Satoshi

Quantum

Million

<h2 id="b-tldr-b">TLDR:</h2>
<ul>
 <li>6.04 million BTC, or 30.2% of the issued Bitcoin supply, already has its public key visible on-chain.</li>
 <li>Operational exposure at 4.12M BTC exceeds structural exposure, driven largely by address reuse behavior.</li>
 <li>Exchange-related balances account for 1.66M BTC, nearly 40% of all operationally unsafe Bitcoin supply.</li>
 <li>Coinbase shows only a 5% of the balance is exposed, while Binance and Bitfinex show 85% and 100%, respectively.</li>
</ul>
<a href="https://blockonomi.com/coinbase-ceo-brian-armstrong-pledges-direct-involvement-in-bitcoins-quantum-defense-strategy/" rel="noopener noreferrer nofollow">Bitcoin’s quantum</a> exposure has become a measurable on-chain reality, with new data revealing the scale of the risk. 
According to blockchain analytics firm Glassnode, approximately 6.04 million BTC—30.2% of the issued supply—currently have their public keys visible on-chain. 
The remaining 13.99 million BTC, or 69.8%, shows no public-key exposure at rest. This data offers a clearer picture of where Bitcoin’s cryptographic vulnerabilities actually stand today.
<h2 id="b-structural-and-operational-exposure-drive-bitcoin-s-quantum-risk-b">Structural and Operational Exposure Drive Bitcoin’s Quantum Risk</h2>
Glassnode separates Bitcoin’s quantum-exposed supply into two distinct categories. Structural exposure accounts for 1.92 million BTC, or 9.6% of issued supply. Operational exposure is the larger share, totaling 4.12 million BTC, equivalent to 20.6% of all issued <a href="https://moneycheck.com/bitcoin-btc-bear-market-shows-unusual-patterns-as-k33-research-identifies-key-differences/" rel="noopener noreferrer nofollow">Bitcoin.</a>
Structural exposure comes from output types that reveal public keys by design. These include early Pay-to-Public-Key (P2PK) outputs from the Satoshi era, legacy bare multisig structures, and modern Taproot (P2TR) outputs.
 Though different in era and purpose, all share one key property: the public key remains visible on-chain while the coin sits unspent.
Satoshi-era coins present a particular challenge within structural exposure. If those coins are lost or abandoned, they cannot be voluntarily migrated to safer address formats. 
As Glassnode <a href="https://x.com/glassnode/status/2057043418694463559?s=20" rel="noopener noreferrer nofollow">notes</a>, Taproot itself is not inherently unsafe — it improves privacy and scripting flexibility. However, its output key remains visible, making it structurally exposed under this specific framework.
Operational exposure, meanwhile, is entirely behavior-driven. Output types such as P2PKH and P2WPKH can protect public keys through hashing. 
However, once a key is revealed during a spend, any remaining balance tied to that address enters the exposed category. This is the address-reuse problem in practice.
<h2 id="b-exchange-custody-practices-shape-the-operational-exposure-landscape-b">Exchange Custody Practices Shape the Operational Exposure Landscape</h2>
Exchange-related balances make up a notable portion of operationally exposed Bitcoin. Within the 4.12 million BTC operationally unsafe bucket, 1.66 million BTC — roughly 8.3% of total supply — is exchange-related. That figure represents about 40% of all operationally unsafe Bitcoin.
Glassnode further noted that exposure varies widely across individual custodians. Coinbase shows only 5% exposed balance among its labeled holdings.<a href="https://parameter.io/binance-ai-security-blocks-over-10-billion-in-cryptocurrency-fraud-attempts/" rel="noopener noreferrer nofollow"> Binance</a> and Bitfinex, however, show 85% and 100% susceptible balances, respectively, under this methodology.
Sovereign treasuries present a different picture entirely. The US, UK, and El Salvador all show 0% quantum exposure among their labeled holdings. Governments have consistently maintained above 99% operationally safe balances over the years.
The data also shows exchanges have drifted from roughly 55% operationally safe in 2018 to around 45% today. Glassnode notes this trend is reversible through standard address-management practices, including avoiding address reuse and rotating change outputs. No immediate risk ranking should be read into these figures.
The post <a href="https://blockonomi.com/bitcoins-quantum-exposed-supply-6-04-million-btc-already-at-risk-glassnode-data-reveals/" rel="noopener noreferrer nofollow">Bitcoin’s Quantum-Exposed Supply: 6.04 Million BTC Already at Risk, Glassnode Data Reveals</a> appeared first on <a href="https://blockonomi.com" rel="noopener noreferrer nofollow">Blockonomi</a>.

Bitcoin’s Quantum-Exposed Supply: 6.04 Million BTC Already at Risk, Glassnode Data Reveals

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