Quantum-safe Bitcoin transaction mined on mainnet—no fork

A “quantum-safe Bitcoin transaction” was mined on Bitcoin mainnet this week without any soft fork, hard fork, or core protocol upgrade. The demo was shown at Bitcoin Asia in Hong Kong and led by Damian Chen, VP of growth at the Starknet Foundation. The transaction uses StarkWare researcher Avihu Levy’s QSB method to mitigate future quantum threats. Because Bitcoin spends in the mempool briefly, the team argues a sufficiently powerful quantum computer could eventually exploit exposed cryptographic material. QSB avoids that risk via “signature grinding,” generating millions of signature candidates until it finds a version with the required structural property. Starknet says the approach prevents fraudulent transfers even if attackers obtain keys or derive private keys from public keys. However, the format is non-standard: ordinary Bitcoin nodes do not recognize it, so it could not propagate through the public mempool and had to be sent directly to a miner willing to accept it. Mining was executed via MARA’s Slipstream service. Trading takeaway: this quantum-safe Bitcoin transaction strengthens the post-quantum risk-management narrative, but it remains experimental due to higher costs, limited relay support, and a workflow that doesn’t change the broader network.