Bitcoin's Quantum Armor Just Shrank From $320 to $66 — Your Future Self May Say Thanks

The estimated computational cost to prepare a quantum-resistant $BTC transaction has fallen below $67, down from roughly $320 on the first such mainnet transaction in August, according to StarkWare. As of StarkWare's Sept. 23 update, its dashboard showed the estimated cost had dropped to $66, a reduction of about 79% from the original benchmark.

"A construction that costs a few hundred dollars per transaction is a demo. One that costs $67 is closer to something a holder with a large unexposed balance might reach for in an emergency," StarkWare wrote. The first Quantum-Safe Bitcoin (QSB) transaction was mined and confirmed on Aug. 26, with engineering work from Tomer Giladi and direct submission through MARA's Slipstream service. Preparing it required approximately 3,100 GPU-hours across roughly 100 GPUs, at a compute cost of about $320, excluding Bitcoin network fees.

StarkWare researcher Avihu Levy published the QSB design in April, outlining a way to add hash-based protection against quantum attacks without changing Bitcoin's consensus rules. He described it at the time as a "last resort measure" due to costs, complexity and limited applicability, while continuing to advocate for protocol-level changes. StarkWare said QSB is an "emergency" solution and that it still favors a soft fork as a better "long-term answer" for broad quantum protection on Bitcoin.

To drive costs down, StarkWare, Yukon Research and Eigen Labs launched the QSB challenge on Sept. 16, inviting developers, researchers and AI agents to optimize the transaction-building software. In its latest update, StarkWare said the challenge produced 62 accepted improvements across two computational tasks needed to prepare a QSB transaction, cutting the estimated computing cost by about 79% in benchmark tests. The development comes amid concerns that a sufficiently powerful quantum computer could break the elliptic-curve digital signatures used by Bitcoin, potentially allowing attackers to steal coins whose public keys are exposed.