Quantum Computing Threatens 10% of Bitcoin Supply, Glassnode Warns

A new report from blockchain analytics firm Glassnode has revealed that approximately 10% of the total Bitcoin supply — roughly 1.92 million BTC — is structurally vulnerable to future quantum computing attacks. The finding underscores a growing concern within the cryptocurrency industry as quantum technology advances toward practical application.

Why These Bitcoins Are at Risk

The vulnerability stems from the design of certain Bitcoin address types that expose public keys by default. Glassnode identified three primary categories at risk: Pay-to-Public-Key (P2PK) outputs from the early Satoshi Nakamoto era, legacy multisig structures such as Pay-to-Multisig (P2MS), and Pay-to-Taproot (P2TR) outputs. Unlike modern addresses that only reveal a public key when a transaction is made, these formats inherently disclose cryptographic information that a sufficiently powerful quantum computer could theoretically exploit to derive private keys.

This is not an immediate threat. Current quantum computers remain far from the capacity needed to break Bitcoin’s elliptic curve cryptography. However, the report emphasizes that the structural exposure is permanent for these coins, meaning they will become increasingly attractive targets as quantum hardware matures.

Historical Context and Scale

The 1.92 million BTC figure includes coins from the earliest days of Bitcoin, including those mined by Satoshi Nakamoto. These coins have remained untouched for over a decade, but their public keys are visible on the blockchain forever. The report notes that while many of these addresses may belong to long-lost wallets or inactive holders, their cryptographic exposure cannot be reversed.

Glassnode’s analysis differentiates between theoretical risk and practical exploitability. The firm stressed that the vulnerability is structural rather than active, but the lack of a migration pathway for these coins presents a long-term security challenge for the network.

Proposed Solutions: BIP-360 and Pay-to-Merkle-Root

In response to the growing quantum threat, the Bitcoin Improvement Proposal BIP-360 has been introduced, suggesting a new output type called Pay-to-Merkle-Root (P2MR). This wallet format is designed to be highly resistant to quantum computing attacks by using Merkle tree structures that obscure public key information until the moment of spending. The proposal also enables voluntary migration, allowing users to move funds from vulnerable addresses to more secure ones without disrupting the existing network.

Adoption of P2MR would require consensus from the Bitcoin community and wallet developers. The proposal is still under discussion, but it represents a proactive step toward future-proofing the network against cryptographic advances.

Why This Matters for Bitcoin Holders

For everyday Bitcoin users, the immediate risk is low. Most modern wallets use SegWit or native SegWit addresses that do not expose public keys until a transaction is signed. However, the report serves as a reminder that the cryptocurrency ecosystem must evolve alongside technological threats. Investors holding large amounts in legacy addresses, particularly those from the early mining era, may want to consider migrating to newer, quantum-resistant formats as they become available.

The broader implication is that quantum computing is no longer a distant theoretical concern for the crypto industry. As research accelerates, the window for implementing defensive measures is narrowing. Glassnode’s report adds urgency to ongoing discussions about cryptographic agility and network upgrades.

Conclusion

Glassnode’s analysis highlights a significant but manageable vulnerability in the Bitcoin network. While no immediate threat exists, the structural exposure of 1.92 million BTC demands attention from developers, miners, and holders alike. Proposals like BIP-360 offer a pathway to security, but their success depends on timely adoption and community consensus. For now, the report serves as a critical wake-up call for an industry that must prepare for a post-quantum future.

FAQs

Q1: Is my Bitcoin at risk from quantum computing right now?
No. Current quantum computers are not powerful enough to break Bitcoin’s cryptography. The risk is future-oriented, and most modern wallets are not structurally vulnerable.

Q2: Which Bitcoin addresses are most vulnerable?
Pay-to-Public-Key (P2PK), Pay-to-Multisig (P2MS), and Pay-to-Taproot (P2TR) outputs are considered structurally vulnerable because they expose public keys by design.

Q3: What can I do to protect my Bitcoin?
Use modern wallet types such as SegWit or native SegWit addresses. Monitor developments around BIP-360 and consider migrating funds to quantum-resistant formats once they are widely supported.