Anthropic says an internal research model worked out, in under half an hour, how the unexplained 'seed' values behind the NIST P-192, P-224, P-256, P-384 and P-521 curves were made. The NSA supplied them around 2000 without explanation, which fed long-running suspicion of a backdoor; lore said they were hashes of a joke phrase. Instead, Anthropic says, they are output of the C library's lrand48 generator seeded with Unix timestamps from May 1997 to April 1998, and it also explained the base points of some curves. Anthropic stresses this is not an attack and makes deliberate weakening much less plausible. Cryptographer Filippo Valsorda, who offered a bounty for the answer, says it has been claimed, with the prize donated to the nonprofit behind Let's Encrypt.

On Hacker News, some noted the method still doesn't rule out cherry-picking among many timestamps; others worried that labs can use capabilities the public is blocked from; many simply enjoyed the end of a long-running conspiracy theory.