BIP-361 Could Lock Away Old Bitcoin to Prevent Quantum Exploits

2026-04-24 · Source: HackerNoon · Field: Technology & Digital — Blockchain & Distributed Ledger Technology, Cybersecurity & Data Privacy, Emerging Technologies & Innovation · Depth: Intermediate, medium

Summary

BIP-361, titled "Post Quantum Migration and Legacy Signature Sunset," is a new proposal drafted by Jameson Lopp and a team of researchers aiming to protect the Bitcoin network from future quantum computer attacks. The proposal outlines a phased plan to transition away from older, quantum-vulnerable signature methods, particularly those used in early Bitcoin transactions that expose public keys. An estimated 1.7 million BTC, and potentially over one-third of the total supply, are currently held in these vulnerable address types, including coins from the Satoshi era. The plan involves blocking new sends to legacy addresses in approximately three years, followed by disabling old signature verification routes entirely a couple of years later, rendering unmigrated coins unspendable. This initiative is framed as a defensive measure to neutralize dormant holdings that could otherwise become targets for quantum-capable attackers, potentially destabilizing the market.

Key takeaway

For investors and long-term holders of Bitcoin, especially those with funds in very old or unspent transaction outputs (UTXOs) from the network's early days, you should proactively move your coins to modern, quantum-resistant address formats. Failing to migrate before the proposed deadlines in BIP-361 could result in your funds becoming permanently unspendable, safeguarding the network but at the cost of your access.

Key insights

BIP-361 proposes a phased migration to quantum-resistant Bitcoin addresses, sunsetting legacy signatures to mitigate future quantum threats.

Principles

• Proactive defense against emerging threats.
• Network integrity outweighs legacy access.
• Adaptation without central authority.

Method

The proposal involves a multi-stage implementation: first, blocking new transactions to legacy addresses, then disabling old signature verification entirely, with a possible third stage for recovery options.

In practice

• Migrate old Bitcoin holdings to new addresses.
• Wallet developers must integrate quantum-safe schemes.
• Assess risk of dormant, early-era BTC.

Topics

• BIP-361
• Quantum Computing Threat
• Bitcoin Security
• Post-Quantum Cryptography
• Legacy Bitcoin Addresses

Code references

• bitcoin/bips

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Editorial summary, takeaway, and curation by AIssential. Original article published by HackerNoon.