Module authenticator_data 

Authenticator data parsing.

The authenticator data (authData) is a binary structure defined in WebAuthn §6.1. It is produced by the authenticator hardware and carries the RP ID binding, user-presence/verification flags, a sign counter, and (during registration) the new credential’s public key encoded as a COSE_Key.

Binary layout

Offset   Len   Field
──────   ───   ─────────────────────────────────────────────────
     0    32   rpIdHash   — SHA-256 of the RP ID
    32     1   flags      — bitmask (UP / UV / AT / ED)
    33     4   signCount  — big-endian u32
    37     *   attestedCredentialData (present iff AT flag is set)
             16   aaguid
              2   credentialIdLength  (big-endian u16)
              *   credentialId
              *   credentialPublicKey (CBOR-encoded COSE_Key)

Structs

AttestedCredentialData

Credential data embedded in the authenticator data during registration.

AuthenticatorData

Fully parsed authenticator data.

AuthenticatorFlags

Decoded flags byte from authenticator data.

Enums

CoseKey

A decoded COSE_Key from the credential’s authenticator data.

Functions

parse_authenticator_data

Parse the raw authenticator data bytes into an AuthenticatorData.

parse_cose_key

Decode a CBOR-encoded COSE_Key and return it as a CoseKey.