Once a wallet signs a transaction, the public key required to verify that signature is permanently published to the Bitcoin blockchain. The risk compounds when a custodian reuses that address, leaves remaining balances in it, or continues directing deposits to wallets that should have been retired. In Glassnode's framework, public key exposure becomes the core metric for identifying wallets that would matter most in a future quantum-attack scenario. The data does not imply an immediate threat because quantum computers remain years away from the scale required to break Bitcoin's encryption.

However, the metric reveals exactly where the network's vulnerabilities are concentrated if advances in quantum hardware eventually make public-key exposure a practical security concern. According to Glassnode, roughly half of all Bitcoin held by labeled exchanges is susceptible under the firm's public-key visibility framework, compared with less than 30% of the non-exchange supply.

Notably, the exposure breaks down into two distinct categories, with the largest being operational risk. This bucket covers 4.12 million Bitcoin and is tied directly to poor wallet management decisions, such as address reuse and partial spending without proper rotation of change outputs. Exchanges account for a significant portion of this risk, holding about 1.66 million exposed Bitcoin, equal to more than 8% of the total issued supply.

Moreover, data suggests custody standards are slipping as trading platforms expand their wallet infrastructure, deposit systems, and liquidity operations. The share of exchange-held Bitcoin considered operationally safe has steadily fallen from about 55% in 2018 to roughly 45% today.

That makes Bitcoin wallet security a measurable custody issue rather than a theoretical protocol debate. A broader look at the data reveals that public-key exposure is wildly uneven across the global financial landscape, fracturing sharply along the lines of crypto-native platforms, traditional Wall Street institutions, and nation-states. The clearest gap appears in crypto exchange wallets, where address reuse and legacy infrastructure leave large balances more visible on-chain. Within the crypto sector alone, security standards vary drastically. With users holding more than $40 billion in Bitcoin on the platform, that methodology places over $34 billion of those assets squarely in the exposed category. Woofun AI notes that the custody divide is glaringly apparent when comparing crypto exchanges to traditional finance heavyweights and retail-focused platforms. The split across these platforms confirms that the vulnerability stems from internal wallet architecture and address rotation policies, rather than from the inherent burden of managing massive liquidity.

By separating the exposed supply into structural and operational categories, the data highlights that operational exposure, the largest vulnerability, can be drastically reduced without waiting for a complex change to Bitcoin's consensus rules. This means that trading platforms can immediately lower their risk profile simply by moving balances to fresh addresses, retiring used wallets, and tightening internal controls around change outputs. This gives custodians a direct path to secure customer funds while the broader Bitcoin community debates longer-term cryptographic solutions. Given that consensus changes are intentionally slow, a broad cryptographic transition would likely unfold over several years. Exchanges, however, have a much shorter path available to them right now. As Bitcoin becomes increasingly embedded in spot ETFs, traditional brokerage accounts, and institutional custody products, the first line of defense against future quantum threats will not come from code upgrades, but from the entities holding the largest pools of customer coins. Woofun AI analysis suggests that wallet hygiene is no longer a back-office detail; it is a highly visible test of whether Bitcoin's custodial layer is prepared for a threat that, while uncertain in its timing, is already measurable on-chain. Bitcoin quantum computing risk is therefore becoming a test of custody before it becomes a protocol-level emergency.