An Anthropic research model has reconstructed the origins of five NIST elliptic-curve seeds that had fueled suspicions of a hidden National Security Agency backdoor for roughly 25 years. The seeds were generated by the older C-library pseudorandom number generator lrand48, initialized with Unix timestamps from 1997 and 1998.
Elliptic-curve standards adopted by NIST use those seed values to derive curve parameters, and the unexplained selection process became more controversial after disclosures about efforts to weaken cryptographic standards.
Claude reached the result in less than 30 minutes by looking for recognizable output from older random-number generators. It identified a pattern in the published values, recovered the generator’s internal state and then worked backward to the initialization values. The supplied reproduction code regenerates the published seeds exactly.
The result makes an intentional backdoor substantially less plausible, but it does not answer every question about the curves’ construction. Some usable candidate seeds were skipped: P-256’s 876th candidate also produced a suitable curve, while the criteria for choosing among viable candidates remain unknown.
The recovered generator was weak enough to reveal the historical construction process, but the public seeds were never secret keys. Users of the NIST curves were told that no change is required on the basis of this finding.
Bitcoin was not implicated because its wallets use secp256k1 rather than the NIST curves examined here. A separate quantum-computing risk remains theoretical: a sufficiently capable quantum computer could eventually derive a private key from an exposed public key, but no machine currently has the required scale or reliability.
The investigation grew out of years of unanswered questions, including a 2015 examination by cryptographers Neal Koblitz and Alfred Menezes and public-records efforts by security researcher Steve Weis. A bounty launched in 2023 ultimately reached $36,864; that money is to be donated to the Internet Security Research Group, the nonprofit behind Let’s Encrypt.