---
title: Claude traces the NIST P-curve seeds to lrand48 seeded with 1997-98 timestamps; no backdoor, no action needed | ctxsec
url: https://ctxsec.com/items/anthropic-ecdsa-seed-origins
description: ""
status: "confirmed (researcher + independent verification)"
published: 2026-10-16
---

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[← AI](/ai) · [markdown](/items/anthropic-ecdsa-seed-origins.md)

confirmed (researcher + independent verification)

2026-10-16

### Claude traces the NIST P-curve seeds to lrand48 seeded with 1997-98 timestamps; no backdoor, no action needed

Anthropic's Frontier Red Team (Oct 16) says Claude worked out, in under half an hour, that the unexplained seeds for NIST P-192, P-224, P-256, P-384 and P-521 were not hashes of a phrase but output of the C library's `lrand48`/`drand48` generator seeded with Unix timestamps. P-256's seed is candidate 1,842 from `srand48(871696354)`, which is 1997-08-16 01:52:34 UTC. Filippo Valsorda reimplemented the algorithm in Go, confirmed it, and paid out his seeds bounty (tripled to $36,864, donated to ISRG). Anthropic says this is not a break and needs no action. Gaps remain: one binary-curve seed and several base points are still unexplained. For defenders it's mainly a data point on AI doing real cryptanalysis-style research by writing its own analysis tools.

Sources: [Anthropic: Claude reveals ECDSA curve origins](https://www.anthropic.com/research/ecdsa-curve-origins) · [Filippo Valsorda: bounty claimed](https://words.filippo.io/seeds-solved/)