StarkWare Executes First Quantum-Resistant Bitcoin Transaction on Mainnet

StarkWare announced on August 27, 2026, that its researcher Avihu Levy successfully executed an experimental quantum-resistant Bitcoin transaction on the mainnet, marking what the company described as the first transaction of its kind. The transaction, confirmed in Bitcoin block 964,199, spent a 10,000-satoshi output using a method designed to protect against potential future threats from quantum computers without altering Bitcoin's consensus rules.

The demonstration utilized Levy's QuantumSafe Bitcoin (QSB) scheme, a cryptographic construction first proposed in April 2026. QSB combines hash-based one-time signatures with computational searches that bind authorization to a specific transaction. The approach is intended to prevent forgery even if a sufficiently powerful quantum computer could break the elliptic-curve cryptography currently used by Bitcoin. According to StarkWare, the process required significant computational resources, with the transaction costing an estimated $150 to $200 and taking several hours to complete. This aligns with earlier estimates from Levy's April proposal, which projected costs between $75 and $150 in GPU computation.