Anthropic researchers used Claude to explain long-mysterious NIST ECDSA curve seeds from FIPS 186-2, previously supplied by NSA without derivation details. Contrary to folklore about hashed passphrases, seeds for P-192, P-224, P-256, P-384, and P-521 match output from C library lrand48() initialized with Unix timestamps (May 1997–April 1998).
Claude recognized lrand48 bit patterns, recovered PRNG state via lattice techniques, and reproduced seeds with published Python. Six ANSI X9.62 base points trace to FreeLIP/NTL RNG recipes. B-163 remains unexplained; larger NIST base points for P-224+ are not fully explained.
Anthropic states this is not a cryptographic break and increases confidence curves were not backdoored. The $36,864 NIST seeds bounty will be donated to ISRG.