@deftypefun {int} {gnutls_ocsp_req_add_cert_id} (gnutls_ocsp_req_t @var{req}, gnutls_digest_algorithm_t @var{digest}, const gnutls_datum_t * @var{issuer_name_hash}, const gnutls_datum_t * @var{issuer_key_hash}, const gnutls_datum_t * @var{serial_number})
@var{req}: should contain a @code{gnutls_ocsp_req_t}  type

@var{digest}: hash algorithm, a @code{gnutls_digest_algorithm_t}  value

@var{issuer_name_hash}: hash of issuer's DN

@var{issuer_key_hash}: hash of issuer's public key

@var{serial_number}: serial number of certificate to check

This function will add another request to the OCSP request for a
particular certificate having the issuer name hash of
 @code{issuer_name_hash} and issuer key hash of  @code{issuer_key_hash} (both
hashed using  @code{digest} ) and serial number  @code{serial_number} .

The information needed corresponds to the CertID structure:

<informalexample><programlisting>
CertID	  ::=     SEQUENCE @{
hashAlgorithm       AlgorithmIdentifier,
issuerNameHash      OCTET STRING, -- Hash of Issuer's DN
issuerKeyHash       OCTET STRING, -- Hash of Issuers public key
serialNumber	CertificateSerialNumber @}
</programlisting></informalexample>

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code is returned.
@end deftypefun