Anthropic says Claude traced five NIST elliptic-curve seeds to the C library’s lrand48 generator, initialized with Unix timestamps—not a hash.
Anthropic reported on October 16 that an internal research version of Claude had identified how the seeds for five NIST elliptic curves were generated. The company says the model found that the values came from the C library’s lrand48 pseudorandom-number generator, initialized with Unix timestamps, rather than from a hash algorithm.
The seeds belong to the NIST P-192, P-224, P-256, P-384 and P-521 curves used in elliptic-curve cryptography. Anthropic says Claude reached the explanation in less than half an hour after an employee asked it to investigate the seeds’ origins without directing it toward the long-circulated theory that they came from a humorous passphrase. For P-256, the published seed was the 1,842nd 20-byte candidate generated in the run Anthropic reconstructed.
To identify the method, Claude searched for patterns consistent with older random-number generators, recovered their internal states, and checked whether those states reproduced the published values. Anthropic also reports matching the same generator pattern in five additional seeds from the ANSI X9.62 standard. The company published code intended to let others reproduce the seed calculations.
The finding addresses a longstanding provenance question about parameters supplied to NIST without an explanation of how they were chosen. Anthropic stresses that it is not a cryptographic break or evidence of a weakness in ECDSA, and says the results make deliberate backdooring less plausible. The report does not settle every question: Anthropic says it could not explain the B-163 seed or the origins of several curve base points.
Anthropic said the $36,864 bounty associated with finding the seeds will be donated to the Internet Security Research Group. The result offers a concrete example of an AI model helping investigate a difficult mathematical and cryptographic question, while the company’s own caveats leave the remaining unexplained parameters open for further scrutiny.