Bitcoin’s developer community has put forward its most aggressive security proposal in the network’s 17-year history. BIP-361, formally titled “Post Quantum Migration and Legacy Signature Sunset,” lays out a phased plan to move every Bitcoin wallet to quantum-resistant cryptography – or permanently freeze the coins inside.
The proposal targets roughly 6.7 million BTC sitting in addresses where public keys have already been exposed through past transactions. At current prices near $77,000, that pool represents more than $500 billion in potentially vulnerable value. Among those coins: an estimated 1.1 million BTC attributed to Satoshi Nakamoto that have never moved.
Why Quantum Computing Threatens Bitcoin Right Now
Bitcoin relies on elliptic curve digital signature algorithm (ECDSA) cryptography to secure transactions. A sufficiently powerful quantum computer could theoretically reverse-engineer private keys from exposed public keys, gaining access to funds without authorization.
Google researchers published findings earlier in 2026 suggesting that quantum machines could break ECDSA signatures within roughly ten minutes under certain conditions. No machine capable of that exists today, but the research compressed what many developers previously considered a 15-to-20-year timeline into something closer to five.
Cardano founder Charles Hoskinson weighed in on April 16, arguing that BIP-361 is effectively a hard fork despite being characterized as a soft fork. He pointed out that the proposal’s zero-knowledge recovery mechanism can’t protect roughly 1.7 million older bitcoins created before BIP-39 seed phrases existed.
The Three-Phase Migration Timeline
BIP-361 breaks the transition into three stages.
Phase A introduces new quantum-resistant address types using post-quantum cryptographic algorithms. Wallet developers would integrate support for these addresses, and Bitcoin holders could voluntarily migrate their funds at any time during this phase.
Phase B sets a migration deadline. After the window closes, any coins that haven’t moved to quantum-safe addresses would be frozen – locked in place and unable to be spent. This is the provision generating the most debate, since it would permanently lock coins belonging to lost wallets, inactive holders, and Satoshi’s stash.
Phase C fully sunsets legacy signature types. Nodes would stop accepting transactions signed with the old ECDSA scheme entirely.
CoinDesk analysis published on April 23 described the real challenge as governance, not mathematics. Freezing Satoshi’s coins would set a precedent that Bitcoin’s protocol can retroactively alter the property rights of any holder who fails to act within a designated window.
The eCash Fork Complication
The quantum debate collided with another proposal on April 24 when long-time developer Paul Sztorc announced eCash, a hard fork of Bitcoin scheduled for block height 964,000 in August 2026. The fork would give every BTC holder equivalent eCash tokens at a 1:1 ratio while also “reassigning” a portion of Satoshi’s coins to early investors – a move the community quickly labeled theft.
Sztorc later posted a second version of the proposal that doesn’t seize Satoshi’s coins, signaling the idea is still fluid. But the overlapping timelines of BIP-361 and eCash have created confusion about which path Bitcoin’s community will ultimately take.
Bitcoin Magazine described the quantum problem as a governance crisis in disguise. A companion proposal called Hourglass would allow quantum attackers to move stolen coins only in limited batches – potentially one BTC per block – throttling the economic damage while transferring fee revenue to miners.
What Bitcoin Holders Should Do Right Now
Holders whose coins sit in addresses that have previously sent transactions have exposed public keys. Those addresses are the ones BIP-361 would target for mandatory migration.
Anyone still using a wallet generated before BIP-39 seed phrases were introduced should begin planning a move to a modern wallet. While BIP-361 hasn’t been activated and no timeline is binding yet, the direction of developer consensus is clear: migration is coming, and voluntary is better than forced.
Forbes ran a profile of Adam Back on April 22 in which the Blockstream CEO pushed back on proposals to freeze quantum-vulnerable coins, arguing that preparation through optional, backward-compatible upgrades is safer than crisis response. His position highlights the split between those who want strict enforcement and those who favor a gentler transition.
FAQ
Will BIP-361 actually freeze Satoshi’s Bitcoin?
If set up as currently proposed, yes. Any coins in quantum-vulnerable addresses that don’t migrate during the Phase B window would be permanently frozen. That includes the estimated 1.1 million BTC attributed to Satoshi.
When would BIP-361 take effect?
No binding timeline has been set. The proposal is still in community review. Phase A could begin within months of consensus, but the full three-phase rollout would likely span several years.
Is my Bitcoin at risk from quantum computers right now?
Not immediately. No quantum computer capable of breaking ECDSA currently exists. But, Google’s 2026 research suggests the timeline may be shorter than previously assumed, which is why developers are pushing for proactive migration.
