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RSA-896 falls to a GPU port of CADO-NFS that Claude wrote, run as a low-priority job on Anthropic's fleet
Stephen A. Weis announced on 2026-09-19 that he factored the 896-bit RSA challenge number using Claude to port CADO-NFS to GPUs and to orchestrate the run across up to 2,048 GPUs at Anthropic as a background job, taking 10 days and roughly 30 GPU-years. This beats the 829-bit public record standing since 2020 and follows an AI-assisted RSA-260 factoring 16 days earlier. Weis is explicit that the general number field sieve itself was not meaningfully accelerated and RSA-2048 is unaffected, but the result says RSA-1024 is now within reach of anyone with a datacenter GPU fleet and spare cycles.
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