The estimated cost of building a quantum-safe Bitcoin transaction fell roughly 80% in a single week, dropping from about $320 to $67 in GPU compute resources, according to results from the Quantum-Safe Bitcoin Optimization Challenge run by StarkWare, Yukon Research, and Eigen Labs.
The open competition invited developers and AI systems to optimize code for quantum-resistant transactions. Leading records were held by developers running AI models, including Anthropic's Opus 5 and Fable 5.1, with OpenAI's GPT-6 Astra, Grok 4.6, and Kimi placing close behind.
How the Optimization Works
The cost reduction stems from improvements to a brute-force search process that runs on a user's own hardware before the transaction reaches the blockchain. The construction requires finding a valid hash output where Bitcoin expects a signature. Since only about one in 70 trillion hash outputs meets requirements, the process involves repeated hashing until a match is found.
One core benchmark improved significantly, jumping from 146 million verified candidates per second to over 820 million on a standard RTX 4090 GPU. Across two competition tracks, 62 improvements were promoted.
Important Limitations
StarkWare emphasized that the $67 figure is an estimate based on stated hardware assumptions, not a market price, and changes each time a solver improves the record. The company also stressed that this work does not make Bitcoin quantum-safe independently. The resulting transactions are nonstandard and must be sent directly to a miner. Additionally, the construction only protects coins whose public key has not already been exposed.
StarkWare maintains that a soft fork remains the more comprehensive long-term solution for quantum safety across the network.
Broader Context
The first quantum-safe Bitcoin transaction was mined on mainnet in the preceding month, representing the initial deployment of StarkWare's construction. The effort reflects growing industry focus on Bitcoin's vulnerability to quantum computing advances and the hypothetical point known as Q-Day, when quantum computers could potentially break the elliptic-curve cryptography securing wallets.
