— Function: int gnutls_pkcs12_bag_decrypt (gnutls_pkcs12_bag_t bag, const char * pass)

bag: The bag

pass: The password used for encryption. This can only be ASCII.

This function will decrypt the given encrypted bag and return 0 on success.

— Function: void gnutls_pkcs12_bag_deinit (gnutls_pkcs12_bag_t bag)

bag: The structure to be initialized

This function will deinitialize a PKCS12 Bag structure.

— Function: int gnutls_pkcs12_bag_encrypt (gnutls_pkcs12_bag_t bag, const char * pass, unsigned int flags)

bag: The bag

pass: The password used for encryption. This can only be ASCII.

flags: should be one of gnutls_pkcs_encrypt_flags_t elements bitwise or'd

This function will encrypt the given bag and return 0 on success.

— Function: int gnutls_pkcs12_bag_get_count (gnutls_pkcs12_bag_t bag)

bag: The bag

This function will return the number of the elements withing the bag.

— Function: int gnutls_pkcs12_bag_get_data (gnutls_pkcs12_bag_t bag, int indx, gnutls_datum_t * data)

bag: The bag

indx: The element of the bag to get the data from

data: where the bag's data will be. Should be treated as constant.

This function will return the bag's data. The data is a constant that is stored into the bag. Should not be accessed after the bag is deleted.

Returns 0 on success and a negative error code on error.

— Function: int gnutls_pkcs12_bag_get_friendly_name (gnutls_pkcs12_bag_t bag, int indx, char ** name)

bag: The bag

indx: The bag's element to add the id

name: will hold a pointer to the name (to be treated as const)

This function will return the friendly name, of the specified bag element. The key ID is usually used to distinguish the local private key and the certificate pair.

Returns 0 on success, or a negative value on error.

— Function: int gnutls_pkcs12_bag_get_key_id (gnutls_pkcs12_bag_t bag, int indx, gnutls_datum_t * id)

bag: The bag

indx: The bag's element to add the id

id: where the ID will be copied (to be treated as const)

This function will return the key ID, of the specified bag element. The key ID is usually used to distinguish the local private key and the certificate pair.

Returns 0 on success, or a negative value on error.

— Function: gnutls_pkcs12_bag_type_t gnutls_pkcs12_bag_get_type (gnutls_pkcs12_bag_t bag, int indx)

bag: The bag

indx: The element of the bag to get the type

This function will return the bag's type. One of the gnutls_pkcs12_bag_type_t enumerations.

— Function: int gnutls_pkcs12_bag_init (gnutls_pkcs12_bag_t * bag)

bag: The structure to be initialized

This function will initialize a PKCS12 bag structure. PKCS12 Bags usually contain private keys, lists of X.509 Certificates and X.509 Certificate revocation lists.

Returns 0 on success.

— Function: int gnutls_pkcs12_bag_set_crl (gnutls_pkcs12_bag_t bag, gnutls_x509_crl_t crl)

bag: The bag

crl: the CRL to be copied.

This function will insert the given CRL into the bag. This is just a wrapper over gnutls_pkcs12_bag_set_data().

Returns the index of the added bag on success, or a negative value on failure.

— Function: int gnutls_pkcs12_bag_set_crt (gnutls_pkcs12_bag_t bag, gnutls_x509_crt_t crt)

bag: The bag

crt: the certificate to be copied.

This function will insert the given certificate into the bag. This is just a wrapper over gnutls_pkcs12_bag_set_data().

Returns the index of the added bag on success, or a negative value on failure.

— Function: int gnutls_pkcs12_bag_set_data (gnutls_pkcs12_bag_t bag, gnutls_pkcs12_bag_type_t type, const gnutls_datum_t * data)

bag: The bag

type: The data's type

data: the data to be copied.

This function will insert the given data of the given type into the bag.

Returns the index of the added bag on success, or a negative value on error.

— Function: int gnutls_pkcs12_bag_set_friendly_name (gnutls_pkcs12_bag_t bag, int indx, const char * name)

bag: The bag

indx: The bag's element to add the id

name: the name

This function will add the given key friendly name, to the specified, by the index, bag element. The name will be encoded as a 'Friendly name' bag attribute, which is usually used to set a user name to the local private key and the certificate pair.

Returns 0 on success, or a negative value on error.

— Function: int gnutls_pkcs12_bag_set_key_id (gnutls_pkcs12_bag_t bag, int indx, const gnutls_datum_t * id)

bag: The bag

indx: The bag's element to add the id

id: the ID

This function will add the given key ID, to the specified, by the index, bag element. The key ID will be encoded as a 'Local key identifier' bag attribute, which is usually used to distinguish the local private key and the certificate pair.

Returns 0 on success, or a negative value on error.

— Function: void gnutls_pkcs12_deinit (gnutls_pkcs12_t pkcs12)

pkcs12: The structure to be initialized

This function will deinitialize a PKCS12 structure.

— Function: int gnutls_pkcs12_export (gnutls_pkcs12_t pkcs12, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

pkcs12: Holds the pkcs12 structure

format: the format of output params. One of PEM or DER.

output_data: will contain a structure PEM or DER encoded

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

This function will export the pkcs12 structure to DER or PEM format.

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

If the structure is PEM encoded, it will have a header of "BEGIN PKCS12".

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_pkcs12_generate_mac (gnutls_pkcs12_t pkcs12, const char * pass)

pkcs12: should contain a gnutls_pkcs12_t structure

pass: The password for the MAC

This function will generate a MAC for the PKCS12 structure. Returns 0 on success.

— Function: int gnutls_pkcs12_get_bag (gnutls_pkcs12_t pkcs12, int indx, gnutls_pkcs12_bag_t bag)

pkcs12: should contain a gnutls_pkcs12_t structure

indx: contains the index of the bag to extract

bag: An initialized bag, where the contents of the bag will be copied

This function will return a Bag from the PKCS12 structure. Returns 0 on success.

After the last Bag has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_pkcs12_import (gnutls_pkcs12_t pkcs12, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, unsigned int flags)

pkcs12: The structure to store the parsed PKCS12.

data: The DER or PEM encoded PKCS12.

format: One of DER or PEM

flags: an ORed sequence of gnutls_privkey_pkcs8_flags

This function will convert the given DER or PEM encoded PKCS12 to the native gnutls_pkcs12_t format. The output will be stored in 'pkcs12'.

If the PKCS12 is PEM encoded it should have a header of "PKCS12".

Returns 0 on success.

— Function: int gnutls_pkcs12_init (gnutls_pkcs12_t * pkcs12)

pkcs12: The structure to be initialized

This function will initialize a PKCS12 structure. PKCS12 structures usually contain lists of X.509 Certificates and X.509 Certificate revocation lists.

Returns 0 on success.

— Function: int gnutls_pkcs12_set_bag (gnutls_pkcs12_t pkcs12, gnutls_pkcs12_bag_t bag)

pkcs12: should contain a gnutls_pkcs12_t structure

bag: An initialized bag

This function will insert a Bag into the PKCS12 structure. Returns 0 on success.

— Function: int gnutls_pkcs12_verify_mac (gnutls_pkcs12_t pkcs12, const char * pass)

pkcs12: should contain a gnutls_pkcs12_t structure

pass: The password for the MAC

This function will verify the MAC for the PKCS12 structure. Returns 0 on success.

— Function: void gnutls_pkcs7_deinit (gnutls_pkcs7_t pkcs7)

pkcs7: The structure to be initialized

This function will deinitialize a PKCS7 structure.

— Function: int gnutls_pkcs7_delete_crl (gnutls_pkcs7_t pkcs7, int indx)

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.

— Function: int gnutls_pkcs7_delete_crt (gnutls_pkcs7_t pkcs7, int indx)

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.

— Function: int gnutls_pkcs7_export (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

pkcs7: Holds the pkcs7 structure

format: the format of output params. One of PEM or DER.

output_data: will contain a structure PEM or DER encoded

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 *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 PKCS7".

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_pkcs7_get_crl_count (gnutls_pkcs7_t pkcs7)

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

Returns a negative value on failure.

— Function: int gnutls_pkcs7_get_crl_raw (gnutls_pkcs7_t pkcs7, int indx, void * crl, size_t * crl_size)

indx: contains the index of the crl to extract

crl: the contents of the crl will be copied there (may be null)

crl_size: should hold the size of the crl

This function will return a crl of the PKCS7 or RFC2630 crl set. Returns 0 on success. If the provided buffer is not long enough, then crl_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.

After the last crl has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_pkcs7_get_crt_count (gnutls_pkcs7_t pkcs7)

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

Returns a negative value on failure.

— Function: int gnutls_pkcs7_get_crt_raw (gnutls_pkcs7_t pkcs7, int indx, void * certificate, size_t * certificate_size)

indx: contains the index of the certificate to extract

certificate: the contents of the certificate will be copied there (may be null)

certificate_size: should hold the size of the certificate

This function will return a certificate of the PKCS7 or RFC2630 certificate set. Returns 0 on success. If the provided buffer is not long enough, then certificate_size is updated and GNUTLS_E_SHORT_MEMORY_BUFFER is returned.

After the last certificate has been read GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_pkcs7_import (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

pkcs7: The structure to store the parsed PKCS7.

data: The DER or PEM encoded PKCS7.

format: One of DER or PEM

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

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

Returns 0 on success.

— Function: int gnutls_pkcs7_init (gnutls_pkcs7_t * pkcs7)

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.

Returns 0 on success.

— Function: int gnutls_pkcs7_set_crl_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crl)

crl: the DER encoded crl to be added

This function will add a crl to the PKCS7 or RFC2630 crl set. Returns 0 on success.

— Function: int gnutls_pkcs7_set_crl (gnutls_pkcs7_t pkcs7, gnutls_x509_crl_t crl)

crl: the DER encoded crl to be added

This function will add a parsed crl to the PKCS7 or RFC2630 crl set. Returns 0 on success.

— Function: int gnutls_pkcs7_set_crt_raw (gnutls_pkcs7_t pkcs7, const gnutls_datum_t * crt)

crt: the DER encoded certificate to be added

This function will add a certificate to the PKCS7 or RFC2630 certificate set. Returns 0 on success.

— Function: int gnutls_pkcs7_set_crt (gnutls_pkcs7_t pkcs7, gnutls_x509_crt_t crt)

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 gnutls_pkcs7_set_crt_raw() .

Returns 0 on success.

— Function: int gnutls_x509_crl_check_issuer (gnutls_x509_crl_t cert, gnutls_x509_crt_t issuer)

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.

A negative value is returned in case of an error.

— Function: void gnutls_x509_crl_deinit (gnutls_x509_crl_t crl)

crl: The structure to be initialized

This function will deinitialize a CRL structure.

— Function: int gnutls_x509_crl_export (gnutls_x509_crl_t crl, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

crl: Holds the revocation list

format: the format of output params. One of PEM or DER.

output_data: will contain a private key PEM or DER encoded

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 GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.

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

Returns 0 on success, and a negative value on failure.

— Function: int gnutls_x509_crl_get_crt_count (gnutls_x509_crl_t crl)

crl: should contain a gnutls_x509_crl_t structure

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

Returns a negative value on failure.

— Function: int gnutls_x509_crl_get_crt_serial (gnutls_x509_crl_t crl, int indx, unsigned char * serial, size_t * serial_size, time_t * t)

crl: should contain a gnutls_x509_crl_t structure

indx: the index of the certificate to extract (starting from 0)

serial: where the serial number will be copied

serial_size: initially holds the size of serial

t: if non null, will hold the time this certificate was revoked

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

Returns a negative value on failure.

— Function: int gnutls_x509_crl_get_dn_oid (gnutls_x509_crl_t crl, int indx, void * oid, size_t * sizeof_oid)

crl: should contain a gnutls_x509_crl_t structure

indx: Specifies which DN OID to send. Use zero to get the first one.

oid: a pointer to a structure to hold the name (may be null)

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.

Returns 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.

— Function: int gnutls_x509_crl_get_issuer_dn_by_oid (gnutls_x509_crl_t crl, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf)

crl: should contain a gnutls_x509_crl_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.

raw_flag: If non zero returns the raw DER data of the DN part.

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

sizeof_buf: initially holds the size of 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 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 zero, 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 gnutls_x509_dn_oid_known().

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

Returns 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.

— Function: int gnutls_x509_crl_get_issuer_dn (const gnutls_x509_crl_t crl, char * buf, size_t * sizeof_buf)

crl: should contain a gnutls_x509_crl_t structure

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

sizeof_buf: initially holds the size of 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 RFC2253. The output string will be ASCII or UTF-8 encoded, depending on the certificate data.

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

Returns 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.

— Function: time_t gnutls_x509_crl_get_next_update (gnutls_x509_crl_t crl)

crl: should contain a 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.

Returns (time_t)-1 on error.

— Function: int gnutls_x509_crl_get_signature_algorithm (gnutls_x509_crl_t crl)

crl: should contain a gnutls_x509_crl_t structure

This function will return a value of the gnutls_sign_algorithm_t enumeration that is the signature algorithm.

Returns a negative value on error.

— Function: time_t gnutls_x509_crl_get_this_update (gnutls_x509_crl_t crl)

crl: should contain a gnutls_x509_crl_t structure

This function will return the time this CRL was issued.

Returns (time_t)-1 on error.

— Function: int gnutls_x509_crl_get_version (gnutls_x509_crl_t crl)

crl: should contain a gnutls_x509_crl_t structure

This function will return the version of the specified CRL.

Returns a negative value on error.

— Function: int gnutls_x509_crl_import (gnutls_x509_crl_t crl, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

crl: The structure to store the parsed CRL.

data: The DER or PEM encoded CRL.

format: One of DER or PEM

This function will convert the given DER or PEM encoded CRL to the native 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".

Returns 0 on success.

— Function: int gnutls_x509_crl_init (gnutls_x509_crl_t * crl)

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.

Returns 0 on success.

— Function: int gnutls_x509_crl_set_crt_serial (gnutls_x509_crl_t crl, const void * serial, size_t serial_size, time_t revocation_time)

crl: should contain a gnutls_x509_crl_t structure

serial: The revoked certificate's serial number

serial_size: Holds the size of the serial field.

revocation_time: The time this certificate was revoked

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

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crl_set_crt (gnutls_x509_crl_t crl, gnutls_x509_crt_t crt, time_t revocation_time)

crl: should contain a gnutls_x509_crl_t structure

crt: should contain a gnutls_x509_crt_t structure with the revoked certificate

revocation_time: The time this certificate was revoked

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

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crl_set_next_update (gnutls_x509_crl_t crl, time_t exp_time)

crl: should contain a gnutls_x509_crl_t structure

exp_time: The actual time

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

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crl_set_this_update (gnutls_x509_crl_t crl, time_t act_time)

crl: should contain a gnutls_x509_crl_t structure

act_time: The actual time

This function will set the time this CRL was issued.

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crl_set_version (gnutls_x509_crl_t crl, unsigned int version)

crl: should contain a gnutls_x509_crl_t structure

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.

Returns 0 on success.

— Function: int gnutls_x509_crl_sign2 (gnutls_x509_crl_t crl, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key, gnutls_digest_algorithm_t dig, unsigned int flags)

crl: should contain a gnutls_x509_crl_t structure

issuer: is the certificate of the certificate issuer

issuer_key: holds the issuer's private key

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

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.

Returns 0 on success.

— Function: int gnutls_x509_crl_sign (gnutls_x509_crl_t crl, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key)

crl: should contain a gnutls_x509_crl_t structure

issuer: is the certificate of the certificate issuer

issuer_key: holds the issuer's private key

This function is the same a gnutls_x509_crl_sign2() with no flags, and SHA1 as the hash algorithm.

Returns 0 on success.

— Function: int gnutls_x509_crl_verify (gnutls_x509_crl_t crl, const gnutls_x509_crt_t * CA_list, int CA_list_length, unsigned int flags, unsigned int * verify)

crl: is the crl to be verified

CA_list: is a certificate list that is considered to be trusted one

CA_list_length: holds the number of CA certificates in CA_list

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

verify: will hold the crl verification output.

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

Returns 0 on success and a negative value in case of an error.

— Function: void gnutls_x509_crq_deinit (gnutls_x509_crq_t crq)

crq: The structure to be initialized

This function will deinitialize a CRL structure.

— Function: int gnutls_x509_crq_export (gnutls_x509_crq_t crq, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

crq: Holds the request

format: the format of output params. One of PEM or DER.

output_data: will contain a certificate request PEM or DER encoded

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 PKCS10

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

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

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_crq_get_attribute_by_oid (gnutls_x509_crq_t crq, const char * oid, int indx, void * buf, size_t * sizeof_buf)

crq: should contain a gnutls_x509_crq_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the attribute list, this specifies which to send. Use zero to get the first one.

buf: a pointer to a structure to hold the attribute data (may be null)

sizeof_buf: initially holds the size of buf

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

Returns 0 on success.

— Function: int gnutls_x509_crq_get_challenge_password (gnutls_x509_crq_t crq, char * pass, size_t * sizeof_pass)

crq: should contain a gnutls_x509_crq_t structure

pass: will hold a null terminated password

sizeof_pass: Initially holds the size of pass.

This function will return the challenge password in the request.

Returns 0 on success.

— Function: int gnutls_x509_crq_get_dn_by_oid (gnutls_x509_crq_t crq, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf)

crq: should contain a gnutls_x509_crq_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.

raw_flag: If non zero returns the raw DER data of the DN part.

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of 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 zero, 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 gnutls_x509_dn_oid_known().

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

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crq_get_dn_oid (gnutls_x509_crq_t crq, int indx, void * oid, size_t * sizeof_oid)

crq: should contain a gnutls_x509_crq_t structure

indx: Specifies which DN OID to send. Use zero to get the first one.

oid: a pointer to a structure to hold the name (may be null)

sizeof_oid: initially holds the size of oid

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

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

Returns 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.

— Function: int gnutls_x509_crq_get_dn (gnutls_x509_crq_t crq, char * buf, size_t * sizeof_buf)

crq: should contain a gnutls_x509_crq_t structure

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of buf

This function will copy the name of the Certificate request subject in the provided buffer. The name will be in the form "C=xxxx,O=yyyy,CN=zzzz" as described in RFC2253. The output string will be ASCII or UTF-8 encoded, depending on the certificate data.

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

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crq_get_pk_algorithm (gnutls_x509_crq_t crq, unsigned int * bits)

crq: should contain a gnutls_x509_crq_t structure

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 a PKCS \10 certificate request.

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.

Returns a member of the gnutls_pk_algorithm_t enumeration on success, or a negative value on error.

— Function: int gnutls_x509_crq_get_version (gnutls_x509_crq_t crq)

crq: should contain a gnutls_x509_crq_t structure

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

Returns a negative value on error.

— Function: int gnutls_x509_crq_import (gnutls_x509_crq_t crq, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

crq: The structure to store the parsed certificate request.

data: The DER or PEM encoded certificate.

format: One of DER or PEM

This function will convert the given DER or PEM encoded Certificate to the native gnutls_x509_crq_t format. The output will be stored in cert.

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

Returns 0 on success.

— Function: int gnutls_x509_crq_init (gnutls_x509_crq_t * crq)

crq: The structure to be initialized

This function will initialize a PKCS10 certificate request structure.

Returns 0 on success.

— Function: int gnutls_x509_crq_set_attribute_by_oid (gnutls_x509_crq_t crq, const char * oid, void * buf, size_t sizeof_buf)

crq: should contain a gnutls_x509_crq_t structure

oid: holds an Object Identified in null terminated string

buf: a pointer to a structure that holds the attribute data

sizeof_buf: holds the size of buf

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

Returns 0 on success.

— Function: int gnutls_x509_crq_set_challenge_password (gnutls_x509_crq_t crq, const char * pass)

crq: should contain a gnutls_x509_crq_t structure

pass: holds a null terminated password

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

Returns 0 on success.

— Function: int gnutls_x509_crq_set_dn_by_oid (gnutls_x509_crq_t crq, const char * oid, unsigned int raw_flag, const void * data, unsigned int sizeof_data)

crq: should contain a gnutls_x509_crq_t structure

oid: holds an Object Identifier in a null terminated string

raw_flag: must be 0, or 1 if the data are DER encoded

data: a pointer to the input data

sizeof_data: holds the size of 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 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.

Returns 0 on success.

— Function: int gnutls_x509_crq_set_key (gnutls_x509_crq_t crq, gnutls_x509_privkey_t key)

crq: should contain a gnutls_x509_crq_t structure

key: holds a private key

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

Returns 0 on success.

— Function: int gnutls_x509_crq_set_version (gnutls_x509_crq_t crq, unsigned int version)

crq: should contain a gnutls_x509_crq_t structure

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.

Returns 0 on success.

— Function: int gnutls_x509_crq_sign2 (gnutls_x509_crq_t crq, gnutls_x509_privkey_t key, gnutls_digest_algorithm_t dig, unsigned int flags)

crq: should contain a gnutls_x509_crq_t structure

key: holds a private key

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

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 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.

Returns 0 on success.

— Function: int gnutls_x509_crq_sign (gnutls_x509_crq_t crq, gnutls_x509_privkey_t key)

crq: should contain a gnutls_x509_crq_t structure

key: holds a private key

This function is the same a gnutls_x509_crq_sign2() with no flags, and SHA1 as the hash algorithm.

Returns 0 on success.

— Function: int gnutls_x509_crt_check_hostname (gnutls_x509_crt_t cert, const char * hostname)

cert: should contain an gnutls_x509_crt_t structure

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 subject alternative name PKIX extension.

Returns non zero on success, and zero on failure.

— Function: int gnutls_x509_crt_check_issuer (gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer)

cert: is the certificate to be checked

issuer: is the certificate of a possible issuer

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

A negative value is returned in case of an error.

— Function: int gnutls_x509_crt_check_revocation (gnutls_x509_crt_t cert, const gnutls_x509_crl_t * crl_list, int crl_list_length)

cert: should contain a gnutls_x509_crt_t structure

crl_list: should contain a list of gnutls_x509_crl_t structures

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.

Returns 0 if the certificate is NOT revoked, and 1 if it is. A negative value is returned on error.

— Function: int gnutls_x509_crt_cpy_crl_dist_points (gnutls_x509_crt_t dst, gnutls_x509_crt_t src)

dst: should contain a gnutls_x509_crt_t structure

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.

Returns 0 on success.

— Function: void gnutls_x509_crt_deinit (gnutls_x509_crt_t cert)

cert: The structure to be initialized

This function will deinitialize a CRL structure.

— Function: int gnutls_x509_crt_export (gnutls_x509_crt_t cert, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

cert: Holds the certificate

format: the format of output params. One of PEM or DER.

output_data: will contain a certificate PEM or DER encoded

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".

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: time_t gnutls_x509_crt_get_activation_time (gnutls_x509_crt_t cert)

cert: should contain a gnutls_x509_crt_t structure

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

Returns (time_t)-1 on error.

— Function: int gnutls_x509_crt_get_authority_key_id (gnutls_x509_crt_t cert, void * ret, size_t * ret_size, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

critical: will be non zero 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.

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_crt_get_ca_status (gnutls_x509_crt_t cert, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

critical: will be non zero 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 zero if the certificate does not have CA flag set.

A negative value may be returned in case of parsing error. If the certificate does not contain the basicConstraints extension GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_x509_crt_get_crl_dist_points (gnutls_x509_crt_t cert, unsigned int seq, void * ret, size_t * ret_size, unsigned int * reason_flags, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

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

ret: is the place where the distribution point will be copied to

ret_size: holds the size of ret.

reason_flags: Revocation reasons flags.

critical: will be non zero if the extension is marked as critical (may be null)

This function will return the CRL distribution points (2.5.29.31), contained in the given certificate.

reason_flags should be an ORed sequence of GNUTLS_CRL_REASON_UNUSED, GNUTLS_CRL_REASON_KEY_COMPROMISE, GNUTLS_CRL_REASON_CA_COMPROMISE, GNUTLS_CRL_REASON_AFFILIATION_CHANGED, GNUTLS_CRL_REASON_SUPERSEEDED, GNUTLS_CRL_REASON_CESSATION_OF_OPERATION, GNUTLS_CRL_REASON_CERTIFICATE_HOLD, GNUTLS_CRL_REASON_PRIVILEGE_WITHDRAWN, GNUTLS_CRL_REASON_AA_COMPROMISE, or zero for all possible reasons.

This is specified in X509v3 Certificate Extensions. GNUTLS will return the distribution point type, or a negative error code on error.

Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates &ret_size if &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 gnutls_x509_subject_alt_name_t.

If the certificate does not have an Alternative name with the specified sequence number then returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;

— Function: int gnutls_x509_crt_get_dn_by_oid (gnutls_x509_crt_t cert, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf)

cert: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.

raw_flag: If non zero returns the raw DER data of the DN part.

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

sizeof_buf: initially holds the size of 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 RFC2253. 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 zero, 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 gnutls_x509_dn_oid_known().

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

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crt_get_dn_oid (gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid)

cert: should contain a gnutls_x509_crt_t structure

indx: This specifies which OID to return. Use zero to get the first one.

oid: a pointer to a buffer to hold the OID (may be null)

sizeof_oid: initially holds the size of oid

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

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

Returns 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.

— Function: int gnutls_x509_crt_get_dn (gnutls_x509_crt_t cert, char * buf, size_t * sizeof_buf)

cert: should contain a gnutls_x509_crt_t structure

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of 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 RFC2253. The output string will be ASCII or UTF-8 encoded, depending on the certificate data.

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

Returns 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. On success 0 is returned.

— Function: time_t gnutls_x509_crt_get_expiration_time (gnutls_x509_crt_t cert)

cert: should contain a gnutls_x509_crt_t structure

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

Returns (time_t)-1 on error.

— Function: int gnutls_x509_crt_get_extension_by_oid (gnutls_x509_crt_t cert, const char * oid, int indx, void * buf, size_t * sizeof_buf, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the extensions, this specifies which to send. Use zero to get the first one.

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of buf

critical: will be non zero 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.

A negative value may be returned in case of parsing error. If the certificate does not contain the specified extension GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_x509_crt_get_extension_oid (gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid)

cert: should contain a gnutls_x509_crt_t structure

indx: Specifies which extension OID to send. Use zero to get the first one.

oid: a pointer to a structure to hold the OID (may be null)

sizeof_oid: initially holds the size of 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.

A negative value may be returned in case of parsing error. If your have reached the last extension available GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_x509_crt_get_fingerprint (gnutls_x509_crt_t cert, gnutls_digest_algorithm_t algo, void * buf, size_t * sizeof_buf)

cert: should contain a gnutls_x509_crt_t structure

algo: is a digest algorithm

buf: a pointer to a structure to hold the fingerprint (may be null)

sizeof_buf: initially holds the size of 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.

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crt_get_issuer_dn_by_oid (gnutls_x509_crt_t cert, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf)

cert: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identified in null terminated string

indx: In case multiple same OIDs exist in the RDN, this specifies which to send. Use zero to get the first one.

raw_flag: If non zero returns the raw DER data of the DN part.

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of 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 RFC2253. 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 zero, 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 gnutls_x509_dn_oid_known().

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

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crt_get_issuer_dn_oid (gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid)

cert: should contain a gnutls_x509_crt_t structure

indx: This specifies which OID to return. Use zero to get the first one.

oid: a pointer to a buffer to hold the OID (may be null)

sizeof_oid: initially holds the size of oid

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

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

Returns 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.

— Function: int gnutls_x509_crt_get_issuer_dn (gnutls_x509_crt_t cert, char * buf, size_t * sizeof_buf)

cert: should contain a gnutls_x509_crt_t structure

buf: a pointer to a structure to hold the name (may be null)

sizeof_buf: initially holds the size of 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 RFC2253. The output string will be ASCII or UTF-8 encoded, depending on the certificate data.

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

Returns 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. On success 0 is returned.

— Function: int gnutls_x509_crt_get_key_id (gnutls_x509_crt_t crt, unsigned int flags, unsigned char * output_data, size_t * output_data_size)

crt: Holds the certificate

flags: should be 0 for now

output_data: will contain the key ID

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.

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_crt_get_key_purpose_oid (gnutls_x509_crt_t cert, int indx, void * oid, size_t * sizeof_oid, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

indx: This specifies which OID to return. Use zero to get the first one.

oid: a pointer to a buffer to hold the OID (may be null)

sizeof_oid: initially holds the size of oid

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 oid is null then only the size will be filled.

Returns 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.

— Function: int gnutls_x509_crt_get_key_usage (gnutls_x509_crt_t cert, unsigned int * key_usage, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

key_usage: where the key usage bits will be stored

critical: will be non zero 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: GNUTLS_KEY_DIGITAL_SIGNATURE, GNUTLS_KEY_NON_REPUDIATION, GNUTLS_KEY_KEY_ENCIPHERMENT, GNUTLS_KEY_DATA_ENCIPHERMENT, GNUTLS_KEY_KEY_AGREEMENT, GNUTLS_KEY_KEY_CERT_SIGN, GNUTLS_KEY_CRL_SIGN, GNUTLS_KEY_ENCIPHER_ONLY, GNUTLS_KEY_DECIPHER_ONLY.

A negative value may be returned in case of parsing error. If the certificate does not contain the keyUsage extension GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE will be returned.

— Function: int gnutls_x509_crt_get_pk_algorithm (gnutls_x509_crt_t cert, unsigned int * bits)

cert: should contain a gnutls_x509_crt_t structure

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.

Returns a member of the gnutls_pk_algorithm_t enumeration on success, or a negative value on error.

— Function: int gnutls_x509_crt_get_pk_dsa_raw (gnutls_x509_crt_t crt, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * g, gnutls_datum_t * y)

crt: Holds the certificate

p: will hold the p

q: will hold the q

g: will hold the g

y: will hold the y

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

— Function: int gnutls_x509_crt_get_pk_rsa_raw (gnutls_x509_crt_t crt, gnutls_datum_t * m, gnutls_datum_t * e)

crt: Holds the certificate

m: will hold the modulus

e: will hold the public exponent

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

— Function: int gnutls_x509_crt_get_serial (gnutls_x509_crt_t cert, void * result, size_t * result_size)

cert: should contain a gnutls_x509_crt_t structure

result: The place where the serial number will be copied

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 opaque.

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_crt_get_signature_algorithm (gnutls_x509_crt_t cert)

cert: should contain a gnutls_x509_crt_t structure

This function will return a value of the gnutls_sign_algorithm_t enumeration that is the signature algorithm.

Returns a negative value on error.

— Function: int gnutls_x509_crt_get_subject_alt_name (gnutls_x509_crt_t cert, unsigned int seq, void * ret, size_t * ret_size, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

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

ret: is the place where the alternative name will be copied to

ret_size: holds the size of ret.

critical: will be non zero if the extension is marked as critical (may be null)

This function will return the alternative names, contained in the given certificate.

This is specified in X509v3 Certificate Extensions. GNUTLS will return the Alternative name (2.5.29.17), or a negative error code.

Returns GNUTLS_E_SHORT_MEMORY_BUFFER if &ret_size is not enough to hold the alternative name. In that case &ret_size will be updated. If everything was ok the type of alternative name is returned. The type is one of the enumerated gnutls_x509_subject_alt_name_t.

If the certificate does not have an Alternative name with the specified sequence number then returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;

— Function: int gnutls_x509_crt_get_subject_key_id (gnutls_x509_crt_t cert, void * ret, size_t * ret_size, unsigned int * critical)

cert: should contain a gnutls_x509_crt_t structure

critical: will be non zero 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).

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_crt_get_version (gnutls_x509_crt_t cert)

cert: should contain a gnutls_x509_crt_t structure

This function will return the version of the specified Certificate.

Returns a negative value on error.

— Function: int gnutls_x509_crt_import (gnutls_x509_crt_t cert, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

cert: The structure to store the parsed certificate.

data: The DER or PEM encoded certificate.

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 cert.

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

Returns 0 on success.

— Function: int gnutls_x509_crt_init (gnutls_x509_crt_t * cert)

cert: The structure to be initialized

This function will initialize an X.509 certificate structure.

Returns 0 on success.

— Function: int gnutls_x509_crt_list_import (gnutls_x509_crt_t * certs, unsigned int * cert_max, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, unsigned int flags)

certs: The structures to store the parsed certificate. Must not be initialized.

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

data: The PEM encoded certificate.

format: One of DER or PEM.

flags: must be zero 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 certs. They will be automatically initialized.

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

Returns the number of certificates read or a negative error value.

— Function: int gnutls_x509_crt_list_verify (const gnutls_x509_crt_t * cert_list, int cert_list_length, const gnutls_x509_crt_t * CA_list, int CA_list_length, const gnutls_x509_crl_t * CRL_list, int CRL_list_length, unsigned int flags, unsigned int * verify)

cert_list: is the certificate list to be verified

cert_list_length: holds the number of certificate in cert_list

CA_list: is the CA list which will be used in verification

CA_list_length: holds the number of CA certificate in CA_list

CRL_list: holds a list of CRLs.

CRL_list_length: the length of CRL list.

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

verify: will hold the certificate verification output.

This function will try to verify the given certificate list and return its status. Note that expiration and activation dates are not checked by this function, you should check them using the appropriate functions.

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 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 gnutls_x509_crt_verify() per list element.

GNUTLS_CERT_INVALID: the certificate chain is not valid.

GNUTLS_CERT_REVOKED: a certificate in the chain has been revoked.

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_crt_set_activation_time (gnutls_x509_crt_t cert, time_t act_time)

cert: should contain a gnutls_x509_crt_t structure

act_time: The actual time

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

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crt_set_authority_key_id (gnutls_x509_crt_t cert, const void * id, size_t id_size)

cert: should contain a gnutls_x509_crt_t structure

id: The key ID

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.

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crt_set_ca_status (gnutls_x509_crt_t crt, unsigned int ca)

crt: should contain a gnutls_x509_crt_t structure

ca: true(1) or false(0). Depending on the Certificate authority status.

This function will set the basicConstraints certificate extension.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_crl_dist_points (gnutls_x509_crt_t crt, gnutls_x509_subject_alt_name_t type, const void * data_string, unsigned int reason_flags)

crt: should contain a gnutls_x509_crt_t structure

type: is one of the gnutls_x509_subject_alt_name_t enumerations

data_string: The data to be set

reason_flags: revocation reasons

This function will set the CRL distribution points certificate extension.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_crq (gnutls_x509_crt_t crt, gnutls_x509_crq_t crq)

crt: should contain a gnutls_x509_crt_t structure

crq: holds a certificate request

This function will set the name and public parameters from the given certificate request to the certificate. Only RSA keys are currently supported.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_dn_by_oid (gnutls_x509_crt_t crt, const char * oid, unsigned int raw_flag, const void * name, unsigned int sizeof_name)

crt: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identifier in a null terminated string

raw_flag: must be 0, or 1 if the data are DER encoded

name: a pointer to the name

sizeof_name: holds the size of 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 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.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_expiration_time (gnutls_x509_crt_t cert, time_t exp_time)

cert: should contain a gnutls_x509_crt_t structure

exp_time: The actual time

This function will set the time this Certificate will expire.

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crt_set_extension_by_oid (gnutls_x509_crt_t crt, const char * oid, const void * buf, size_t sizeof_buf, unsigned int critical)

crt: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identified in null terminated string

buf: a pointer to a DER encoded data

sizeof_buf: holds the size of buf

critical: should be non zero 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.

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_crt_set_issuer_dn_by_oid (gnutls_x509_crt_t crt, const char * oid, unsigned int raw_flag, const void * name, unsigned int sizeof_name)

crt: should contain a gnutls_x509_crt_t structure

oid: holds an Object Identifier in a null terminated string

raw_flag: must be 0, or 1 if the data are DER encoded

name: a pointer to the name

sizeof_name: holds the size of 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 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.

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.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_key_purpose_oid (gnutls_x509_crt_t cert, const void * oid, unsigned int critical)

cert: should contain a gnutls_x509_crt_t structure

oid: a pointer to a null terminated string that holds the OID

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.

On success 0 is returned.

— Function: int gnutls_x509_crt_set_key_usage (gnutls_x509_crt_t crt, unsigned int usage)

crt: should contain a gnutls_x509_crt_t structure

usage: an ORed sequence of the GNUTLS_KEY_* elements.

This function will set the keyUsage certificate extension.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_key (gnutls_x509_crt_t crt, gnutls_x509_privkey_t key)

crt: should contain a gnutls_x509_crt_t structure

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.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_serial (gnutls_x509_crt_t cert, const void * serial, size_t serial_size)

cert: should contain a gnutls_x509_crt_t structure

serial: The serial number

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 opaque.

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crt_set_subject_alternative_name (gnutls_x509_crt_t crt, gnutls_x509_subject_alt_name_t type, const char * data_string)

crt: should contain a gnutls_x509_crt_t structure

type: is one of the gnutls_x509_subject_alt_name_t enumerations

data_string: The data to be set

This function will set the subject alternative name certificate extension.

Returns 0 on success.

— Function: int gnutls_x509_crt_set_subject_key_id (gnutls_x509_crt_t cert, const void * id, size_t id_size)

cert: should contain a gnutls_x509_crt_t structure

id: The key ID

id_size: Holds the size of the serial field.

This function will set the X.509 certificate's subject key ID extension.

Returns 0 on success, or a negative value in case of an error.

— Function: int gnutls_x509_crt_set_version (gnutls_x509_crt_t crt, unsigned int version)

crt: should contain a gnutls_x509_crt_t structure

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.

Returns 0 on success.

— Function: int gnutls_x509_crt_sign2 (gnutls_x509_crt_t crt, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key, gnutls_digest_algorithm_t dig, unsigned int flags)

crt: should contain a gnutls_x509_crt_t structure

issuer: is the certificate of the certificate issuer

issuer_key: holds the issuer's private key

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

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.

Returns 0 on success.

— Function: int gnutls_x509_crt_sign (gnutls_x509_crt_t crt, gnutls_x509_crt_t issuer, gnutls_x509_privkey_t issuer_key)

crt: should contain a gnutls_x509_crt_t structure

issuer: is the certificate of the certificate issuer

issuer_key: holds the issuer's private key

This function is the same a gnutls_x509_crt_sign2() with no flags, and SHA1 as the hash algorithm.

Returns 0 on success.

— Function: int gnutls_x509_crt_to_xml (gnutls_x509_crt_t cert, gnutls_datum_t * res, int detail)

cert: should contain a gnutls_x509_crt_t structure

res: The datum that will hold the result

detail: The detail level (must be GNUTLS_XML_SHOW_ALL or GNUTLS_XML_NORMAL)

This function will return the XML structures of the given X.509 certificate. The XML structures are allocated internally (with malloc) and stored into res.

NOTE: This function is currently not implemented. See the NEWS entry for version 1.3.5.

Returns a negative error code in case of an error.

— Function: int gnutls_x509_crt_verify_data (gnutls_x509_crt_t crt, unsigned int flags, const gnutls_datum_t * data, const gnutls_datum_t * signature)

crt: Holds the certificate

flags: should be 0 for now

data: holds the data to be signed

signature: contains the signature

This function will verify the given signed data, using the parameters from the certificate.

In case of a verification failure 0 is returned, and 1 on success.

— Function: int gnutls_x509_crt_verify (gnutls_x509_crt_t cert, const gnutls_x509_crt_t * CA_list, int CA_list_length, unsigned int flags, unsigned int * verify)

cert: is the certificate to be verified

CA_list: is one certificate that is considered to be trusted one

CA_list_length: holds the number of CA certificate in CA_list

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

verify: will hold the certificate verification output.

This function will try to verify the given certificate and return its status. The verification output in this functions cannot be GNUTLS_CERT_NOT_VALID.

Returns 0 on success and a negative value in case of an error.

— Function: int gnutls_x509_dn_oid_known (const char * oid)

oid: holds an Object Identifier in a null terminated string

This function will inform about known DN OIDs. This is useful since functions like 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.

Returns 1 on known OIDs and 0 otherwise.

— Function: int gnutls_x509_privkey_cpy (gnutls_x509_privkey_t dst, gnutls_x509_privkey_t src)

dst: The destination key, which should be initialized.

src: The source key

This function will copy a private key from source to destination key.

— Function: void gnutls_x509_privkey_deinit (gnutls_x509_privkey_t key)

key: The structure to be initialized

This function will deinitialize a private key structure.

— Function: int gnutls_x509_privkey_export_dsa_raw (gnutls_x509_privkey_t key, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * g, gnutls_datum_t * y, gnutls_datum_t * x)

p: will hold the p

q: will hold the q

g: will hold the g

y: will hold the y

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 gnutls_malloc() and will be stored in the appropriate datum.

— Function: int gnutls_x509_privkey_export_pkcs8 (gnutls_x509_privkey_t key, gnutls_x509_crt_fmt_t format, const char * password, unsigned int flags, void * output_data, size_t * output_data_size)

key: Holds the key

format: the format of output params. One of PEM or DER.

password: the password that will be used to encrypt the key.

flags: an ORed sequence of gnutls_pkcs_encrypt_flags_t

output_data: will contain a private key PEM or DER encoded

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. Currently only RSA keys can be exported since there is no documented standard for other keys. If the flags do not specify the encryption cipher, then the default 3DES (PBES2) will be used.

The 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.

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_privkey_export_rsa_raw (gnutls_x509_privkey_t key, gnutls_datum_t * m, gnutls_datum_t * e, gnutls_datum_t * d, gnutls_datum_t * p, gnutls_datum_t * q, gnutls_datum_t * u)

key: a structure that holds the rsa parameters

m: will hold the modulus

e: will hold the public exponent

d: will hold the private exponent

p: will hold the first prime (p)

q: will hold the second prime (q)

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 gnutls_malloc() and will be stored in the appropriate datum.

— Function: int gnutls_x509_privkey_export (gnutls_x509_privkey_t key, gnutls_x509_crt_fmt_t format, void * output_data, size_t * output_data_size)

key: Holds the key

format: the format of output params. One of PEM or DER.

output_data: will contain a private key PEM or DER encoded

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 *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 RSA PRIVATE KEY".

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_privkey_fix (gnutls_x509_privkey_t key)

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.

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_privkey_generate (gnutls_x509_privkey_t key, gnutls_pk_algorithm_t algo, unsigned int bits, unsigned int flags)

key: should contain a gnutls_x509_privkey_t structure

algo: is one of RSA or DSA.

bits: the size of the modulus

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.

Returns 0 on success or a negative value on error.

— Function: int gnutls_x509_privkey_get_key_id (gnutls_x509_privkey_t key, unsigned int flags, unsigned char * output_data, size_t * output_data_size)

key: Holds the key

flags: should be 0 for now

output_data: will contain the key ID

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 *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.

Return value: In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_privkey_get_pk_algorithm (gnutls_x509_privkey_t key)

key: should contain a gnutls_x509_privkey_t structure

This function will return the public key algorithm of a private key.

Returns a member of the gnutls_pk_algorithm_t enumeration on success, or a negative value on error.

— Function: int gnutls_x509_privkey_import_dsa_raw (gnutls_x509_privkey_t key, const gnutls_datum_t * p, const gnutls_datum_t * q, const gnutls_datum_t * g, const gnutls_datum_t * y, const gnutls_datum_t * x)

key: The structure to store the parsed key

p: holds the p

q: holds the q

g: holds the g

y: holds the y

x: holds the x

This function will convert the given DSA raw parameters to the native gnutls_x509_privkey_t format. The output will be stored in key.

— Function: int gnutls_x509_privkey_import_pkcs8 (gnutls_x509_privkey_t key, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format, const char * password, unsigned int flags)

key: The structure to store the parsed key

data: The DER or PEM encoded key.

format: One of DER or PEM

password: the password to decrypt the key (if it is encrypted).

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 key. Currently only RSA keys can be imported, and flags can only be used to indicate an unencrypted key.

The 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.

Returns 0 on success.

— Function: int gnutls_x509_privkey_import_rsa_raw (gnutls_x509_privkey_t key, const gnutls_datum_t * m, const gnutls_datum_t * e, const gnutls_datum_t * d, const gnutls_datum_t * p, const gnutls_datum_t * q, const gnutls_datum_t * u)

key: The structure to store the parsed key

m: holds the modulus

e: holds the public exponent

d: holds the private exponent

p: holds the first prime (p)

q: holds the second prime (q)

u: holds the coefficient

This function will convert the given RSA raw parameters to the native gnutls_x509_privkey_t format. The output will be stored in key.

— Function: int gnutls_x509_privkey_import (gnutls_x509_privkey_t key, const gnutls_datum_t * data, gnutls_x509_crt_fmt_t format)

key: The structure to store the parsed key

data: The DER or PEM encoded certificate.

format: One of DER or PEM

This function will convert the given DER or PEM encoded key to the native gnutls_x509_privkey_t format. The output will be stored in key .

If the key is PEM encoded it should have a header of "RSA PRIVATE KEY", or "DSA PRIVATE KEY".

Returns 0 on success.

— Function: int gnutls_x509_privkey_init (gnutls_x509_privkey_t * key)

key: The structure to be initialized

This function will initialize an private key structure.

Returns 0 on success.

— Function: int gnutls_x509_privkey_sign_data (gnutls_x509_privkey_t key, gnutls_digest_algorithm_t digest, unsigned int flags, const gnutls_datum_t * data, void * signature, size_t * signature_size)

key: Holds the key

digest: should be MD5 or SHA1

flags: should be 0 for now

data: holds the data to be signed

signature: will contain the signature

signature_size: holds the size of signature (and will be replaced by the new size)

This function will sign the given data using a signature algorithm supported by the private key. Signature algorithms are always used together with a hash functions. Different hash functions may be used for the RSA algorithm, but only SHA-1 for the DSA keys.

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

In case of failure a negative value will be returned, and 0 on success.

— Function: int gnutls_x509_privkey_verify_data (gnutls_x509_privkey_t key, unsigned int flags, const gnutls_datum_t * data, const gnutls_datum_t * signature)

key: Holds the key

flags: should be 0 for now

data: holds the data to be signed

signature: contains the signature

This function will verify the given signed data, using the parameters in the private key.

In case of a verification failure 0 is returned, and 1 on success.

— Function: int gnutls_x509_rdn_get_by_oid (const gnutls_datum_t * idn, const char * oid, int indx, unsigned int raw_flag, void * buf, size_t * sizeof_buf)

idn: should contain a DER encoded RDN sequence

oid: an Object Identifier

indx: In case multiple same OIDs exist in the RDN indicates which to send. Use 0 for the first one.

raw_flag: If non zero then the raw DER data are returned.

buf: a pointer to a structure to hold the peer's name

sizeof_buf: holds the size of 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 RFC2253.

Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates *sizeof_buf if the provided buffer is not long enough, and 0 on success.

— Function: int gnutls_x509_rdn_get_oid (const gnutls_datum_t * idn, int indx, void * buf, size_t * sizeof_buf)

idn: should contain a DER encoded RDN sequence

indx: Indicates which OID to return. Use 0 for the first one.

This function will return the specified Object identifier, of the RDN sequence.

Returns GNUTLS_E_SHORT_MEMORY_BUFFER and updates *sizeof_buf if the provided buffer is not long enough, and 0 on success.

— Function: int gnutls_x509_rdn_get (const gnutls_datum_t * idn, char * buf, size_t * sizeof_buf)

idn: should contain a DER encoded RDN sequence

buf: a pointer to a structure to hold the peer's name

sizeof_buf: holds the size of 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 RFC2253.

If the provided buffer is not long enough, returns GNUTLS_E_SHORT_MEMORY_BUFFER and *sizeof_buf will be updated. On success 0 is returned.