NIST curves: P-256 seed was drawn in 1997, Filippo Valsorda checks Anthropic's result
Anthropic found that the unexplained seeds of NIST's P-192 to P-521 curves, supplied by the NSA, came from the lrand48 generator seeded with 1997 and 1998 timestamps. Cryptographer Filippo Valsorda confirmed the finding and puts the remaining freedom at about 30 bits, too little for a backdoor, so distrust of P-256 no longer justifies migrating away from it.