A week of AI-assisted coding has brought the estimated GPU cost of preparing a quantum-resistant bitcoin transaction down to $66 from about $320, according to StarkWare, the company behind the research. The earlier figure came from a transaction mined on Bitcoin in August. Preparing it took roughly 3,100 hours of computing time across a fleet of about 100 graphics processors. That $320 was the cost of the computing work done before the transaction reached Bitcoin, separate from the fee paid to put it on the blockchain.