Named QSB, the scheme was published April 9 by StarkWare CPO Avihu Levy and works entirely within Bitcoin's existing script rules — no soft fork, no miner signaling required. It relies on RIPEMD-160 pre-image resistance, a hash function quantum computers can only attack via Grover's algorithm, which yields a quadratic rather than exponential speedup, leaving roughly 118 bits of effective security. Each transaction costs $75–$150 in GPU compute and routes directly to miners outside the normal mempool. The tradeoffs are significant: protection applies only to newly created outputs, Lightning Network compatibility is absent, and the estimated 4 million BTC in legacy P2PK addresses — the most quantum-vulnerable format — remains unaffected. Levy frames QSB explicitly as a last-resort contingency, not a replacement for a protocol-level upgrade — but it establishes that a quantum emergency response exists within Bitcoin's current ruleset, requiring no one's permission to deploy.