Nearly $500 Billion in Bitcoin Vulnerable to Future Quantum Computing Attacks: Glassnode

Nearly a third of everyone Bitcoin In circulation — more than 6 million coins worth more than $469 billion as of this writing — are already vulnerable to theft if powerful quantum computers become a reality, according to research It was published on Wednesday by blockchain analytics firm Glassnode.

The analysis, which examines the Bitcoin blockchain to identify coins whose public encryption keys have already been exposed, found that 6.04 million bitcoins, or 30.2% of the supply issued, is Vulnerable to quantitative riskwhile the remaining 13.99 million BTC shows no public key exposure. The estimate for uncovered coins is lower than some existing figures, which have ranged Closer to 7 million BTC.

The concern stems from Bitcoin’s security infrastructure. Each coin is controlled by a private key, which matches 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 this scenario, any coin whose public key has already been exposed on-chain would be immediately targetable – without any transaction required.

Glassnode divides exposed exposure into two distinct categories. The structural exposure represents 1.92 million BTC, or 9.6% of the issued supply. These coins are locked in text formats that reveal the public key by design, including early “public key payment” outputs associated with Bitcoin’s pseudonymous founder. Satoshi NakamotoAnd older multi-signature architectures and newer Taproot outputs.

Many of these coins may be physically immovable – lost wallets or dormant holdings that cannot be voluntarily migrated to more secure address formats.

The largest and most actionable category is what Glassnode calls operational exposure. The total operating exposure is 4.12 million BTC, or 20.6% of the issued supply. These currencies were not inherently vulnerable, but became so through address reuse – a practice in which a wallet receives multiple transactions to the same address, eventually broadcasting the public key during spending and leaving any remaining balance exposed.

Exchanges loom large in this category. Within the operationally insecure pool, there are 1.66 million bitcoins, or 8.3% of the total supply, associated with the exchange – representing about 40% of all operationally insecure bitcoins. Exposure is strikingly uneven across platforms. Among the largest exchanges, Coinbase’s rated balances appear largely concentrated in uncovered structures, with only 5% exposed, while Binance and Bitfinex show relatively highly sensitive balances – 85% and 100%, respectively.

Glassnode was careful to note that its findings should not be read as a risk rating or indication of the financial solvency of any particular company, stressing that the data reflects custody design choices rather than imminent risk. Sovereign Bitcoin holdings fared much better: the US, UK and El Salvador all showed zero quantitative exposure.

The report stops short of predicting when, or whether, a quantum computer capable of decrypting Bitcoin will exist. It positions its analysis as a baseline instead, noting that for exchanges and custodians, addressing hygiene, managing reserves, reducing key reuse and migration planning are practical tools with which to reduce visible exposure.

These findings arrive as the progress of quantum computing accelerates globally and as the Bitcoin developer community debates protocol-level responses, including a proposed update known as BIP-360 that would introduce more quantum-resistant transaction formats. Another formal proposal The coins will freeze Which are not migrated by a specified deadline.

“Q-Day” estimates – when a quantum computer comes online that is powerful enough to break the encryption that secures blockchains e.g Bitcoin and Ethereum-Ranges From 2030 to 2032 and beyond. The US government announced on Thursday that it would do so Investing more than $2 billion On quantum startups and foundries planned to fuel US industry.