FIDO_CRED_VERIFY(3)

NAME
fido_cred_verify - verifies the attestation signature of a FIDO 2 credential

SYNOPSIS
#include <fido.h>
int
fido_cred_verify(const fido_cred_t *cred);

DESCRIPTION
The fido_cred_verify() function verifies whether the attestation signature contained in cred matches the attributes of the credential. Before using fido_cred_verify() in a sensitive context, the reader is strongly encouraged to make herself familiar with the FIDO 2 credential attestation process as defined in the Web Authentication (webauthn) standard.

A brief description follows:

The fido_cred_verify() function verifies whether the client data hash, relying party ID, credential ID, type, and resident/discoverable key and user verification attributes of cred have been attested by the holder of the private counterpart of the public key contained in the credential's x509 certificate.

Please note that the x509 certificate itself is not verified.

The attestation statement formats supported by fido_cred_verify() are packed and fido-u2f. The attestation type implemented by fido_cred_verify() is Basic Attestation. The attestation key pair is assumed to be of the type ES256. Other attestation formats and types are not supported.

RETURN VALUES
The error codes returned by fido_cred_verify() are defined in <fido/err.h>. If cred does not contain attestation data, then FIDO_ERR_INVALID_ARGUMENT is returned. If cred passes verification, then FIDO_OK is returned.

SEE ALSO
fido_cred_new(3), fido_cred_set_authdata(3)