In just one week of AI-assisted coding competition, StarkWare slashed the estimated cost of a quantum-resistant Bitcoin transaction from $320 to $66. The result, announced in late September 2026, highlights both the emerging maturity of post-quantum safety nets and the leverage AI coding tools now give to cryptographic optimization work.
🔑 Key takeaways
- The cost of a Quantum-Safe Bitcoin (QSB) transaction dropped from $320 to $66 in one week.
- The competition was run by StarkWare, Yukon Research and Eigen Labs, with developers leaning heavily on AI coding assistants.
- 62 code improvements were accepted, multiplying throughput by roughly 6x on an NVIDIA RTX 4090.
- The $66 figure is still a benchmark, not a verified mainnet transaction.
- Only MARA, via its Slipstream service, currently accepts this type of transaction.
A pioneer transaction at $320
The original $320 figure is not a simulation: it comes from a transaction actually mined on Bitcoin on August 26, 2026, at block 964,199. Submitted through MARA‘s Slipstream service — one of the largest publicly traded mining operators — the transaction required roughly 3,100 GPU-hours spread across a fleet of about 100 graphics processors.
That cost reflects the computation performed before the transaction reached the Bitcoin network. It is separate from standard mining fees paid for block inclusion, and represents the price of a heavy cryptographic operation: producing a so-called « quantum-safe » signature, designed to withstand a future quantum computer capable of breaking the ECDSA (Elliptic Curve Digital Signature Algorithm) signatures that secure every Bitcoin UTXO today.
Six days of competition, 6x faster
To make that cost practical, StarkWare open-sourced the code and launched an optimization competition on September 16, 2026 in partnership with Yukon Research and Eigen Labs. The prize pool topped $20,000, attracting developers armed with generative AI coding tools (Cursor, Copilot, Claude Code and others).
The results, published on Yukon Research’s leaderboard, are striking. The leading submission tested about 881 million candidates per second, versus 146 million for the initial code — a ~6x gain on the same NVIDIA RTX 4090 card. In total, 62 pull requests were merged during the week, many of them derived from AI-generated suggestions and refined by human reviewers.
« What Avihu illustrated is that lifeboats exist. That is not a reason to relax. It is a reason to build more of them, and to build them now. »
Eli Ben-Sasson, CEO of StarkWare
Benchmark vs reality: how real is $66?
The $66 figure deserves careful reading. It is a projection derived from competition tests, not a verified mainnet transaction. Applied to the cost breakdown of the August 26 transaction, the speedups published on the competition site suggest closer to $83, according to CoinDesk’s calculations.
The Yukon Research site notes that later record runs surpass these measurements, without specifying which ones would bring the estimate back down to $66. The next decisive milestone will therefore be a second QSB transaction actually mined, with a verified on-chain computation cost.
| Metric | Before competition | After competition |
|---|---|---|
| GPU throughput (RTX 4090) | ~146M candidates/s | ~881M candidates/s |
| QSB transaction cost | ~$320 (real) | ~$66 (theoretical) |
| Accepted improvements | — | 62 merged PRs |
| Total GPU-hours | ~3,100 h (~100 GPUs) | Not disclosed |
| Period | August 26, 2026 | Sept. 16-23, 2026 |
Structural limits of the QSB method
Beyond cost, the QSB method comes with significant constraints. First presented by StarkWare researcher Avihu Levy in April 2026 as a « last-resort measure« , it relies on a hash-based signature scheme that resists quantum attacks, unlike standard ECDSA signatures.
The method works within Bitcoin’s existing consensus rules, without requiring a protocol upgrade — a major plus in an ecosystem notoriously slow to evolve. But it imposes several structural constraints:
- Transactions must be submitted directly to a willing miner, since they don’t propagate through the standard mempool.
- Today, only MARA via Slipstream accepts this kind of operation, creating a temporary centralization point.
- Only bitcoins whose public keys have not yet been exposed on-chain are protected — i.e. addresses that have never made an outgoing transaction (unspent P2PKH or P2TR outputs).
The threat itself remains on the horizon. Chinese researchers advanced quantum attack benchmarks against secp256k1, the elliptic curve used by Bitcoin, this year. While the window is not deemed imminent given current hardware trajectories, it is no longer considered infinite. The Bitcoin community is closely tracking Shor’s-algorithm progress on cryptographically relevant hardware.
Conclusion: optimization vs a closing window
A 5x reduction in the cost of a quantum-safe Bitcoin transaction in a single week of AI-assisted coding is real progress, but it doesn’t change the bigger picture. QSB remains a costly patch, centralized on a single operator, and Bitcoin’s long-term resilience to quantum computing will ultimately depend on heavier protocol changes — for instance, native post-quantum signature schemes shipped via a dedicated soft fork.
For holders, the practical message is unchanged: avoid address reuse, sweep funds to fresh addresses, and keep keys offline. For the ecosystem, the priority is clear — turn StarkWare’s lifeboats into a genuinely open and decentralized standard, before the preparation window closes.
Sources
- CoinDesk — A week of AI coding cut a quantum-safe bitcoin transaction estimate from $320 to $66
- Industry Events — StarkWare quantum-safe Bitcoin cost reduction
- TFTC — Quantum-safe Bitcoin cost reduction via AI coding challenge
- TradersUnion — StarkWare quantum-safe BTC cost cut
- CryptoNews.net — Bitcoin news
- KuCoin News — StarkWare cuts quantum-safe BTC transaction cost to $66
This article is for informational and educational purposes only. It does not constitute investment advice. Do your own research (DYOR) before making any decision.
