How Claude Solved the NIST Curve Seed Mystery in Under Half an Hour (and How to Try the Same Move)
Anthropic's Frontier Red Team published how an internal research model traced the starting numbers behind five NIST elliptic-curve standards to an old C-library random generator seeded with a timestamp. Here is what happened, the two public-domain scripts, and the approach you can copy on your own puzzles
For about 25 years nobody could say where the starting numbers (the seeds) of the NIST curves P-192, P-224, P-256, P-384 and P-521 came from. Earlier researchers followed a hint that they were hash outputs, and the lack of a clear source fed a worry that a backdoor could be hiding in them. On 16 October 2026 Anthropic's Frontier Red Team posted the answer.
What Claude found
- The seeds were not hash outputs. They came from the C library's lrand48 random generator, seeded with a Unix timestamp.
- An employee asked an internal research model to work out how the seeds were made, without giving it the hint that had misled earlier researchers.
- Claude guessed that 1990s random-number output would be recognisable, wrote a scanner for it, and noticed that the top bits of some seeds were all zero. That matched lrand48.
- It recovered the truncated generator states with lattice reduction (LLL) and stepped the state back to a timestamp. The first discovery took under half an hour.
- Six curves' base points trace to the FreeLIP/NTL random generator with small integer seeds.
- The authors say this is not a break in the curves. A simple, reproducible method makes a backdoor less plausible.
Run it yourself
- Open the post: anthropic.com/research/ecdsa-curve-origins
- Download the two Python scripts it links. Both are released under CC0 1.0 (public domain).
- Run the first to regenerate the seeds from timestamps and candidate indices; run the second to regenerate six base points from their generator seeds.
- Compare the output with the published NIST values in the post.
Free, for your email
Get the full setup steps + the copy-paste setup prompt
The rest of this guide (3 more sections, 1 copy-paste prompt) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.
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