Community reaction has been mixed. Cypherpunk Jimmy Song tweeted on April 16, 2026: “BIP361 is a complete non-starter for me, but I would still like to see an attempt by its supporters to put it on the Bitcoin network as either a soft fork or a hard fork. Not because I want to get a ‘fork dividend,’ but because we need to see how these things play out.” Supporters of BIP-361 argue that the original Bitcoin ethos of self-ownership without centralized censorship is outdated in the face of quantum threats.

Quantum Hacking Feasibility and Counterarguments

Opponents of BIP-361 argue that quantum computing poses a less imminent threat than proponents suggest. Satoshi Nakamoto’s addresses use the P2PK standard, which exposes public keys and leaves them theoretically vulnerable to quantum attacks. However, Satoshi’s holdings are spread across more than 22,000 addresses, meaning each would need to be individually hacked before coins could be released.

Critics also note that quantum computers are not yet readily available outside research contexts, and using them for attacks may be prohibitively expensive in the near term. While quantum algorithms continue to improve and lower the computational requirements for attacks, viable quantum hacking remains far from practical reality.

Alternative solutions have been proposed, including a hard fork to a quantum-proof network at a predetermined block with a long grace period for claiming coins—an approach similar to one suggested by Satoshi Nakamoto in Bitcoin’s early days. Some community members suggest leaving the network as-is, treating old wallets as a bounty for quantum computer developers.

The debate underscores a fundamental tension: how to ensure Bitcoin’s long-term survival against future threats without undermining its market value, reputation, and the proof-of-work consensus achieved to date. Address freezing may protect large holdings and prevent a flash crash if wallets are compromised, but critics argue it contradicts Bitcoin’s core ethos of avoiding censorship and asset freezes.

FAQ

What is BIP-361 and when was it proposed? BIP-361 is a proposal to address Bitcoin’s potential vulnerability to quantum computing attacks through a “post quantum migration and legacy signature sunset” mechanism. The proposal went live on April 14 and remains in draft phase with no deadline for signaling support.

How much Bitcoin could be at risk from quantum attacks? Rough estimates suggest approximately 6.7M BTC may be at risk due to being held in early, less secure addresses, particularly those using the P2PK standard like Satoshi Nakamoto’s holdings.

Is quantum hacking a realistic near-term threat to Bitcoin? According to the source, quantum computers are not yet readily available outside research contexts, and using them for attacks may be prohibitively expensive in the near term. While quantum algorithms are improving, viable quantum hacking remains far from practical reality.