Anthropic says Claude traced the origins of ECDSA curve seeds

Anthropic says Claude discovered the origins of the seeds used for the NIST P-192, P-224, P-256, P-384 and P-521 curves, closing decades of speculation about possible backdoors in ECDSA parameters. According to the company, the seeds did not come from a hash function, but from the output of the C library’s lrand48 pseudorandom-number generator, initialized with a Unix timestamp. The algorithm tested 20-byte candidates over multiple iterations until it found the standardized seed; for P-256, it took 1,842 iterations.

The discovery was made in under half an hour in October 2026, after an Anthropic employee asked an internal research model to investigate without providing the previously suspected humorous-phrase clue. The company says the result is not a cryptographic break or a new weakness and makes deliberate backdoors less plausible. It also says users do not need to take any action.