According to CoinMeta, researcher StarkWare has developed a quantum-safe locking scheme ( QSB ) for Bitcoin's mainnet that does not require a soft fork. The first QSB output was completed and spent on August 26, 2026, in block 964,199. The computational cost of GPU has decreased from approximately $320 to about $50. This scheme utilizes hash calculations to build a locking mechanism, but it faces limitations such as high computational costs, non-compliance with Bitcoin Core's default relay rules, and a lack of supporting infrastructure. For now, it is only considered an emergency research solution.