Overview
- StarkWare published a QSB transaction that Bitcoin confirmed on August 26, 2026, proving a hash‑based spend can be mined without changing consensus rules or a soft fork.
- Quantum‑Safe Bitcoin swaps elliptic‑curve signatures for Lamport‑style hash signatures that rely on RIPEMD‑160 and deliver about 118‑bit second preimage resistance.
- Creating a QSB spend requires heavy off‑chain GPU searches that reporters estimate cost roughly $75–$150 per transaction and sometimes run higher.
- The mined transaction was nonstandard and bypassed normal mempool relay by using MARA’s Slipstream to submit directly to a miner, so ordinary wallets and nodes will not accept it by default.
- QSB protects legacy outputs but does not cover Taproot outputs, Lightning channels, previously exposed or dormant public keys, and researchers say independent review, wallet lifecycle tools and protocol‑level migration plans such as SHRINCS and BIP proposals are the next priorities.