Bitcoin's Quantum Clock: 6.9M BTC, Including Satoshi's, Sit in Exposed Addresses
Project Eleven estimates roughly 6.9 million BTC sit in addresses with exposed public keys, including Satoshi's coins, and resource estimates for a full 256-bit elliptic-curve break have fallen below 500,000 physical qubits.
Roughly 6.9 million BTC — about a third of the total supply — sit in addresses with exposed public keys, leaving them squarely in the line of fire if quantum computers reach key-breaking scale, according to research highlighted by CoinDesk.
How the exposure happened
The estimate comes from Project Eleven and includes Satoshi Nakamoto's roughly 1 million BTC, untouched since the network's earliest years. A side effect of the 2021 Taproot upgrade is that any bitcoin spent since activation publishes the public key protecting whatever balance remains at that address. Quantum attackers wouldn't need to race against an in-flight transaction; they could grind through exposed addresses at their own pace.
How close is "close"?
An independent researcher recently used publicly accessible quantum hardware to break a 15-bit elliptic-curve key, claiming Project Eleven's 1 BTC Q-Day Prize in the largest public demonstration to date. That is far from threatening bitcoin's 256-bit curve, but resource estimates for a full 256-bit break have fallen below 500,000 physical qubits. Migration paths like BIP-360, which would add quantum-safe address types, have been proposed but no concrete consensus has emerged from Bitcoin developers.
Why It Matters
Quantum risk is no longer a tail-of-tails for BTC — it's a governance problem. The hard question isn't whether to migrate signatures, it's what to do with the unmovable Satoshi-era coins, which can't be re-signed without their owner. Any answer — freeze, burn, recover — sets a brutal precedent. Expect this debate to intensify as post-quantum hardware milestones land, not after they do.
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