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Nearly $500B in Bitcoin Is Exposed to Future Quantum Computing Attacks: Glassnode
TL;DR
Over 30% of Bitcoin, worth nearly $500 billion, is exposed to potential quantum computing attacks due to public key vulnerabilities. This includes 6.04 million BTC, primarily from exchanges and address reuse.
Key points
- 30% of Bitcoin has public key exposure
- 6.04 million BTC worth over $469 billion is vulnerable
- Exchanges hold 40% of operationally exposed Bitcoin
- Vulnerability arises from script designs and address reuse
- Shor's algorithm poses a threat to Bitcoin security
Mentioned in this story
Glassnode
In brief
- More than 30% of all Bitcoin already has its public key exposed on-chain, making it theoretically vulnerable to a future quantum computer attack.
- The exposure breaks into two types: structural from script designs that reveal keys by default, and operational from address-reuse behavior.
- Exchanges account for roughly 40% of operationally exposed Bitcoin, though the risk varies widely by platform and can be reduced through better wallet hygiene.
Nearly one-third of all Bitcoin in circulation—over 6 million coins worth over $469 billion as of this writing—is already vulnerable to theft if powerful quantum computers become a reality, according to research published Wednesday by blockchain analytics firm Glassnode.
The analysis, which examines the Bitcoin blockchain to determine which coins have already had their public cryptographic keys exposed, found that 6.04 million BTC, or 30.2% of the issued supply, is exposed to quantum risk, while the remaining 13.99 million BTC shows no public-key exposure. The estimate of exposed coins is lower than some existing figures, which have ranged closer to 7 million BTC.
The concern stems from the architecture underlying Bitcoin's security. Each coin is controlled by a private key, matched to a public key visible on the blockchain only under certain conditions. The quantum concern is that a sufficiently capable quantum computer, using an algorithm known as Shor's algorithm, could in principle recover a private key from a known public key.
In that scenario, any coin whose public key has already been revealed on-chain would be immediately targetable—no transaction required.
Glassnode separates the exposed supply into two distinct categories. Structural exposure accounts for 1.92 million BTC, or 9.6% of the issued supply. These are coins locked in script formats that reveal the public key by design, including early "pay-to-public-key" outputs associated with Bitcoin's pseudonymous founder Satoshi Nakamoto, legacy multisignature structures, and more recent Taproot outputs.
Many of these coins may be effectively immovable—lost wallets or dormant holdings that cannot be voluntarily migrated to safer address formats.
Q&A
How much Bitcoin is exposed to quantum computing attacks?
More than 6 million Bitcoin, or 30.2% of the total supply, is exposed to potential quantum computing attacks.
What are the main reasons Bitcoin is vulnerable to quantum attacks?
Bitcoin's vulnerability arises from structural issues in script designs and operational risks from address reuse behavior.
Which platforms hold the most operationally exposed Bitcoin?
Exchanges account for roughly 40% of the operationally exposed Bitcoin, but the risk varies by platform.
What is Shor's algorithm and its significance to Bitcoin security?
Shor's algorithm is a quantum computing algorithm that could potentially recover a private key from a known public key, threatening Bitcoin's security.
