RSA-896 Factored With Claude Orchestrating 2,048 GPUs Over 10 Days, 30 GPU-Years

matthew_d_green · x · 2026-09-24

Cryptography is in interesting times: McEliece security drastically reduced, a concrete attack on Chaum's blind signatures—and Stephen A. Weis claims to have factored the RSA-896 challenge number on September 19, 2026, using Claude to port CADO-NFS to GPUs and orchestrate a fleet of up to 2,048 GPUs as low-priority jobs at Anthropic. The computation ran 10 days, roughly 30 GPU-years of compute, with full polynomial parameters published. He stresses GNFS runtime wasn't meaningfully improved and deployed RSA-2048 keys remain safe—but the result demonstrates RSA-1024 keys are now vulnerable to many actors with data-center-scale GPU fleets.

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