April 2026 — A significant development has emerged in the Bitcoin community with the introduction of Bitcoin Improvement Proposal 361 (BIP-361), titled “Post Quantum Migration and Legacy Signature Sunset.” Proposed by cypherpunk Jameson Lopp and a team of five other developers, this draft aims to proactively address the long-term threat posed by quantum computing to legacy Bitcoin addresses.
The proposal seeks to gradually phase out quantum-vulnerable address types and signature schemes, encouraging (and eventually enforcing) migration to more secure, quantum-resistant standards.
Understanding the Quantum Threat to Bitcoin
Quantum computers, once sufficiently advanced, could potentially break current elliptic curve cryptography (ECDSA and Schnorr signatures) used in Bitcoin. Legacy formats — particularly early Pay-to-Public-Key (P2PK) addresses and reused addresses where public keys are exposed on-chain — are especially at risk.
Estimates suggest that a substantial portion of Bitcoin supply (potentially up to several million BTC, including early Satoshi-era coins) remains in these vulnerable structures. If a powerful quantum computer becomes capable of deriving private keys from public keys, it could lead to unauthorized spending and significant market disruption.
BIP-361 introduces a structured, phased approach to mitigate this risk before it materializes.
Key Elements of BIP-361
The proposal outlines a three-phase migration plan with clear timelines after potential activation:
Phase A (approx. 3 years after activation): Prevents new Bitcoin from being sent to legacy quantum-vulnerable addresses. This creates a strong incentive for users and services to migrate funds to quantum-safe address types.
Phase B (approx. 2 years after Phase A): Invalidates legacy signature schemes network-wide, effectively freezing any remaining coins in vulnerable addresses. Holders would technically still own the coins, but they would become unspendable using current methods.
Long-term Recovery Option: The proposal leaves room for future mechanisms, such as zero-knowledge proofs, that could potentially allow recovery of frozen funds for legitimate owners who missed the migration window.
This mechanism is designed as a “private incentive” system — rather than forcing immediate action, it uses the network’s consensus rules to encourage proactive security upgrades.
Why This Proposal Matters
BIP-361 represents a forward-thinking step in Bitcoin’s evolution:
Network Security: It strengthens Bitcoin’s resilience against future quantum attacks, protecting the integrity of the protocol for decades to come.
User Responsibility: It places the onus on holders, exchanges, and wallet providers to move funds to safer addresses in a timely manner.
Market Implications: Successful implementation could boost long-term confidence in Bitcoin as a robust digital asset, while any large-scale freezing of legacy coins (including dormant early wallets) may influence supply dynamics and market sentiment.
At Aston Pirs Group, we see this as a responsible and necessary discussion within the Bitcoin community. While the proposal is still in draft stage and requires broad consensus for activation, it highlights the network’s ability to adapt to emerging technological threats.
Outlook and Recommendations: Insights from Aston Pirs Group Experts
Although quantum computers capable of breaking Bitcoin’s cryptography are not an immediate reality, proactive measures like BIP-361 demonstrate maturity in the ecosystem. Key factors to monitor include:
Community feedback and potential revisions to the BIP.
Development of quantum-resistant signature schemes (such as those based on lattice cryptography or hash-based signatures).
Wallet and exchange readiness to support new address types.
Broader regulatory and institutional views on quantum risk management.
We recommend that Bitcoin holders and institutions:
Review their current wallet addresses and migrate funds from legacy formats (especially P2PK and reused addresses) to modern, more secure types where possible.
Use hardware wallets and services that already support newer address standards.
Stay informed about the progress of BIP-361 and related proposals (e.g., BIP-360 for quantum-resistant transactions).
Conclusion
Bitcoin Proposal BIP-361 underscores the community’s commitment to long-term security and resilience in the face of advancing quantum computing technology. By targeting quantum-vulnerable addresses through a phased migration and eventual sunset of legacy signatures, it aims to safeguard the network without disrupting its decentralized nature.
Aston Pirs Group continues to closely track Bitcoin protocol developments, on-chain security trends, and emerging risks in the digital asset space. We provide clients with professional analysis and strategic guidance to navigate both opportunities and challenges in cryptocurrency markets.
The future of Bitcoin lies in continuous improvement — and proposals like BIP-361 are essential steps toward building a more quantum-resistant financial infrastructure.