Quantum

Cryptocurrency

Bitcoin

Europe's top law enforcement agency has issued a measured but pointed warning to the crypto industry: quantum computing is not going to destroy Bitcoin's blockchain, but it could drain the wallets of millions of holders who have exposed their public keys.
<cite>On October 7, 2026, Europol's European Cybercrime Centre (EC3) published two reports on how quantum computing could affect crypto and encrypted data.</cite> The agency's central finding drew a clear line between the underlying blockchain and the wallets people use to hold their coins.
<h2 id="wallets-are-the-weak-point-not-the-chain">Wallets Are the Weak Point, Not the Chain</h2>
<cite>Cryptocurrency wallets, rather than blockchains themselves, are the main point of exposure to future quantum-computing attacks, Europol said.</cite><cite>Blockchain hash functions, including those protecting Bitcoin's transaction history and mining process, are considerably more resistant to quantum attacks than the public-key cryptography securing wallets.</cite>
<cite>Roughly 6.9 million bitcoin sit in addresses with exposed public keys, including early pay-to-public-key outputs and many long-dormant holdings.</cite> That figure accounts for around 30% of Bitcoin's total supply. <cite>The distinction is especially critical for addresses from the earliest days of Bitcoin, referred to as the "Satoshi era," whose public keys have already become visible on-chain.</cite><cite>A powerful enough quantum computer could use those keys to derive the corresponding private key.</cite>
<cite>Europol said exposed keys cannot be made safe retroactively, an issue that has sparked debate across the Bitcoin community over whether to freeze BTC in Satoshi-era wallets as the quantum threat grows.</cite><cite>Quantum computers capable of carrying out such attacks do not exist yet, and Europol did not predict when they will. However, the agency said "proactive adaptation, rather than systemic collapse, is the most likely outcome."</cite>
<h2 id="migration-at-scale-a-76-day-problem">Migration at Scale: A 76-Day Problem</h2>
<cite>Europol cited a 2024 study estimating that converting every Bitcoin unspent transaction output (UTXO) to a quantum-resistant format would require at least 76 days of cumulative block space.</cite><cite>Reserving 25% of each block for the migration would stretch that process to about 300 days.</cite> Unlike a centralised system, Bitcoin has no single authority that can mandate an overnight upgrade.
<cite>Europol's recommended response is a phased, systematic move to quantum-resistant cryptography, a call directed at blockchain developers, wallet providers, policymakers, and everyday users alike.</cite><cite>The European Commission's roadmap requires member states to begin transitioning to post-quantum security measures by the end of 2026.</cite>
<cite>NIST has finalized three post-quantum standards and urges organizations to begin migration as soon as possible.</cite><cite>Draft BIP-361 proposes a planned migration away from legacy ECDSA and Schnorr signatures after a post-quantum Bitcoin output type becomes available, though the proposal remains a draft and has not been activated on Bitcoin.</cite>
Sources: <a href="https://www.coindesk.com/tech/2026/10/07/quantum-computers-threaten-exposed-private-keys-rather-than-blockchains-europol-warns" rel="noopener noreferrer nofollow">CoinDesk: Europol urges phased shift to post-quantum security</a> <a href="https://cryptobriefing.com/europol-crypto-wallets-quantum-attack-risk/" rel="noopener noreferrer nofollow">Crypto Briefing: Europol warns crypto wallets are the weak spot for future quantum attacks</a> <a href="https://news.bitcoin.com/technology/europol-warns-quantum-threat-could-put-crypto-fortunes-risk/" rel="noopener noreferrer nofollow">Bitcoin.com News: Europol Warns Quantum Threat Could Put Crypto Fortunes at Risk</a>

Europol Flags 30% Of Bitcoin Supply as Quantum Vulnerable

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