Imported Upstream version 3.0.21

[platform/upstream/gnutls.git] / doc / x509-api.texi

@subheading gnutls_pkcs7_deinit
@anchor{gnutls_pkcs7_deinit}
@deftypefun {void} {gnutls_pkcs7_deinit} (gnutls_pkcs7_t @var{pkcs7})
@var{pkcs7}: The structure to be initialized

This function will deinitialize a PKCS7 structure.
@end deftypefun

@subheading gnutls_pkcs7_delete_crl
@anchor{gnutls_pkcs7_delete_crl}
@deftypefun {int} {gnutls_pkcs7_delete_crl} (gnutls_pkcs7_t @var{pkcs7}, int @var{indx})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{indx}: the index of the crl to delete

This function will delete a crl from a PKCS7 or RFC2630 crl set.
Index starts from 0. Returns 0 on success.

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

@subheading gnutls_pkcs7_delete_crt
@anchor{gnutls_pkcs7_delete_crt}
@deftypefun {int} {gnutls_pkcs7_delete_crt} (gnutls_pkcs7_t @var{pkcs7}, int @var{indx})
@var{pkcs7}: should contain a gnutls_pkcs7_t structure

@var{indx}: the index of the certificate to delete

This function will delete a certificate from a PKCS7 or RFC2630
certificate set.  Index starts from 0. Returns 0 on success.

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

@subheading gnutls_pkcs7_export
@anchor{gnutls_pkcs7_export}
@deftypefun {int} {gnutls_pkcs7_export} (gnutls_pkcs7_t @var{pkcs7}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{pkcs7}: Holds the pkcs7 structure

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a structure PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the pkcs7 structure to DER or PEM format.

If the buffer provided is not long enough to hold the output, then
* @code{output_data_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER} 
will be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN PKCS7".

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

@subheading gnutls_pkcs7_get_crl_count
@anchor{gnutls_pkcs7_get_crl_count}
@deftypefun {int} {gnutls_pkcs7_get_crl_count} (gnutls_pkcs7_t @var{pkcs7})
@var{pkcs7}: should contain a gnutls_pkcs7_t structure

This function will return the number of certifcates in the PKCS7
or RFC2630 crl set.

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

@subheading gnutls_pkcs7_get_crl_raw
@anchor{gnutls_pkcs7_get_crl_raw}
@deftypefun {int} {gnutls_pkcs7_get_crl_raw} (gnutls_pkcs7_t @var{pkcs7}, int @var{indx}, void * @var{crl}, size_t * @var{crl_size})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{indx}: contains the index of the crl to extract

@var{crl}: the contents of the crl will be copied there (may be null)

@var{crl_size}: should hold the size of the crl

This function will return a crl of the PKCS7 or RFC2630 crl set.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.  If the provided buffer is not long enough,
then  @code{crl_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  is
returned.  After the last crl has been read
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be returned.
@end deftypefun

@subheading gnutls_pkcs7_get_crt_count
@anchor{gnutls_pkcs7_get_crt_count}
@deftypefun {int} {gnutls_pkcs7_get_crt_count} (gnutls_pkcs7_t @var{pkcs7})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

This function will return the number of certifcates in the PKCS7
or RFC2630 certificate set.

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

@subheading gnutls_pkcs7_get_crt_raw
@anchor{gnutls_pkcs7_get_crt_raw}
@deftypefun {int} {gnutls_pkcs7_get_crt_raw} (gnutls_pkcs7_t @var{pkcs7}, int @var{indx}, void * @var{certificate}, size_t * @var{certificate_size})
@var{pkcs7}: should contain a gnutls_pkcs7_t structure

@var{indx}: contains the index of the certificate to extract

@var{certificate}: the contents of the certificate will be copied
there (may be null)

@var{certificate_size}: should hold the size of the certificate

This function will return a certificate of the PKCS7 or RFC2630
certificate set.

After the last certificate has been read
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be returned.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.  If the provided buffer is not long enough,
then  @code{certificate_size} is updated and
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  is returned.
@end deftypefun

@subheading gnutls_pkcs7_import
@anchor{gnutls_pkcs7_import}
@deftypefun {int} {gnutls_pkcs7_import} (gnutls_pkcs7_t @var{pkcs7}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format})
@var{pkcs7}: The structure to store the parsed PKCS7.

@var{data}: The DER or PEM encoded PKCS7.

@var{format}: One of DER or PEM

This function will convert the given DER or PEM encoded PKCS7 to
the native @code{gnutls_pkcs7_t}  format.  The output will be stored in
 @code{pkcs7} .

If the PKCS7 is PEM encoded it should have a header of "PKCS7".

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

@subheading gnutls_pkcs7_init
@anchor{gnutls_pkcs7_init}
@deftypefun {int} {gnutls_pkcs7_init} (gnutls_pkcs7_t * @var{pkcs7})
@var{pkcs7}: The structure to be initialized

This function will initialize a PKCS7 structure. PKCS7 structures
usually contain lists of X.509 Certificates and X.509 Certificate
revocation lists.

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

@subheading gnutls_pkcs7_set_crl
@anchor{gnutls_pkcs7_set_crl}
@deftypefun {int} {gnutls_pkcs7_set_crl} (gnutls_pkcs7_t @var{pkcs7}, gnutls_x509_crl_t @var{crl})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{crl}: the DER encoded crl to be added

This function will add a parsed CRL to the PKCS7 or RFC2630 crl
set.

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

@subheading gnutls_pkcs7_set_crl_raw
@anchor{gnutls_pkcs7_set_crl_raw}
@deftypefun {int} {gnutls_pkcs7_set_crl_raw} (gnutls_pkcs7_t @var{pkcs7}, const gnutls_datum_t * @var{crl})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{crl}: the DER encoded crl to be added

This function will add a crl to the PKCS7 or RFC2630 crl set.

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

@subheading gnutls_pkcs7_set_crt
@anchor{gnutls_pkcs7_set_crt}
@deftypefun {int} {gnutls_pkcs7_set_crt} (gnutls_pkcs7_t @var{pkcs7}, gnutls_x509_crt_t @var{crt})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{crt}: the certificate to be copied.

This function will add a parsed certificate to the PKCS7 or
RFC2630 certificate set.  This is a wrapper function over
@code{gnutls_pkcs7_set_crt_raw()}  .

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

@subheading gnutls_pkcs7_set_crt_raw
@anchor{gnutls_pkcs7_set_crt_raw}
@deftypefun {int} {gnutls_pkcs7_set_crt_raw} (gnutls_pkcs7_t @var{pkcs7}, const gnutls_datum_t * @var{crt})
@var{pkcs7}: should contain a @code{gnutls_pkcs7_t}  structure

@var{crt}: the DER encoded certificate to be added

This function will add a certificate to the PKCS7 or RFC2630
certificate set.

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

@subheading gnutls_x509_crl_check_issuer
@anchor{gnutls_x509_crl_check_issuer}
@deftypefun {int} {gnutls_x509_crl_check_issuer} (gnutls_x509_crl_t @var{crl}, gnutls_x509_crt_t @var{issuer})
@var{crl}: is the CRL to be checked

@var{issuer}: is the certificate of a possible issuer

This function will check if the given CRL was issued by the given
issuer certificate.  It will return true (1) if the given CRL was
issued by the given issuer, and false (0) if not.

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

@subheading gnutls_x509_crl_deinit
@anchor{gnutls_x509_crl_deinit}
@deftypefun {void} {gnutls_x509_crl_deinit} (gnutls_x509_crl_t @var{crl})
@var{crl}: The structure to be initialized

This function will deinitialize a CRL structure.
@end deftypefun

@subheading gnutls_x509_crl_export
@anchor{gnutls_x509_crl_export}
@deftypefun {int} {gnutls_x509_crl_export} (gnutls_x509_crl_t @var{crl}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{crl}: Holds the revocation list

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a private key PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will
be replaced by the actual size of parameters)

This function will export the revocation list to DER or PEM format.

If the buffer provided is not long enough to hold the output, then
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN X509 CRL".

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

@subheading gnutls_x509_crl_get_authority_key_gn_serial
@anchor{gnutls_x509_crl_get_authority_key_gn_serial}
@deftypefun {int} {gnutls_x509_crl_get_authority_key_gn_serial} (gnutls_x509_crl_t @var{crl}, unsigned int @var{seq}, void * @var{alt}, size_t * @var{alt_size}, unsigned int * @var{alt_type}, void* @var{serial}, size_t * @var{serial_size}, unsigned int * @var{critical})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{alt}: is the place where the alternative name will be copied to

@var{alt_size}: holds the size of alt.

@var{alt_type}: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).

@var{serial}: buffer to store the serial number (may be null)

@var{serial_size}: Holds the size of the serial field (may be null)

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the X.509 authority key
identifier when stored as a general name (authorityCertIssuer) 
and serial number.

Because more than one general names might be stored
 @code{seq} can be used as a counter to request them all until 
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Returns:} Returns 0 on success, or an error code.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crl_get_authority_key_id
@anchor{gnutls_x509_crl_get_authority_key_id}
@deftypefun {int} {gnutls_x509_crl_get_authority_key_id} (gnutls_x509_crl_t @var{crl}, void * @var{id}, size_t * @var{id_size}, unsigned int * @var{critical})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{id}: The place where the identifier will be copied

@var{id_size}: Holds the size of the result field.

@var{critical}: will be non (0) if the extension is marked as critical
(may be null)

This function will return the CRL authority's key identifier.  This
is obtained by the X.509 Authority Key identifier extension field
(2.5.29.35).  Note that this function 
only returns the keyIdentifier field of the extension and
@code{GNUTLS_E_X509_UNSUPPORTED_EXTENSION} , if the extension contains
the name and serial number of the certificate. In that case
@code{gnutls_x509_crl_get_authority_key_gn_serial()}  may be used.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_get_crt_count
@anchor{gnutls_x509_crl_get_crt_count}
@deftypefun {int} {gnutls_x509_crl_get_crt_count} (gnutls_x509_crl_t @var{crl})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

This function will return the number of revoked certificates in the
given CRL.

@strong{Returns:} number of certificates, a negative error code on failure.
@end deftypefun

@subheading gnutls_x509_crl_get_crt_serial
@anchor{gnutls_x509_crl_get_crt_serial}
@deftypefun {int} {gnutls_x509_crl_get_crt_serial} (gnutls_x509_crl_t @var{crl}, int @var{indx}, unsigned char * @var{serial}, size_t * @var{serial_size}, time_t * @var{t})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{indx}: the index of the certificate to extract (starting from 0)

@var{serial}: where the serial number will be copied

@var{serial_size}: initially holds the size of serial

@var{t}: if non null, will hold the time this certificate was revoked

This function will retrieve the serial number of the specified, by
the index, revoked certificate.

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

@subheading gnutls_x509_crl_get_dn_oid
@anchor{gnutls_x509_crl_get_dn_oid}
@deftypefun {int} {gnutls_x509_crl_get_dn_oid} (gnutls_x509_crl_t @var{crl}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{indx}: Specifies which DN OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the name (may be null)

@var{sizeof_oid}: initially holds the size of 'oid'

This function will extract the requested OID of the name of the CRL
issuer, specified by the given index.

If oid is null then only the size will be filled.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the sizeof_oid will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crl_get_extension_data
@anchor{gnutls_x509_crl_get_extension_data}
@deftypefun {int} {gnutls_x509_crl_get_extension_data} (gnutls_x509_crl_t @var{crl}, int @var{indx}, void * @var{data}, size_t * @var{sizeof_data})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{data}: a pointer to a structure to hold the data (may be null)

@var{sizeof_data}: initially holds the size of  @code{oid} 

This function will return the requested extension data in the CRL.
The extension data will be stored as a string in the provided
buffer.

Use @code{gnutls_x509_crl_get_extension_info()}  to extract the OID and
critical flag.  Use @code{gnutls_x509_crl_get_extension_info()}  instead,
if you want to get data indexed by the extension OID rather than
sequence.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_get_extension_info
@anchor{gnutls_x509_crl_get_extension_info}
@deftypefun {int} {gnutls_x509_crl_get_extension_info} (gnutls_x509_crl_t @var{crl}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid}, unsigned int * @var{critical})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{indx}: Specifies which extension OID to send, use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID

@var{sizeof_oid}: initially holds the maximum size of  @code{oid} , on return
holds actual size of  @code{oid} .

@var{critical}: output variable with critical flag, may be NULL.

This function will return the requested extension OID in the CRL,
and the critical flag for it.  The extension OID will be stored as
a string in the provided buffer.  Use
@code{gnutls_x509_crl_get_extension_data()}  to extract the data.

If the buffer provided is not long enough to hold the output, then
* @code{sizeof_oid} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be
returned.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_get_extension_oid
@anchor{gnutls_x509_crl_get_extension_oid}
@deftypefun {int} {gnutls_x509_crl_get_extension_oid} (gnutls_x509_crl_t @var{crl}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{indx}: Specifies which extension OID to send, use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID (may be null)

@var{sizeof_oid}: initially holds the size of  @code{oid} 

This function will return the requested extension OID in the CRL.
The extension OID will be stored as a string in the provided
buffer.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_get_issuer_dn
@anchor{gnutls_x509_crl_get_issuer_dn}
@deftypefun {int} {gnutls_x509_crl_get_issuer_dn} (const gnutls_x509_crl_t @var{crl}, char * @var{buf}, size_t * @var{sizeof_buf})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{buf}: a pointer to a structure to hold the peer's name (may be null)

@var{sizeof_buf}: initially holds the size of  @code{buf} 

This function will copy the name of the CRL issuer in the provided
buffer. The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.

If buf is @code{NULL}  then only the size will be filled.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the sizeof_buf will be updated
with the required size, and 0 on success.
@end deftypefun

@subheading gnutls_x509_crl_get_issuer_dn_by_oid
@anchor{gnutls_x509_crl_get_issuer_dn_by_oid}
@deftypefun {int} {gnutls_x509_crl_get_issuer_dn_by_oid} (gnutls_x509_crl_t @var{crl}, const char * @var{oid}, int @var{indx}, unsigned int @var{raw_flag}, void * @var{buf}, size_t * @var{sizeof_buf})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.

@var{raw_flag}: If non (0) returns the raw DER data of the DN part.

@var{buf}: a pointer to a structure to hold the peer's name (may be null)

@var{sizeof_buf}: initially holds the size of  @code{buf} 

This function will extract the part of the name of the CRL issuer
specified by the given OID. The output will be encoded as described
in RFC4514. The output string will be ASCII or UTF-8 encoded,
depending on the certificate data.

Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 -- in
hex format with a '#' prefix.  You can check about known OIDs
using @code{gnutls_x509_dn_oid_known()} .

If buf is null then only the size will be filled.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the sizeof_buf will be updated
with the required size, and 0 on success.
@end deftypefun

@subheading gnutls_x509_crl_get_next_update
@anchor{gnutls_x509_crl_get_next_update}
@deftypefun {time_t} {gnutls_x509_crl_get_next_update} (gnutls_x509_crl_t @var{crl})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

This function will return the time the next CRL will be issued.
This field is optional in a CRL so it might be normal to get an
error instead.

@strong{Returns:} when the next CRL will be issued, or (time_t)-1 on error.
@end deftypefun

@subheading gnutls_x509_crl_get_number
@anchor{gnutls_x509_crl_get_number}
@deftypefun {int} {gnutls_x509_crl_get_number} (gnutls_x509_crl_t @var{crl}, void * @var{ret}, size_t * @var{ret_size}, unsigned int * @var{critical})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

@var{ret}: The place where the number will be copied

@var{ret_size}: Holds the size of the result field.

@var{critical}: will be non (0) if the extension is marked as critical
(may be null)

This function will return the CRL number extension.  This is
obtained by the CRL Number extension field (2.5.29.20).

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_get_raw_issuer_dn
@anchor{gnutls_x509_crl_get_raw_issuer_dn}
@deftypefun {int} {gnutls_x509_crl_get_raw_issuer_dn} (gnutls_x509_crl_t @var{crl}, gnutls_datum_t * @var{dn})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{dn}: will hold the starting point of the DN

This function will return a pointer to the DER encoded DN structure
and the length.

@strong{Returns:} a negative error code on error, and (0) on success.

@strong{Since:} 2.12.0
@end deftypefun

@subheading gnutls_x509_crl_get_signature
@anchor{gnutls_x509_crl_get_signature}
@deftypefun {int} {gnutls_x509_crl_get_signature} (gnutls_x509_crl_t @var{crl}, char * @var{sig}, size_t * @var{sizeof_sig})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{sig}: a pointer where the signature part will be copied (may be null).

@var{sizeof_sig}: initially holds the size of  @code{sig} 

This function will extract the signature field of a CRL.

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

@subheading gnutls_x509_crl_get_signature_algorithm
@anchor{gnutls_x509_crl_get_signature_algorithm}
@deftypefun {int} {gnutls_x509_crl_get_signature_algorithm} (gnutls_x509_crl_t @var{crl})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

This function will return a value of the @code{gnutls_sign_algorithm_t} 
enumeration that is the signature algorithm.

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

@subheading gnutls_x509_crl_get_this_update
@anchor{gnutls_x509_crl_get_this_update}
@deftypefun {time_t} {gnutls_x509_crl_get_this_update} (gnutls_x509_crl_t @var{crl})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

This function will return the time this CRL was issued.

@strong{Returns:} when the CRL was issued, or (time_t)-1 on error.
@end deftypefun

@subheading gnutls_x509_crl_get_version
@anchor{gnutls_x509_crl_get_version}
@deftypefun {int} {gnutls_x509_crl_get_version} (gnutls_x509_crl_t @var{crl})
@var{crl}: should contain a @code{gnutls_x509_crl_t}  structure

This function will return the version of the specified CRL.

@strong{Returns:} The version number, or a negative error code on error.
@end deftypefun

@subheading gnutls_x509_crl_import
@anchor{gnutls_x509_crl_import}
@deftypefun {int} {gnutls_x509_crl_import} (gnutls_x509_crl_t @var{crl}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format})
@var{crl}: The structure to store the parsed CRL.

@var{data}: The DER or PEM encoded CRL.

@var{format}: One of DER or PEM

This function will convert the given DER or PEM encoded CRL
to the native @code{gnutls_x509_crl_t}  format. The output will be stored in 'crl'.

If the CRL is PEM encoded it should have a header of "X509 CRL".

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

@subheading gnutls_x509_crl_init
@anchor{gnutls_x509_crl_init}
@deftypefun {int} {gnutls_x509_crl_init} (gnutls_x509_crl_t * @var{crl})
@var{crl}: The structure to be initialized

This function will initialize a CRL structure. CRL stands for
Certificate Revocation List. A revocation list usually contains
lists of certificate serial numbers that have been revoked by an
Authority. The revocation lists are always signed with the
authority's private key.

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

@subheading gnutls_x509_crl_list_import
@anchor{gnutls_x509_crl_list_import}
@deftypefun {int} {gnutls_x509_crl_list_import} (gnutls_x509_crl_t * @var{crls}, unsigned int * @var{crl_max}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format}, unsigned int @var{flags})
@var{crls}: The structures to store the parsed CRLs. Must not be initialized.

@var{crl_max}: Initially must hold the maximum number of crls. It will be updated with the number of crls available.

@var{data}: The PEM encoded CRLs

@var{format}: One of DER or PEM.

@var{flags}: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.

This function will convert the given PEM encoded CRL list
to the native gnutls_x509_crl_t format. The output will be stored
in  @code{crls} .  They will be automatically initialized.

If the Certificate is PEM encoded it should have a header of "X509 CRL".

@strong{Returns:} the number of certificates read or a negative error value.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crl_list_import2
@anchor{gnutls_x509_crl_list_import2}
@deftypefun {int} {gnutls_x509_crl_list_import2} (gnutls_x509_crl_t ** @var{crls}, unsigned int * @var{size}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format}, unsigned int @var{flags})
@var{crls}: The structures to store the parsed crl list. Must not be initialized.

@var{size}: It will contain the size of the list.

@var{data}: The PEM encoded CRL.

@var{format}: One of DER or PEM.

@var{flags}: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.

This function will convert the given PEM encoded CRL list
to the native gnutls_x509_crl_t format. The output will be stored
in  @code{crls} .  They will be automatically initialized.

If the Certificate is PEM encoded it should have a header of "X509
CRL".

@strong{Returns:} the number of certificates read or a negative error value.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crl_print
@anchor{gnutls_x509_crl_print}
@deftypefun {int} {gnutls_x509_crl_print} (gnutls_x509_crl_t @var{crl}, gnutls_certificate_print_formats_t @var{format}, gnutls_datum_t * @var{out})
@var{crl}: The structure to be printed

@var{format}: Indicate the format to use

@var{out}: Newly allocated datum with (0) terminated string.

This function will pretty print a X.509 certificate revocation
list, suitable for display to a human.

The output  @code{out} needs to be deallocate using @code{gnutls_free()} .

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

@subheading gnutls_x509_crl_set_authority_key_id
@anchor{gnutls_x509_crl_set_authority_key_id}
@deftypefun {int} {gnutls_x509_crl_set_authority_key_id} (gnutls_x509_crl_t @var{crl}, const void * @var{id}, size_t @var{id_size})
@var{crl}: a CRL of type @code{gnutls_x509_crl_t} 

@var{id}: The key ID

@var{id_size}: Holds the size of the serial field.

This function will set the CRL's authority key ID extension.  Only
the keyIdentifier field can be set with this function. This may
be used by an authority that holds multiple private keys, to distinguish
the used key.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_set_crt
@anchor{gnutls_x509_crl_set_crt}
@deftypefun {int} {gnutls_x509_crl_set_crt} (gnutls_x509_crl_t @var{crl}, gnutls_x509_crt_t @var{crt}, time_t @var{revocation_time})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{crt}: a certificate of type @code{gnutls_x509_crt_t}  with the revoked certificate

@var{revocation_time}: The time this certificate was revoked

This function will set a revoked certificate's serial number to the CRL.

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

@subheading gnutls_x509_crl_set_crt_serial
@anchor{gnutls_x509_crl_set_crt_serial}
@deftypefun {int} {gnutls_x509_crl_set_crt_serial} (gnutls_x509_crl_t @var{crl}, const void * @var{serial}, size_t @var{serial_size}, time_t @var{revocation_time})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{serial}: The revoked certificate's serial number

@var{serial_size}: Holds the size of the serial field.

@var{revocation_time}: The time this certificate was revoked

This function will set a revoked certificate's serial number to the CRL.

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

@subheading gnutls_x509_crl_set_next_update
@anchor{gnutls_x509_crl_set_next_update}
@deftypefun {int} {gnutls_x509_crl_set_next_update} (gnutls_x509_crl_t @var{crl}, time_t @var{exp_time})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{exp_time}: The actual time

This function will set the time this CRL will be updated.

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

@subheading gnutls_x509_crl_set_number
@anchor{gnutls_x509_crl_set_number}
@deftypefun {int} {gnutls_x509_crl_set_number} (gnutls_x509_crl_t @var{crl}, const void * @var{nr}, size_t @var{nr_size})
@var{crl}: a CRL of type @code{gnutls_x509_crl_t} 

@var{nr}: The CRL number

@var{nr_size}: Holds the size of the nr field.

This function will set the CRL's number extension. This
is to be used as a unique and monotonic number assigned to
the CRL by the authority.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crl_set_this_update
@anchor{gnutls_x509_crl_set_this_update}
@deftypefun {int} {gnutls_x509_crl_set_this_update} (gnutls_x509_crl_t @var{crl}, time_t @var{act_time})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{act_time}: The actual time

This function will set the time this CRL was issued.

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

@subheading gnutls_x509_crl_set_version
@anchor{gnutls_x509_crl_set_version}
@deftypefun {int} {gnutls_x509_crl_set_version} (gnutls_x509_crl_t @var{crl}, unsigned int @var{version})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{version}: holds the version number. For CRLv1 crls must be 1.

This function will set the version of the CRL. This
must be one for CRL version 1, and so on. The CRLs generated
by gnutls should have a version number of 2.

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

@subheading gnutls_x509_crl_sign2
@anchor{gnutls_x509_crl_sign2}
@deftypefun {int} {gnutls_x509_crl_sign2} (gnutls_x509_crl_t @var{crl}, gnutls_x509_crt_t @var{issuer}, gnutls_x509_privkey_t @var{issuer_key}, gnutls_digest_algorithm_t @var{dig}, unsigned int @var{flags})
@var{crl}: should contain a gnutls_x509_crl_t structure

@var{issuer}: is the certificate of the certificate issuer

@var{issuer_key}: holds the issuer's private key

@var{dig}: The message digest to use. GNUTLS_DIG_SHA1 is the safe choice unless you know what you're doing.

@var{flags}: must be 0

This function will sign the CRL with the issuer's private key, and
will copy the issuer's information into the CRL.

This must be the last step in a certificate CRL since all
the previously set parameters are now signed.

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

@subheading gnutls_x509_crl_verify
@anchor{gnutls_x509_crl_verify}
@deftypefun {int} {gnutls_x509_crl_verify} (gnutls_x509_crl_t @var{crl}, const gnutls_x509_crt_t * @var{CA_list}, int @var{CA_list_length}, unsigned int @var{flags}, unsigned int * @var{verify})
@var{crl}: is the crl to be verified

@var{CA_list}: is a certificate list that is considered to be trusted one

@var{CA_list_length}: holds the number of CA certificates in CA_list

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

@var{verify}: will hold the crl verification output.

This function will try to verify the given crl and return its status.
See @code{gnutls_x509_crt_list_verify()}  for a detailed description of
return values.

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

@subheading gnutls_x509_crq_deinit
@anchor{gnutls_x509_crq_deinit}
@deftypefun {void} {gnutls_x509_crq_deinit} (gnutls_x509_crq_t @var{crq})
@var{crq}: The structure to be initialized

This function will deinitialize a PKCS@code{10}  certificate request
structure.
@end deftypefun

@subheading gnutls_x509_crq_export
@anchor{gnutls_x509_crq_export}
@deftypefun {int} {gnutls_x509_crq_export} (gnutls_x509_crq_t @var{crq}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a certificate request PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the certificate request to a PEM or DER
encoded PKCS10 structure.

If the buffer provided is not long enough to hold the output, then
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be returned and
* @code{output_data_size} will be updated.

If the structure is PEM encoded, it will have a header of "BEGIN
NEW CERTIFICATE REQUEST".

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

@subheading gnutls_x509_crq_get_attribute_by_oid
@anchor{gnutls_x509_crq_get_attribute_by_oid}
@deftypefun {int} {gnutls_x509_crq_get_attribute_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, int @var{indx}, void * @var{buf}, size_t * @var{sizeof_buf})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{oid}: holds an Object Identified in (0)-terminated string

@var{indx}: In case multiple same OIDs exist in the attribute list, this
specifies which to send, use (0) to get the first one

@var{buf}: a pointer to a structure to hold the attribute data (may be @code{NULL} )

@var{sizeof_buf}: initially holds the size of  @code{buf} 

This function will return the attribute in the certificate request
specified by the given Object ID.  The attribute will be DER
encoded.

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

@subheading gnutls_x509_crq_get_attribute_data
@anchor{gnutls_x509_crq_get_attribute_data}
@deftypefun {int} {gnutls_x509_crq_get_attribute_data} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{data}, size_t * @var{sizeof_data})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{indx}: Specifies which attribute OID to send. Use (0) to get the first one.

@var{data}: a pointer to a structure to hold the data (may be null)

@var{sizeof_data}: initially holds the size of  @code{oid} 

This function will return the requested attribute data in the
certificate request.  The attribute data will be stored as a string in the
provided buffer.

Use @code{gnutls_x509_crq_get_attribute_info()}  to extract the OID.
Use @code{gnutls_x509_crq_get_attribute_by_oid()}  instead,
if you want to get data indexed by the attribute OID rather than
sequence.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_attribute_info
@anchor{gnutls_x509_crq_get_attribute_info}
@deftypefun {int} {gnutls_x509_crq_get_attribute_info} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{indx}: Specifies which attribute OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID

@var{sizeof_oid}: initially holds the maximum size of  @code{oid} , on return
holds actual size of  @code{oid} .

This function will return the requested attribute OID in the
certificate, and the critical flag for it.  The attribute OID will
be stored as a string in the provided buffer.  Use
@code{gnutls_x509_crq_get_attribute_data()}  to extract the data.

If the buffer provided is not long enough to hold the output, then
* @code{sizeof_oid} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be
returned.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_basic_constraints
@anchor{gnutls_x509_crq_get_basic_constraints}
@deftypefun {int} {gnutls_x509_crq_get_basic_constraints} (gnutls_x509_crq_t @var{crq}, unsigned int * @var{critical}, unsigned int * @var{ca}, int * @var{pathlen})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{critical}: will be non (0) if the extension is marked as critical

@var{ca}: pointer to output integer indicating CA status, may be NULL,
value is 1 if the certificate CA flag is set, 0 otherwise.

@var{pathlen}: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pathLenConstraint
field and the actual value, -1 indicate that the field is absent.

This function will read the certificate's basic constraints, and
return the certificates CA status.  It reads the basicConstraints
X.509 extension (2.5.29.19).

@strong{Returns:} If the certificate is a CA a positive value will be
returned, or (0) if the certificate does not have CA flag set.
A negative error code may be returned in case of errors.  If the
certificate does not contain the basicConstraints extension
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_challenge_password
@anchor{gnutls_x509_crq_get_challenge_password}
@deftypefun {int} {gnutls_x509_crq_get_challenge_password} (gnutls_x509_crq_t @var{crq}, char * @var{pass}, size_t * @var{sizeof_pass})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{pass}: will hold a (0)-terminated password string

@var{sizeof_pass}: Initially holds the size of  @code{pass} .

This function will return the challenge password in the request.
The challenge password is intended to be used for requesting a
revocation of the certificate.

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

@subheading gnutls_x509_crq_get_dn
@anchor{gnutls_x509_crq_get_dn}
@deftypefun {int} {gnutls_x509_crq_get_dn} (gnutls_x509_crq_t @var{crq}, char * @var{buf}, size_t * @var{sizeof_buf})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{buf}: a pointer to a structure to hold the name (may be @code{NULL} )

@var{sizeof_buf}: initially holds the size of  @code{buf} 

This function will copy the name of the Certificate request subject
to the provided buffer.  The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC 2253. The output string
 @code{buf} will be ASCII or UTF-8 encoded, depending on the certificate
data.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is not
long enough, and in that case the * @code{sizeof_buf} will be updated with
the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crq_get_dn_by_oid
@anchor{gnutls_x509_crq_get_dn_by_oid}
@deftypefun {int} {gnutls_x509_crq_get_dn_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, int @var{indx}, unsigned int @var{raw_flag}, void * @var{buf}, size_t * @var{sizeof_buf})
@var{crq}: should contain a gnutls_x509_crq_t structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the RDN, this specifies
which to send. Use (0) to get the first one.

@var{raw_flag}: If non (0) returns the raw DER data of the DN part.

@var{buf}: a pointer to a structure to hold the name (may be @code{NULL} )

@var{sizeof_buf}: initially holds the size of  @code{buf} 

This function will extract the part of the name of the Certificate
request subject, specified by the given OID. The output will be
encoded as described in RFC2253. The output string will be ASCII
or UTF-8 encoded, depending on the certificate data.

Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC2253 --
in hex format with a '\#' prefix.  You can check about known OIDs
using @code{gnutls_x509_dn_oid_known()} .

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the * @code{sizeof_buf} will be
updated with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crq_get_dn_oid
@anchor{gnutls_x509_crq_get_dn_oid}
@deftypefun {int} {gnutls_x509_crq_get_dn_oid} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid})
@var{crq}: should contain a gnutls_x509_crq_t structure

@var{indx}: Specifies which DN OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the name (may be @code{NULL} )

@var{sizeof_oid}: initially holds the size of  @code{oid} 

This function will extract the requested OID of the name of the
certificate request subject, specified by the given index.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the * @code{sizeof_oid} will be
updated with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crq_get_extension_by_oid
@anchor{gnutls_x509_crq_get_extension_by_oid}
@deftypefun {int} {gnutls_x509_crq_get_extension_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, int @var{indx}, void * @var{buf}, size_t * @var{sizeof_buf}, unsigned int * @var{critical})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the extensions, this
specifies which to send. Use (0) to get the first one.

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{sizeof_buf}: initially holds the size of  @code{buf} 

@var{critical}: will be non (0) if the extension is marked as critical

This function will return the extension specified by the OID in
the certificate.  The extensions will be returned as binary data
DER encoded, in the provided buffer.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If the certificate does not
contain the specified extension
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_extension_data
@anchor{gnutls_x509_crq_get_extension_data}
@deftypefun {int} {gnutls_x509_crq_get_extension_data} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{data}, size_t * @var{sizeof_data})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{data}: a pointer to a structure to hold the data (may be null)

@var{sizeof_data}: initially holds the size of  @code{oid} 

This function will return the requested extension data in the
certificate.  The extension data will be stored as a string in the
provided buffer.

Use @code{gnutls_x509_crq_get_extension_info()}  to extract the OID and
critical flag.  Use @code{gnutls_x509_crq_get_extension_by_oid()}  instead,
if you want to get data indexed by the extension OID rather than
sequence.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_extension_info
@anchor{gnutls_x509_crq_get_extension_info}
@deftypefun {int} {gnutls_x509_crq_get_extension_info} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid}, unsigned int * @var{critical})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID

@var{sizeof_oid}: initially holds the maximum size of  @code{oid} , on return
holds actual size of  @code{oid} .

@var{critical}: output variable with critical flag, may be NULL.

This function will return the requested extension OID in the
certificate, and the critical flag for it.  The extension OID will
be stored as a string in the provided buffer.  Use
@code{gnutls_x509_crq_get_extension_data()}  to extract the data.

If the buffer provided is not long enough to hold the output, then
* @code{sizeof_oid} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be
returned.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error code in case of an error.  If your have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_key_id
@anchor{gnutls_x509_crq_get_key_id}
@deftypefun {int} {gnutls_x509_crq_get_key_id} (gnutls_x509_crq_t @var{crq}, unsigned int @var{flags}, unsigned char * @var{output_data}, size_t * @var{output_data_size})
@var{crq}: a certificate of type @code{gnutls_x509_crq_t} 

@var{flags}: should be 0 for now

@var{output_data}: will contain the key ID

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will return a unique ID the depends on the public key
parameters.  This ID can be used in checking whether a certificate
corresponds to the given private key.

If the buffer provided is not long enough to hold the output, then
* @code{output_data_size} is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.

@strong{Returns:} In case of failure a negative error code will be
returned, and 0 on success.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_key_purpose_oid
@anchor{gnutls_x509_crq_get_key_purpose_oid}
@deftypefun {int} {gnutls_x509_crq_get_key_purpose_oid} (gnutls_x509_crq_t @var{crq}, int @var{indx}, void * @var{oid}, size_t * @var{sizeof_oid}, unsigned int * @var{critical})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{indx}: This specifies which OID to return, use (0) to get the first one

@var{oid}: a pointer to a buffer to hold the OID (may be @code{NULL} )

@var{sizeof_oid}: initially holds the size of  @code{oid} 

@var{critical}: output variable with critical flag, may be @code{NULL} .

This function will extract the key purpose OIDs of the Certificate
specified by the given index.  These are stored in the Extended Key
Usage extension (2.5.29.37).  See the GNUTLS_KP_* definitions for
human readable names.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the * @code{sizeof_oid} will be
updated with the required size.  On success 0 is returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_key_rsa_raw
@anchor{gnutls_x509_crq_get_key_rsa_raw}
@deftypefun {int} {gnutls_x509_crq_get_key_rsa_raw} (gnutls_x509_crq_t @var{crq}, gnutls_datum_t * @var{m}, gnutls_datum_t * @var{e})
@var{crq}: Holds the certificate

@var{m}: will hold the modulus

@var{e}: will hold the public exponent

This function will export the RSA public key's parameters found in
the given structure.  The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_key_usage
@anchor{gnutls_x509_crq_get_key_usage}
@deftypefun {int} {gnutls_x509_crq_get_key_usage} (gnutls_x509_crq_t @var{crq}, unsigned int * @var{key_usage}, unsigned int * @var{critical})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{key_usage}: where the key usage bits will be stored

@var{critical}: will be non (0) if the extension is marked as critical

This function will return certificate's key usage, by reading the
keyUsage X.509 extension (2.5.29.15).  The key usage value will
ORed values of the: @code{GNUTLS_KEY_DIGITAL_SIGNATURE} ,
@code{GNUTLS_KEY_NON_REPUDIATION} , @code{GNUTLS_KEY_KEY_ENCIPHERMENT} ,
@code{GNUTLS_KEY_DATA_ENCIPHERMENT} , @code{GNUTLS_KEY_KEY_AGREEMENT} ,
@code{GNUTLS_KEY_KEY_CERT_SIGN} , @code{GNUTLS_KEY_CRL_SIGN} ,
@code{GNUTLS_KEY_ENCIPHER_ONLY} , @code{GNUTLS_KEY_DECIPHER_ONLY} .

@strong{Returns:} the certificate key usage, or a negative error code in case of
parsing error.  If the certificate does not contain the keyUsage
extension @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be
returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_pk_algorithm
@anchor{gnutls_x509_crq_get_pk_algorithm}
@deftypefun {int} {gnutls_x509_crq_get_pk_algorithm} (gnutls_x509_crq_t @var{crq}, unsigned int * @var{bits})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{bits}: if bits is non-@code{NULL}  it will hold the size of the parameters' in bits

This function will return the public key algorithm of a PKCS@code{10} 
certificate request.

If bits is non-@code{NULL} , it should have enough size to hold the
parameters size in bits.  For RSA the bits returned is the modulus.
For DSA the bits returned are of the public exponent.

@strong{Returns:} a member of the @code{gnutls_pk_algorithm_t}  enumeration on
success, or a negative error code on error.
@end deftypefun

@subheading gnutls_x509_crq_get_private_key_usage_period
@anchor{gnutls_x509_crq_get_private_key_usage_period}
@deftypefun {int} {gnutls_x509_crq_get_private_key_usage_period} (gnutls_x509_crq_t @var{crq}, time_t* @var{activation}, time_t* @var{expiration}, unsigned int * @var{critical})
@var{crq}: -- undescribed --

@var{activation}: The activation time

@var{expiration}: The expiration time

@var{critical}: the extension status

This function will return the expiration and activation
times of the private key of the certificate.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
if the extension is not present, otherwise a negative error value.
@end deftypefun

@subheading gnutls_x509_crq_get_subject_alt_name
@anchor{gnutls_x509_crq_get_subject_alt_name}
@deftypefun {int} {gnutls_x509_crq_get_subject_alt_name} (gnutls_x509_crq_t @var{crq}, unsigned int @var{seq}, void * @var{ret}, size_t * @var{ret_size}, unsigned int * @var{ret_type}, unsigned int * @var{critical})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{seq}: specifies the sequence number of the alt name, 0 for the
first one, 1 for the second etc.

@var{ret}: is the place where the alternative name will be copied to

@var{ret_size}: holds the size of ret.

@var{ret_type}: holds the @code{gnutls_x509_subject_alt_name_t}  name type

@var{critical}: will be non (0) if the extension is marked as critical
(may be null)

This function will return the alternative names, contained in the
given certificate.  It is the same as
@code{gnutls_x509_crq_get_subject_alt_name()}  except for the fact that it
will return the type of the alternative name in  @code{ret_type} even if
the function fails for some reason (i.e.  the buffer provided is
not enough).

@strong{Returns:} the alternative subject name type on success, one of the
enumerated @code{gnutls_x509_subject_alt_name_t} .  It will return
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if  @code{ret_size} is not large enough to
hold the value.  In that case  @code{ret_size} will be updated with the
required size.  If the certificate request does not have an
Alternative name with the specified sequence number then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_subject_alt_othername_oid
@anchor{gnutls_x509_crq_get_subject_alt_othername_oid}
@deftypefun {int} {gnutls_x509_crq_get_subject_alt_othername_oid} (gnutls_x509_crq_t @var{crq}, unsigned int @var{seq}, void * @var{ret}, size_t * @var{ret_size})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{ret}: is the place where the otherName OID will be copied to

@var{ret_size}: holds the size of ret.

This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.

This function is only useful if
@code{gnutls_x509_crq_get_subject_alt_name()}  returned
@code{GNUTLS_SAN_OTHERNAME} .

@strong{Returns:} the alternative subject name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs,
it will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. @code{GNUTLS_SAN_OTHERNAME_XMPP} , and @code{GNUTLS_SAN_OTHERNAME}  for
unknown OIDs.  It will return @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if
 @code{ret_size} is not large enough to hold the value.  In that case
 @code{ret_size} will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_get_version
@anchor{gnutls_x509_crq_get_version}
@deftypefun {int} {gnutls_x509_crq_get_version} (gnutls_x509_crq_t @var{crq})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

This function will return the version of the specified Certificate
request.

@strong{Returns:} version of certificate request, or a negative error code on
error.
@end deftypefun

@subheading gnutls_x509_crq_import
@anchor{gnutls_x509_crq_import}
@deftypefun {int} {gnutls_x509_crq_import} (gnutls_x509_crq_t @var{crq}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format})
@var{crq}: The structure to store the parsed certificate request.

@var{data}: The DER or PEM encoded certificate.

@var{format}: One of DER or PEM

This function will convert the given DER or PEM encoded certificate
request to a @code{gnutls_x509_crq_t}  structure.  The output will be
stored in  @code{crq} .

If the Certificate is PEM encoded it should have a header of "NEW
CERTIFICATE REQUEST".

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

@subheading gnutls_x509_crq_init
@anchor{gnutls_x509_crq_init}
@deftypefun {int} {gnutls_x509_crq_init} (gnutls_x509_crq_t * @var{crq})
@var{crq}: The structure to be initialized

This function will initialize a PKCS@code{10}  certificate request
structure.

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

@subheading gnutls_x509_crq_print
@anchor{gnutls_x509_crq_print}
@deftypefun {int} {gnutls_x509_crq_print} (gnutls_x509_crq_t @var{crq}, gnutls_certificate_print_formats_t @var{format}, gnutls_datum_t * @var{out})
@var{crq}: The structure to be printed

@var{format}: Indicate the format to use

@var{out}: Newly allocated datum with (0) terminated string.

This function will pretty print a certificate request, suitable for
display to a human.

The output  @code{out} needs to be deallocate using @code{gnutls_free()} .

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_set_attribute_by_oid
@anchor{gnutls_x509_crq_set_attribute_by_oid}
@deftypefun {int} {gnutls_x509_crq_set_attribute_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, void * @var{buf}, size_t @var{sizeof_buf})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{oid}: holds an Object Identified in (0)-terminated string

@var{buf}: a pointer to a structure that holds the attribute data

@var{sizeof_buf}: holds the size of  @code{buf} 

This function will set the attribute in the certificate request
specified by the given Object ID.  The attribute must be be DER
encoded.

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

@subheading gnutls_x509_crq_set_basic_constraints
@anchor{gnutls_x509_crq_set_basic_constraints}
@deftypefun {int} {gnutls_x509_crq_set_basic_constraints} (gnutls_x509_crq_t @var{crq}, unsigned int @var{ca}, int @var{pathLenConstraint})
@var{crq}: a certificate request of type @code{gnutls_x509_crq_t} 

@var{ca}: true(1) or false(0) depending on the Certificate authority status.

@var{pathLenConstraint}: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.

This function will set the basicConstraints certificate extension.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_set_challenge_password
@anchor{gnutls_x509_crq_set_challenge_password}
@deftypefun {int} {gnutls_x509_crq_set_challenge_password} (gnutls_x509_crq_t @var{crq}, const char * @var{pass})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{pass}: holds a (0)-terminated password

This function will set a challenge password to be used when
revoking the request.

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

@subheading gnutls_x509_crq_set_dn_by_oid
@anchor{gnutls_x509_crq_set_dn_by_oid}
@deftypefun {int} {gnutls_x509_crq_set_dn_by_oid} (gnutls_x509_crq_t @var{crq}, const char * @var{oid}, unsigned int @var{raw_flag}, const void * @var{data}, unsigned int @var{sizeof_data})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{oid}: holds an Object Identifier in a (0)-terminated string

@var{raw_flag}: must be 0, or 1 if the data are DER encoded

@var{data}: a pointer to the input data

@var{sizeof_data}: holds the size of  @code{data} 

This function will set the part of the name of the Certificate
request subject, specified by the given OID.  The input string
should be ASCII or UTF-8 encoded.

Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs.  You can test
for known OIDs using @code{gnutls_x509_dn_oid_known()} .  For OIDs that are
not known (by gnutls) you should properly DER encode your data, and
call this function with raw_flag set.

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

@subheading gnutls_x509_crq_set_key
@anchor{gnutls_x509_crq_set_key}
@deftypefun {int} {gnutls_x509_crq_set_key} (gnutls_x509_crq_t @var{crq}, gnutls_x509_privkey_t @var{key})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{key}: holds a private key

This function will set the public parameters from the given private
key to the request.  

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

@subheading gnutls_x509_crq_set_key_purpose_oid
@anchor{gnutls_x509_crq_set_key_purpose_oid}
@deftypefun {int} {gnutls_x509_crq_set_key_purpose_oid} (gnutls_x509_crq_t @var{crq}, const void * @var{oid}, unsigned int @var{critical})
@var{crq}: a certificate of type @code{gnutls_x509_crq_t} 

@var{oid}: a pointer to a (0)-terminated string that holds the OID

@var{critical}: Whether this extension will be critical or not

This function will set the key purpose OIDs of the Certificate.
These are stored in the Extended Key Usage extension (2.5.29.37)
See the GNUTLS_KP_* definitions for human readable names.

Subsequent calls to this function will append OIDs to the OID list.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_set_key_rsa_raw
@anchor{gnutls_x509_crq_set_key_rsa_raw}
@deftypefun {int} {gnutls_x509_crq_set_key_rsa_raw} (gnutls_x509_crq_t @var{crq}, const gnutls_datum_t * @var{m}, const gnutls_datum_t * @var{e})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{m}: holds the modulus

@var{e}: holds the public exponent

This function will set the public parameters from the given private
key to the request. Only RSA keys are currently supported.

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

@strong{Since:} 2.6.0
@end deftypefun

@subheading gnutls_x509_crq_set_key_usage
@anchor{gnutls_x509_crq_set_key_usage}
@deftypefun {int} {gnutls_x509_crq_set_key_usage} (gnutls_x509_crq_t @var{crq}, unsigned int @var{usage})
@var{crq}: a certificate request of type @code{gnutls_x509_crq_t} 

@var{usage}: an ORed sequence of the GNUTLS_KEY_* elements.

This function will set the keyUsage certificate extension.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_set_private_key_usage_period
@anchor{gnutls_x509_crq_set_private_key_usage_period}
@deftypefun {int} {gnutls_x509_crq_set_private_key_usage_period} (gnutls_x509_crq_t @var{crq}, time_t @var{activation}, time_t @var{expiration})
@var{crq}: a certificate of type @code{gnutls_x509_crq_t} 

@var{activation}: The activation time

@var{expiration}: The expiration time

This function will set the private key usage period extension (2.5.29.16).

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

@subheading gnutls_x509_crq_set_subject_alt_name
@anchor{gnutls_x509_crq_set_subject_alt_name}
@deftypefun {int} {gnutls_x509_crq_set_subject_alt_name} (gnutls_x509_crq_t @var{crq}, gnutls_x509_subject_alt_name_t @var{nt}, const void * @var{data}, unsigned int @var{data_size}, unsigned int @var{flags})
@var{crq}: a certificate request of type @code{gnutls_x509_crq_t} 

@var{nt}: is one of the @code{gnutls_x509_subject_alt_name_t}  enumerations

@var{data}: The data to be set

@var{data_size}: The size of data to be set

@var{flags}: @code{GNUTLS_FSAN_SET}  to clear previous data or
@code{GNUTLS_FSAN_APPEND}  to append.

This function will set the subject alternative name certificate
extension.  It can set the following types:

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crq_set_version
@anchor{gnutls_x509_crq_set_version}
@deftypefun {int} {gnutls_x509_crq_set_version} (gnutls_x509_crq_t @var{crq}, unsigned int @var{version})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{version}: holds the version number, for v1 Requests must be 1

This function will set the version of the certificate request.  For
version 1 requests this must be one.

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

@subheading gnutls_x509_crq_sign2
@anchor{gnutls_x509_crq_sign2}
@deftypefun {int} {gnutls_x509_crq_sign2} (gnutls_x509_crq_t @var{crq}, gnutls_x509_privkey_t @var{key}, gnutls_digest_algorithm_t @var{dig}, unsigned int @var{flags})
@var{crq}: should contain a @code{gnutls_x509_crq_t}  structure

@var{key}: holds a private key

@var{dig}: The message digest to use, i.e., @code{GNUTLS_DIG_SHA1} 

@var{flags}: must be 0

This function will sign the certificate request with a private key.
This must be the same key as the one used in
@code{gnutls_x509_crt_set_key()}  since a certificate request is self
signed.

This must be the last step in a certificate request generation
since all the previously set parameters are now signed.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.
@code{GNUTLS_E_ASN1_VALUE_NOT_FOUND}  is returned if you didn't set all
information in the certificate request (e.g., the version using
@code{gnutls_x509_crq_set_version()} ).
@end deftypefun

@subheading gnutls_x509_crq_verify
@anchor{gnutls_x509_crq_verify}
@deftypefun {int} {gnutls_x509_crq_verify} (gnutls_x509_crq_t @var{crq}, unsigned int @var{flags})
@var{crq}: is the crq to be verified

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

This function will verify self signature in the certificate
request and return its status.

@strong{Returns:} In case of a verification failure @code{GNUTLS_E_PK_SIG_VERIFY_FAILED}  
is returned, and zero or positive code on success.

Since 2.12.0
@end deftypefun

@subheading gnutls_x509_crt_check_hostname
@anchor{gnutls_x509_crt_check_hostname}
@deftypefun {int} {gnutls_x509_crt_check_hostname} (gnutls_x509_crt_t @var{cert}, const char * @var{hostname})
@var{cert}: should contain an gnutls_x509_crt_t structure

@var{hostname}: A null terminated string that contains a DNS name

This function will check if the given certificate's subject matches
the given hostname.  This is a basic implementation of the matching
described in RFC2818 (HTTPS), which takes into account wildcards,
and the DNSName/IPAddress subject alternative name PKIX extension.

@strong{Returns:} non (0) for a successful match, and (0) on failure.
@end deftypefun

@subheading gnutls_x509_crt_check_issuer
@anchor{gnutls_x509_crt_check_issuer}
@deftypefun {int} {gnutls_x509_crt_check_issuer} (gnutls_x509_crt_t @var{cert}, gnutls_x509_crt_t @var{issuer})
@var{cert}: is the certificate to be checked

@var{issuer}: is the certificate of a possible issuer

This function will check if the given certificate was issued by the
given issuer.

@strong{Returns:} It will return true (1) if the given certificate is issued
by the given issuer, and false (0) if not.  A negative error code is
returned in case of an error.
@end deftypefun

@subheading gnutls_x509_crt_check_revocation
@anchor{gnutls_x509_crt_check_revocation}
@deftypefun {int} {gnutls_x509_crt_check_revocation} (gnutls_x509_crt_t @var{cert}, const gnutls_x509_crl_t * @var{crl_list}, int @var{crl_list_length})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{crl_list}: should contain a list of gnutls_x509_crl_t structures

@var{crl_list_length}: the length of the crl_list

This function will return check if the given certificate is
revoked.  It is assumed that the CRLs have been verified before.

@strong{Returns:} 0 if the certificate is NOT revoked, and 1 if it is.  A
negative error code is returned on error.
@end deftypefun

@subheading gnutls_x509_crt_cpy_crl_dist_points
@anchor{gnutls_x509_crt_cpy_crl_dist_points}
@deftypefun {int} {gnutls_x509_crt_cpy_crl_dist_points} (gnutls_x509_crt_t @var{dst}, gnutls_x509_crt_t @var{src})
@var{dst}: a certificate of type @code{gnutls_x509_crt_t} 

@var{src}: the certificate where the dist points will be copied from

This function will copy the CRL distribution points certificate
extension, from the source to the destination certificate.
This may be useful to copy from a CA certificate to issued ones.

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

@subheading gnutls_x509_crt_deinit
@anchor{gnutls_x509_crt_deinit}
@deftypefun {void} {gnutls_x509_crt_deinit} (gnutls_x509_crt_t @var{cert})
@var{cert}: The structure to be deinitialized

This function will deinitialize a certificate structure.
@end deftypefun

@subheading gnutls_x509_crt_export
@anchor{gnutls_x509_crt_export}
@deftypefun {int} {gnutls_x509_crt_export} (gnutls_x509_crt_t @var{cert}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{cert}: Holds the certificate

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a certificate PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the certificate to DER or PEM format.

If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN CERTIFICATE".

@strong{Returns:} In case of failure a negative error code will be
returned, and 0 on success.
@end deftypefun

@subheading gnutls_x509_crt_get_activation_time
@anchor{gnutls_x509_crt_get_activation_time}
@deftypefun {time_t} {gnutls_x509_crt_get_activation_time} (gnutls_x509_crt_t @var{cert})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

This function will return the time this Certificate was or will be
activated.

@strong{Returns:} activation time, or (time_t)-1 on error.
@end deftypefun

@subheading gnutls_x509_crt_get_authority_info_access
@anchor{gnutls_x509_crt_get_authority_info_access}
@deftypefun {int} {gnutls_x509_crt_get_authority_info_access} (gnutls_x509_crt_t @var{crt}, unsigned int @var{seq}, int @var{what}, gnutls_datum_t * @var{data}, unsigned int * @var{critical})
@var{crt}: Holds the certificate

@var{seq}: specifies the sequence number of the access descriptor (0 for the first one, 1 for the second etc.)

@var{what}: what data to get, a @code{gnutls_info_access_what_t}  type.

@var{data}: output data to be freed with @code{gnutls_free()} .

@var{critical}: pointer to output integer that is set to non-0 if the extension is marked as critical (may be @code{NULL} )

This function extracts the Authority Information Access (AIA)
extension, see RFC 5280 section 4.2.2.1 for more information.  The
AIA extension holds a sequence of AccessDescription (AD) data:

<informalexample><programlisting>
AuthorityInfoAccessSyntax  ::=
SEQUENCE SIZE (1..MAX) OF AccessDescription

AccessDescription  ::=  SEQUENCE @{
accessMethod          OBJECT IDENTIFIER,
accessLocation        GeneralName  @}
</programlisting></informalexample>

The  @code{seq} input parameter is used to indicate which member of the
sequence the caller is interested in.  The first member is 0, the
second member 1 and so on.  When the  @code{seq} value is out of bounds,
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

The type of data returned in  @code{data} is specified via  @code{what} which
should be @code{gnutls_info_access_what_t}  values.

If  @code{what} is @code{GNUTLS_IA_ACCESSMETHOD_OID}  then  @code{data} will hold the
accessMethod OID (e.g., "1.3.6.1.5.5.7.48.1").

If  @code{what} is @code{GNUTLS_IA_ACCESSLOCATION_GENERALNAME_TYPE} ,  @code{data} will
hold the accessLocation GeneralName type (e.g.,
"uniformResourceIdentifier").

If  @code{what} is @code{GNUTLS_IA_URI} ,  @code{data} will hold the accessLocation URI
data.  Requesting this  @code{what} value leads to an error if the
accessLocation is not of the "uniformResourceIdentifier" type.

If  @code{what} is @code{GNUTLS_IA_OCSP_URI} ,  @code{data} will hold the OCSP URI.
Requesting this  @code{what} value leads to an error if the accessMethod
is not 1.3.6.1.5.5.7.48.1 aka OSCP, or if accessLocation is not of
the "uniformResourceIdentifier" type.

If  @code{what} is @code{GNUTLS_IA_CAISSUERS_URI} ,  @code{data} will hold the caIssuers
URI.  Requesting this  @code{what} value leads to an error if the
accessMethod is not 1.3.6.1.5.5.7.48.2 aka caIssuers, or if
accessLocation is not of the "uniformResourceIdentifier" type.

More  @code{what} values may be allocated in the future as needed.

If  @code{data} is NULL, the function does the same without storing the
output data, that is, it will set  @code{critical} and do error checking
as usual.

The value of the critical flag is returned in * @code{critical} .  Supply a
NULL  @code{critical} if you want the function to make sure the extension
is non-critical, as required by RFC 5280.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, @code{GNUTLS_E_INVALID_REQUEST}  on
invalid  @code{crt} , @code{GNUTLS_E_CONSTRAINT_ERROR}  if the extension is
incorrectly marked as critical (use a non-NULL  @code{critical} to
override), @code{GNUTLS_E_UNKNOWN_ALGORITHM}  if the requested OID does
not match (e.g., when using @code{GNUTLS_IA_OCSP_URI} ), otherwise a
negative error code.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crt_get_authority_key_gn_serial
@anchor{gnutls_x509_crt_get_authority_key_gn_serial}
@deftypefun {int} {gnutls_x509_crt_get_authority_key_gn_serial} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{alt}, size_t * @var{alt_size}, unsigned int * @var{alt_type}, void* @var{serial}, size_t * @var{serial_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{alt}: is the place where the alternative name will be copied to

@var{alt_size}: holds the size of alt.

@var{alt_type}: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).

@var{serial}: buffer to store the serial number (may be null)

@var{serial_size}: Holds the size of the serial field (may be null)

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the X.509 authority key
identifier when stored as a general name (authorityCertIssuer) 
and serial number.

Because more than one general names might be stored
 @code{seq} can be used as a counter to request them all until 
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
if the extension is not present, otherwise a negative error value.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crt_get_authority_key_id
@anchor{gnutls_x509_crt_get_authority_key_id}
@deftypefun {int} {gnutls_x509_crt_get_authority_key_id} (gnutls_x509_crt_t @var{cert}, void * @var{id}, size_t * @var{id_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{id}: The place where the identifier will be copied

@var{id_size}: Holds the size of the id field.

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the X.509v3 certificate authority's key
identifier.  This is obtained by the X.509 Authority Key
identifier extension field (2.5.29.35). Note that this function
only returns the keyIdentifier field of the extension and
@code{GNUTLS_E_X509_UNSUPPORTED_EXTENSION} , if the extension contains
the name and serial number of the certificate. In that case
@code{gnutls_x509_crt_get_authority_key_gn_serial()}  may be used.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
if the extension is not present, otherwise a negative error value.
@end deftypefun

@subheading gnutls_x509_crt_get_basic_constraints
@anchor{gnutls_x509_crt_get_basic_constraints}
@deftypefun {int} {gnutls_x509_crt_get_basic_constraints} (gnutls_x509_crt_t @var{cert}, unsigned int * @var{critical}, unsigned int * @var{ca}, int * @var{pathlen})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{critical}: will be non (0) if the extension is marked as critical

@var{ca}: pointer to output integer indicating CA status, may be NULL,
value is 1 if the certificate CA flag is set, 0 otherwise.

@var{pathlen}: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pathLenConstraint
field and the actual value, -1 indicate that the field is absent.

This function will read the certificate's basic constraints, and
return the certificates CA status.  It reads the basicConstraints
X.509 extension (2.5.29.19).

@strong{Returns:} If the certificate is a CA a positive value will be
returned, or (0) if the certificate does not have CA flag set.  A
negative error code may be returned in case of errors.  If the
certificate does not contain the basicConstraints extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_ca_status
@anchor{gnutls_x509_crt_get_ca_status}
@deftypefun {int} {gnutls_x509_crt_get_ca_status} (gnutls_x509_crt_t @var{cert}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{critical}: will be non (0) if the extension is marked as critical

This function will return certificates CA status, by reading the
basicConstraints X.509 extension (2.5.29.19). If the certificate is
a CA a positive value will be returned, or (0) if the certificate
does not have CA flag set.

Use @code{gnutls_x509_crt_get_basic_constraints()}  if you want to read the
pathLenConstraint field too.

@strong{Returns:} A negative error code may be returned in case of parsing error.
If the certificate does not contain the basicConstraints extension
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_crl_dist_points
@anchor{gnutls_x509_crt_get_crl_dist_points}
@deftypefun {int} {gnutls_x509_crt_get_crl_dist_points} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{ret}, size_t * @var{ret_size}, unsigned int * @var{reason_flags}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the distribution point (0 for the first one, 1 for the second etc.)

@var{ret}: is the place where the distribution point will be copied to

@var{ret_size}: holds the size of ret.

@var{reason_flags}: Revocation reasons flags.

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function retrieves the CRL distribution points (2.5.29.31),
contained in the given certificate in the X509v3 Certificate
Extensions.

 @code{reason_flags} should be an ORed sequence of
@code{GNUTLS_CRL_REASON_UNUSED} , @code{GNUTLS_CRL_REASON_KEY_COMPROMISE} ,
@code{GNUTLS_CRL_REASON_CA_COMPROMISE} ,
@code{GNUTLS_CRL_REASON_AFFILIATION_CHANGED} ,
@code{GNUTLS_CRL_REASON_SUPERSEEDED} ,
@code{GNUTLS_CRL_REASON_CESSATION_OF_OPERATION} ,
@code{GNUTLS_CRL_REASON_CERTIFICATE_HOLD} ,
@code{GNUTLS_CRL_REASON_PRIVILEGE_WITHDRAWN} ,
@code{GNUTLS_CRL_REASON_AA_COMPROMISE} , or (0) for all possible reasons.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  and updates  @code{ret_size} if
 @code{ret_size} is not enough to hold the distribution point, or the
type of the distribution point if everything was ok. The type is
one of the enumerated @code{gnutls_x509_subject_alt_name_t} .  If the
certificate does not have an Alternative name with the specified
sequence number then @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is
returned.
@end deftypefun

@subheading gnutls_x509_crt_get_dn
@anchor{gnutls_x509_crt_get_dn}
@deftypefun {int} {gnutls_x509_crt_get_dn} (gnutls_x509_crt_t @var{cert}, char * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

This function will copy the name of the Certificate in the provided
buffer. The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as
described in RFC4514. The output string will be ASCII or UTF-8
encoded, depending on the certificate data.

If  @code{buf} is null then only the size will be filled. 

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is not
long enough, and in that case the  @code{buf_size} will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_dn_by_oid
@anchor{gnutls_x509_crt_get_dn_by_oid}
@deftypefun {int} {gnutls_x509_crt_get_dn_by_oid} (gnutls_x509_crt_t @var{cert}, const char * @var{oid}, int @var{indx}, unsigned int @var{raw_flag}, void * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.

@var{raw_flag}: If non (0) returns the raw DER data of the DN part.

@var{buf}: a pointer where the DN part will be copied (may be null).

@var{buf_size}: initially holds the size of  @code{buf} 

This function will extract the part of the name of the Certificate
subject specified by the given OID. The output, if the raw flag is
not used, will be encoded as described in RFC4514. Thus a string
that is ASCII or UTF-8 encoded, depending on the certificate data.

Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 --
in hex format with a '#' prefix.  You can check about known OIDs
using @code{gnutls_x509_dn_oid_known()} .

If  @code{buf} is null then only the size will be filled. If the  @code{raw_flag} is not specified the output is always null terminated, although the
 @code{buf_size} will not include the null character.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the *buf_size will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_dn_oid
@anchor{gnutls_x509_crt_get_dn_oid}
@deftypefun {int} {gnutls_x509_crt_get_dn_oid} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{oid}, size_t * @var{oid_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: This specifies which OID to return. Use (0) to get the first one.

@var{oid}: a pointer to a buffer to hold the OID (may be null)

@var{oid_size}: initially holds the size of  @code{oid} 

This function will extract the OIDs of the name of the Certificate
subject specified by the given index.

If  @code{oid} is null then only the size will be filled. The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the  @code{oid_size} will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_expiration_time
@anchor{gnutls_x509_crt_get_expiration_time}
@deftypefun {time_t} {gnutls_x509_crt_get_expiration_time} (gnutls_x509_crt_t @var{cert})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

This function will return the time this Certificate was or will be
expired.

@strong{Returns:} expiration time, or (time_t)-1 on error.
@end deftypefun

@subheading gnutls_x509_crt_get_extension_by_oid
@anchor{gnutls_x509_crt_get_extension_by_oid}
@deftypefun {int} {gnutls_x509_crt_get_extension_by_oid} (gnutls_x509_crt_t @var{cert}, const char * @var{oid}, int @var{indx}, void * @var{buf}, size_t * @var{buf_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the extensions, this specifies which to send. Use (0) to get the first one.

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

@var{critical}: will be non (0) if the extension is marked as critical

This function will return the extension specified by the OID in the
certificate.  The extensions will be returned as binary data DER
encoded, in the provided buffer.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned,
otherwise a negative error code is returned. If the certificate does not
contain the specified extension
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_extension_data
@anchor{gnutls_x509_crt_get_extension_data}
@deftypefun {int} {gnutls_x509_crt_get_extension_data} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{data}, size_t * @var{sizeof_data})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{data}: a pointer to a structure to hold the data (may be null)

@var{sizeof_data}: initially holds the size of  @code{oid} 

This function will return the requested extension data in the
certificate.  The extension data will be stored as a string in the
provided buffer.

Use @code{gnutls_x509_crt_get_extension_info()}  to extract the OID and
critical flag.  Use @code{gnutls_x509_crt_get_extension_by_oid()}  instead,
if you want to get data indexed by the extension OID rather than
sequence.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_extension_info
@anchor{gnutls_x509_crt_get_extension_info}
@deftypefun {int} {gnutls_x509_crt_get_extension_info} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{oid}, size_t * @var{oid_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID

@var{oid_size}: initially holds the maximum size of  @code{oid} , on return
holds actual size of  @code{oid} .

@var{critical}: output variable with critical flag, may be NULL.

This function will return the requested extension OID in the
certificate, and the critical flag for it.  The extension OID will
be stored as a string in the provided buffer.  Use
@code{gnutls_x509_crt_get_extension_data()}  to extract the data.

If the buffer provided is not long enough to hold the output, then
 @code{oid_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will be
returned. The  @code{oid} returned will be null terminated, although 
 @code{oid_size} will not account for the trailing null.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_extension_oid
@anchor{gnutls_x509_crt_get_extension_oid}
@deftypefun {int} {gnutls_x509_crt_get_extension_oid} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{oid}, size_t * @var{oid_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: Specifies which extension OID to send. Use (0) to get the first one.

@var{oid}: a pointer to a structure to hold the OID (may be null)

@var{oid_size}: initially holds the size of  @code{oid} 

This function will return the requested extension OID in the certificate.
The extension OID will be stored as a string in the provided buffer.

The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned,
otherwise a negative error code is returned.  If you have reached the
last extension available @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
will be returned.
@end deftypefun

@subheading gnutls_x509_crt_get_fingerprint
@anchor{gnutls_x509_crt_get_fingerprint}
@deftypefun {int} {gnutls_x509_crt_get_fingerprint} (gnutls_x509_crt_t @var{cert}, gnutls_digest_algorithm_t @var{algo}, void * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{algo}: is a digest algorithm

@var{buf}: a pointer to a structure to hold the fingerprint (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

This function will calculate and copy the certificate's fingerprint
in the provided buffer.

If the buffer is null then only the size will be filled.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the *buf_size will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_issuer
@anchor{gnutls_x509_crt_get_issuer}
@deftypefun {int} {gnutls_x509_crt_get_issuer} (gnutls_x509_crt_t @var{cert}, gnutls_x509_dn_t * @var{dn})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{dn}: output variable with pointer to uint8_t DN

Return the Certificate's Issuer DN as an uint8_t data type.  You may
use @code{gnutls_x509_dn_get_rdn_ava()}  to decode the DN.

Note that  @code{dn} should be treated as constant. Because points 
into the  @code{cert} object, you may not deallocate  @code{cert} and continue to access  @code{dn} .

@strong{Returns:} Returns 0 on success, or an error code.
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_alt_name
@anchor{gnutls_x509_crt_get_issuer_alt_name}
@deftypefun {int} {gnutls_x509_crt_get_issuer_alt_name} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{ian}, size_t * @var{ian_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{ian}: is the place where the alternative name will be copied to

@var{ian_size}: holds the size of ian.

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function retrieves the Issuer Alternative Name (2.5.29.18),
contained in the given certificate in the X509v3 Certificate
Extensions.

When the SAN type is otherName, it will extract the data in the
otherName's value field, and @code{GNUTLS_SAN_OTHERNAME}  is returned.
You may use @code{gnutls_x509_crt_get_subject_alt_othername_oid()}  to get
the corresponding OID and the "virtual" SAN types (e.g.,
@code{GNUTLS_SAN_OTHERNAME_XMPP} ).

If an otherName OID is known, the data will be decoded.  Otherwise
the returned data will be DER encoded, and you will have to decode
it yourself.  Currently, only the RFC 3920 id-on-xmppAddr Issuer
AltName is recognized.

@strong{Returns:} the alternative issuer name type on success, one of the
enumerated @code{gnutls_x509_subject_alt_name_t} .  It will return
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if  @code{ian_size} is not large enough
to hold the value.  In that case  @code{ian_size} will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Since:} 2.10.0
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_alt_name2
@anchor{gnutls_x509_crt_get_issuer_alt_name2}
@deftypefun {int} {gnutls_x509_crt_get_issuer_alt_name2} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{ian}, size_t * @var{ian_size}, unsigned int * @var{ian_type}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{ian}: is the place where the alternative name will be copied to

@var{ian_size}: holds the size of ret.

@var{ian_type}: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the alternative names, contained in the
given certificate. It is the same as
@code{gnutls_x509_crt_get_issuer_alt_name()}  except for the fact that it
will return the type of the alternative name in  @code{ian_type} even if
the function fails for some reason (i.e.  the buffer provided is
not enough).

@strong{Returns:} the alternative issuer name type on success, one of the
enumerated @code{gnutls_x509_subject_alt_name_t} .  It will return
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if  @code{ian_size} is not large enough
to hold the value.  In that case  @code{ian_size} will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Since:} 2.10.0
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_alt_othername_oid
@anchor{gnutls_x509_crt_get_issuer_alt_othername_oid}
@deftypefun {int} {gnutls_x509_crt_get_issuer_alt_othername_oid} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{ret}, size_t * @var{ret_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{ret}: is the place where the otherName OID will be copied to

@var{ret_size}: holds the size of ret.

This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.

If  @code{oid} is null then only the size will be filled. The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

This function is only useful if
@code{gnutls_x509_crt_get_issuer_alt_name()}  returned
@code{GNUTLS_SAN_OTHERNAME} .

@strong{Returns:} the alternative issuer name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs, it
will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. @code{GNUTLS_SAN_OTHERNAME_XMPP} , and @code{GNUTLS_SAN_OTHERNAME}  for
unknown OIDs.  It will return @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if
 @code{ret_size} is not large enough to hold the value.  In that case
 @code{ret_size} will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.

@strong{Since:} 2.10.0
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_dn
@anchor{gnutls_x509_crt_get_issuer_dn}
@deftypefun {int} {gnutls_x509_crt_get_issuer_dn} (gnutls_x509_crt_t @var{cert}, char * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

This function will copy the name of the Certificate issuer in the
provided buffer. The name will be in the form
"C=xxxx,O=yyyy,CN=zzzz" as described in RFC4514. The output string
will be ASCII or UTF-8 encoded, depending on the certificate data.

If  @code{buf} is null then only the size will be filled. 

@strong{Returns:} GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the  @code{buf_size} will be updated with
the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_dn_by_oid
@anchor{gnutls_x509_crt_get_issuer_dn_by_oid}
@deftypefun {int} {gnutls_x509_crt_get_issuer_dn_by_oid} (gnutls_x509_crt_t @var{cert}, const char * @var{oid}, int @var{indx}, unsigned int @var{raw_flag}, void * @var{buf}, size_t * @var{buf_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{oid}: holds an Object Identified in null terminated string

@var{indx}: In case multiple same OIDs exist in the RDN, this specifies which to send. Use (0) to get the first one.

@var{raw_flag}: If non (0) returns the raw DER data of the DN part.

@var{buf}: a pointer to a structure to hold the name (may be null)

@var{buf_size}: initially holds the size of  @code{buf} 

This function will extract the part of the name of the Certificate
issuer specified by the given OID. The output, if the raw flag is not
used, will be encoded as described in RFC4514. Thus a string that is
ASCII or UTF-8 encoded, depending on the certificate data.

Some helper macros with popular OIDs can be found in gnutls/x509.h
If raw flag is (0), this function will only return known OIDs as
text. Other OIDs will be DER encoded, as described in RFC4514 --
in hex format with a '#' prefix.  You can check about known OIDs
using @code{gnutls_x509_dn_oid_known()} .

If  @code{buf} is null then only the size will be filled. If the  @code{raw_flag} is not specified the output is always null terminated, although the
 @code{buf_size} will not include the null character.

@strong{Returns:} GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the  @code{buf_size} will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_dn_oid
@anchor{gnutls_x509_crt_get_issuer_dn_oid}
@deftypefun {int} {gnutls_x509_crt_get_issuer_dn_oid} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{oid}, size_t * @var{oid_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: This specifies which OID to return. Use (0) to get the first one.

@var{oid}: a pointer to a buffer to hold the OID (may be null)

@var{oid_size}: initially holds the size of  @code{oid} 

This function will extract the OIDs of the name of the Certificate
issuer specified by the given index.

If  @code{oid} is null then only the size will be filled. The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

@strong{Returns:} GNUTLS_E_SHORT_MEMORY_BUFFER if the provided buffer is not
long enough, and in that case the  @code{oid_size} will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_issuer_unique_id
@anchor{gnutls_x509_crt_get_issuer_unique_id}
@deftypefun {int} {gnutls_x509_crt_get_issuer_unique_id} (gnutls_x509_crt_t @var{crt}, char * @var{buf}, size_t * @var{buf_size})
@var{crt}: Holds the certificate

@var{buf}: user allocated memory buffer, will hold the unique id

@var{buf_size}: size of user allocated memory buffer (on input), will hold
actual size of the unique ID on return.

This function will extract the issuerUniqueID value (if present) for
the given certificate.

If the user allocated memory buffer is not large enough to hold the
full subjectUniqueID, then a GNUTLS_E_SHORT_MEMORY_BUFFER error will be
returned, and buf_size will be set to the actual length.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.

@strong{Since:} 2.12.0
@end deftypefun

@subheading gnutls_x509_crt_get_key_id
@anchor{gnutls_x509_crt_get_key_id}
@deftypefun {int} {gnutls_x509_crt_get_key_id} (gnutls_x509_crt_t @var{crt}, unsigned int @var{flags}, unsigned char * @var{output_data}, size_t * @var{output_data_size})
@var{crt}: Holds the certificate

@var{flags}: should be 0 for now

@var{output_data}: will contain the key ID

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will return a unique ID the depends on the public
key parameters. This ID can be used in checking whether a
certificate corresponds to the given private key.

If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.

@strong{Returns:} In case of failure a negative error code will be
returned, and 0 on success.
@end deftypefun

@subheading gnutls_x509_crt_get_key_purpose_oid
@anchor{gnutls_x509_crt_get_key_purpose_oid}
@deftypefun {int} {gnutls_x509_crt_get_key_purpose_oid} (gnutls_x509_crt_t @var{cert}, int @var{indx}, void * @var{oid}, size_t * @var{oid_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{indx}: This specifies which OID to return. Use (0) to get the first one.

@var{oid}: a pointer to a buffer to hold the OID (may be null)

@var{oid_size}: initially holds the size of  @code{oid} 

@var{critical}: output flag to indicate criticality of extension

This function will extract the key purpose OIDs of the Certificate
specified by the given index.  These are stored in the Extended Key
Usage extension (2.5.29.37) See the GNUTLS_KP_* definitions for
human readable names.

If  @code{oid} is null then only the size will be filled. The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

@strong{Returns:} @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if the provided buffer is
not long enough, and in that case the *oid_size will be updated
with the required size.  On success 0 is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_key_usage
@anchor{gnutls_x509_crt_get_key_usage}
@deftypefun {int} {gnutls_x509_crt_get_key_usage} (gnutls_x509_crt_t @var{cert}, unsigned int * @var{key_usage}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{key_usage}: where the key usage bits will be stored

@var{critical}: will be non (0) if the extension is marked as critical

This function will return certificate's key usage, by reading the
keyUsage X.509 extension (2.5.29.15). The key usage value will ORed
values of the: @code{GNUTLS_KEY_DIGITAL_SIGNATURE} ,
@code{GNUTLS_KEY_NON_REPUDIATION} , @code{GNUTLS_KEY_KEY_ENCIPHERMENT} ,
@code{GNUTLS_KEY_DATA_ENCIPHERMENT} , @code{GNUTLS_KEY_KEY_AGREEMENT} ,
@code{GNUTLS_KEY_KEY_CERT_SIGN} , @code{GNUTLS_KEY_CRL_SIGN} ,
@code{GNUTLS_KEY_ENCIPHER_ONLY} , @code{GNUTLS_KEY_DECIPHER_ONLY} .

@strong{Returns:} the certificate key usage, or a negative error code in case of
parsing error.  If the certificate does not contain the keyUsage
extension @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  will be
returned.
@end deftypefun

@subheading gnutls_x509_crt_get_pk_algorithm
@anchor{gnutls_x509_crt_get_pk_algorithm}
@deftypefun {int} {gnutls_x509_crt_get_pk_algorithm} (gnutls_x509_crt_t @var{cert}, unsigned int * @var{bits})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{bits}: if bits is non null it will hold the size of the parameters' in bits

This function will return the public key algorithm of an X.509
certificate.

If bits is non null, it should have enough size to hold the parameters
size in bits. For RSA the bits returned is the modulus.
For DSA the bits returned are of the public
exponent.

@strong{Returns:} a member of the @code{gnutls_pk_algorithm_t}  enumeration on
success, or a negative error code on error.
@end deftypefun

@subheading gnutls_x509_crt_get_pk_dsa_raw
@anchor{gnutls_x509_crt_get_pk_dsa_raw}
@deftypefun {int} {gnutls_x509_crt_get_pk_dsa_raw} (gnutls_x509_crt_t @var{crt}, gnutls_datum_t * @var{p}, gnutls_datum_t * @var{q}, gnutls_datum_t * @var{g}, gnutls_datum_t * @var{y})
@var{crt}: Holds the certificate

@var{p}: will hold the p

@var{q}: will hold the q

@var{g}: will hold the g

@var{y}: will hold the y

This function will export the DSA public key's parameters found in
the given certificate.  The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.
@end deftypefun

@subheading gnutls_x509_crt_get_pk_rsa_raw
@anchor{gnutls_x509_crt_get_pk_rsa_raw}
@deftypefun {int} {gnutls_x509_crt_get_pk_rsa_raw} (gnutls_x509_crt_t @var{crt}, gnutls_datum_t * @var{m}, gnutls_datum_t * @var{e})
@var{crt}: Holds the certificate

@var{m}: will hold the modulus

@var{e}: will hold the public exponent

This function will export the RSA public key's parameters found in
the given structure.  The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.
@end deftypefun

@subheading gnutls_x509_crt_get_private_key_usage_period
@anchor{gnutls_x509_crt_get_private_key_usage_period}
@deftypefun {int} {gnutls_x509_crt_get_private_key_usage_period} (gnutls_x509_crt_t @var{cert}, time_t* @var{activation}, time_t* @var{expiration}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{activation}: The activation time

@var{expiration}: The expiration time

@var{critical}: the extension status

This function will return the expiration and activation
times of the private key of the certificate. It relies on
the PKIX extension 2.5.29.16 being present.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
if the extension is not present, otherwise a negative error value.
@end deftypefun

@subheading gnutls_x509_crt_get_proxy
@anchor{gnutls_x509_crt_get_proxy}
@deftypefun {int} {gnutls_x509_crt_get_proxy} (gnutls_x509_crt_t @var{cert}, unsigned int * @var{critical}, int * @var{pathlen}, char ** @var{policyLanguage}, char ** @var{policy}, size_t * @var{sizeof_policy})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{critical}: will be non (0) if the extension is marked as critical

@var{pathlen}: pointer to output integer indicating path length (may be
NULL), non-negative error codes indicate a present pCPathLenConstraint
field and the actual value, -1 indicate that the field is absent.

@var{policyLanguage}: output variable with OID of policy language

@var{policy}: output variable with policy data

@var{sizeof_policy}: output variable size of policy data

This function will get information from a proxy certificate.  It
reads the ProxyCertInfo X.509 extension (1.3.6.1.5.5.7.1.14).

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

@subheading gnutls_x509_crt_get_raw_dn
@anchor{gnutls_x509_crt_get_raw_dn}
@deftypefun {int} {gnutls_x509_crt_get_raw_dn} (gnutls_x509_crt_t @var{cert}, gnutls_datum_t * @var{start})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{start}: will hold the starting point of the DN

This function will return a pointer to the DER encoded DN structure and
the length.

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

@subheading gnutls_x509_crt_get_raw_issuer_dn
@anchor{gnutls_x509_crt_get_raw_issuer_dn}
@deftypefun {int} {gnutls_x509_crt_get_raw_issuer_dn} (gnutls_x509_crt_t @var{cert}, gnutls_datum_t * @var{start})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{start}: will hold the starting point of the DN

This function will return a pointer to the DER encoded DN structure
and the length.

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

@subheading gnutls_x509_crt_get_serial
@anchor{gnutls_x509_crt_get_serial}
@deftypefun {int} {gnutls_x509_crt_get_serial} (gnutls_x509_crt_t @var{cert}, void * @var{result}, size_t * @var{result_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{result}: The place where the serial number will be copied

@var{result_size}: Holds the size of the result field.

This function will return the X.509 certificate's serial number.
This is obtained by the X509 Certificate serialNumber field. Serial
is not always a 32 or 64bit number. Some CAs use large serial
numbers, thus it may be wise to handle it as something uint8_t.

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

@subheading gnutls_x509_crt_get_signature
@anchor{gnutls_x509_crt_get_signature}
@deftypefun {int} {gnutls_x509_crt_get_signature} (gnutls_x509_crt_t @var{cert}, char * @var{sig}, size_t * @var{sizeof_sig})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{sig}: a pointer where the signature part will be copied (may be null).

@var{sizeof_sig}: initially holds the size of  @code{sig} 

This function will extract the signature field of a certificate.

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

@subheading gnutls_x509_crt_get_signature_algorithm
@anchor{gnutls_x509_crt_get_signature_algorithm}
@deftypefun {int} {gnutls_x509_crt_get_signature_algorithm} (gnutls_x509_crt_t @var{cert})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

This function will return a value of the @code{gnutls_sign_algorithm_t} 
enumeration that is the signature algorithm that has been used to
sign this certificate.

@strong{Returns:} a @code{gnutls_sign_algorithm_t}  value, or a negative error code on
error.
@end deftypefun

@subheading gnutls_x509_crt_get_subject
@anchor{gnutls_x509_crt_get_subject}
@deftypefun {int} {gnutls_x509_crt_get_subject} (gnutls_x509_crt_t @var{cert}, gnutls_x509_dn_t * @var{dn})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{dn}: output variable with pointer to uint8_t DN.

Return the Certificate's Subject DN as an uint8_t data type.  You
may use @code{gnutls_x509_dn_get_rdn_ava()}  to decode the DN. 

Note that  @code{dn} should be treated as constant. Because points 
into the  @code{cert} object, you may not deallocate  @code{cert} and continue to access  @code{dn} .

@strong{Returns:} Returns 0 on success, or an error code.
@end deftypefun

@subheading gnutls_x509_crt_get_subject_alt_name
@anchor{gnutls_x509_crt_get_subject_alt_name}
@deftypefun {int} {gnutls_x509_crt_get_subject_alt_name} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{san}, size_t * @var{san_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{san}: is the place where the alternative name will be copied to

@var{san_size}: holds the size of san.

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function retrieves the Alternative Name (2.5.29.17), contained
in the given certificate in the X509v3 Certificate Extensions.

When the SAN type is otherName, it will extract the data in the
otherName's value field, and @code{GNUTLS_SAN_OTHERNAME}  is returned.
You may use @code{gnutls_x509_crt_get_subject_alt_othername_oid()}  to get
the corresponding OID and the "virtual" SAN types (e.g.,
@code{GNUTLS_SAN_OTHERNAME_XMPP} ).

If an otherName OID is known, the data will be decoded.  Otherwise
the returned data will be DER encoded, and you will have to decode
it yourself.  Currently, only the RFC 3920 id-on-xmppAddr SAN is
recognized.

@strong{Returns:} the alternative subject name type on success, one of the
enumerated @code{gnutls_x509_subject_alt_name_t} .  It will return
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if  @code{san_size} is not large enough to
hold the value.  In that case  @code{san_size} will be updated with the
required size.  If the certificate does not have an Alternative
name with the specified sequence number then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_subject_alt_name2
@anchor{gnutls_x509_crt_get_subject_alt_name2}
@deftypefun {int} {gnutls_x509_crt_get_subject_alt_name2} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{san}, size_t * @var{san_size}, unsigned int * @var{san_type}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{san}: is the place where the alternative name will be copied to

@var{san_size}: holds the size of ret.

@var{san_type}: holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t).

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the alternative names, contained in the
given certificate. It is the same as
@code{gnutls_x509_crt_get_subject_alt_name()}  except for the fact that it
will return the type of the alternative name in  @code{san_type} even if
the function fails for some reason (i.e.  the buffer provided is
not enough).

@strong{Returns:} the alternative subject name type on success, one of the
enumerated @code{gnutls_x509_subject_alt_name_t} .  It will return
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if  @code{san_size} is not large enough
to hold the value.  In that case  @code{san_size} will be updated with
the required size.  If the certificate does not have an
Alternative name with the specified sequence number then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_subject_alt_othername_oid
@anchor{gnutls_x509_crt_get_subject_alt_othername_oid}
@deftypefun {int} {gnutls_x509_crt_get_subject_alt_othername_oid} (gnutls_x509_crt_t @var{cert}, unsigned int @var{seq}, void * @var{oid}, size_t * @var{oid_size})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{seq}: specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.)

@var{oid}: is the place where the otherName OID will be copied to

@var{oid_size}: holds the size of ret.

This function will extract the type OID of an otherName Subject
Alternative Name, contained in the given certificate, and return
the type as an enumerated element.

This function is only useful if
@code{gnutls_x509_crt_get_subject_alt_name()}  returned
@code{GNUTLS_SAN_OTHERNAME} .

If  @code{oid} is null then only the size will be filled. The  @code{oid} returned will be null terminated, although  @code{oid_size} will not
account for the trailing null.

@strong{Returns:} the alternative subject name type on success, one of the
enumerated gnutls_x509_subject_alt_name_t.  For supported OIDs, it
will return one of the virtual (GNUTLS_SAN_OTHERNAME_*) types,
e.g. @code{GNUTLS_SAN_OTHERNAME_XMPP} , and @code{GNUTLS_SAN_OTHERNAME}  for
unknown OIDs.  It will return @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  if
 @code{ian_size} is not large enough to hold the value.  In that case
 @code{ian_size} will be updated with the required size.  If the
certificate does not have an Alternative name with the specified
sequence number and with the otherName type then
@code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE}  is returned.
@end deftypefun

@subheading gnutls_x509_crt_get_subject_key_id
@anchor{gnutls_x509_crt_get_subject_key_id}
@deftypefun {int} {gnutls_x509_crt_get_subject_key_id} (gnutls_x509_crt_t @var{cert}, void * @var{ret}, size_t * @var{ret_size}, unsigned int * @var{critical})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

@var{ret}: The place where the identifier will be copied

@var{ret_size}: Holds the size of the result field.

@var{critical}: will be non (0) if the extension is marked as critical (may be null)

This function will return the X.509v3 certificate's subject key
identifier.  This is obtained by the X.509 Subject Key identifier
extension field (2.5.29.14).

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, @code{GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE} 
if the extension is not present, otherwise a negative error value.
@end deftypefun

@subheading gnutls_x509_crt_get_subject_unique_id
@anchor{gnutls_x509_crt_get_subject_unique_id}
@deftypefun {int} {gnutls_x509_crt_get_subject_unique_id} (gnutls_x509_crt_t @var{crt}, char * @var{buf}, size_t * @var{buf_size})
@var{crt}: Holds the certificate

@var{buf}: user allocated memory buffer, will hold the unique id

@var{buf_size}: size of user allocated memory buffer (on input), will hold
actual size of the unique ID on return.

This function will extract the subjectUniqueID value (if present) for
the given certificate.

If the user allocated memory buffer is not large enough to hold the
full subjectUniqueID, then a GNUTLS_E_SHORT_MEMORY_BUFFER error will be
returned, and buf_size will be set to the actual length.

@strong{Returns:} @code{GNUTLS_E_SUCCESS}  on success, otherwise a negative error code.
@end deftypefun

@subheading gnutls_x509_crt_get_version
@anchor{gnutls_x509_crt_get_version}
@deftypefun {int} {gnutls_x509_crt_get_version} (gnutls_x509_crt_t @var{cert})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  structure

This function will return the version of the specified Certificate.

@strong{Returns:} version of certificate, or a negative error code on error.
@end deftypefun

@subheading gnutls_x509_crt_import
@anchor{gnutls_x509_crt_import}
@deftypefun {int} {gnutls_x509_crt_import} (gnutls_x509_crt_t @var{cert}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format})
@var{cert}: The structure to store the parsed certificate.

@var{data}: The DER or PEM encoded certificate.

@var{format}: One of DER or PEM

This function will convert the given DER or PEM encoded Certificate
to the native gnutls_x509_crt_t format. The output will be stored
in  @code{cert} .

If the Certificate is PEM encoded it should have a header of "X509
CERTIFICATE", or "CERTIFICATE".

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

@subheading gnutls_x509_crt_init
@anchor{gnutls_x509_crt_init}
@deftypefun {int} {gnutls_x509_crt_init} (gnutls_x509_crt_t * @var{cert})
@var{cert}: The structure to be initialized

This function will initialize an X.509 certificate structure.

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

@subheading gnutls_x509_crt_list_import
@anchor{gnutls_x509_crt_list_import}
@deftypefun {int} {gnutls_x509_crt_list_import} (gnutls_x509_crt_t * @var{certs}, unsigned int * @var{cert_max}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format}, unsigned int @var{flags})
@var{certs}: The structures to store the parsed certificate. Must not be initialized.

@var{cert_max}: Initially must hold the maximum number of certs. It will be updated with the number of certs available.

@var{data}: The PEM encoded certificate.

@var{format}: One of DER or PEM.

@var{flags}: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.

This function will convert the given PEM encoded certificate list
to the native gnutls_x509_crt_t format. The output will be stored
in  @code{certs} .  They will be automatically initialized.

The flag @code{GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED}  will cause
import to fail if the certificates in the provided buffer are more
than the available structures. The @code{GNUTLS_X509_CRT_LIST_FAIL_IF_UNSORTED} 
flag will cause the function to fail if the provided list is not
sorted from subject to issuer.

If the Certificate is PEM encoded it should have a header of "X509
CERTIFICATE", or "CERTIFICATE".

@strong{Returns:} the number of certificates read or a negative error value.
@end deftypefun

@subheading gnutls_x509_crt_list_import2
@anchor{gnutls_x509_crt_list_import2}
@deftypefun {int} {gnutls_x509_crt_list_import2} (gnutls_x509_crt_t ** @var{certs}, unsigned int * @var{size}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format}, unsigned int @var{flags})
@var{certs}: The structures to store the parsed certificate. Must not be initialized.

@var{size}: It will contain the size of the list.

@var{data}: The PEM encoded certificate.

@var{format}: One of DER or PEM.

@var{flags}: must be (0) or an OR'd sequence of gnutls_certificate_import_flags.

This function will convert the given PEM encoded certificate list
to the native gnutls_x509_crt_t format. The output will be stored
in  @code{certs} which will be initialized.

If the Certificate is PEM encoded it should have a header of "X509
CERTIFICATE", or "CERTIFICATE".

@strong{Returns:} the number of certificates read or a negative error value.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crt_list_verify
@anchor{gnutls_x509_crt_list_verify}
@deftypefun {int} {gnutls_x509_crt_list_verify} (const gnutls_x509_crt_t * @var{cert_list}, int @var{cert_list_length}, const gnutls_x509_crt_t * @var{CA_list}, int @var{CA_list_length}, const gnutls_x509_crl_t * @var{CRL_list}, int @var{CRL_list_length}, unsigned int @var{flags}, unsigned int * @var{verify})
@var{cert_list}: is the certificate list to be verified

@var{cert_list_length}: holds the number of certificate in cert_list

@var{CA_list}: is the CA list which will be used in verification

@var{CA_list_length}: holds the number of CA certificate in CA_list

@var{CRL_list}: holds a list of CRLs.

@var{CRL_list_length}: the length of CRL list.

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

@var{verify}: will hold the certificate verification output.

This function will try to verify the given certificate list and
return its status.  If no flags are specified (0), this function
will use the basicConstraints (2.5.29.19) PKIX extension. This
means that only a certificate authority is allowed to sign a
certificate.

You must also check the peer's name in order to check if the verified
certificate belongs to the actual peer.

The certificate verification output will be put in  @code{verify} and will
be one or more of the gnutls_certificate_status_t enumerated
elements bitwise or'd.  For a more detailed verification status use
@code{gnutls_x509_crt_verify()}  per list element.

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

@subheading gnutls_x509_crt_print
@anchor{gnutls_x509_crt_print}
@deftypefun {int} {gnutls_x509_crt_print} (gnutls_x509_crt_t @var{cert}, gnutls_certificate_print_formats_t @var{format}, gnutls_datum_t * @var{out})
@var{cert}: The structure to be printed

@var{format}: Indicate the format to use

@var{out}: Newly allocated datum with (0) terminated string.

This function will pretty print a X.509 certificate, suitable for
display to a human.

If the format is @code{GNUTLS_CRT_PRINT_FULL}  then all fields of the
certificate will be output, on multiple lines.  The
@code{GNUTLS_CRT_PRINT_ONELINE}  format will generate one line with some
selected fields, which is useful for logging purposes.

The output  @code{out} needs to be deallocate using @code{gnutls_free()} .

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

@subheading gnutls_x509_crt_set_activation_time
@anchor{gnutls_x509_crt_set_activation_time}
@deftypefun {int} {gnutls_x509_crt_set_activation_time} (gnutls_x509_crt_t @var{cert}, time_t @var{act_time})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{act_time}: The actual time

This function will set the time this Certificate was or will be
activated.

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

@subheading gnutls_x509_crt_set_authority_info_access
@anchor{gnutls_x509_crt_set_authority_info_access}
@deftypefun {int} {gnutls_x509_crt_set_authority_info_access} (gnutls_x509_crt_t @var{crt}, int @var{what}, gnutls_datum_t * @var{data})
@var{crt}: Holds the certificate

@var{what}: what data to get, a @code{gnutls_info_access_what_t}  type.

@var{data}: output data to be freed with @code{gnutls_free()} .

This function sets the Authority Information Access (AIA)
extension, see RFC 5280 section 4.2.2.1 for more information.  

The type of data stored in  @code{data} is specified via  @code{what} which
should be @code{gnutls_info_access_what_t}  values.

If  @code{what} is @code{GNUTLS_IA_OCSP_URI} ,  @code{data} will hold the OCSP URI.
If  @code{what} is @code{GNUTLS_IA_CAISSUERS_URI} ,  @code{data} will hold the caIssuers
URI.  

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_crt_set_authority_key_id
@anchor{gnutls_x509_crt_set_authority_key_id}
@deftypefun {int} {gnutls_x509_crt_set_authority_key_id} (gnutls_x509_crt_t @var{cert}, const void * @var{id}, size_t @var{id_size})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{id}: The key ID

@var{id_size}: Holds the size of the serial field.

This function will set the X.509 certificate's authority key ID extension.
Only the keyIdentifier field can be set with this function.

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

@subheading gnutls_x509_crt_set_basic_constraints
@anchor{gnutls_x509_crt_set_basic_constraints}
@deftypefun {int} {gnutls_x509_crt_set_basic_constraints} (gnutls_x509_crt_t @var{crt}, unsigned int @var{ca}, int @var{pathLenConstraint})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{ca}: true(1) or false(0). Depending on the Certificate authority status.

@var{pathLenConstraint}: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.

This function will set the basicConstraints certificate extension.

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

@subheading gnutls_x509_crt_set_ca_status
@anchor{gnutls_x509_crt_set_ca_status}
@deftypefun {int} {gnutls_x509_crt_set_ca_status} (gnutls_x509_crt_t @var{crt}, unsigned int @var{ca})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{ca}: true(1) or false(0). Depending on the Certificate authority status.

This function will set the basicConstraints certificate extension.
Use @code{gnutls_x509_crt_set_basic_constraints()}  if you want to control
the pathLenConstraint field too.

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

@subheading gnutls_x509_crt_set_crl_dist_points
@anchor{gnutls_x509_crt_set_crl_dist_points}
@deftypefun {int} {gnutls_x509_crt_set_crl_dist_points} (gnutls_x509_crt_t @var{crt}, gnutls_x509_subject_alt_name_t @var{type}, const void * @var{data_string}, unsigned int @var{reason_flags})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{type}: is one of the gnutls_x509_subject_alt_name_t enumerations

@var{data_string}: The data to be set

@var{reason_flags}: revocation reasons

This function will set the CRL distribution points certificate extension.

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

@subheading gnutls_x509_crt_set_crl_dist_points2
@anchor{gnutls_x509_crt_set_crl_dist_points2}
@deftypefun {int} {gnutls_x509_crt_set_crl_dist_points2} (gnutls_x509_crt_t @var{crt}, gnutls_x509_subject_alt_name_t @var{type}, const void * @var{data}, unsigned int @var{data_size}, unsigned int @var{reason_flags})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{type}: is one of the gnutls_x509_subject_alt_name_t enumerations

@var{data}: The data to be set

@var{data_size}: The data size

@var{reason_flags}: revocation reasons

This function will set the CRL distribution points certificate extension.

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

@strong{Since:} 2.6.0
@end deftypefun

@subheading gnutls_x509_crt_set_crq
@anchor{gnutls_x509_crt_set_crq}
@deftypefun {int} {gnutls_x509_crt_set_crq} (gnutls_x509_crt_t @var{crt}, gnutls_x509_crq_t @var{crq})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{crq}: holds a certificate request

This function will set the name and public parameters as well as
the extensions from the given certificate request to the certificate. 
Only RSA keys are currently supported.

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

@subheading gnutls_x509_crt_set_crq_extensions
@anchor{gnutls_x509_crt_set_crq_extensions}
@deftypefun {int} {gnutls_x509_crt_set_crq_extensions} (gnutls_x509_crt_t @var{crt}, gnutls_x509_crq_t @var{crq})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{crq}: holds a certificate request

This function will set extensions from the given request to the
certificate.

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

@strong{Since:} 2.8.0
@end deftypefun

@subheading gnutls_x509_crt_set_dn_by_oid
@anchor{gnutls_x509_crt_set_dn_by_oid}
@deftypefun {int} {gnutls_x509_crt_set_dn_by_oid} (gnutls_x509_crt_t @var{crt}, const char * @var{oid}, unsigned int @var{raw_flag}, const void * @var{name}, unsigned int @var{sizeof_name})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{oid}: holds an Object Identifier in a null terminated string

@var{raw_flag}: must be 0, or 1 if the data are DER encoded

@var{name}: a pointer to the name

@var{sizeof_name}: holds the size of  @code{name} 

This function will set the part of the name of the Certificate
subject, specified by the given OID. The input string should be
ASCII or UTF-8 encoded.

Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs. You can test
for known OIDs using @code{gnutls_x509_dn_oid_known()} . For OIDs that are
not known (by gnutls) you should properly DER encode your data,
and call this function with  @code{raw_flag} set.

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

@subheading gnutls_x509_crt_set_expiration_time
@anchor{gnutls_x509_crt_set_expiration_time}
@deftypefun {int} {gnutls_x509_crt_set_expiration_time} (gnutls_x509_crt_t @var{cert}, time_t @var{exp_time})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{exp_time}: The actual time

This function will set the time this Certificate will expire.

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

@subheading gnutls_x509_crt_set_extension_by_oid
@anchor{gnutls_x509_crt_set_extension_by_oid}
@deftypefun {int} {gnutls_x509_crt_set_extension_by_oid} (gnutls_x509_crt_t @var{crt}, const char * @var{oid}, const void * @var{buf}, size_t @var{sizeof_buf}, unsigned int @var{critical})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{oid}: holds an Object Identified in null terminated string

@var{buf}: a pointer to a DER encoded data

@var{sizeof_buf}: holds the size of  @code{buf} 

@var{critical}: should be non (0) if the extension is to be marked as critical

This function will set an the extension, by the specified OID, in
the certificate.  The extension data should be binary data DER
encoded.

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

@subheading gnutls_x509_crt_set_issuer_dn_by_oid
@anchor{gnutls_x509_crt_set_issuer_dn_by_oid}
@deftypefun {int} {gnutls_x509_crt_set_issuer_dn_by_oid} (gnutls_x509_crt_t @var{crt}, const char * @var{oid}, unsigned int @var{raw_flag}, const void * @var{name}, unsigned int @var{sizeof_name})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{oid}: holds an Object Identifier in a null terminated string

@var{raw_flag}: must be 0, or 1 if the data are DER encoded

@var{name}: a pointer to the name

@var{sizeof_name}: holds the size of  @code{name} 

This function will set the part of the name of the Certificate
issuer, specified by the given OID.  The input string should be
ASCII or UTF-8 encoded.

Some helper macros with popular OIDs can be found in gnutls/x509.h
With this function you can only set the known OIDs. You can test
for known OIDs using @code{gnutls_x509_dn_oid_known()} . For OIDs that are
not known (by gnutls) you should properly DER encode your data,
and call this function with  @code{raw_flag} set.

Normally you do not need to call this function, since the signing
operation will copy the signer's name as the issuer of the
certificate.

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

@subheading gnutls_x509_crt_set_key
@anchor{gnutls_x509_crt_set_key}
@deftypefun {int} {gnutls_x509_crt_set_key} (gnutls_x509_crt_t @var{crt}, gnutls_x509_privkey_t @var{key})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{key}: holds a private key

This function will set the public parameters from the given
private key to the certificate. Only RSA keys are currently
supported.

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

@subheading gnutls_x509_crt_set_key_purpose_oid
@anchor{gnutls_x509_crt_set_key_purpose_oid}
@deftypefun {int} {gnutls_x509_crt_set_key_purpose_oid} (gnutls_x509_crt_t @var{cert}, const void * @var{oid}, unsigned int @var{critical})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{oid}: a pointer to a null terminated string that holds the OID

@var{critical}: Whether this extension will be critical or not

This function will set the key purpose OIDs of the Certificate.
These are stored in the Extended Key Usage extension (2.5.29.37)
See the GNUTLS_KP_* definitions for human readable names.

Subsequent calls to this function will append OIDs to the OID list.

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

@subheading gnutls_x509_crt_set_key_usage
@anchor{gnutls_x509_crt_set_key_usage}
@deftypefun {int} {gnutls_x509_crt_set_key_usage} (gnutls_x509_crt_t @var{crt}, unsigned int @var{usage})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{usage}: an ORed sequence of the GNUTLS_KEY_* elements.

This function will set the keyUsage certificate extension.

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

@subheading gnutls_x509_crt_set_private_key_usage_period
@anchor{gnutls_x509_crt_set_private_key_usage_period}
@deftypefun {int} {gnutls_x509_crt_set_private_key_usage_period} (gnutls_x509_crt_t @var{crt}, time_t @var{activation}, time_t @var{expiration})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{activation}: The activation time

@var{expiration}: The expiration time

This function will set the private key usage period extension (2.5.29.16).

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

@subheading gnutls_x509_crt_set_proxy
@anchor{gnutls_x509_crt_set_proxy}
@deftypefun {int} {gnutls_x509_crt_set_proxy} (gnutls_x509_crt_t @var{crt}, int @var{pathLenConstraint}, const char * @var{policyLanguage}, const char * @var{policy}, size_t @var{sizeof_policy})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{pathLenConstraint}: non-negative error codes indicate maximum length of path,
and negative error codes indicate that the pathLenConstraints field should
not be present.

@var{policyLanguage}: OID describing the language of  @code{policy} .

@var{policy}: uint8_t byte array with policy language, can be @code{NULL} 

@var{sizeof_policy}: size of  @code{policy} .

This function will set the proxyCertInfo extension.

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

@subheading gnutls_x509_crt_set_proxy_dn
@anchor{gnutls_x509_crt_set_proxy_dn}
@deftypefun {int} {gnutls_x509_crt_set_proxy_dn} (gnutls_x509_crt_t @var{crt}, gnutls_x509_crt_t @var{eecrt}, unsigned int @var{raw_flag}, const void * @var{name}, unsigned int @var{sizeof_name})
@var{crt}: a gnutls_x509_crt_t structure with the new proxy cert

@var{eecrt}: the end entity certificate that will be issuing the proxy

@var{raw_flag}: must be 0, or 1 if the CN is DER encoded

@var{name}: a pointer to the CN name, may be NULL (but MUST then be added later)

@var{sizeof_name}: holds the size of  @code{name} 

This function will set the subject in  @code{crt} to the end entity's
 @code{eecrt} subject name, and add a single Common Name component  @code{name} of size  @code{sizeof_name} .  This corresponds to the required proxy
certificate naming style.  Note that if  @code{name} is @code{NULL} , you MUST
set it later by using @code{gnutls_x509_crt_set_dn_by_oid()}  or similar.

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

@subheading gnutls_x509_crt_set_serial
@anchor{gnutls_x509_crt_set_serial}
@deftypefun {int} {gnutls_x509_crt_set_serial} (gnutls_x509_crt_t @var{cert}, const void * @var{serial}, size_t @var{serial_size})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{serial}: The serial number

@var{serial_size}: Holds the size of the serial field.

This function will set the X.509 certificate's serial number.
Serial is not always a 32 or 64bit number.  Some CAs use large
serial numbers, thus it may be wise to handle it as something
uint8_t.

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

@subheading gnutls_x509_crt_set_subject_alternative_name
@anchor{gnutls_x509_crt_set_subject_alternative_name}
@deftypefun {int} {gnutls_x509_crt_set_subject_alternative_name} (gnutls_x509_crt_t @var{crt}, gnutls_x509_subject_alt_name_t                                               @var{type}, const char * @var{data_string})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{type}: is one of the gnutls_x509_subject_alt_name_t enumerations

@var{data_string}: The data to be set, a (0) terminated string

This function will set the subject alternative name certificate
extension. This function assumes that data can be expressed as a null
terminated string.

The name of the function is unfortunate since it is incosistent with
@code{gnutls_x509_crt_get_subject_alt_name()} .

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

@subheading gnutls_x509_crt_set_subject_alt_name
@anchor{gnutls_x509_crt_set_subject_alt_name}
@deftypefun {int} {gnutls_x509_crt_set_subject_alt_name} (gnutls_x509_crt_t @var{crt}, gnutls_x509_subject_alt_name_t @var{type}, const void * @var{data}, unsigned int @var{data_size}, unsigned int @var{flags})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{type}: is one of the gnutls_x509_subject_alt_name_t enumerations

@var{data}: The data to be set

@var{data_size}: The size of data to be set

@var{flags}: GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. 

This function will set the subject alternative name certificate
extension. It can set the following types:

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

@strong{Since:} 2.6.0
@end deftypefun

@subheading gnutls_x509_crt_set_subject_key_id
@anchor{gnutls_x509_crt_set_subject_key_id}
@deftypefun {int} {gnutls_x509_crt_set_subject_key_id} (gnutls_x509_crt_t @var{cert}, const void * @var{id}, size_t @var{id_size})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{id}: The key ID

@var{id_size}: Holds the size of the serial field.

This function will set the X.509 certificate's subject key ID
extension.

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

@subheading gnutls_x509_crt_set_version
@anchor{gnutls_x509_crt_set_version}
@deftypefun {int} {gnutls_x509_crt_set_version} (gnutls_x509_crt_t @var{crt}, unsigned int @var{version})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{version}: holds the version number. For X.509v1 certificates must be 1.

This function will set the version of the certificate.  This must
be one for X.509 version 1, and so on.  Plain certificates without
extensions must have version set to one.

To create well-formed certificates, you must specify version 3 if
you use any certificate extensions.  Extensions are created by
functions such as @code{gnutls_x509_crt_set_subject_alt_name()} 
or @code{gnutls_x509_crt_set_key_usage()} .

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

@subheading gnutls_x509_crt_sign
@anchor{gnutls_x509_crt_sign}
@deftypefun {int} {gnutls_x509_crt_sign} (gnutls_x509_crt_t @var{crt}, gnutls_x509_crt_t @var{issuer}, gnutls_x509_privkey_t @var{issuer_key})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{issuer}: is the certificate of the certificate issuer

@var{issuer_key}: holds the issuer's private key

This function is the same a @code{gnutls_x509_crt_sign2()}  with no flags,
and SHA1 as the hash algorithm.

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

@subheading gnutls_x509_crt_sign2
@anchor{gnutls_x509_crt_sign2}
@deftypefun {int} {gnutls_x509_crt_sign2} (gnutls_x509_crt_t @var{crt}, gnutls_x509_crt_t @var{issuer}, gnutls_x509_privkey_t @var{issuer_key}, gnutls_digest_algorithm_t @var{dig}, unsigned int @var{flags})
@var{crt}: a certificate of type @code{gnutls_x509_crt_t} 

@var{issuer}: is the certificate of the certificate issuer

@var{issuer_key}: holds the issuer's private key

@var{dig}: The message digest to use, @code{GNUTLS_DIG_SHA1}  is a safe choice

@var{flags}: must be 0

This function will sign the certificate with the issuer's private key, and
will copy the issuer's information into the certificate.

This must be the last step in a certificate generation since all
the previously set parameters are now signed.

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

@subheading gnutls_x509_crt_verify
@anchor{gnutls_x509_crt_verify}
@deftypefun {int} {gnutls_x509_crt_verify} (gnutls_x509_crt_t @var{cert}, const gnutls_x509_crt_t * @var{CA_list}, int @var{CA_list_length}, unsigned int @var{flags}, unsigned int * @var{verify})
@var{cert}: is the certificate to be verified

@var{CA_list}: is one certificate that is considered to be trusted one

@var{CA_list_length}: holds the number of CA certificate in CA_list

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

@var{verify}: will hold the certificate verification output.

This function will try to verify the given certificate and return
its status.

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

@subheading gnutls_x509_dn_deinit
@anchor{gnutls_x509_dn_deinit}
@deftypefun {void} {gnutls_x509_dn_deinit} (gnutls_x509_dn_t @var{dn})
@var{dn}: a DN uint8_t object pointer.

This function deallocates the DN object as returned by
@code{gnutls_x509_dn_import()} .

@strong{Since:} 2.4.0
@end deftypefun

@subheading gnutls_x509_dn_export
@anchor{gnutls_x509_dn_export}
@deftypefun {int} {gnutls_x509_dn_export} (gnutls_x509_dn_t @var{dn}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{dn}: Holds the uint8_t DN object

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a DN PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the DN to DER or PEM format.

If the buffer provided is not long enough to hold the output, then
* @code{output_data_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER} 
will be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN NAME".

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

@subheading gnutls_x509_dn_get_rdn_ava
@anchor{gnutls_x509_dn_get_rdn_ava}
@deftypefun {int} {gnutls_x509_dn_get_rdn_ava} (gnutls_x509_dn_t @var{dn}, int @var{irdn}, int @var{iava}, gnutls_x509_ava_st * @var{ava})
@var{dn}: input variable with uint8_t DN pointer

@var{irdn}: index of RDN

@var{iava}: index of AVA.

@var{ava}: Pointer to structure which will hold output information.

Get pointers to data within the DN.

Note that  @code{ava} will contain pointers into the  @code{dn} structure, so you
should not modify any data or deallocate it.  Note also that the DN
in turn points into the original certificate structure, and thus
you may not deallocate the certificate and continue to access  @code{dn} .

@strong{Returns:} Returns 0 on success, or an error code.
@end deftypefun

@subheading gnutls_x509_dn_import
@anchor{gnutls_x509_dn_import}
@deftypefun {int} {gnutls_x509_dn_import} (gnutls_x509_dn_t @var{dn}, const gnutls_datum_t * @var{data})
@var{dn}: the structure that will hold the imported DN

@var{data}: should contain a DER encoded RDN sequence

This function parses an RDN sequence and stores the result to a
@code{gnutls_x509_dn_t}  structure. The structure must have been initialized
with @code{gnutls_x509_dn_init()} . You may use @code{gnutls_x509_dn_get_rdn_ava()}  to
decode the DN.

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

@strong{Since:} 2.4.0
@end deftypefun

@subheading gnutls_x509_dn_init
@anchor{gnutls_x509_dn_init}
@deftypefun {int} {gnutls_x509_dn_init} (gnutls_x509_dn_t * @var{dn})
@var{dn}: the object to be initialized

This function initializes a @code{gnutls_x509_dn_t}  structure.

The object returned must be deallocated using
@code{gnutls_x509_dn_deinit()} .

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

@strong{Since:} 2.4.0
@end deftypefun

@subheading gnutls_x509_dn_oid_known
@anchor{gnutls_x509_dn_oid_known}
@deftypefun {int} {gnutls_x509_dn_oid_known} (const char * @var{oid})
@var{oid}: holds an Object Identifier in a null terminated string

This function will inform about known DN OIDs. This is useful since
functions like @code{gnutls_x509_crt_set_dn_by_oid()}  use the information
on known OIDs to properly encode their input. Object Identifiers
that are not known are not encoded by these functions, and their
input is stored directly into the ASN.1 structure. In that case of
unknown OIDs, you have the responsibility of DER encoding your
data.

@strong{Returns:} 1 on known OIDs and 0 otherwise.
@end deftypefun

@subheading gnutls_x509_dn_oid_name
@anchor{gnutls_x509_dn_oid_name}
@deftypefun {const char*} {gnutls_x509_dn_oid_name} (const char * @var{oid}, unsigned int @var{flags})
@var{oid}: holds an Object Identifier in a null terminated string

@var{flags}: 0 or @code{GNUTLS_X509_DN_OID_} *

This function will return the name of a known DN OID. If
@code{GNUTLS_X509_DN_OID_RETURN_OID}  is specified this function
will return the given OID if no descriptive name has been
found.

@strong{Returns:} A null terminated string or NULL otherwise.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_privkey_cpy
@anchor{gnutls_x509_privkey_cpy}
@deftypefun {int} {gnutls_x509_privkey_cpy} (gnutls_x509_privkey_t @var{dst}, gnutls_x509_privkey_t @var{src})
@var{dst}: The destination key, which should be initialized.

@var{src}: The source key

This function will copy a private key from source to destination
key. Destination has to be initialized.

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

@subheading gnutls_x509_privkey_deinit
@anchor{gnutls_x509_privkey_deinit}
@deftypefun {void} {gnutls_x509_privkey_deinit} (gnutls_x509_privkey_t @var{key})
@var{key}: The structure to be deinitialized

This function will deinitialize a private key structure.
@end deftypefun

@subheading gnutls_x509_privkey_export
@anchor{gnutls_x509_privkey_export}
@deftypefun {int} {gnutls_x509_privkey_export} (gnutls_x509_privkey_t @var{key}, gnutls_x509_crt_fmt_t @var{format}, void * @var{output_data}, size_t * @var{output_data_size})
@var{key}: Holds the key

@var{format}: the format of output params. One of PEM or DER.

@var{output_data}: will contain a private key PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the private key to a PKCS1 structure for
RSA keys, or an integer sequence for DSA keys.  The DSA keys are in
the same format with the parameters used by openssl.

If the buffer provided is not long enough to hold the output, then
* @code{output_data_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER} 
will be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN RSA PRIVATE KEY".

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

@subheading gnutls_x509_privkey_export_dsa_raw
@anchor{gnutls_x509_privkey_export_dsa_raw}
@deftypefun {int} {gnutls_x509_privkey_export_dsa_raw} (gnutls_x509_privkey_t @var{key}, gnutls_datum_t * @var{p}, gnutls_datum_t * @var{q}, gnutls_datum_t * @var{g}, gnutls_datum_t * @var{y}, gnutls_datum_t * @var{x})
@var{key}: a structure that holds the DSA parameters

@var{p}: will hold the p

@var{q}: will hold the q

@var{g}: will hold the g

@var{y}: will hold the y

@var{x}: will hold the x

This function will export the DSA private key's parameters found
in the given structure. The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

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

@subheading gnutls_x509_privkey_export_ecc_raw
@anchor{gnutls_x509_privkey_export_ecc_raw}
@deftypefun {int} {gnutls_x509_privkey_export_ecc_raw} (gnutls_x509_privkey_t @var{key}, gnutls_ecc_curve_t * @var{curve}, gnutls_datum_t * @var{x}, gnutls_datum_t * @var{y}, gnutls_datum_t* @var{k})
@var{key}: a structure that holds the rsa parameters

@var{curve}: will hold the curve

@var{x}: will hold the x coordinate

@var{y}: will hold the y coordinate

@var{k}: will hold the private key

This function will export the ECC private key's parameters found
in the given structure. The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_privkey_export_pkcs8
@anchor{gnutls_x509_privkey_export_pkcs8}
@deftypefun {int} {gnutls_x509_privkey_export_pkcs8} (gnutls_x509_privkey_t @var{key}, gnutls_x509_crt_fmt_t @var{format}, const char * @var{password}, unsigned int @var{flags}, void * @var{output_data}, size_t * @var{output_data_size})
@var{key}: Holds the key

@var{format}: the format of output params. One of PEM or DER.

@var{password}: the password that will be used to encrypt the key.

@var{flags}: an ORed sequence of gnutls_pkcs_encrypt_flags_t

@var{output_data}: will contain a private key PEM or DER encoded

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will export the private key to a PKCS8 structure.
Both RSA and DSA keys can be exported. For DSA keys we use
PKCS @code{11}  definitions. If the flags do not specify the encryption
cipher, then the default 3DES (PBES2) will be used.

The  @code{password} can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.

If the buffer provided is not long enough to hold the output, then
*output_data_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER will
be returned.

If the structure is PEM encoded, it will have a header
of "BEGIN ENCRYPTED PRIVATE KEY" or "BEGIN PRIVATE KEY" if
encryption is not used.

@strong{Returns:} In case of failure a negative error code will be
returned, and 0 on success.
@end deftypefun

@subheading gnutls_x509_privkey_export_rsa_raw
@anchor{gnutls_x509_privkey_export_rsa_raw}
@deftypefun {int} {gnutls_x509_privkey_export_rsa_raw} (gnutls_x509_privkey_t @var{key}, gnutls_datum_t * @var{m}, gnutls_datum_t * @var{e}, gnutls_datum_t * @var{d}, gnutls_datum_t * @var{p}, gnutls_datum_t * @var{q}, gnutls_datum_t * @var{u})
@var{key}: a structure that holds the rsa parameters

@var{m}: will hold the modulus

@var{e}: will hold the public exponent

@var{d}: will hold the private exponent

@var{p}: will hold the first prime (p)

@var{q}: will hold the second prime (q)

@var{u}: will hold the coefficient

This function will export the RSA private key's parameters found
in the given structure. The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

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

@subheading gnutls_x509_privkey_export_rsa_raw2
@anchor{gnutls_x509_privkey_export_rsa_raw2}
@deftypefun {int} {gnutls_x509_privkey_export_rsa_raw2} (gnutls_x509_privkey_t @var{key}, gnutls_datum_t * @var{m}, gnutls_datum_t * @var{e}, gnutls_datum_t * @var{d}, gnutls_datum_t * @var{p}, gnutls_datum_t * @var{q}, gnutls_datum_t * @var{u}, gnutls_datum_t * @var{e1}, gnutls_datum_t * @var{e2})
@var{key}: a structure that holds the rsa parameters

@var{m}: will hold the modulus

@var{e}: will hold the public exponent

@var{d}: will hold the private exponent

@var{p}: will hold the first prime (p)

@var{q}: will hold the second prime (q)

@var{u}: will hold the coefficient

@var{e1}: will hold e1 = d mod (p-1)

@var{e2}: will hold e2 = d mod (q-1)

This function will export the RSA private key's parameters found
in the given structure. The new parameters will be allocated using
@code{gnutls_malloc()}  and will be stored in the appropriate datum.

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

@strong{Since:} 2.12.0
@end deftypefun

@subheading gnutls_x509_privkey_fix
@anchor{gnutls_x509_privkey_fix}
@deftypefun {int} {gnutls_x509_privkey_fix} (gnutls_x509_privkey_t @var{key})
@var{key}: Holds the key

This function will recalculate the secondary parameters in a key.
In RSA keys, this can be the coefficient and exponent1,2.

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

@subheading gnutls_x509_privkey_generate
@anchor{gnutls_x509_privkey_generate}
@deftypefun {int} {gnutls_x509_privkey_generate} (gnutls_x509_privkey_t @var{key}, gnutls_pk_algorithm_t @var{algo}, unsigned int @var{bits}, unsigned int @var{flags})
@var{key}: should contain a @code{gnutls_x509_privkey_t}  structure

@var{algo}: is one of the algorithms in @code{gnutls_pk_algorithm_t} .

@var{bits}: the size of the modulus

@var{flags}: unused for now.  Must be 0.

This function will generate a random private key. Note that this
function must be called on an empty private key.

Do not set the number of bits directly, use @code{gnutls_sec_param_to_pk_bits()} .

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

@subheading gnutls_x509_privkey_get_key_id
@anchor{gnutls_x509_privkey_get_key_id}
@deftypefun {int} {gnutls_x509_privkey_get_key_id} (gnutls_x509_privkey_t @var{key}, unsigned int @var{flags}, unsigned char * @var{output_data}, size_t * @var{output_data_size})
@var{key}: Holds the key

@var{flags}: should be 0 for now

@var{output_data}: will contain the key ID

@var{output_data_size}: holds the size of output_data (and will be
replaced by the actual size of parameters)

This function will return a unique ID the depends on the public key
parameters. This ID can be used in checking whether a certificate
corresponds to the given key.

If the buffer provided is not long enough to hold the output, then
* @code{output_data_size} is updated and @code{GNUTLS_E_SHORT_MEMORY_BUFFER}  will
be returned.  The output will normally be a SHA-1 hash output,
which is 20 bytes.

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

@subheading gnutls_x509_privkey_get_pk_algorithm
@anchor{gnutls_x509_privkey_get_pk_algorithm}
@deftypefun {int} {gnutls_x509_privkey_get_pk_algorithm} (gnutls_x509_privkey_t @var{key})
@var{key}: should contain a @code{gnutls_x509_privkey_t}  structure

This function will return the public key algorithm of a private
key.

@strong{Returns:} a member of the @code{gnutls_pk_algorithm_t}  enumeration on
success, or a negative error code on error.
@end deftypefun

@subheading gnutls_x509_privkey_import
@anchor{gnutls_x509_privkey_import}
@deftypefun {int} {gnutls_x509_privkey_import} (gnutls_x509_privkey_t @var{key}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format})
@var{key}: The structure to store the parsed key

@var{data}: The DER or PEM encoded certificate.

@var{format}: One of DER or PEM

This function will convert the given DER or PEM encoded key to the
native @code{gnutls_x509_privkey_t}  format. The output will be stored in
 @code{key} .

If the key is PEM encoded it should have a header of "RSA PRIVATE
KEY", or "DSA PRIVATE KEY".

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

@subheading gnutls_x509_privkey_import_dsa_raw
@anchor{gnutls_x509_privkey_import_dsa_raw}
@deftypefun {int} {gnutls_x509_privkey_import_dsa_raw} (gnutls_x509_privkey_t @var{key}, const gnutls_datum_t * @var{p}, const gnutls_datum_t * @var{q}, const gnutls_datum_t * @var{g}, const gnutls_datum_t * @var{y}, const gnutls_datum_t * @var{x})
@var{key}: The structure to store the parsed key

@var{p}: holds the p

@var{q}: holds the q

@var{g}: holds the g

@var{y}: holds the y

@var{x}: holds the x

This function will convert the given DSA raw parameters to the
native @code{gnutls_x509_privkey_t}  format.  The output will be stored
in  @code{key} .

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

@subheading gnutls_x509_privkey_import_ecc_raw
@anchor{gnutls_x509_privkey_import_ecc_raw}
@deftypefun {int} {gnutls_x509_privkey_import_ecc_raw} (gnutls_x509_privkey_t @var{key}, gnutls_ecc_curve_t @var{curve}, const gnutls_datum_t * @var{x}, const gnutls_datum_t * @var{y}, const gnutls_datum_t * @var{k})
@var{key}: The structure to store the parsed key

@var{curve}: holds the curve

@var{x}: holds the x

@var{y}: holds the y

@var{k}: holds the k

This function will convert the given elliptic curve parameters to the
native @code{gnutls_x509_privkey_t}  format.  The output will be stored
in  @code{key} .

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_privkey_import_pkcs8
@anchor{gnutls_x509_privkey_import_pkcs8}
@deftypefun {int} {gnutls_x509_privkey_import_pkcs8} (gnutls_x509_privkey_t @var{key}, const gnutls_datum_t * @var{data}, gnutls_x509_crt_fmt_t @var{format}, const char * @var{password}, unsigned int @var{flags})
@var{key}: The structure to store the parsed key

@var{data}: The DER or PEM encoded key.

@var{format}: One of DER or PEM

@var{password}: the password to decrypt the key (if it is encrypted).

@var{flags}: 0 if encrypted or GNUTLS_PKCS_PLAIN if not encrypted.

This function will convert the given DER or PEM encoded PKCS8 2.0
encrypted key to the native gnutls_x509_privkey_t format. The
output will be stored in  @code{key} .  Both RSA and DSA keys can be
imported, and flags can only be used to indicate an unencrypted
key.

The  @code{password} can be either ASCII or UTF-8 in the default PBES2
encryption schemas, or ASCII for the PKCS12 schemas.

If the Certificate is PEM encoded it should have a header of
"ENCRYPTED PRIVATE KEY", or "PRIVATE KEY". You only need to
specify the flags if the key is DER encoded, since in that case
the encryption status cannot be auto-detected.

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

@subheading gnutls_x509_privkey_import_rsa_raw
@anchor{gnutls_x509_privkey_import_rsa_raw}
@deftypefun {int} {gnutls_x509_privkey_import_rsa_raw} (gnutls_x509_privkey_t @var{key}, const gnutls_datum_t * @var{m}, const gnutls_datum_t * @var{e}, const gnutls_datum_t * @var{d}, const gnutls_datum_t * @var{p}, const gnutls_datum_t * @var{q}, const gnutls_datum_t * @var{u})
@var{key}: The structure to store the parsed key

@var{m}: holds the modulus

@var{e}: holds the public exponent

@var{d}: holds the private exponent

@var{p}: holds the first prime (p)

@var{q}: holds the second prime (q)

@var{u}: holds the coefficient

This function will convert the given RSA raw parameters to the
native @code{gnutls_x509_privkey_t}  format.  The output will be stored in
 @code{key} .

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

@subheading gnutls_x509_privkey_import_rsa_raw2
@anchor{gnutls_x509_privkey_import_rsa_raw2}
@deftypefun {int} {gnutls_x509_privkey_import_rsa_raw2} (gnutls_x509_privkey_t @var{key}, const gnutls_datum_t * @var{m}, const gnutls_datum_t * @var{e}, const gnutls_datum_t * @var{d}, const gnutls_datum_t * @var{p}, const gnutls_datum_t * @var{q}, const gnutls_datum_t * @var{u}, const gnutls_datum_t * @var{e1}, const gnutls_datum_t * @var{e2})
@var{key}: The structure to store the parsed key

@var{m}: holds the modulus

@var{e}: holds the public exponent

@var{d}: holds the private exponent

@var{p}: holds the first prime (p)

@var{q}: holds the second prime (q)

@var{u}: holds the coefficient

@var{e1}: holds e1 = d mod (p-1)

@var{e2}: holds e2 = d mod (q-1)

This function will convert the given RSA raw parameters to the
native @code{gnutls_x509_privkey_t}  format.  The output will be stored in
 @code{key} .

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

@subheading gnutls_x509_privkey_init
@anchor{gnutls_x509_privkey_init}
@deftypefun {int} {gnutls_x509_privkey_init} (gnutls_x509_privkey_t * @var{key})
@var{key}: The structure to be initialized

This function will initialize an private key structure.

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

@subheading gnutls_x509_privkey_sec_param
@anchor{gnutls_x509_privkey_sec_param}
@deftypefun {gnutls_sec_param_t} {gnutls_x509_privkey_sec_param} (gnutls_x509_privkey_t @var{key})
@var{key}: a key structure

This function will return the security parameter appropriate with
this private key.

@strong{Returns:} On success, a valid security parameter is returned otherwise
@code{GNUTLS_SEC_PARAM_UNKNOWN}  is returned.

@strong{Since:} 2.12.0
@end deftypefun

@subheading gnutls_x509_privkey_verify_params
@anchor{gnutls_x509_privkey_verify_params}
@deftypefun {int} {gnutls_x509_privkey_verify_params} (gnutls_x509_privkey_t @var{key})
@var{key}: should contain a @code{gnutls_x509_privkey_t}  structure

This function will verify the private key parameters.

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

@subheading gnutls_x509_rdn_get
@anchor{gnutls_x509_rdn_get}
@deftypefun {int} {gnutls_x509_rdn_get} (const gnutls_datum_t * @var{idn}, char * @var{buf}, size_t * @var{sizeof_buf})
@var{idn}: should contain a DER encoded RDN sequence

@var{buf}: a pointer to a structure to hold the peer's name

@var{sizeof_buf}: holds the size of  @code{buf} 

This function will return the name of the given RDN sequence.  The
name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as described in
RFC4514.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, or
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  is returned and * @code{sizeof_buf} is
updated if the provided buffer is not long enough, otherwise a
negative error value.
@end deftypefun

@subheading gnutls_x509_rdn_get_by_oid
@anchor{gnutls_x509_rdn_get_by_oid}
@deftypefun {int} {gnutls_x509_rdn_get_by_oid} (const gnutls_datum_t * @var{idn}, const char * @var{oid}, int @var{indx}, unsigned int @var{raw_flag}, void * @var{buf}, size_t * @var{sizeof_buf})
@var{idn}: should contain a DER encoded RDN sequence

@var{oid}: an Object Identifier

@var{indx}: In case multiple same OIDs exist in the RDN indicates which
to send. Use 0 for the first one.

@var{raw_flag}: If non (0) then the raw DER data are returned.

@var{buf}: a pointer to a structure to hold the peer's name

@var{sizeof_buf}: holds the size of  @code{buf} 

This function will return the name of the given Object identifier,
of the RDN sequence.  The name will be encoded using the rules
from RFC4514.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, or
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  is returned and * @code{sizeof_buf} is
updated if the provided buffer is not long enough, otherwise a
negative error value.
@end deftypefun

@subheading gnutls_x509_rdn_get_oid
@anchor{gnutls_x509_rdn_get_oid}
@deftypefun {int} {gnutls_x509_rdn_get_oid} (const gnutls_datum_t * @var{idn}, int @var{indx}, void * @var{buf}, size_t * @var{sizeof_buf})
@var{idn}: should contain a DER encoded RDN sequence

@var{indx}: Indicates which OID to return. Use 0 for the first one.

@var{buf}: a pointer to a structure to hold the peer's name OID

@var{sizeof_buf}: holds the size of  @code{buf} 

This function will return the specified Object identifier, of the
RDN sequence.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, or
@code{GNUTLS_E_SHORT_MEMORY_BUFFER}  is returned and * @code{sizeof_buf} is
updated if the provided buffer is not long enough, otherwise a
negative error value.

@strong{Since:} 2.4.0
@end deftypefun

@subheading gnutls_x509_trust_list_add_cas
@anchor{gnutls_x509_trust_list_add_cas}
@deftypefun {int} {gnutls_x509_trust_list_add_cas} (gnutls_x509_trust_list_t @var{list}, const gnutls_x509_crt_t * @var{clist}, int @var{clist_size}, unsigned int @var{flags})
@var{list}: The structure of the list

@var{clist}: A list of CAs

@var{clist_size}: The length of the CA list

@var{flags}: should be 0.

This function will add the given certificate authorities
to the trusted list. The list of CAs must not be deinitialized
during this structure's lifetime.

@strong{Returns:} The number of added elements is returned.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_add_crls
@anchor{gnutls_x509_trust_list_add_crls}
@deftypefun {int} {gnutls_x509_trust_list_add_crls} (gnutls_x509_trust_list_t @var{list}, const gnutls_x509_crl_t * @var{crl_list}, int @var{crl_size}, unsigned int @var{flags}, unsigned int @var{verification_flags})
@var{list}: The structure of the list

@var{crl_list}: A list of CRLs

@var{crl_size}: The length of the CRL list

@var{flags}: if GNUTLS_TL_VERIFY_CRL is given the CRLs will be verified before being added.

@var{verification_flags}: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL

This function will add the given certificate revocation lists
to the trusted list. The list of CRLs must not be deinitialized
during this structure's lifetime.

This function must be called after @code{gnutls_x509_trust_list_add_cas()} 
to allow verifying the CRLs for validity.

@strong{Returns:} The number of added elements is returned.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_add_named_crt
@anchor{gnutls_x509_trust_list_add_named_crt}
@deftypefun {int} {gnutls_x509_trust_list_add_named_crt} (gnutls_x509_trust_list_t @var{list}, gnutls_x509_crt_t @var{cert}, const void * @var{name}, size_t @var{name_size}, unsigned int @var{flags})
@var{list}: The structure of the list

@var{cert}: A certificate

@var{name}: An identifier for the certificate

@var{name_size}: The size of the identifier

@var{flags}: should be 0.

This function will add the given certificate to the trusted
list and associate it with a name. The certificate will not be
be used for verification with @code{gnutls_x509_trust_list_verify_crt()} 
but only with @code{gnutls_x509_trust_list_verify_named_crt()} .

In principle this function can be used to set individual "server"
certificates that are trusted by the user for that specific server
but for no other purposes.

The certificate must not be deinitialized during the lifetime
of the trusted list.

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_add_system_trust
@anchor{gnutls_x509_trust_list_add_system_trust}
@deftypefun {int} {gnutls_x509_trust_list_add_system_trust} (gnutls_x509_trust_list_t @var{list}, unsigned int @var{tl_flags}, unsigned int @var{tl_vflags})
@var{list}: The structure of the list

@var{tl_flags}: GNUTLS_TL_*

@var{tl_vflags}: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL

This function adds the system's default trusted certificate
authorities to the trusted list.

@strong{Returns:} The number of added elements is returned.

@strong{Since:} 3.1
@end deftypefun

@subheading gnutls_x509_trust_list_add_trust_file
@anchor{gnutls_x509_trust_list_add_trust_file}
@deftypefun {int} {gnutls_x509_trust_list_add_trust_file} (gnutls_x509_trust_list_t @var{list}, const char* @var{ca_file}, const char* @var{crl_file}, gnutls_x509_crt_fmt_t @var{type}, unsigned int @var{tl_flags}, unsigned int @var{tl_vflags})
@var{list}: The structure of the list

@var{ca_file}: A file containing a list of CAs (optional)

@var{crl_file}: A file containing a list of CRLs (optional)

@var{type}: The format of the certificates

@var{tl_flags}: GNUTLS_TL_*

@var{tl_vflags}: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL

This function will add the given certificate authorities
to the trusted list. pkcs11 URLs are also accepted, instead
of files, by this function.

@strong{Returns:} The number of added elements is returned.

@strong{Since:} 3.1
@end deftypefun

@subheading gnutls_x509_trust_list_add_trust_mem
@anchor{gnutls_x509_trust_list_add_trust_mem}
@deftypefun {int} {gnutls_x509_trust_list_add_trust_mem} (gnutls_x509_trust_list_t @var{list}, const gnutls_datum_t * @var{cas}, const gnutls_datum_t * @var{crls}, gnutls_x509_crt_fmt_t @var{type}, unsigned int @var{tl_flags}, unsigned int @var{tl_vflags})
@var{list}: The structure of the list

@var{cas}: -- undescribed --

@var{crls}: -- undescribed --

@var{type}: The format of the certificates

@var{tl_flags}: GNUTLS_TL_*

@var{tl_vflags}: gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL

This function will add the given certificate authorities
to the trusted list. 

@strong{Returns:} The number of added elements is returned.

@strong{Since:} 3.1
@end deftypefun

@subheading gnutls_x509_trust_list_deinit
@anchor{gnutls_x509_trust_list_deinit}
@deftypefun {void} {gnutls_x509_trust_list_deinit} (gnutls_x509_trust_list_t @var{list}, unsigned int @var{all})
@var{list}: The structure to be deinitialized

@var{all}: if non-(0) it will deinitialize all the certificates and CRLs contained in the structure.

This function will deinitialize a trust list.

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_get_issuer
@anchor{gnutls_x509_trust_list_get_issuer}
@deftypefun {int} {gnutls_x509_trust_list_get_issuer} (gnutls_x509_trust_list_t @var{list}, gnutls_x509_crt_t @var{cert}, gnutls_x509_crt_t * @var{issuer}, unsigned int @var{flags})
@var{list}: The structure of the list

@var{cert}: is the certificate to find issuer for

@var{issuer}: Will hold the issuer if any. Should be treated as constant.

@var{flags}: Use (0).

This function will attempt to find the issuer of the
given certificate.

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_init
@anchor{gnutls_x509_trust_list_init}
@deftypefun {int} {gnutls_x509_trust_list_init} (gnutls_x509_trust_list_t * @var{list}, unsigned int @var{size})
@var{list}: The structure to be initialized

@var{size}: The size of the internal hash table. Use (0) for default size.

This function will initialize an X.509 trust list structure.

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_verify_crt
@anchor{gnutls_x509_trust_list_verify_crt}
@deftypefun {int} {gnutls_x509_trust_list_verify_crt} (gnutls_x509_trust_list_t @var{list}, gnutls_x509_crt_t * @var{cert_list}, unsigned int @var{cert_list_size}, unsigned int @var{flags}, unsigned int * @var{verify}, gnutls_verify_output_function @var{func})
@var{list}: The structure of the list

@var{cert_list}: is the certificate list to be verified

@var{cert_list_size}: is the certificate list size

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

@var{verify}: will hold the certificate verification output.

@var{func}: If non-null will be called on each chain element verification with the output.

This function will try to verify the given certificate and return
its status.

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

@strong{Since:} 3.0
@end deftypefun

@subheading gnutls_x509_trust_list_verify_named_crt
@anchor{gnutls_x509_trust_list_verify_named_crt}
@deftypefun {int} {gnutls_x509_trust_list_verify_named_crt} (gnutls_x509_trust_list_t @var{list}, gnutls_x509_crt_t @var{cert}, const void * @var{name}, size_t @var{name_size}, unsigned int @var{flags}, unsigned int * @var{verify}, gnutls_verify_output_function @var{func})
@var{list}: The structure of the list

@var{cert}: is the certificate to be verified

@var{name}: is the certificate's name

@var{name_size}: is the certificate's name size

@var{flags}: Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations.

@var{verify}: will hold the certificate verification output.

@var{func}: If non-null will be called on each chain element verification with the output.

This function will try to find a matching named certificate. If a
match is found the certificate is considered valid. In addition to that
this function will also check CRLs.

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

@strong{Since:} 3.0
@end deftypefun