Crypto analytics platform Glassnode has revealed that nearly 10% of the circulating Bitcoin supply is structurally unsafe against potential quantum computing breakthroughs. The risk stems from specific network output designs that natively expose public keys on-chain, rendering them vulnerable to asymmetric cryptographic exploits like Shor’s algorithm, regardless of an address owner’s key management practices.
Mechanics of Quantum Vulnerability
According to Glassnode’s data, this structurally exposed cohort comprises approximately 1.92 million BTC. The core issue lies within legacy and modern address architectures that reveal public keys or their equivalents by design. This includes early Satoshi-era Pay-to-Public-Key (P2PK) outputs, Pay-to-Multisig (P2MS) legacy structures, and contemporary Pay-to-Taproot (P2TR) key path spends.
Satoshi Nakamoto’s legendary holdings account for the largest single share of this vulnerable capital, representing roughly 1.1 million BTC, or 5.5% of the total supply. An additional 620,000 Satoshi-era coins (3.1%) and 200,000 modern Taproot-addressed coins (1%) round out the rest of the structurally compromised category. Crucially, a quantum computer would require roughly 2,330 logical qubits and billions of quantum gates to successfully break Bitcoin’s underlying elliptic curve cryptography (ECC), according to white papers published by Ark Invest.
Operational Risks and Institutional Exposure
Beyond the structural vulnerabilities, Glassnode highlights an additional 4.12 million BTC, representing 20.6% of the total supply, that is classified as operationally unsafe. These tokens are not fundamentally broken by protocol architecture but are exposed due to poor address hygiene, recurring key reuse, or flawed custodial management workflows.
At an institutional and enterprise level, this operational exposure varies wildly across major entities.
Franklin Templeton, WisdomTree, and Robinhood hold 100% of their Bitcoin in quantum-exposed formats. Neobank Revolut sits at 99%, while Grayscale retains 52% exposure. Conversely, Fidelity remains highly insulated, exposing just 2% of its total Bitcoin holdings.
Meanwhile, only 5% of Coinbase’s total corporate BTC reserves are exposed. This stands in stark contrast to Binance, which exhibits an 85% exposure rate, and Bitfinex, where effectively 100% of holdings are currently classified as vulnerable.
Protocol Mitigation: BIP-360 Proposal
The silver lining is that 13.99 million BTC, roughly 69.8% of the total circulating supply, remains completely unexposed and mathematically secure against near-term quantum threats. This consensus aligns closely with previous research indicating that approximately 65% of the network remains structurally sound.
To neutralize the remaining threat vectors, developers are focusing on technical mitigations like Bitcoin Improvement Proposal 360 (BIP-360). This draft proposal introduces a brand-new output format known as Pay-to-Merkle-Root (P2MR). By disabling Taproot’s default key path spending mechanism and routing transactions strictly through script-path commitments, P2MR prevents public keys from leaking onto the ledger during long-term storage. While BIP-360 does not introduce post-quantum digital signatures, it systematically downsizes the network’s address attack surface. This buys critical coordination time for the global node network while broader industry post-quantum cryptographic standards mature over the coming decade.
