Bitcoin’s Quantum-Safe Emergency Plan Just Got 82% Cheaper

Bitcoin’s emergency defense against a future quantum attack just became dramatically cheaper to prepare.

Researchers working through an open optimization challenge have cut the estimated GPU cost of building a Quantum-Safe Bitcoin transaction from roughly $320 to $59. That is an 82% reduction in a matter of weeks—and it came from faster software, not a new chip or a change to Bitcoin itself.

CryptoSlate reports that the Quantum-Safe Bitcoin, or QSB, method uses hash-based cryptography and a computational puzzle to protect specially prepared coins from the kind of signature-breaking attack a powerful quantum computer could someday perform. The latest estimate matters because the first mainnet demonstration consumed about 3,100 GPU-hours and cost approximately $320 in compute.

The new $59 figure comes from benchmarked GPU workloads after participants pushed verified search throughput above one billion candidates per second on an Nvidia RTX 4090, compared with roughly 146 million in the original baseline. Network fees are separate, and the benchmark has not yet been used to build and mine another complete production transaction.

StarkWare launched the public optimization effort with Yukon Research and Eigen Labs in September, putting more than $20,000 in rewards behind the search for faster code.

1/ Our quantum-safe Bitcoin transaction cost ~$320 in GPU compute.
Can you bring that down?

Today, we’re launching the Quantum-Safe Bitcoin Autoresearch Challenge in partnership with @yukonresearch and @eigenlabs.

Over $20,000 in rewards for improving the code:… pic.twitter.com/PqhUJyLZ8t

— StarkWare (@StarkWareLtd) September 16, 2026

The gain is real, but the distinction is crucial: $59 is still a benchmark estimate. It has not yet been demonstrated by preparing and mining another complete QSB transaction at that price.

StarkWare’s own technical explanation says the expensive work happens before the transaction reaches Bitcoin. The system searches for a rare hash output that fits the rigid format Bitcoin expects where a signature would normally appear.

Only about one in 70 trillion candidate hashes has the needed shape. Faster searching means fewer GPU-hours and a lower bill, while every promoted optimization is checked against a CPU reference implementation.

The result could make QSB more practical as a last-resort option for large holdings, but it does not make the Bitcoin network quantum-safe. The transactions are nonstandard and do not travel through the ordinary mempool.

They must be submitted directly to a willing miner. The protection also applies only to coins deliberately placed into the special construction.

6/ That's an 82% reduction through open collaboration.

Huge thanks to @yukonresearch, @eigenlabs and everyone involved!

While QSB doesn't make Bitcoin quantum-safe overnight, it makes a potential emergency fallback significantly cheaper to generate 🫡

The next goal? Bring the…

— StarkWare (@StarkWareLtd) October 12, 2026

The scale of the underlying risk explains the urgency. CryptoSlate cited research estimating that about 6.04 million BTC sit behind exposed public keys.

Current quantum computers cannot take those coins. Researchers are preparing for hardware that could eventually defeat Bitcoin’s elliptic-curve signatures.

The cost curve is moving fast, and the fallback is getting more credible. QSB still remains an emergency bridge while Bitcoin developers debate a broader protocol-level migration.

StarkWare itself says a soft fork is the better long-term answer. Cutting the bill to $59 makes the lifeboat easier to launch; it does not repair the ship.

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