Quantum‑Safe Bitcoin Transaction Costs Drop 80% After AI‑Driven Optimization Challenge

StarkWare announced that the estimated GPU compute cost for building a quantum‑safe Bitcoin transaction fell from roughly $320 to $67 after a week‑long open competition. The contest, called the Quantum‑Safe Bitcoin Optimization Challenge, invited developers and AI models to improve the brute‑force search code that runs on a user’s own hardware before a transaction reaches the blockchain.

Competition results

Participants achieved a dramatic speed increase, raising the verified‑candidate benchmark from 146 million to over 820 million candidates per second on a standard RTX 4090 GPU. Sixty‑two improvements were recorded across two challenge tracks.

AI models lead the leaderboard

• Anthropic’s Opus 5 and Fable 5.1 held the top records.
• OpenAI’s GPT‑6 Astra, Grok 4.6 and Kimi followed closely.

How the cost reduction works

The expensive part of a quantum‑safe transaction is a brute‑force search that hashes inputs repeatedly until a hash with a specific shape is found. Faster code reduces the number of GPU‑hours required, which appears as a lower compute cost rather than a lower Bitcoin fee.

Limitations and future outlook

StarkWare cautioned that the $67 figure is an estimate based on specific hardware assumptions and does not represent a market price. The construction remains non‑standard, must be sent directly to a miner, and only protects coins whose public key has not been exposed. A soft‑fork solution is still considered the preferred long‑term approach for Bitcoin’s quantum resistance.

Context

The work comes as the crypto industry monitors “Q‑Day,” the hypothetical moment when quantum computers could break Bitcoin’s elliptic‑curve cryptography. Companies such as Coinbase are already preparing post‑quantum custody strategies.