nx_x509_pubkey_ed.nx

nx_x509_pubkey_ed.nx -- extract a 32-byte Ed25519 public key from an X.509 SubjectPublicKeyInfo. Phase 0b §I.4 piece 5a of the chain-walker arc. Trivial parallel to nx_x509_pubkey_ec.nx -- Ed25519 BIT STRING content is just the 32 raw pubkey bytes (RFC 8410 §4 -- no leading indicator, no compressed/uncompressed split). x509_parse already strips the BIT STRING's "unused bits" prefix byte, so cert.pubkey_off points at the first key byte and cert.pubkey_len == 32 for an Ed25519 key. Public API: nx_x509_pubkey_extract_ed25519(buf, cert, out_32) -> verdict nx_x509_pubkey_ed_verdict_is_valid(v) -> 0|1 Sealed verdict: NX_X509_PUBKEY_ED_OK 32 bytes copied NX_X509_PUBKEY_ED_BAD_LEN pubkey_len != 32 Per Cardinals 9 (single-responsibility -- extract, not verify or alg-identify) and 12 (defensive at boundaries -- length check). license_tier: INDEPENDENT_REDERIVE genealogy_id: international-research-sources/ietf/rfc_8410 lineage_id: nishi_x509_pubkey_ed25519_q10