Bitcoin Quantum Exposure: Glassnode Says 30% of Supply Is Highly Vulnerable

A new study by Glassnode is putting fresh focus on a security risk for the wider Bitcoin (BTC) ecosystem—one that relates not to today’s cryptography, but to what could happen if quantum computers become powerful enough to run the right algorithms. 

Glassnode breaks the concern into two distinct categories: structural exposure and operational exposure. Structural exposure covers outputs where the script type itself reveals the public key by design. Operational exposure is different. 

In the study’s breakdown, structural exposure accounts for 1.92 million BTC, equal to 9.6% of issued supply. Operational exposure is larger, totaling 4.12 million BTC, or 20.6%. Within this operational bucket, exchange-related balances alone come to 1.63 million BTC, or 8.1% of all issued Bitcoin. 

Glassnode’s at-rest framework matters here because the attacker would not need the owner to move the coins. If the public key is already visible on-chain, the coin is considered exposed; if the public key is not visible on-chain, the coin is not exposed under this specific model.

Under Glassnode’s structural exposure definition, the output type itself reveals the relevant public-key information, independent of how carefully the owner manages addresses. 

While these script types come from different eras and were built for different purposes, they share the same property in Glassnode’s framework: the public key, or a public-key equivalent, is visible by default on-chain. That means these coins are targetable while they remain unspent.

Instead, they become exposed because the public key has already been revealed at some point during spending, yet Bitcoin remains associated with the same key or script arrangement. Glassnode describes this as an “address reuse problem.” 

Glassnode classifies 4.12 million Bitcoin, or 20.6% of issued supply, as operationally unsafe, and within that bucket, it highlights exchanges as a major labeled subset.

Among the largest exchanges, Glassnode reports that Coinbase labeled balances appear largely concentrated in non-exposed structures, with only 5% exposed balance. By contrast, Binance and Bitfinex show dramatically higher susceptible balances—85% and 100%, respectively.

For the countries covered in the report—the United States, the United Kingdom, and El Salvador—Glassnode indicates 0% quantum exposure to their Bitcoin holdings.

Featured image created with OpenArt, chart from TradingView.com