Factoring RSA 260

The Cognition team used a GPU-optimized implementation of the General Number Field Sieve, based on a heavily modified CADO-NFS, to factor RSA-260, a 260-digit integer, at a cost of roughly 4,900 GPU-days (about $400 k). The effort required 643 GPU-days for polynomial selection, the remainder for lattice sieving and linear system solving, and demonstrates that RSA-1024 could be broken for around $30 million, while RSA-2048 remains vastly harder.