Bitcoin developers have proposed BIP-361 to freeze early P2PK addresses against potential quantum threats. The proposal has sparked controversy because it could affect long-dormant holdings, possibly including Satoshi-era coins, highlighting the industry’s shift from theoretical concern to practical defense.

Charles Hoskinson says roughly 34% of Bitcoin has exposed public keys and could be vulnerable to quantum attacks in the 2030s. He argues BIP-361 is insufficient and says major institutions may eventually push Bitcoin toward a hard fork to address the risk.

Six Bitcoin developers, including Jameson Lopp, have proposed draft BIP-361 to address future quantum computing risks by restricting vulnerable old addresses. The proposal could affect about 34% of BTC supply and has sparked debate over security versus user sovereignty.

Six Bitcoin developers, including Jameson Lopp, have introduced draft proposal BIP-361 to address future quantum computing risks. The plan could affect around 34% of BTC supply by restricting vulnerable old addresses, sparking debate over security and user sovereignty.

IOSG argues that quantum computing is less a sudden “endgame” for crypto than a long-duration repricing of blockchain security assumptions. In its latest analysis, the firm frames Q-Day—the point when a fault-tolerant quantum computer gains practical power to break mainstream public-key cryptography—as a systemic deadline for Web3 infrastructure. The report says Shor’s algorithm could undermine the cryptographic trust roots of major public blockchains such as Bitcoin and Ethereum, both of which rely heavily on elliptic-curve cryptography. The bigger constraint, however, is not the absence of post-quantum cryptographic tools, but the difficulty of coordinating migration across protocols, wallets, custodians, exchanges, bridges, and governance structures. IOSG highlights that Bitcoin’s biggest challenge lies in exposed public keys, dormant UTXOs, and the political question of whether legacy coins should be frozen or left vulnerable. Ethereum, by contrast, faces a broader engineering challenge: replacing cryptographic assumptions across the execution layer, consensus layer, data availability stack, and parts of the ZK ecosystem. The report concludes that while the broader preparation period may span 5 to 15 years, the practical engineering comfort window could be only 5 to 8 years.

A MarsBit analysis argues that quantum computing is unlikely to erase blockchains overnight, but it could trigger a long, systemic rewrite of crypto security assumptions. The piece frames the main risk around “Q-Day,” the point at which a cryptographically relevant fault-tolerant quantum computer becomes capable of breaking mainstream public-key cryptography in practice. Current estimates place that window mostly around 2035–2045, with more aggressive scenarios suggesting 2030–2035. The report says the real issue is not the absence of post-quantum cryptography, but whether the crypto industry can coordinate migration before attacks become economically viable. Bitcoin’s challenge is concentrated in exposed public keys, dormant legacy UTXOs, signature bloat, and governance conflict over how to treat coins that never migrate. Ethereum, by contrast, faces a broader full-stack transition involving EOAs, validator signatures, KZG commitments, data availability, and parts of the ZK stack. The article concludes that post-quantum migration is fundamentally a coordination and governance problem, not a simple cryptographic swap. For markets, repricing may begin well before Q-Day itself if hardware roadmaps accelerate, resource estimates fall, or regulators and custodians start demanding PQC compliance.

Onchain analyst James Check argues that the most realistic quantum risk is concentrated in about 1.7 million BTC held in vulnerable Satoshi-era P2PK addresses. A forced sell-off could trigger a bear market, but historical market data suggests Bitcoin could absorb the pressure over months rather than face a fatal collapse.

Charles Hoskinson outlined three Bitcoin responses to quantum threats, saying even under BIP-361 about 1.7 million BTC could remain vulnerable, including roughly 1.1 million coins believed to belong to Satoshi Nakamoto.