Glassnode's latest analysis flags a critical vulnerability in Bitcoin's security model. Nearly 10% of the network's total supply sits in addresses that lack adequate protection against quantum computing attacks.
The vulnerability stems from Bitcoin addresses that reuse public keys. Once a user spends from an address, their public key becomes visible on the blockchain. Quantum computers theoretically could derive private keys from exposed public keys using Shor's algorithm, compromising funds in these addresses. Glassnode's data shows approximately 1.9 million Bitcoin sits in this structurally exposed state.
The at-risk coins cluster primarily in three categories. First, dormant coins from Bitcoin's early years where address reuse was common practice. Second, coins held in addresses whose public keys have already been revealed through transaction history. Third, outputs from multisig arrangements and other complex scripts that expose keys during spending.
The research underscores why Bitcoin developers proposed BIP-360, a quantum-resistant upgrade designed to protect the network before quantum computers mature into a genuine threat. The proposal aims to implement post-quantum cryptographic algorithms that withstand quantum-level computation.
Current quantum computing remains far from cracking Bitcoin's elliptic curve cryptography. Google's recent quantum breakthroughs, while notable, don't threaten Bitcoin's 256-bit ECDSA standard today. However, the trajectory of quantum development justifies preventative action. Experts estimate a functionally quantum computer capable of breaking Bitcoin could emerge in 10 to 20 years, though estimates vary widely.
The 10% exposure represents an asymmetric risk. While 90% of Bitcoin supply maintains current quantum protection through address isolation and key management practices, the legacy coins pose a serious concern if quantum capabilities accelerate unexpectedly. Exchanges and custodians holding older coins face particular pressure to migrate funds to quantum-safe addresses preemptively.
Bitcoin's security model assumes public keys remain hidden until necessary. The protocol could theoretically shift to quantum-resistant algorithms through consensus upgrade, though coordinating such a fundamental change across the decentralized network presents operational challenges. Glassnode