Quantum-Safe Bitcoin Transaction Confirmed on Mainnet

A quantum-safe transaction has been confirmed on Bitcoin's mainnet, but it may not be enough to protect all holders from future quantum computing threats. On August 26, a transaction using StarkWare researcher Avihu Levy's construction was included in block 964,199, demonstrating that some holders can migrate funds away from quantum risk without waiting for a protocol upgrade.

The transaction used a hash-based spending path instead of elliptic-curve signatures, which are vulnerable to attacks by future quantum computers. However, StarkWare Chief Executive Eli Ben-Sasson warned that this workaround does not make Bitcoin quantum-safe and that broader solutions are still needed to protect the network at scale.

The protection offered by Levy's Quantum-Safe Bitcoin (QSB) construction only applies to coins whose public keys remain hidden behind a hash. Coins with visible public keys, including those using older address formats or Taproot outputs, are not protected and remain vulnerable to quantum attacks.