Bitcoin Proposal Targets Quantum Threat with Controversial Signature Changes
By John Nada·Apr 15, 2026·4 min read
BIP-361, a new Bitcoin proposal, aims to combat quantum threats but raises concerns about ownership and governance, reflecting a crucial moment for the crypto community.
A new proposal aimed at addressing the looming risk of quantum attacks on Bitcoin has sparked significant debate within the community. The plan, known as BIP-361, seeks to disable Bitcoin's existing signature verification methods over a five-year period. This move is seen by some as a necessary defense against potential quantum vulnerabilities, while others criticize it as a form of confiscation.
BIP-361 proposes a phased approach to transition Bitcoin's users away from current signature schemes, eventually freezing coins that do not migrate to quantum-resistant addresses. Dubbed the "Post Quantum Migration and Legacy Signature Sunset," the proposal would stop users from sending Bitcoin to older address types vulnerable to quantum attacks, and ultimately disable the cryptographic methods the network has relied on to verify transactions since its creation. As noted by co-author Jameson Lopp and five other developers, the proposal emphasizes the urgency of transitioning to a more secure framework as the threat of quantum computing becomes increasingly tangible.
Quantum attacks could theoretically allow advanced computers to derive private keys from public keys on a blockchain, jeopardizing the security of wallets. The moment when a quantum computer emerges with sufficient power to break the encryption used by Bitcoin is known as "Q-Day." The proposal outlines a three-phase timeline that includes blocking access to vulnerable addresses after three years, followed by freezing all legacy coins two years later. This strategy aims to protect over 34% of Bitcoin that currently has exposed public keys, leaving them at risk of theft if a sufficiently powerful quantum computer emerges.
Critics of BIP-361 argue that it contradicts Bitcoin's foundational principle of ownership, encapsulated in the phrase 'not your keys, not your coins.' Frederic Fosco, co-founder of Bitcoin metaprotocol OPNET, labeled the proposal as a form of confiscation, suggesting that it rewrites the narrative of ownership by enabling the protocol to freeze coins for reasons deemed important by its developers. This shift in governance raises concerns about the potential for future interventions, whether for quantum threats or other regulatory compliance.
The implications of adopting BIP-361 could be significant. By rendering existing transactions invalid, it marks the first instance of forcing a choice between collective network security and individual access to funds. Such a contentious upgrade could fracture the network, as dissent over protocol changes could lead to a split among users and miners. As Leo Fan, founder of decentralized compute network Cysic, articulated, this proposal alters the understanding of ownership, making timely migration a prerequisite for maintaining access to funds.
Security experts emphasize the urgency of addressing quantum risks, reflecting the broader shift in the tech landscape. Earlier in March, Google published a formal timeline to transition its infrastructure to post-quantum cryptography by 2029, calling the quantum frontier "closer than may appear." This context underscores a growing consensus around the necessity for proactive measures in the face of evolving technological threats.
Yet, not all stakeholders agree on the necessity of such drastic measures. Enrico Rubboli, founder of layer-2 sidechain Mintlayer, highlighted the precarious balance that Bitcoin's decentralized governance must maintain. He noted that without a hard deadline for migration, the system risks collapse in the event of a quantum theft, as it would expose the vulnerability of all accounts with unprotected public keys. BIP-361 remains in draft status with no activation timeline and depends on BIP-360, a separate quantum-resistant transaction framework still under review.
As discussions around BIP-361 unfold, it is important to recognize the potential consequences of a contested upgrade. An unprotected chain's price could collapse the moment someone demonstrates a single quantum theft, as it would prove that every exposed address is now fair game. This scenario raises critical questions about the long-term viability of Bitcoin if a quantum threat is not adequately addressed.
The debate over BIP-361 reflects a critical crossroads for the Bitcoin community. With quantum computing capable of disrupting the fabric of blockchain security, the choices made today will shape the future of asset ownership and governance in the crypto space. As Chris Peikert, a core researcher at cryptography firm Fhenix Research, noted, adopting BIP-361 would mean that any coins still secured solely by ECDSA signatures would be effectively forfeited. The fundamental principles of Bitcoin are being tested as the community navigates these unprecedented challenges.
As proponents and opponents of BIP-361 grapple with the implications of this proposal, the stakes are high. The path forward remains laden with uncertainty, and the decision-making process surrounding BIP-361 will determine not just the fate of Bitcoin, but potentially the broader landscape of cryptocurrencies in the face of emerging quantum threats.