Bitcoiners are pushing to secure legacy wallets before the quantum era arrives by freezing quantum-vulnerable P2PK addresses with exposed public keys. The BIP-361 proposal prevents future quantum computers from using public data to derive private keys and steal funds.

BIP-361 is a draft Bitcoin Improvement Proposal introduced in April 2026 by professional cypherpunk Jameson Lopp and five other contributors. Lopp argues that the defensive proposal creates a private incentive to upgrade the Bitcoin ecosystem’s protection of its collective interest and trust against malicious attackers exploiting breakthroughs in quantum computing. 

The proposal further suggests a three-phase migration plan with a scheduled timeline following the upgrade activation.

Phase A (3 years post-activation) prohibits users from sending new BTC to old-style addresses, which can still send but cannot receive new funds. Phase B (5 years post-activation) will invalidate legacy signatures (ECDSA and Schorr), while Phase C (recovery) proposes a rescue plan using zero-knowledge proofs (ZKPs). 

BIP-361 targets Satoshi’s BTC stash

The proposal targets approximately 6.7 million BTC (~34% of total supply) held in legacy formats, such as P2PK, where public keys are already exposed. It explicitly mentions that Satoshi Nakamoto’s early reserves totaling about 1.1 million BTC are highly vulnerable to quantum derivation.

Frozen funds remaining at these addresses will supposedly become unspendable using the most common BTC transfer methods today.

The main reason this matters is that academic roadmaps now estimate a cryptographically relevant quantum computer as early as 2027-2030, according to a mid-2025 McKinsey report. And this is worrying because victims may not know the attack is underway.

Quantum attackers could derive a private key from known public keys, then transfer all the funds weeks or months later, covertly bleeding out victims under the radar of chain watchers.

The BIP-361 proposal emphasizes that there is near-certainty that all P2PK private keys will be uncovered and used to drain funds from unsuspecting victims. 

The proposal argues that the longer this migration is postponed, the harder it will become to coordinate exchanges, custodians, wallets, and miners.

Economically motivated attackers could stay hidden for as long as possible, while malicious attackers could be out to destroy everything. Some may even be motivated to destroy value and trust in Bitcoin rather than extract value. A clear timeline with defined deadlines is the only credible defense. 

MARA Protocol engineer says BIP-361 will quantum-harden Bitcoin

Hunter Beast, MARA Protocol Engineer and co-author of BIP-360, describes the broader BIP-361 roadmap as a necessary precaution to quantum-harden Bitcoin before threats of the quantum computing era become practical.

He emphasizes that quantum threats are not as far from reality as currently perceived. Beast notes that the accelerated development of new quantum techniques suggests that the timeframe to act may be as short as three years. 

The BIP-361 proposal also emphasizes that Bitcoin remains secure only for the foreseeable future, warning that the industry should avoid waiting for last-minute emergency responses. However, critics argue that the forced migration and freezing of funds are authoritarian and contrary to Bitcoin’s ethos as an “opt-in” decentralized asset. 

Bitcoin researcher Mark Erhardt faced immediate pushback after circulating the proposal, with commenters labeling it confiscatory for its mandate to invalidate old signatures and freeze funds.

TFTC founder Marty Bent also characterizes the approach as inconsistent with the Bitcoin community’s long-standing expectations regarding the coin’s non-coercive nature.

Meanwhile, Bernstein analysts suggest that the market has already partially priced in quantum risks through recent drawdowns. The analysts view the threat as real but manageable without the need for an immediate, forced overhaul. 

Major players like Coinbase and BlackRock have also recently flagged quantum computing as a material risk to the crypto industry in regulatory filings. Their concern adds weight to the urgency of the BIP-361 discussion.

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