StarkWare's Quantum-Safe Bitcoin Optimization Challenge reduced the estimated GPU computing cost of preparing an experimental quantum-resistant Bitcoin transaction to between $66 and $67 from about $320 in a week. The Sept. 16 contest, run with Yukon Research and Eigen Labs and offering more than $20,000 in prizes, produced 62 accepted improvements by Sept. 23. Transaction-pinning throughput on an RTX 4090 rose from roughly 146 million candidates per second to more than 820 million, reducing the computing time needed to prepare a QSB transaction. QSB uses hash-based cryptographic locks with roughly 118-bit preimage resistance to move eligible Bitcoin within existing consensus rules, requiring neither a soft fork nor a protocol upgrade. The first QSB transaction reached Bitcoin's mainnet on Aug. 26, 2026, in block 964,199, after requiring about 3,100 GPU-hours and an estimated $320 in compute resources. StarkWare describes the system as a limited emergency measure, while maintaining that a comprehensive soft fork would offer broader long-term quantum protection.