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Glassnode research has placed nearly $500 billion in Bitcoin under future quantum computing risk, adding fresh urgency to a debate that still carries deep doubt across the crypto industry.
The data shows that exposed public keys, address reuse, and old wallet structures now sit at the center of a security discussion tied to a technology that may not arrive for years.
Glassnode found that 6.04 million BTC, worth about $469 billion, already have their public keys exposed on-chain. This figure represents 30.2% of the issued Bitcoin supply. The firm said another 13.99 million BTC shows no public-key exposure.
The concern comes from how Bitcoin protects ownership. A private key controls each coin, while a public key appears on-chain under certain conditions. A powerful quantum computer could use Shor’s algorithm to derive a private key from a known public key. In that case, coins with exposed keys could face direct theft.
Glassnode split the exposed supply into two groups. Structural exposure accounts for 1.92 million BTC, or 9.6% of issued supply. This category includes early pay-to-public-key outputs linked to Satoshi-era wallets, legacy multisignature formats and Taproot outputs that reveal public keys by design.
Operational exposure makes up the larger category. Glassnode counted 4.12 million BTC, or 20.6% of supply, in this group. These coins became exposed through address reuse. A wallet may receive several payments to one address, then reveal its public key after a spend while still holding a balance there.
Exchanges account for 1.66 million BTC, equal to 8.3% of total supply and about 40% of all operationally unsafe Bitcoin. Glassnode said this reflects custody design and address practices, not an immediate solvency warning.
The exposure also varies across large platforms. Glassnode’s labeled data shows Coinbase balances mostly sit in non-exposed structures, with about 5% exposed. Binance and Bitfinex show higher susceptible balances at 85% and 100%. Glassnode warned readers not to treat the figures as a ranking of company safety.
The report did not predict when a quantum computer strong enough to break Bitcoin keys may exist. Instead, it framed the data as a baseline for exchanges, custodians, and developers. Practical steps include less address reuse, better reserve handling, and migration planning.
Industry views remain divided. RippleX engineering head Ayo Akinyele said, “The threat has moved from theoretical to credible.” However, Mysten Labs chief cryptographer Kostas Chalkias said, “It’s a theoretical computer that doesn’t exist yet,” and added, “The danger is decades away.” These doubts remain central to the debate.
Developers and firms have started to test possible defenses. Bitcoin discussions include BIP-360, which would add more quantum-resistant transaction formats. Another proposal would freeze coins that fail to migrate before a set deadline.
AmericanFortress also proposed a post-quantum signature scheme that uses a soft fork and zero-knowledge proofs to protect dormant wallets. Its CEO, Michal Pospieszalski, said Satoshi-era wallets could receive protection through a ‘minor BIP.’ Still, governance would need to decide whether frozen funds should move, remain locked, burn, or face another outcome after Q-Day if the threat becomes real.
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