6.7 Million BTC Have a Deadline
The most consequential Bitcoin Improvement Proposal in years doesn't add a feature. It takes one away.
BIP-361, published in mid-April 2026 by Jameson Lopp and five other researchers, lays out a structured five-year plan to migrate the entire Bitcoin network away from its current elliptic-curve cryptography and toward quantum-resistant signature schemes. The mechanism is simple and blunt: addresses that don't migrate in time will be frozen at the consensus level.
That means roughly 6.7 million BTC sitting in legacy address formats today — including coins in lost wallets, dormant early-miner addresses, and Satoshi's own estimated 1.1 million BTC — could become permanently unspendable if this proposal activates.
Why Now
Bitcoin's current security relies on the Elliptic Curve Digital Signature Algorithm (ECDSA) and Schnorr signatures. Both are considered safe against classical computers but are theoretically vulnerable to a sufficiently powerful quantum computer running Shor's algorithm.
Earlier this year, Google researchers published findings suggesting a cryptographically relevant quantum computer (CRQC) could break ECDSA signatures within approximately ten minutes. No such machine exists today, and most experts place practical quantum threats at least a decade away. But the Bitcoin network moves slowly by design — consensus changes take years to debate, activate, and deploy.
BIP-361's authors argue that waiting until quantum computers are imminent would be too late. The migration needs to start now, while there's time.
The Three Phases
The proposal structures the transition into three stages, each escalating the pressure to move coins into new quantum-safe address formats.
Phase A — No New Deposits to Legacy Addresses (~3 Years After Activation)
The first phase blocks anyone from sending bitcoin to old-style addresses (P2PKH, P2SH, P2WPKH, P2WSH, and P2TR). Users can still spend from these addresses — they just can't receive new funds into them. This forces wallets, exchanges, and services to adopt the new quantum-resistant formats.
Phase B — Legacy Signatures Invalidated (~5 Years After Activation)
The hard cutoff. All legacy ECDSA and Schnorr signatures become invalid at the consensus level. Any bitcoin still sitting in vulnerable addresses is effectively frozen — it can't be spent, can't be moved, and for all practical purposes ceases to circulate.
Phase C — Recovery Via Zero-Knowledge Proofs (Optional, Under Research)
A proposed escape hatch. Owners of frozen coins could use zero-knowledge proofs tied to their BIP-39 seed phrases to demonstrate ownership without exposing private keys, then migrate funds into quantum-safe outputs. This phase remains theoretical and is not yet part of the formal specification.
The Property Rights Problem
The backlash has been immediate and fierce. Across developer forums and social media, critics have labeled BIP-361 "authoritarian" and "predatory."
The core objection: Bitcoin's value proposition rests on the guarantee that no one can seize or freeze your coins without your private key. BIP-361 would do exactly that — not through a hack or a government order, but through a consensus rule change that renders certain coins unspendable.
Adam Back, the Blockstream CEO whose Hashcash invention is cited in the Bitcoin whitepaper, has pushed back on the forced-migration approach. He argues the network should add optional quantum-resistant address types now, letting users migrate voluntarily, without ever freezing legacy coins.
Proponents counter that optional migration would leave a massive attack surface. If even a fraction of vulnerable coins remain unprotected when quantum computers arrive, an attacker could sweep them — crashing the market and undermining trust in Bitcoin's entire security model.
What This Means for Holders
BIP-361 is a draft. No activation timeline has been set. It has not reached the stage of a Bitcoin Core pull request, let alone a soft fork signaling period. But it has shifted the Overton window on quantum preparedness from "someday problem" to "active engineering debate."
If you hold bitcoin in any wallet, the practical implications are straightforward:
- Coins in modern hardware wallets with active firmware updates will almost certainly support new address formats when they arrive.
- Coins in paper wallets, brain wallets, or wallets whose software is no longer maintained would need to be moved manually before any freeze deadline.
- Lost coins and Satoshi's coins would be permanently frozen under this proposal — a feature its authors frame as a security necessity, and its critics frame as theft by consensus.
Bitcoin Gate Take
BIP-361 forces Bitcoin to confront its deepest philosophical tension: immutability versus survival. The proposal is almost certainly too aggressive in its current form — freezing coins at the consensus level sets a precedent that many Bitcoiners will never accept. But the underlying problem is real and getting closer. The most likely outcome is a compromise: optional quantum-resistant addresses ship first, with forced migration debated only if and when quantum computers become a demonstrable threat. Either way, the days of "set it and forget it" cold storage may be numbered. If you're holding coins in legacy formats, start paying attention to your wallet software's upgrade roadmap.