Claude Solves Decades-Old ECDSA Curve Seed Mystery in Under 30 Minutes

The Anthropic Frontier Red Team has officially announced that Claude solved a cryptographic mystery that had puzzled the community for decades: the origin of the seeds for the standard ECDSA elliptic curves. Without any hints, Claude deduced in under half an hour where the seeds for P-192, P-224, P-256, P-384, and P-521 all came from—and the answer was surprisingly mundane: they were simply random numbers based on the system timestamp.

Confirmed

• Anthropic published an article describing the incident: an employee asked an internal research model to deduce, without hints, the origin of the NIST ECDSA curve seeds, and in under half an hour Claude identified the source of all five standard curves' seeds (m3)
• ECDSA is the most widely used elliptic curve signature standard, incorporated into FIPS by NIST in 2000; the seed parameters for curves like NIST P-256 have been supplied by the NSA with no explanation ever since adoption (m1, m2)
• freddi summed up the irony: the crypto community spent roughly 13 years wearing "tinfoil hats" suspecting the NSA had hidden a backdoor in the P-256 seeds, only for the answer to turn out to be srand48(time(NULL))—a plain hash of an English phrase plus the system timestamp (m4)
• scaling01 added a link to the Wikipedia ECDSA entry, with the same core facts: in the late 1990s the NSA supplied the standard curves' seed parameters without explanation (m5)

Why it matters

• The drama of this "cold case" lies in the contrast: the community long assumed the worst about possible NSA backdoors in the seeds, while the real answer was a mundane timestamp-based random number—freddi quipped that "13 years of tinfoil hat wearing was for nothing"
• The episode also demonstrates frontier models' ability to reason and do cryptographic archaeology without hints, and was publicly showcased by the Anthropic Frontier Red Team as a result

2026-10-17 ~ 2026-10-17 · 6 related posts

• 13 Years of Tinfoil Hats, and the Answer Was Just srand48(time(NULL)) — ___freddi___ · 2026-10-17
• Claude Cracks Decades-Old Crypto Mystery: Origins of NIST P-256 Curve Seeds Revealed — matthew_d_green · 2026-10-17
• [source] Claude cracks 30-year mystery: ECDSA curve seeds were just RNG output — scaling01 · 2026-10-17
• More on Claude's ECDSA seed revelation: the Wikipedia context — scaling01 · 2026-10-17
• [source] Claude cracks 25-year-old ECDSA curve-origin mystery in under 30 minutes — Yuchenj_UW · 2026-10-17

1 near-duplicate retellings: voooooogel