The price of building a quantum-resistant Bitcoin transaction has plunged nearly 80% in a single week, after developers and AI models competed to optimize the code behind it.
According to StarkWare, which ran the competition alongside Yukon Research and Eigen Labs, the estimated cost of constructing such a transaction fell from about $320 to roughly $67 in GPU compute.
The figure comes from the dashboard of the Quantum-Safe Bitcoin Optimization Challenge, an open contest launched to see how far outside solvers could push the number down.
The first quantum-safe Bitcoin transaction was mined on mainnet last month, a construction StarkWare developed to protect coins without requiring a network-wide fork. That initial transaction took roughly 3,100 GPU-hours and cost around $320 to build. One week of open competition cut most of that away.
The savings come from raw speed. The expensive part of the process is a brute-force search that happens on a user's own hardware before anything reaches the blockchain, which is why it shows up as a GPU bill rather than a Bitcoin fee. The construction slots a hash where Bitcoin expects a signature, and because only about one in 70 trillion hash outputs takes the required shape, finding a valid one means hashing inputs over and over until one fits. Faster code means fewer GPU-hours for the same result.
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Notably, the leading records were held by developers running AI models, with StarkWare citing Anthropic's Opus 5 and Fable 5.1 at the top and OpenAI's GPT-6 Astra, Grok 4.6, and Kimi close behind.
StarkWare was careful to temper expectations. The $67 is an estimate under stated hardware assumptions, not a market price, and it shifts each time a solver beats the record.
The company stressed the effort doesn't make Bitcoin quantum-safe on its own : the transactions are nonstandard and must be sent directly to a miner, and the construction only shields coins whose public key hasn't already been exposed. StarkWare maintains that a soft fork remains the better long-term fix .
The work lands amid intensifying focus on Bitcoin's exposure to " Q-Day ," the hypothetical point when quantum computers could break the elliptic-curve cryptography securing wallets. Firms including Coinbase are already drafting post-quantum custody playbooks .