The First Quantum-Resistant Bitcoin Transaction Has Been Mined

A StarkWare researcher has successfully sent the first Bitcoin transaction designed to resist attacks from a sufficiently powerful quantum computer. The experimental transaction landed on Bitcoin’s mainnet without requiring a soft fork or any change to the network’s consensus rules.

While the achievement is significant, it is not a full fix for Bitcoin’s potential quantum problem. It is better understood as a demonstration that users can create a quantum-resistant escape hatch today, even while developers continue debating a permanent protocol-level solution.

Quantum computers pose a potentially serious problem for Bitcoin because much of the network’s security depends on cryptographic assumptions that powerful enough machines could eventually defeat. Bitcoin uses elliptic-curve cryptography for the signatures that prove ownership of coins. A cryptographically-relevant quantum computer running Shor’s algorithm could theoretically derive a private key from an exposed public key, allowing an attacker to spend funds they do not own.

The biggest practical concern is the bitcoin already sitting in addresses that could eventually be vulnerable to a quantum attack. Glassnode estimated in May that roughly 6.04 million BTC, or 30.2% of the issued supply, had public keys exposed on-chain. At a bitcoin price of $80,000, that translates to roughly $483 billion worth of potentially vulnerable coins.