Anthropic published research on October 16 showing how Claude reconstructed the public seed behind P-256, a NIST-standardized cryptographic curve used for Ethereum passkey signing. The finding provides new evidence addressing long-standing concerns about the curve's origins.
P-256's public seed is a design input used to derive a coefficient in the curve's equation, distinct from the private signing credentials that authorize wallet activity. Unexplained seeds supplied by the U.S. National Security Agency had fueled suspicion about deliberately weakened parameters.
Anthropic's research initializes the C-library generator lrand48 with the timestamp for August 16, 1997, at 01:52:34 UTC. The generator produces a sequence of candidate seeds, with candidate 1,842 returning the published P-256 value. Anthropic says this provides a repeatable recipe for the public constant and makes deliberate backdoors less plausible.
The company describes no new attack or curve weakness and states users need take no action. The research identifies no new vulnerabilities in P-256 itself.
Ethereum Connection
The relevance to Ethereum runs through EIP-7951, which specifies verification of signatures using P-256, also called secp256r1. The proposal names Apple Secure Enclave, Android Keystore, and FIDO2/WebAuthn devices as relevant hardware, connecting wallet authorization with signing capabilities built into devices and authenticators.
EIP-7951 names device-native signing, multifactor authentication, and simpler key management as uses for account abstraction. P-256VERIFY, the operation specified in EIP-7951, takes a message hash, a signature, and a public key, then checks the signature's validity.
P-256 differs from secp256k1, the curve already used in Ethereum. The finding is relevant to P-256-compatible signing rather than all Ethereum wallets.
Unresolved Questions
Anthropic reports that candidate 876 also yielded a prime-order curve of the required size, leaving selection criteria unclear. The number of generation runs and the origin of P-256's base point, a separate fixed mathematical point, remain unknown.
