A new Bitcoin proposal, BIP-361, aims to protect vulnerable wallets from a future quantum computer by phasing out the legacy signatures that leave many coins exposed, though its author stress
A new Bitcoin proposal, BIP-361, aims to protect vulnerable wallets from a future quantum computer by phasing out the legacy signatures that leave many coins exposed, though its author stresses it is a contingency draft and not a plan ready for activation.
BIP-361 is a Bitcoin Improvement Proposal titled "Post Quantum Migration and Legacy Signature Sunset." It is currently marked Draft and Informational, with an assigned date of February 11, 2026, according to the proposal text. For related coverage, see Two New Wallets Sell 72 BTC, Open 20x Long ETH Bets.
In plain terms, the proposal sets a pre-announced deadline for phasing out older ECDSA and Schnorr signatures. The idea is that failing to upgrade would create added friction for accessing funds, nudging holders toward quantum-resistant addresses. For related coverage, see Spot Bitcoin ETFs Add $132M as Ether ETFs See $36.73M Inflows.
The vulnerable wallets in question are those that have already exposed their public key on-chain. Once a public key is visible, a sufficiently powerful quantum attacker could in theory derive the private key and steal the coins.
The scale of that exposure is the core reason the proposal exists. The BIP states that as of March 1, 2026, over 34% of all bitcoin had already revealed a public key on-chain and could be stolen by a powerful quantum attacker.
Bitcoin Already Exposed 34%+ Share of all bitcoin that BIP-361 says had exposed public keys as of March 1, 2026.The proposal frames wallet safety as a network-level concern rather than an individual one. If a third of the supply is exposed, a successful quantum attack would not just harm a few holders but could undermine confidence across the entire ecosystem.
Some wallets are more exposed than others depending on whether their public key has ever been revealed. Reused addresses and older address formats are generally the most at risk, which is why the debate over dormant coins has intensified alongside broader Bitcoin quantum fears.
The stakes are highest for coins that can no longer be moved by their owners. That concern has fueled a separate governance fight over whether Satoshi's roughly 1.1 million bitcoin should be frozen if left unmigrated, a debate that has divided experts.
Because Bitcoin has no central authority, a response has to move through its technical governance process. That makes a proposal-based path the natural venue, similar to how policy ideas such as a strategic Bitcoin reserve bill get debated openly before any adoption.
The proposal lays out a staged migration rather than a single cutoff. Phase A would begin 160,000 blocks, about three years, after activation, and would disallow sending funds to quantum-vulnerable addresses.
Phase A Delay 160,000 blocks The proposed Phase A restriction window is about three years after activation.Phase B would begin two years after Phase A and tighten verification of ECDSA and Schnorr spends. The abstract describes that step as a flag day five years after activation.
CoinDesk reported on April 15, 2026 that the plan would require holders to migrate coins to quantum-resistant addresses or risk having those coins permanently frozen by the network, in its explainer on the proposal. That freezing risk is the sharpest concern for everyday users.
For wallet providers, the practical work would center on supporting quantum-resistant address types and guiding users through migration well before any deadline. The multi-year runway is designed to give that ecosystem time to adapt, a consideration that also matters to the roughly 2,000 institutional investors reporting Bitcoin holdings in recent filings.
The most important caveat comes from the author himself. Jameson Lopp said on April 15, 2026 that BIP-361 is not a spec and not proposed for activation, calling it a rough idea for a contingency plan that needs more R&D.
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 readers should watch next is whether the draft attracts enough research and community support to evolve into a formal specification. For now it remains an informational contingency idea, and no activation timeline has been proposed.
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.
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