A Bitcoin proposal known as BIP-361 aims to protect vulnerable wallets from a future quantum computing attack, laying out a staged plan to freeze and migrate coins whose public keys are already exposed on-chain. Despite its recent resurgence in discussion, the draft is not new and remains far from activation.
TLDR KEYPOINTS
- BIP-361 is a draft informational proposal titled “Post Quantum Migration and Legacy Signature Sunset,” assigned in February 2026.
- It targets wallets whose public keys have been revealed on-chain, which a powerful quantum attacker could exploit.
- The plan is phased, unaudited in parts, and has no activation timeline set.
What BIP-361 Proposes for Vulnerable Wallets
BIP-361 is a draft informational Bitcoin proposal titled “Post Quantum Migration and Legacy Signature Sunset,” assigned on February 11, 2026 with Jameson Lopp and five co-authors listed. For related coverage, see H.R.8957: New Bill Proposes Strategic Bitcoin Reserve With Transparent Management.
The “vulnerable wallets” in question are those whose public keys have already been exposed on the blockchain. A sufficiently powerful quantum computer could, in theory, derive the private key from an exposed public key and spend the coins. For related coverage, see Strategic Bitcoin Reserve Bill Drops 1M BTC Target, Adds 20-Year Lockup.
The scale is significant: more than 34% of all bitcoin had revealed a public key on-chain as of March 1, 2026, according to the proposal, defining the pool of coins it is trying to protect.
The mechanism is a set of phases. Phase A would stop new sends to quantum-vulnerable addresses, while Phase B would invalidate ECDSA and Schnorr spends at a flag day five years after activation, effectively sunsetting legacy signatures.
The proposal ties into the same quantum-risk debate behind Bitcoin’s earlier quantum freeze proposal for the protocol, which sought to lock down at-risk coins rather than let them be swept.
Why the Proposal Matters for Bitcoin Wallet Security
The risk BIP-361 addresses is not an active exploit today but a “harvest now, decrypt later” scenario, where exposed public keys sit on the chain until quantum hardware matures enough to break them.
Crucially, the plan is deliberately gradual rather than an immediate cutoff. The draft gives Phase A a 160,000-block delay, roughly three years, before restrictions would take effect.
The trade-off is stark. Sunsetting legacy signatures protects exposed coins from future theft, but it also means holders who never migrate could see their spends rejected, a limitation that separates BIP-361 from consensus-light approaches like a quantum-safe Bitcoin with no consensus changes.
Recovery for affected users is the unresolved piece. A standalone Phase C is still to be determined and would rely on a zero-knowledge proof of possession of a corresponding BIP-39 seed phrase, meaning protection is not universal for every wallet.
Jameson Lopp, who wrote the proposal, has publicly downplayed how ready it is. He said BIP-361 is not a spec proposed for activation but a contingency idea that still needs more research and development.
Thoughts on BIP-361:
* I know folks don't like it. I don't like it myself. I wrote it because I like the alternative even less.
* It isn't a spec, nor is it proposed for activation. It's a rough idea for a contingency plan that needs more R&D.
* I hope it never needs to be…
— Jameson Lopp (@lopp) April 15, 2026
Source: @lopp on X
What Comes Next if BIP-361 Gains Support
The proposal is still early-stage. Bitcoin Magazine reported on April 15, 2026 that BIP-361 remained in draft form with no activation timeline set.
The draft does sketch concrete deployment mechanics. It proposes a BIP9-style activation with a start time of January 1, 2027 UTC, a 90% mainnet threshold of 1,815 blocks, and a min_activation_height of 709632.
Any adoption would require broad social consensus across node operators, miners, wallets, exchanges, and custodians, similar to how other soft-fork efforts such as BIP 110’s stalled miner support have struggled to clear that bar.
Work on the recovery side is advancing separately. CoinDesk reported on July 19, 2026 that Project Eleven’s prototype recovery proof runs in 243 milliseconds on a laptop, though the scheme remains unaudited and incomplete.
Market reaction has been muted. Bitcoin traded at $64,492, up about 0.39% over 24 hours, with sentiment leaning cautious as the crypto Fear & Greed Index sat at 28, in “Fear” territory.
Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency and digital asset markets carry significant risk. Always do your own research before making decisions.