Claude helped uncover the origins of five NIST curve parameters

In October 2026, the Claude model helped Anthropic researchers determine the origins of the seed values for five NIST prime elliptic curves: P-192, P-224, P-256, P-384, and P-521. The values, or seed parameters, had previously been published without an explanation of how they were obtained.

According to Anthropic, the values were not produced by hashing: they were generated by the lrand48 pseudorandom number generator, initialized with Unix time. The program generated candidate seeds in sequence until it found a published value. For example, the P-256 value appeared after 1,842 iterations.

Claude searched the published values for distinctive patterns and reconstructed the generator’s states. The researchers then verified that the recovered parameters could reproduce the seeds. For some curves, they had to reconstruct the initialization time from the generator’s data; the authors also note that generation of the four binary curves may have used time divided by two.

Anthropic emphasizes that the result is neither a break nor the discovery of a vulnerability. The authors believe the finding makes the theory that weaknesses were deliberately built into these parameters less plausible. However, the researchers were unable to explain the origin of the B-163 curve’s seed parameter or the base points of several curves.

Image: Freiman, Stephen W.
Dapkunas, Stanley J. Public domain

Translation editors: Соловьев В., Пеков А.