x509: GnuTLS API Reference Manual

## x509 x509 |

## Functions

int | gnutls_x509_crt_init ()
void | gnutls_x509_crt_deinit ()
void | gnutls_x509_crt_set_flags ()
unsigned | gnutls_x509_crt_equals ()
unsigned | gnutls_x509_crt_equals2 ()
int | gnutls_x509_crt_import ()
int | gnutls_x509_crt_list_import2 ()
int | gnutls_x509_crt_list_import ()
int | gnutls_x509_crt_import_url ()
int | gnutls_x509_crt_list_import_url ()
int | gnutls_x509_crt_export ()
int | gnutls_x509_crt_export2 ()
int | gnutls_x509_crt_get_private_key_usage_period ()
int | gnutls_x509_crt_get_issuer_dn ()
int | gnutls_x509_crt_get_issuer_dn2 ()
int | gnutls_x509_crt_get_issuer_dn3 ()
int | gnutls_x509_crt_get_issuer_dn_oid ()
int | gnutls_x509_crt_get_issuer_dn_by_oid ()
int | gnutls_x509_crt_get_dn ()
int | gnutls_x509_crt_get_dn2 ()
int | gnutls_x509_crt_get_dn3 ()
int | gnutls_x509_crt_get_dn_oid ()
int | gnutls_x509_crt_get_dn_by_oid ()
unsigned | gnutls_x509_crt_check_hostname ()
unsigned | gnutls_x509_crt_check_hostname2 ()
unsigned | gnutls_x509_crt_check_email ()
unsigned | gnutls_x509_crt_check_ip ()
int | gnutls_x509_crt_get_signature_algorithm ()
int | gnutls_x509_crt_get_signature ()
int | gnutls_x509_crt_get_version ()
int | gnutls_x509_crt_get_pk_oid ()
int | gnutls_x509_crt_get_signature_oid ()
int | gnutls_x509_crt_get_key_id ()
int | gnutls_x509_crt_set_private_key_usage_period ()
int | gnutls_x509_crt_set_authority_key_id ()
int | gnutls_x509_crt_get_authority_key_id ()
int | gnutls_x509_crt_get_authority_key_gn_serial ()
int | gnutls_x509_crt_get_subject_key_id ()
int | gnutls_x509_crt_get_subject_unique_id ()
int | gnutls_x509_crt_get_issuer_unique_id ()
void | gnutls_x509_crt_set_pin_function ()
int | gnutls_x509_crt_get_authority_info_access ()
unsigned | gnutls_x509_name_constraints_check ()
unsigned | gnutls_x509_name_constraints_check_crt ()
int | gnutls_x509_name_constraints_init ()
void | gnutls_x509_name_constraints_deinit ()
int | gnutls_x509_crt_get_name_constraints ()
int | gnutls_x509_name_constraints_add_permitted ()
int | gnutls_x509_name_constraints_add_excluded ()
int | gnutls_x509_crt_set_name_constraints ()
int | gnutls_x509_name_constraints_get_permitted ()
int | gnutls_x509_name_constraints_get_excluded ()
int | gnutls_x509_cidr_to_rfc5280 ()
int | gnutls_x509_crt_get_crl_dist_points ()
int | gnutls_x509_crt_set_crl_dist_points2 ()
int | gnutls_x509_crt_set_crl_dist_points ()
int | gnutls_x509_crt_cpy_crl_dist_points ()
int | gnutls_x509_crl_sign ()
int | gnutls_x509_crl_sign2 ()
time_t | gnutls_x509_crt_get_activation_time ()
time_t | gnutls_x509_crt_get_expiration_time ()
int | gnutls_x509_crt_get_serial ()
int | gnutls_x509_spki_init ()
void | gnutls_x509_spki_deinit ()
int | gnutls_x509_spki_get_rsa_pss_params ()
void | gnutls_x509_spki_set_rsa_pss_params ()
int | gnutls_x509_crt_get_pk_algorithm ()
int | gnutls_x509_crt_set_spki ()
int | gnutls_x509_crt_get_spki ()
int | gnutls_x509_crt_get_pk_rsa_raw ()
int | gnutls_x509_crt_get_pk_dsa_raw ()
int | gnutls_x509_crt_get_pk_ecc_raw ()
int | gnutls_x509_crt_get_pk_gost_raw ()
int | gnutls_x509_crt_get_subject_alt_name ()
int | gnutls_x509_crt_get_subject_alt_name2 ()
int | gnutls_x509_crt_get_subject_alt_othername_oid ()
int | gnutls_x509_crt_get_issuer_alt_name ()
int | gnutls_x509_crt_get_issuer_alt_name2 ()
int | gnutls_x509_crt_get_issuer_alt_othername_oid ()
int | gnutls_x509_crt_get_ca_status ()
int | gnutls_x509_crt_get_basic_constraints ()
int | gnutls_x509_crt_get_key_usage ()
int | gnutls_x509_crt_set_key_usage ()
int | gnutls_x509_crt_set_authority_info_access ()
int | gnutls_x509_crt_get_inhibit_anypolicy ()
int | gnutls_x509_crt_set_inhibit_anypolicy ()
int | gnutls_x509_crt_get_proxy ()
int | gnutls_x509_tlsfeatures_init ()
void | gnutls_x509_tlsfeatures_deinit ()
int | gnutls_x509_tlsfeatures_get ()
int | gnutls_x509_crt_set_tlsfeatures ()
int | gnutls_x509_crt_get_tlsfeatures ()
unsigned | gnutls_x509_tlsfeatures_check_crt ()
void | gnutls_x509_policy_release ()
int | gnutls_x509_crt_get_policy ()
int | gnutls_x509_crt_set_policy ()
int | gnutls_x509_dn_oid_known ()
const char * | gnutls_x509_dn_oid_name ()
int | gnutls_x509_crt_get_extension_oid ()
int | gnutls_x509_crt_get_extension_by_oid ()
int | gnutls_x509_crq_get_signature_algorithm ()
int | gnutls_x509_crq_get_extension_by_oid2 ()
int | gnutls_x509_crt_get_extension_info ()
int | gnutls_x509_crt_get_extension_data ()
int | gnutls_x509_crt_get_extension_data2 ()
int | gnutls_x509_crt_set_extension_by_oid ()
int | gnutls_x509_crt_set_dn ()
int | gnutls_x509_crt_set_dn_by_oid ()
int | gnutls_x509_crt_set_issuer_dn_by_oid ()
int | gnutls_x509_crt_set_issuer_dn ()
int | gnutls_x509_crt_set_version ()
int | gnutls_x509_crt_set_key ()
int | gnutls_x509_crt_set_ca_status ()
int | gnutls_x509_crt_set_basic_constraints ()
int | gnutls_x509_crt_set_subject_unique_id ()
int | gnutls_x509_crt_set_issuer_unique_id ()
int | gnutls_x509_crt_set_subject_alternative_name ()
int | gnutls_x509_crt_set_subject_alt_name ()
int | gnutls_x509_crt_set_subject_alt_othername ()
int | gnutls_x509_crt_set_issuer_alt_name ()
int | gnutls_x509_crt_set_issuer_alt_othername ()
int | gnutls_x509_crt_sign ()
int | gnutls_x509_crt_sign2 ()
int | gnutls_x509_crt_set_activation_time ()
int | gnutls_x509_crt_set_expiration_time ()
int | gnutls_x509_crt_set_serial ()
int | gnutls_x509_crt_set_subject_key_id ()
int | gnutls_x509_crt_set_proxy_dn ()
int | gnutls_x509_crt_set_proxy ()
int | gnutls_x509_crt_print ()
int | gnutls_x509_crl_print ()
int | gnutls_x509_crt_get_raw_issuer_dn ()
int | gnutls_x509_crt_get_raw_dn ()
int | gnutls_x509_rdn_get ()
int | gnutls_x509_rdn_get2 ()
int | gnutls_x509_rdn_get_oid ()
int | gnutls_x509_rdn_get_by_oid ()
int | gnutls_x509_crt_get_subject ()
int | gnutls_x509_crt_get_issuer ()
int | gnutls_x509_dn_get_rdn_ava ()
int | gnutls_x509_dn_get_str ()
int | gnutls_x509_dn_get_str2 ()
int | gnutls_x509_dn_set_str ()
int | gnutls_x509_dn_init ()
int | gnutls_x509_dn_import ()
int | gnutls_x509_dn_export ()
int | gnutls_x509_dn_export2 ()
void | gnutls_x509_dn_deinit ()
int | gnutls_x509_crl_init ()
void | gnutls_x509_crl_deinit ()
int | gnutls_x509_crl_import ()
int | gnutls_x509_crl_export ()
int | gnutls_x509_crl_export2 ()
int | gnutls_x509_crl_get_raw_issuer_dn ()
int | gnutls_x509_crl_get_issuer_dn ()
int | gnutls_x509_crl_get_issuer_dn2 ()
int | gnutls_x509_crl_get_issuer_dn3 ()
int | gnutls_x509_crl_get_issuer_dn_by_oid ()
int | gnutls_x509_crl_get_dn_oid ()
int | gnutls_x509_crl_get_signature_algorithm ()
int | gnutls_x509_crl_get_signature ()
int | gnutls_x509_crl_get_version ()
int | gnutls_x509_crl_get_signature_oid ()
time_t | gnutls_x509_crl_get_this_update ()
time_t | gnutls_x509_crl_get_next_update ()
int | gnutls_x509_crl_get_crt_count ()
int | gnutls_x509_crl_get_crt_serial ()
int | gnutls_x509_crl_iter_crt_serial ()
void | gnutls_x509_crl_iter_deinit ()
unsigned | gnutls_x509_crl_check_issuer ()
int | gnutls_x509_crl_list_import2 ()
int | gnutls_x509_crl_list_import ()
int | gnutls_x509_crl_set_version ()
int | gnutls_x509_crl_set_this_update ()
int | gnutls_x509_crl_set_next_update ()
int | gnutls_x509_crl_set_crt_serial ()
int | gnutls_x509_crl_set_crt ()
int | gnutls_x509_crl_get_authority_key_id ()
int | gnutls_x509_crl_get_authority_key_gn_serial ()
int | gnutls_x509_crl_get_number ()
int | gnutls_x509_crl_get_extension_oid ()
int | gnutls_x509_crl_get_extension_info ()
int | gnutls_x509_crl_get_extension_data ()
int | gnutls_x509_crl_get_extension_data2 ()
int | gnutls_x509_crl_set_authority_key_id ()
int | gnutls_x509_crl_set_number ()
#define | GNUTLS_PROFILE_TO_VFLAGS()
#define | GNUTLS_VFLAGS_TO_PROFILE()
const char * | gnutls_certificate_verification_profile_get_name ()
int | gnutls_x509_crt_list_verify ()
int | gnutls_x509_crt_verify ()
int | gnutls_x509_crl_verify ()
int | gnutls_x509_crt_verify_data2 ()
int | gnutls_x509_crt_check_revocation ()
int | gnutls_x509_crt_get_fingerprint ()
int | gnutls_x509_crt_get_key_purpose_oid ()
int | gnutls_x509_crt_set_key_purpose_oid ()
unsigned | gnutls_x509_crt_check_key_purpose ()
#define | GNUTLS_PKCS_CIPHER_MASK()
const char * | gnutls_pkcs_schema_get_name ()
const char * | gnutls_pkcs_schema_get_oid ()
int | gnutls_x509_privkey_init ()
void | gnutls_x509_privkey_deinit ()
gnutls_sec_param_t | gnutls_x509_privkey_sec_param ()
void | gnutls_x509_privkey_set_pin_function ()
int | gnutls_x509_privkey_cpy ()
int | gnutls_x509_privkey_import ()
int | gnutls_x509_privkey_import_pkcs8 ()
int | gnutls_x509_privkey_import_openssl ()
int | gnutls_pkcs8_info ()
int | gnutls_x509_privkey_import2 ()
int | gnutls_x509_privkey_import_rsa_raw ()
int | gnutls_x509_privkey_import_rsa_raw2 ()
int | gnutls_x509_privkey_import_ecc_raw ()
int | gnutls_x509_privkey_import_gost_raw ()
int | gnutls_x509_privkey_fix ()
int | gnutls_x509_privkey_export_dsa_raw ()
int | gnutls_x509_privkey_import_dsa_raw ()
int | gnutls_x509_privkey_import_dh_raw ()
int | gnutls_x509_privkey_get_pk_algorithm ()
int | gnutls_x509_privkey_get_pk_algorithm2 ()
int | gnutls_x509_privkey_get_spki ()
int | gnutls_x509_privkey_set_spki ()
int | gnutls_x509_privkey_get_key_id ()
int | gnutls_x509_privkey_generate ()
void | gnutls_x509_privkey_set_flags ()
int | gnutls_x509_privkey_generate2 ()
int | gnutls_x509_privkey_verify_seed ()
int | gnutls_x509_privkey_get_seed ()
int | gnutls_x509_privkey_verify_params ()
int | gnutls_x509_privkey_export ()
int | gnutls_x509_privkey_export2 ()
int | gnutls_x509_privkey_export_pkcs8 ()
int | gnutls_x509_privkey_export2_pkcs8 ()
int | gnutls_x509_privkey_export_rsa_raw2 ()
int | gnutls_x509_privkey_export_rsa_raw ()
int | gnutls_x509_privkey_export_ecc_raw ()
int | gnutls_x509_privkey_export_gost_raw ()
int | gnutls_x509_privkey_sign_data ()
int | gnutls_x509_crq_sign ()
int | gnutls_x509_crq_sign2 ()
int | gnutls_x509_crq_print ()
int | gnutls_x509_crq_verify ()
int | gnutls_x509_crq_init ()
void | gnutls_x509_crq_deinit ()
int | gnutls_x509_crq_import ()
int | gnutls_x509_crq_get_private_key_usage_period ()
int | gnutls_x509_crq_get_dn ()
int | gnutls_x509_crq_get_dn2 ()
int | gnutls_x509_crq_get_dn3 ()
int | gnutls_x509_crq_get_dn_oid ()
int | gnutls_x509_crq_get_dn_by_oid ()
int | gnutls_x509_crq_set_dn ()
int | gnutls_x509_crq_set_dn_by_oid ()
int | gnutls_x509_crq_set_version ()
int | gnutls_x509_crq_get_version ()
int | gnutls_x509_crq_set_key ()
int | gnutls_x509_crq_set_extension_by_oid ()
int | gnutls_x509_crq_set_challenge_password ()
int | gnutls_x509_crq_get_challenge_password ()
int | gnutls_x509_crq_set_attribute_by_oid ()
int | gnutls_x509_crq_get_attribute_by_oid ()
int | gnutls_x509_crq_export ()
int | gnutls_x509_crq_export2 ()
int | gnutls_x509_crt_set_crq ()
int | gnutls_x509_crt_set_crq_extensions ()
int | gnutls_x509_crt_set_crq_extension_by_oid ()
int | gnutls_x509_crq_set_private_key_usage_period ()
int | gnutls_x509_crq_set_key_rsa_raw ()
int | gnutls_x509_crq_set_subject_alt_name ()
int | gnutls_x509_crq_set_subject_alt_othername ()
int | gnutls_x509_crq_set_key_usage ()
int | gnutls_x509_crq_set_basic_constraints ()
int | gnutls_x509_crq_set_key_purpose_oid ()
int | gnutls_x509_crq_get_key_purpose_oid ()
int | gnutls_x509_crq_get_extension_data ()
int | gnutls_x509_crq_get_extension_data2 ()
int | gnutls_x509_crq_get_extension_info ()
int | gnutls_x509_crq_get_attribute_data ()
int | gnutls_x509_crq_get_attribute_info ()
int | gnutls_x509_crq_get_pk_algorithm ()
int | gnutls_x509_crq_get_spki ()
int | gnutls_x509_crq_set_spki ()
int | gnutls_x509_crq_get_signature_oid ()
int | gnutls_x509_crq_get_pk_oid ()
int | gnutls_x509_crq_get_key_id ()
int | gnutls_x509_crq_get_key_rsa_raw ()
int | gnutls_x509_crq_get_key_usage ()
int | gnutls_x509_crq_get_basic_constraints ()
int | gnutls_x509_crq_get_subject_alt_name ()
int | gnutls_x509_crq_get_subject_alt_othername_oid ()
int | gnutls_x509_crq_get_extension_by_oid ()
int | gnutls_x509_crq_get_tlsfeatures ()
int | gnutls_x509_crq_set_tlsfeatures ()
int | gnutls_x509_crt_get_extension_by_oid2 ()
int | gnutls_x509_trust_list_init ()
void | gnutls_x509_trust_list_deinit ()
int | gnutls_x509_trust_list_get_issuer ()
int | gnutls_x509_trust_list_get_issuer_by_dn ()
int | gnutls_x509_trust_list_get_issuer_by_subject_key_id ()
int | gnutls_x509_trust_list_add_cas ()
int | gnutls_x509_trust_list_remove_cas ()
int | gnutls_x509_trust_list_add_named_crt ()
int | gnutls_x509_trust_list_add_crls ()
int | gnutls_x509_trust_list_iter_get_ca ()
void | gnutls_x509_trust_list_iter_deinit ()
void | gnutls_session_set_verify_output_function ()
int | gnutls_x509_trust_list_verify_named_crt ()
int | gnutls_x509_trust_list_verify_crt2 ()
int | gnutls_x509_trust_list_verify_crt ()
int | gnutls_x509_trust_list_add_trust_mem ()
int | gnutls_x509_trust_list_add_trust_file ()
int | gnutls_x509_trust_list_add_trust_dir ()
int | gnutls_x509_trust_list_remove_trust_file ()
int | gnutls_x509_trust_list_remove_trust_mem ()
int | gnutls_x509_trust_list_add_system_trust ()
void | gnutls_x509_trust_list_set_getissuer_function ()
void | gnutls_x509_trust_list_set_ptr ()
void * | gnutls_x509_trust_list_get_ptr ()
void | gnutls_certificate_set_trust_list ()
void | gnutls_certificate_get_trust_list ()
void | gnutls_x509_ext_deinit ()
int | gnutls_x509_ext_print ()

## Types and Values

#define | GNUTLS_OID_X520_COUNTRY_NAME
#define | GNUTLS_OID_X520_ORGANIZATION_NAME
#define | GNUTLS_OID_X520_ORGANIZATIONAL_UNIT_NAME
#define | GNUTLS_OID_X520_COMMON_NAME
#define | GNUTLS_OID_X520_LOCALITY_NAME
#define | GNUTLS_OID_X520_STATE_OR_PROVINCE_NAME
#define | GNUTLS_OID_X520_INITIALS
#define | GNUTLS_OID_X520_GENERATION_QUALIFIER
#define | GNUTLS_OID_X520_SURNAME
#define | GNUTLS_OID_X520_GIVEN_NAME
#define | GNUTLS_OID_X520_TITLE
#define | GNUTLS_OID_X520_DN_QUALIFIER
#define | GNUTLS_OID_X520_PSEUDONYM
#define | GNUTLS_OID_X520_POSTALCODE
#define | GNUTLS_OID_X520_NAME
#define | GNUTLS_OID_LDAP_DC
#define | GNUTLS_OID_LDAP_UID
#define | GNUTLS_OID_PKCS9_EMAIL
#define | GNUTLS_OID_PKIX_DATE_OF_BIRTH
#define | GNUTLS_OID_PKIX_PLACE_OF_BIRTH
#define | GNUTLS_OID_PKIX_GENDER
#define | GNUTLS_OID_PKIX_COUNTRY_OF_CITIZENSHIP
#define | GNUTLS_OID_PKIX_COUNTRY_OF_RESIDENCE
#define | GNUTLS_KP_TLS_WWW_SERVER
#define | GNUTLS_KP_TLS_WWW_CLIENT
#define | GNUTLS_KP_CODE_SIGNING
#define | GNUTLS_KP_MS_SMART_CARD_LOGON
#define | GNUTLS_KP_EMAIL_PROTECTION
#define | GNUTLS_KP_TIME_STAMPING
#define | GNUTLS_KP_OCSP_SIGNING
#define | GNUTLS_KP_IPSEC_IKE
#define | GNUTLS_KP_ANY
#define | GNUTLS_KP_FLAG_DISALLOW_ANY
#define | GNUTLS_OID_AIA
#define | GNUTLS_OID_AD_OCSP
#define | GNUTLS_OID_AD_CAISSUERS
#define | GNUTLS_FSAN_SET
#define | GNUTLS_FSAN_APPEND
#define | GNUTLS_FSAN_ENCODE_OCTET_STRING
#define | GNUTLS_FSAN_ENCODE_UTF8_STRING
#define | GNUTLS_X509EXT_OID_SUBJECT_KEY_ID
#define | GNUTLS_X509EXT_OID_KEY_USAGE
#define | GNUTLS_X509EXT_OID_PRIVATE_KEY_USAGE_PERIOD
#define | GNUTLS_X509EXT_OID_SAN
#define | GNUTLS_X509EXT_OID_IAN
#define | GNUTLS_X509EXT_OID_BASIC_CONSTRAINTS
#define | GNUTLS_X509EXT_OID_NAME_CONSTRAINTS
#define | GNUTLS_X509EXT_OID_CRL_DIST_POINTS
#define | GNUTLS_X509EXT_OID_CRT_POLICY
#define | GNUTLS_X509EXT_OID_AUTHORITY_KEY_ID
#define | GNUTLS_X509EXT_OID_EXTENDED_KEY_USAGE
#define | GNUTLS_X509EXT_OID_INHIBIT_ANYPOLICY
#define | GNUTLS_X509EXT_OID_AUTHORITY_INFO_ACCESS
#define | GNUTLS_X509EXT_OID_PROXY_CRT_INFO
#define | GNUTLS_X509EXT_OID_TLSFEATURES
#define | GNUTLS_X509EXT_OID_CT_SCT_V1
#define | GNUTLS_X509_OID_POLICY_ANY
enum | gnutls_certificate_import_flags
enum | gnutls_x509_crt_flags
enum | gnutls_keyid_flags_t
enum | gnutls_info_access_what_t
typedef | gnutls_x509_name_constraints_t
#define | GNUTLS_EXT_FLAG_APPEND
#define | GNUTLS_NAME_CONSTRAINTS_FLAG_APPEND
#define | GNUTLS_CRL_REASON_SUPERSEEDED
enum | gnutls_x509_crl_reason_flags_t
#define | GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION
typedef | gnutls_x509_spki_t
typedef | gnutls_x509_tlsfeatures_t
#define | GNUTLS_MAX_QUALIFIERS
enum | gnutls_x509_qualifier_t
| gnutls_x509_policy_st
#define | GNUTLS_X509_DN_OID_RETURN_OID
typedef | gnutls_x509_dn_t
| gnutls_x509_ava_st
#define | GNUTLS_X509_DN_FLAG_COMPAT
typedef | gnutls_x509_crl_iter_t
#define | gnutls_x509_crl_get_certificate_count
#define | gnutls_x509_crl_get_certificate
enum | gnutls_certificate_verify_flags
#define | GNUTLS_VERIFY_ALLOW_BROKEN
enum | gnutls_certificate_verification_profiles_t
#define | GNUTLS_VFLAGS_PROFILE_MASK
#define | GNUTLS_PKCS8_PLAIN
#define | GNUTLS_PKCS8_USE_PKCS12_3DES
#define | GNUTLS_PKCS8_USE_PKCS12_ARCFOUR
#define | GNUTLS_PKCS8_USE_PKCS12_RC2_40
enum | gnutls_pkcs_encrypt_flags_t
#define | GNUTLS_PKCS_USE_PKCS12_3DES
#define | GNUTLS_PKCS_USE_PKCS12_ARCFOUR
#define | GNUTLS_PKCS_USE_PKCS12_RC2_40
#define | GNUTLS_PKCS_USE_PBES2_3DES
#define | GNUTLS_PKCS_USE_PBES2_AES_128
#define | GNUTLS_PKCS_USE_PBES2_AES_192
#define | GNUTLS_PKCS_USE_PBES2_AES_256
#define | GNUTLS_PKCS_USE_PBES2_GOST_TC26Z
#define | GNUTLS_PKCS_USE_PBES2_GOST_CPA
#define | GNUTLS_PKCS_USE_PBES2_GOST_CPB
#define | GNUTLS_PKCS_USE_PBES2_GOST_CPC
#define | GNUTLS_PKCS_USE_PBES2_GOST_CPD
enum | gnutls_keygen_types_t
| gnutls_keygen_data_st
typedef | gnutls_x509_trust_list_t
typedef | gnutls_x509_trust_list_iter_t
enum | gnutls_trust_list_flags_t
| gnutls_x509_ext_st

## Description

## Functions

### gnutls_x509_crt_init ()

    int
    gnutls_x509_crt_init (gnutls_x509_crt_t *cert);

This function will initialize an X.509 certificate structure.

#### Parameters

cert | A pointer to the type to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_deinit ()

    void
    gnutls_x509_crt_deinit (gnutls_x509_crt_t cert);

This function will deinitialize a certificate structure.

#### Parameters

cert | The data to be deinitialized |

### gnutls_x509_crt_set_flags ()

    void
    gnutls_x509_crt_set_flags (gnutls_x509_crt_t cert,
                               unsigned  flags);

This function will set flags for the specified certificate. Currently this is useful for the `GNUTLS_X509_CRT_FLAG_IGNORE_SANITY` which allows importing certificates even if they have known issues.

#### Parameters

cert | A type gnutls_x509_crt_t |
flags | flags from the `gnutls_x509_crt_flags` |

Since: 3.6.0

### gnutls_x509_crt_equals ()

    unsigned
    gnutls_x509_crt_equals (gnutls_x509_crt_t cert1,
                            gnutls_x509_crt_t cert2);

### gnutls_x509_crt_equals2 ()

    unsigned
    gnutls_x509_crt_equals2 (gnutls_x509_crt_t cert1,
                             const gnutls_datum_t *der);

### gnutls_x509_crt_import ()

    int
    gnutls_x509_crt_import (gnutls_x509_crt_t cert,
                            const gnutls_datum_t *data,
                            gnutls_x509_crt_fmt_t format);

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".

#### Parameters

cert | The data to store the parsed certificate. |
data | The DER or PEM encoded certificate. |
format | One of DER or PEM |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_list_import2 ()

    int
    gnutls_x509_crt_list_import2 (gnutls_x509_crt_t **certs,
                                  unsigned int *size,
                                  const gnutls_datum_t *data,
                                  gnutls_x509_crt_fmt_t format,
                                  unsigned int 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` which will be allocated and initialized.

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

To deinitialize `certs` , you need to deinitialize each crt structure independently, and use `gnutls_free()` at `certs` .

#### Parameters

certs | Will hold the parsed certificate list. |
size | It will contain the size of the list. |
data | The PEM encoded certificate. |
format | One of DER or PEM. |
flags | must be (0) or an OR'd sequence of gnutls_certificate_import_flags. |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

Since: 3.0

### gnutls_x509_crt_list_import ()

    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);

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.

The flag `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 `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".

#### Parameters

certs | Indicates where the parsed list will be copied to. 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 (0) or an OR'd sequence of gnutls_certificate_import_flags. |

#### Returns

the number of certificates read or a negative error value.

### gnutls_x509_crt_import_url ()

    int
    gnutls_x509_crt_import_url (gnutls_x509_crt_t crt,
                                const char *url,
                                unsigned int flags);

This function will import a certificate present in a PKCS11 token or any type of back-end that supports URLs.

In previous versions of gnutls this function was named gnutls_x509_crt_import_pkcs11_url, and the old name is an alias to this one.

#### Parameters

crt | A certificate of type gnutls_x509_crt_t |
url | A PKCS 11 url |
flags | One of GNUTLS_PKCS11_OBJ_* flags for PKCS11 URLs or zero otherwise |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.0

### gnutls_x509_crt_list_import_url ()

    int
    gnutls_x509_crt_list_import_url (gnutls_x509_crt_t **certs,
                                     unsigned int *size,
                                     const char *url,
                                     gnutls_pin_callback_t pin_fn,
                                     void *pin_fn_userdata,
                                     unsigned int flags);

This function will import a certificate chain present in a PKCS11 token or any type of back-end that supports URLs. The certificates must be deinitialized afterwards using `gnutls_x509_crt_deinit()` and the returned pointer must be freed using `gnutls_free()`.

The URI provided must be the first certificate in the chain; subsequent certificates will be retrieved using `gnutls_pkcs11_get_raw_issuer()` or equivalent functionality for the supported URI.

#### Parameters

certs | Will hold the allocated certificate list. |
size | It will contain the size of the list. |
url | A PKCS 11 url |
pin_fn | a PIN callback if not globally set |
pin_fn_userdata | parameter for the PIN callback |
flags | One of GNUTLS_PKCS11_OBJ_* flags for PKCS11 URLs or zero otherwise |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.3

### gnutls_x509_crt_export ()

    int
    gnutls_x509_crt_export (gnutls_x509_crt_t cert,
                            gnutls_x509_crt_fmt_t format,
                            void *output_data,
                            size_t *output_data_size);

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".

#### Parameters

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) |

#### Returns

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

### gnutls_x509_crt_export2 ()

    int
    gnutls_x509_crt_export2 (gnutls_x509_crt_t cert,
                             gnutls_x509_crt_fmt_t format,
                             gnutls_datum_t *out);

This function will export the certificate to DER or PEM format. The output buffer is allocated using `gnutls_malloc()`.

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

#### Parameters

cert | Holds the certificate |
format | the format of output params. One of PEM or DER. |
out | will contain a certificate PEM or DER encoded |

#### Returns

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

Since: 3.1.3

### gnutls_x509_crt_get_private_key_usage_period ()

    int
    gnutls_x509_crt_get_private_key_usage_period
                                   (gnutls_x509_crt_t cert,
                                    time_t *activation,
                                    time_t *expiration,
                                    unsigned int *critical);

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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
activation | The activation time |
expiration | The expiration time |
critical | the extension status |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

### gnutls_x509_crt_get_issuer_dn ()

    int
    gnutls_x509_crt_get_issuer_dn (gnutls_x509_crt_t cert,
                                   char *buf,
                                   size_t *buf_size);

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

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crt_get_issuer_dn3()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
buf | a pointer to a structure to hold the name (may be null) |
buf_size | initially holds the size of `buf` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the DN does not exist, or another error value on error. On success 0 is returned.

### gnutls_x509_crt_get_issuer_dn2 ()

    int
    gnutls_x509_crt_get_issuer_dn2 (gnutls_x509_crt_t cert,
                                    gnutls_datum_t *dn);

This function will allocate buffer and copy the name of issuer of the Certificate. 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.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crt_get_issuer_dn3()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.1.10

### gnutls_x509_crt_get_issuer_dn3 ()

    int
    gnutls_x509_crt_get_issuer_dn3 (gnutls_x509_crt_t cert,
                                    gnutls_datum_t *dn,
                                    unsigned  flags);

This function will allocate buffer and copy the name of issuer of the Certificate. 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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |
flags | zero or `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.7

### gnutls_x509_crt_get_issuer_dn_oid ()

    int
    gnutls_x509_crt_get_issuer_dn_oid (gnutls_x509_crt_t cert,
                                       unsigned  indx,
                                       void *oid,
                                       size_t *oid_size);

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. The `oid` returned will be null terminated, although `oid_size` will not account for the trailing null.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | This specifies which OID to return. Use (0) to get the first one. |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if there are no data in the current index. On success 0 is returned.

### gnutls_x509_crt_get_issuer_dn_by_oid ()

    int
    gnutls_x509_crt_get_issuer_dn_by_oid (gnutls_x509_crt_t cert,
                                          const char *oid,
                                          unsigned  indx,
                                          unsigned int raw_flag,
                                          void *buf,
                                          size_t *buf_size);

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 `gnutls_x509_dn_oid_known()`.

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
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 (0) 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) |
buf_size | initially holds the size of `buf` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if there are no data in the current index. On success 0 is returned.

### gnutls_x509_crt_get_dn ()

    int
    gnutls_x509_crt_get_dn (gnutls_x509_crt_t cert,
                            char *buf,
                            size_t *buf_size);

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.

The `buf` returned will be null terminated and the `buf_size` will account for the trailing null. If `buf` is null then only the size will be filled.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crt_get_dn3()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
buf | a pointer to a structure to hold the name (may be null) |
buf_size | initially holds the size of `buf` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the DN does not exist, or another error value on error. On success 0 is returned.

### gnutls_x509_crt_get_dn2 ()

    int
    gnutls_x509_crt_get_dn2 (gnutls_x509_crt_t cert,
                             gnutls_datum_t *dn);

This function will allocate buffer and copy the name of the Certificate. 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.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crt_get_dn3()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.1.10

### gnutls_x509_crt_get_dn3 ()

    int
    gnutls_x509_crt_get_dn3 (gnutls_x509_crt_t cert,
                             gnutls_datum_t *dn,
                             unsigned  flags);

This function will allocate buffer and copy the name of the Certificate. 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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |
flags | zero or `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.7

### gnutls_x509_crt_get_dn_oid ()

    int
    gnutls_x509_crt_get_dn_oid (gnutls_x509_crt_t cert,
                                unsigned  indx,
                                void *oid,
                                size_t *oid_size);

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. The `oid` returned will be null terminated, although `oid_size` will not account for the trailing null.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | This specifies which OID to return. Use (0) to get the first one. |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if there are no data in the current index. On success 0 is returned.

### gnutls_x509_crt_get_dn_by_oid ()

    int
    gnutls_x509_crt_get_dn_by_oid (gnutls_x509_crt_t cert,
                                   const char *oid,
                                   unsigned  indx,
                                   unsigned int raw_flag,
                                   void *buf,
                                   size_t *buf_size);

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 `gnutls_x509_dn_oid_known()`.

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
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 (0) 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). |
buf_size | initially holds the size of `buf` |

#### Returns

`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. `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if there are no data in the current index. On success 0 is returned.

### gnutls_x509_crt_check_hostname ()

    unsigned
    gnutls_x509_crt_check_hostname (gnutls_x509_crt_t cert,
                                    const char *hostname);

This function will check if the given certificate's subject matches the given hostname. This is a basic implementation of the matching described in RFC6125, and takes into account wildcards, and the DNSName/IPAddress subject alternative name PKIX extension.

For details see also `gnutls_x509_crt_check_hostname2()`.

#### Parameters

cert | should contain an gnutls_x509_crt_t type |
hostname | A null terminated string that contains a DNS name |

#### Returns

non-zero for a successful match, and zero on failure.

### gnutls_x509_crt_check_hostname2 ()

    unsigned
    gnutls_x509_crt_check_hostname2 (gnutls_x509_crt_t cert,
                                     const char *hostname,
                                     unsigned int flags);

This function will check if the given certificate's subject matches the given hostname. This is a basic implementation of the matching described in RFC6125, and takes into account wildcards, and the DNSName/IPAddress subject alternative name PKIX extension.

IPv4 addresses are accepted by this function in the dotted-decimal format (e.g, ddd.ddd.ddd.ddd), and IPv6 addresses in the hexadecimal x:x:x:x:x:x:x:x format. For them the IPAddress subject alternative name extension is consulted. Previous versions to 3.6.0 of GnuTLS in case of a non-match would consult (in a non-standard extension) the DNSname and CN fields. This is no longer the case.

When the flag `GNUTLS_VERIFY_DO_NOT_ALLOW_WILDCARDS` is specified no wildcards are considered. Otherwise they are only considered if the domain name consists of three components or more, and the wildcard starts at the leftmost position.

When the flag `GNUTLS_VERIFY_DO_NOT_ALLOW_IP_MATCHES` is specified, the input will be treated as a DNS name, and matching of textual IP addresses against the IPAddress part of the alternative name will not be allowed.

The function `gnutls_x509_crt_check_ip()` is available for matching IP addresses.

#### Parameters

cert | should contain an gnutls_x509_crt_t type |
hostname | A null terminated string that contains a DNS name |
flags | gnutls_certificate_verify_flags |

#### Returns

non-zero for a successful match, and zero on failure.

Since: 3.3.0

### gnutls_x509_crt_check_email ()

    unsigned
    gnutls_x509_crt_check_email (gnutls_x509_crt_t cert,
                                 const char *email,
                                 unsigned int flags);

This function will check if the given certificate's subject matches the given email address.

#### Parameters

cert | should contain an gnutls_x509_crt_t type |
email | A null terminated string that contains an email address (RFC822) |
flags | should be zero |

#### Returns

non-zero for a successful match, and zero on failure.

### gnutls_x509_crt_check_ip ()

    unsigned
    gnutls_x509_crt_check_ip (gnutls_x509_crt_t cert,
                              const unsigned char *ip,
                              unsigned int ip_size,
                              unsigned int flags);

This function will check if the IP allowed IP addresses in the certificate's subject alternative name match the provided IP address.

#### Parameters

cert | should contain an gnutls_x509_crt_t type |
ip | A pointer to the raw IP address |
ip_size | the number of bytes in ip (4 or 16) |
flags | should be zero |

#### Returns

non-zero for a successful match, and zero on failure.

### gnutls_x509_crt_get_signature_algorithm ()

    int
    gnutls_x509_crt_get_signature_algorithm
                                   (gnutls_x509_crt_t cert);

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

Since 3.6.0 this function never returns a negative error code. Error cases and unknown/unsupported signature algorithms are mapped to `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |

#### Returns

a gnutls_sign_algorithm_t value

### gnutls_x509_crt_get_signature ()

    int
    gnutls_x509_crt_get_signature (gnutls_x509_crt_t cert,
                                   char *sig,
                                   size_t *sizeof_sig);

This function will extract the signature field of a certificate.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
sig | a pointer where the signature part will be copied (may be null). |
sig_size | initially holds the size of `sig` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_get_version ()

    int
    gnutls_x509_crt_get_version (gnutls_x509_crt_t cert);

This function will return the version of the specified Certificate.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |

#### Returns

version of certificate, or a negative error code on error.

### gnutls_x509_crt_get_pk_oid ()

    int
    gnutls_x509_crt_get_pk_oid (gnutls_x509_crt_t cert,
                                char *oid,
                                size_t *oid_size);

This function will return the OID of the public key algorithm on that certificate. This is function is useful in the case `gnutls_x509_crt_get_pk_algorithm()` returned `GNUTLS_PK_UNKNOWN`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

zero or a negative error code on error.

Since: 3.5.0

### gnutls_x509_crt_get_signature_oid ()

    int
    gnutls_x509_crt_get_signature_oid (gnutls_x509_crt_t cert,
                                       char *oid,
                                       size_t *oid_size);

This function will return the OID of the signature algorithm that has been used to sign this certificate. This is function is useful in the case `gnutls_x509_crt_get_signature_algorithm()` returned `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

zero or a negative error code on error.

Since: 3.5.0

### gnutls_x509_crt_get_key_id ()

    int
    gnutls_x509_crt_get_key_id (gnutls_x509_crt_t crt,
                                unsigned int flags,
                                unsigned char *output_data,
                                size_t *output_data_size);

This function will return a unique ID that 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.

#### Parameters

crt | Holds the certificate |
flags | should be one of the flags from `gnutls_keyid_flags_t` |
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) |

#### Returns

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

### gnutls_x509_crt_set_private_key_usage_period ()

    int
    gnutls_x509_crt_set_private_key_usage_period
                                   (gnutls_x509_crt_t crt,
                                    time_t activation,
                                    time_t expiration);

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

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
activation | The activation time |
expiration | The expiration time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_authority_key_id ()

    int
    gnutls_x509_crt_set_authority_key_id (gnutls_x509_crt_t cert,
                                          const void *id,
                                          size_t id_size);

This function will set the X.509 certificate's authority key ID extension. Only the keyIdentifier field can be set with this function.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
id | The key ID |
id_size | Holds the size of the key ID field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_get_authority_key_id ()

    int
    gnutls_x509_crt_get_authority_key_id (gnutls_x509_crt_t cert,
                                          void *id,
                                          size_t *id_size,
                                          unsigned int *critical);

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 `GNUTLS_E_X509_UNSUPPORTED_EXTENSION`, if the extension contains the name and serial number of the certificate. In that case `gnutls_x509_crt_get_authority_key_gn_serial()` may be used.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
id | The place where the identifier will be copied |
id_size | Holds the size of the id field. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

### gnutls_x509_crt_get_authority_key_gn_serial ()

    int
    gnutls_x509_crt_get_authority_key_gn_serial
                                   (gnutls_x509_crt_t cert,
                                    unsigned int seq,
                                    void *alt,
                                    size_t *alt_size,
                                    unsigned int *alt_type,
                                    void *serial,
                                    size_t *serial_size,
                                    unsigned int *critical);

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 `seq` can be used as a counter to request them all until `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
alt | is the place where the alternative name will be copied to |
alt_size | holds the size of alt. |
alt_type | holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t). |
serial | buffer to store the serial number (may be null) |
serial_size | Holds the size of the serial field (may be null) |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

Since: 3.0

### gnutls_x509_crt_get_subject_key_id ()

    int
    gnutls_x509_crt_get_subject_key_id (gnutls_x509_crt_t cert,
                                        void *ret,
                                        size_t *ret_size,
                                        unsigned int *critical);

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).

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
ret | The place where the identifier will be copied |
ret_size | Holds the size of the result field. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

### gnutls_x509_crt_get_subject_unique_id ()

    int
    gnutls_x509_crt_get_subject_unique_id (gnutls_x509_crt_t crt,
                                           char *buf,
                                           size_t *buf_size);

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.

This function had a bug prior to 3.4.8 that prevented the setting of `NULL` `buf` to discover the `buf_size` . To use this function safely with the older versions the `buf` must be a valid buffer that can hold at least a single byte if `buf_size` is zero.

#### Parameters

crt | Holds the certificate |
buf | user allocated memory buffer, will hold the unique id |
buf_size | size of user allocated memory buffer (on input), will hold actual size of the unique ID on return. |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

### gnutls_x509_crt_get_issuer_unique_id ()

    int
    gnutls_x509_crt_get_issuer_unique_id (gnutls_x509_crt_t crt,
                                          char *buf,
                                          size_t *buf_size);

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.

This function had a bug prior to 3.4.8 that prevented the setting of `NULL` `buf` to discover the `buf_size` . To use this function safely with the older versions the `buf` must be a valid buffer that can hold at least a single byte if `buf_size` is zero.

#### Parameters

crt | Holds the certificate |
buf | user allocated memory buffer, will hold the unique id |
buf_size | size of user allocated memory buffer (on input), will hold actual size of the unique ID on return. |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

Since: 2.12.0

### gnutls_x509_crt_set_pin_function ()

    void
    gnutls_x509_crt_set_pin_function (gnutls_x509_crt_t crt,
                                      gnutls_pin_callback_t fn,
                                      void *userdata);

This function will set a callback function to be used when it is required to access a protected object. This function overrides the global function set using `gnutls_pkcs11_set_pin_function()`.

Note that this callback is currently used only during the import of a PKCS 11 certificate with `gnutls_x509_crt_import_url()`.

#### Parameters

crt | The certificate structure |
fn | the callback |
userdata | data associated with the callback |

Since: 3.1.0

### gnutls_x509_crt_get_authority_info_access ()

    int
    gnutls_x509_crt_get_authority_info_access
                                   (gnutls_x509_crt_t crt,
                                    unsigned int seq,
                                    int what,
                                    gnutls_datum_t *data,
                                    unsigned int *critical);

Note that a simpler API to access the authority info data is provided by `gnutls_x509_aia_get()` and `gnutls_x509_ext_import_aia()`.

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.

The `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 `seq` value is out of bounds, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

The type of data returned in `data` is specified via `what` which should be gnutls_info_access_what_t values.

If `what` is `GNUTLS_IA_ACCESSMETHOD_OID` then `data` will hold the accessMethod OID (e.g., "1.3.6.1.5.5.7.48.1").

If `what` is `GNUTLS_IA_ACCESSLOCATION_GENERALNAME_TYPE`, `data` will hold the accessLocation GeneralName type (e.g., "uniformResourceIdentifier").

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

If `what` is `GNUTLS_IA_OCSP_URI`, `data` will hold the OCSP URI. Requesting this `what` value leads to an error if the accessMethod is not 1.3.6.1.5.5.7.48.1 aka OCSP, or if accessLocation is not of the "uniformResourceIdentifier" type. In that case `GNUTLS_E_UNKNOWN_ALGORITHM` will be returned, and `seq` should be increased and this function called again.

If `what` is `GNUTLS_IA_CAISSUERS_URI`, `data` will hold the caIssuers URI. Requesting this `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. In that case handle as in `GNUTLS_IA_OCSP_URI`.

More `what` values may be allocated in the future as needed.

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

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

#### Parameters

crt | Holds the certificate |
seq | specifies the sequence number of the access descriptor (0 for the first one, 1 for the second etc.) |
what | what data to get, a gnutls_info_access_what_t type. |
data | output data to be freed with `gnutls_free()`. |
critical | pointer to output integer that is set to non-zero if the extension is marked as critical (may be `NULL`) |

#### Returns

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

Since: 3.0

### gnutls_x509_name_constraints_check ()

    unsigned
    gnutls_x509_name_constraints_check (gnutls_x509_name_constraints_t nc,
                                        gnutls_x509_subject_alt_name_t type,
                                        const gnutls_datum_t *name);

This function will check the provided name against the constraints in `nc` using the RFC5280 rules. Currently this function is limited to DNS names, emails and IP addresses (of type `GNUTLS_SAN_DNSNAME`, `GNUTLS_SAN_RFC822NAME` and `GNUTLS_SAN_IPADDRESS`).

#### Parameters

nc | the extracted name constraints |
type | the type of the constraint to check (of type gnutls_x509_subject_alt_name_t) |
name | the name to be checked |

#### Returns

zero if the provided name is not acceptable, and non-zero otherwise.

Since: 3.3.0

### gnutls_x509_name_constraints_check_crt ()

    unsigned
    gnutls_x509_name_constraints_check_crt
                                   (gnutls_x509_name_constraints_t nc,
                                    gnutls_x509_subject_alt_name_t type,
                                    gnutls_x509_crt_t crt);

This function will check the provided certificate names against the constraints in `nc` using the RFC5280 rules. It will traverse all the certificate's names and alternative names.

Currently this function is limited to DNS names and emails (of type `GNUTLS_SAN_DNSNAME` and `GNUTLS_SAN_RFC822NAME`).

#### Parameters

nc | the extracted name constraints |
type | the type of the constraint to check (of type gnutls_x509_subject_alt_name_t) |
cert | the certificate to be checked |

#### Returns

zero if the provided name is not acceptable, and non-zero otherwise.

Since: 3.3.0

### gnutls_x509_name_constraints_init ()

    int
    gnutls_x509_name_constraints_init (gnutls_x509_name_constraints_t *nc);

This function will initialize a name constraints type.

#### Parameters

nc | The nameconstraints |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_name_constraints_deinit ()

    void
    gnutls_x509_name_constraints_deinit (gnutls_x509_name_constraints_t nc);

This function will deinitialize a name constraints type.

#### Parameters

nc | The nameconstraints |

Since: 3.3.0

### gnutls_x509_crt_get_name_constraints ()

    int
    gnutls_x509_crt_get_name_constraints (gnutls_x509_crt_t crt,
                                          gnutls_x509_name_constraints_t nc,
                                          unsigned int flags,
                                          unsigned int *critical);

This function will return an intermediate type containing the name constraints of the provided CA certificate. That structure can be used in combination with `gnutls_x509_name_constraints_check()` to verify whether a server's name is in accordance with the constraints.

When the `flags` is set to `GNUTLS_EXT_FLAG_APPEND`, then if the `nc` structure is empty this function will behave identically as if the flag was not set. Otherwise if there are elements in the `nc` structure then the constraints will be merged with the existing constraints following RFC5280 p6.1.4 (excluded constraints will be appended, permitted will be intersected).

Note that `nc` must be initialized prior to calling this function.

#### Parameters

crt | should contain a gnutls_x509_crt_t type |
nc | The nameconstraints intermediate type |
flags | zero or `GNUTLS_EXT_FLAG_APPEND` |
critical | the extension status |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_name_constraints_add_permitted ()

    int
    gnutls_x509_name_constraints_add_permitted
                                   (gnutls_x509_name_constraints_t nc,
                                    gnutls_x509_subject_alt_name_t type,
                                    const gnutls_datum_t *name);

This function will add a name constraint to the list of permitted constraints. The constraints `type` can be any of the following types: `GNUTLS_SAN_DNSNAME`, `GNUTLS_SAN_RFC822NAME`, `GNUTLS_SAN_DN`, `GNUTLS_SAN_URI`, `GNUTLS_SAN_IPADDRESS`. For the latter, an IP address in network byte order is expected, followed by its network mask.

#### Parameters

nc | The nameconstraints |
type | The type of the constraints |
name | The data of the constraints |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_name_constraints_add_excluded ()

    int
    gnutls_x509_name_constraints_add_excluded
                                   (gnutls_x509_name_constraints_t nc,
                                    gnutls_x509_subject_alt_name_t type,
                                    const gnutls_datum_t *name);

This function will add a name constraint to the list of excluded constraints. The constraints `type` can be any of the following types: `GNUTLS_SAN_DNSNAME`, `GNUTLS_SAN_RFC822NAME`, `GNUTLS_SAN_DN`, `GNUTLS_SAN_URI`, `GNUTLS_SAN_IPADDRESS`. For the latter, an IP address in network byte order is expected, followed by its network mask (which is 4 bytes in IPv4 or 16-bytes in IPv6).

#### Parameters

nc | The nameconstraints |
type | The type of the constraints |
name | The data of the constraints |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_crt_set_name_constraints ()

    int
    gnutls_x509_crt_set_name_constraints (gnutls_x509_crt_t crt,
                                          gnutls_x509_name_constraints_t nc,
                                          unsigned int critical);

This function will set the provided name constraints to the certificate extension list. This extension is always marked as critical.

#### Parameters

crt | The certificate |
nc | The nameconstraints structure |
critical | whether this extension will be critical |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_name_constraints_get_permitted ()

    int
    gnutls_x509_name_constraints_get_permitted
                                   (gnutls_x509_name_constraints_t nc,
                                    unsigned  idx,
                                    unsigned *type,
                                    gnutls_datum_t *name);

This function will return an intermediate type containing the name constraints of the provided CA certificate. That structure can be used in combination with `gnutls_x509_name_constraints_check()` to verify whether a server's name is in accordance with the constraints.

The name should be treated as constant and valid for the lifetime of `nc` .

#### Parameters

nc | the extracted name constraints |
idx | the index of the constraint |
type | the type of the constraint (of type gnutls_x509_subject_alt_name_t) |
name | the name in the constraint (of the specific type) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_name_constraints_get_excluded ()

    int
    gnutls_x509_name_constraints_get_excluded
                                   (gnutls_x509_name_constraints_t nc,
                                    unsigned  idx,
                                    unsigned *type,
                                    gnutls_datum_t *name);

This function will return an intermediate type containing the name constraints of the provided CA certificate. That structure can be used in combination with `gnutls_x509_name_constraints_check()` to verify whether a server's name is in accordance with the constraints.

The name should be treated as constant and valid for the lifetime of `nc` .

#### Parameters

nc | the extracted name constraints |
idx | the index of the constraint |
type | the type of the constraint (of type gnutls_x509_subject_alt_name_t) |
name | the name in the constraint (of the specific type) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_cidr_to_rfc5280 ()

    int
    gnutls_x509_cidr_to_rfc5280 (const char *cidr,
                                 gnutls_datum_t *cidr_rfc5280);

This function will convert text CIDR range with prefix (such as '10.0.0.0/8') to RFC5280 (IP address in network byte order followed by its network mask). Works for both IPv4 and IPv6.

The resulting object is directly usable for IP name constraints usage, for example in functions `gnutls_x509_name_constraints_add_permitted` or `gnutls_x509_name_constraints_add_excluded`.

The data in datum needs to be deallocated using `gnutls_free()`.

#### Parameters

cidr | CIDR in RFC4632 format (IP/prefix), null-terminated |
cidr_rfc5280 | CIDR range converted to RFC5280 format |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.4

### gnutls_x509_crt_get_crl_dist_points ()

    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);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the distribution point (0 for the first one, 1 for the second etc.) |
san | is the place where the distribution point will be copied to |
san_size | holds the size of ret. |
reason_flags | Revocation reasons. An ORed sequence of flags from `gnutls_x509_crl_reason_flags_t`. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### 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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

### gnutls_x509_crt_set_crl_dist_points2 ()

    int
    gnutls_x509_crt_set_crl_dist_points2 (gnutls_x509_crt_t crt,
                                          gnutls_x509_subject_alt_name_t type,
                                          const void *data,
                                          unsigned int data_size,
                                          unsigned int reason_flags);

This function will set the CRL distribution points certificate extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
type | is one of the gnutls_x509_subject_alt_name_t enumerations |
data | The data to be set |
data_size | The data size |
reason_flags | revocation reasons |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.6.0

### gnutls_x509_crt_set_crl_dist_points ()

    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);

This function will set the CRL distribution points certificate extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
type | is one of the gnutls_x509_subject_alt_name_t enumerations |
data_string | The data to be set |
reason_flags | revocation reasons |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_cpy_crl_dist_points ()

    int
    gnutls_x509_crt_cpy_crl_dist_points (gnutls_x509_crt_t dst,
                                         gnutls_x509_crt_t src);

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.

#### Parameters

dst | a certificate of type gnutls_x509_crt_t |
src | the certificate where the dist points will be copied from |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_sign ()

    int
    gnutls_x509_crl_sign (gnutls_x509_crl_t crl,
                          gnutls_x509_crt_t issuer,
                          gnutls_x509_privkey_t issuer_key);

This function is the same a `gnutls_x509_crl_sign2()` with no flags, and an appropriate hash algorithm. The hash algorithm used may vary between versions of GnuTLS, and it is tied to the security level of the issuer's public key.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
issuer | is the certificate of the certificate issuer |
issuer_key | holds the issuer's private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_sign2 ()

    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);

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.

A known limitation of this function is, that a newly-signed CRL will not be fully functional (e.g., for signature verification), until it is exported an re-imported.

After GnuTLS 3.6.1 the value of `dig` may be `GNUTLS_DIG_UNKNOWN`, and in that case, a suitable but reasonable for the key algorithm will be selected.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
issuer | is the certificate of the certificate issuer |
issuer_key | holds the issuer's private key |
dig | The message digest to use. GNUTLS_DIG_SHA256 is the safe choice unless you know what you're doing. |
flags | must be 0 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_get_activation_time ()

    time_t
    gnutls_x509_crt_get_activation_time (gnutls_x509_crt_t cert);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |

#### Returns

activation time, or (time_t)-1 on error.

### gnutls_x509_crt_get_expiration_time ()

    time_t
    gnutls_x509_crt_get_expiration_time (gnutls_x509_crt_t cert);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |

#### Returns

expiration time, or (time_t)-1 on error.

### gnutls_x509_crt_get_serial ()

    int
    gnutls_x509_crt_get_serial (gnutls_x509_crt_t cert,
                                void *result,
                                size_t *result_size);

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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
result | The place where the serial number will be copied |
result_size | Holds the size of the result field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_spki_init ()

    int
    gnutls_x509_spki_init (gnutls_x509_spki_t *spki);

This function will initialize a SubjectPublicKeyInfo structure used in PKIX. The structure is used to set additional parameters in the public key information field of a certificate.

#### Parameters

spki | A pointer to the type to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.0

### gnutls_x509_spki_deinit ()

    void
    gnutls_x509_spki_deinit (gnutls_x509_spki_t spki);

This function will deinitialize a SubjectPublicKeyInfo structure.

#### Parameters

spki | the SubjectPublicKeyInfo structure |

Since: 3.6.0

### gnutls_x509_spki_get_rsa_pss_params ()

    int
    gnutls_x509_spki_get_rsa_pss_params (gnutls_x509_spki_t spki,
                                         gnutls_digest_algorithm_t *dig,
                                         unsigned int *salt_size);

This function will get the public key algorithm parameters of RSA-PSS type.

#### Parameters

spki | the SubjectPublicKeyInfo structure |
dig | if non-NULL, it will hold the digest algorithm |
salt_size | if non-NULL, it will hold the salt size |

#### Returns

zero if the parameters are present or a negative value on error.

Since: 3.6.0

### gnutls_x509_spki_set_rsa_pss_params ()

    void
    gnutls_x509_spki_set_rsa_pss_params (gnutls_x509_spki_t spki,
                                         gnutls_digest_algorithm_t dig,
                                         unsigned int salt_size);

This function will set the public key parameters for an RSA-PSS algorithm, in the SubjectPublicKeyInfo structure.

#### Parameters

spki | the SubjectPublicKeyInfo structure |
dig | a digest algorithm of type gnutls_digest_algorithm_t |
salt_size | the size of salt string |

Since: 3.6.0

### gnutls_x509_crt_get_pk_algorithm ()

    int
    gnutls_x509_crt_get_pk_algorithm (gnutls_x509_crt_t cert,
                                      unsigned int *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.

Unknown/unsupported algorithms are mapped to `GNUTLS_PK_UNKNOWN`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
bits | if bits is non null it will hold the size of the parameters' in bits |

#### Returns

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

### gnutls_x509_crt_set_spki ()

    int
    gnutls_x509_crt_set_spki (gnutls_x509_crt_t crt,
                              const gnutls_x509_spki_t spki,
                              unsigned int flags);

This function will set the certificate's subject public key information explicitly. This is intended to be used in the cases where a single public key (e.g., RSA) can be used for multiple signature algorithms (RSA PKCS1-1.5, and RSA-PSS).

To export the public key (i.e., the SubjectPublicKeyInfo part), check `gnutls_pubkey_import_x509()`.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
spki | a SubjectPublicKeyInfo structure of type gnutls_x509_spki_t |
flags | must be zero |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.0

### gnutls_x509_crt_get_spki ()

    int
    gnutls_x509_crt_get_spki (gnutls_x509_crt_t cert,
                              gnutls_x509_spki_t spki,
                              unsigned int flags);

This function will return the public key information of an X.509 certificate. The provided `spki` must be initialized.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
spki | a SubjectPublicKeyInfo structure of type gnutls_x509_spki_t |
flags | must be zero |

Since: 3.6.0

### gnutls_x509_crt_get_pk_rsa_raw ()

    int
    gnutls_x509_crt_get_pk_rsa_raw (gnutls_x509_crt_t crt,
                                    gnutls_datum_t *m,
                                    gnutls_datum_t *e);

This function will export the RSA public 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.

#### Parameters

crt | Holds the certificate |
m | will hold the modulus |
e | will hold the public exponent |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

### gnutls_x509_crt_get_pk_dsa_raw ()

    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);

This function will export the DSA public 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.

#### Parameters

crt | Holds the certificate |
p | will hold the p |
q | will hold the q |
g | will hold the g |
y | will hold the y |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

### gnutls_x509_crt_get_pk_ecc_raw ()

    int
    gnutls_x509_crt_get_pk_ecc_raw (gnutls_x509_crt_t crt,
                                    gnutls_ecc_curve_t *curve,
                                    gnutls_datum_t *x,
                                    gnutls_datum_t *y);

This function will export the ECC public 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.

In EdDSA curves the `y` parameter will be `NULL` and the other parameters will be in the native format for the curve.

#### Parameters

crt | Holds the certificate |
curve | will hold the curve |
x | will hold the x-coordinate |
y | will hold the y-coordinate |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

Since: 3.4.1

### gnutls_x509_crt_get_pk_gost_raw ()

    int
    gnutls_x509_crt_get_pk_gost_raw (gnutls_x509_crt_t crt,
                                     gnutls_ecc_curve_t *curve,
                                     gnutls_digest_algorithm_t *digest,
                                     gnutls_gost_paramset_t *paramset,
                                     gnutls_datum_t *x,
                                     gnutls_datum_t *y);

This function will export the GOST public 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.

#### Parameters

crt | Holds the certificate |
curve | will hold the curve |
digest | will hold the digest |
paramset | will hold the GOST parameter set ID |
x | will hold the x-coordinate |
y | will hold the y-coordinate |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error code.

Since: 3.6.3

### gnutls_x509_crt_get_subject_alt_name ()

    int
    gnutls_x509_crt_get_subject_alt_name (gnutls_x509_crt_t cert,
                                          unsigned int seq,
                                          void *san,
                                          size_t *san_size,
                                          unsigned int *critical);

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 `GNUTLS_SAN_OTHERNAME` is returned. You may use `gnutls_x509_crt_get_subject_alt_othername_oid()` to get the corresponding OID and the "virtual" SAN types (e.g., `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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
san | is the place where the alternative name will be copied to |
san_size | holds the size of san. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

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

### gnutls_x509_crt_get_subject_alt_name2 ()

    int
    gnutls_x509_crt_get_subject_alt_name2 (gnutls_x509_crt_t cert,
                                           unsigned int seq,
                                           void *san,
                                           size_t *san_size,
                                           unsigned int *san_type,
                                           unsigned int *critical);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
san | is the place where the alternative name will be copied to |
san_size | holds the size of ret. |
san_type | holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t). |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

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

### gnutls_x509_crt_get_subject_alt_othername_oid ()

    int
    gnutls_x509_crt_get_subject_alt_othername_oid
                                   (gnutls_x509_crt_t cert,
                                    unsigned int seq,
                                    void *oid,
                                    size_t *oid_size);

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 `gnutls_x509_crt_get_subject_alt_name()` returned `GNUTLS_SAN_OTHERNAME`.

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
oid | is the place where the otherName OID will be copied to |
oid_size | holds the size of ret. |

#### 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. `GNUTLS_SAN_OTHERNAME_XMPP`, and `GNUTLS_SAN_OTHERNAME` for unknown OIDs. It will return `GNUTLS_E_SHORT_MEMORY_BUFFER` if `ian_size` is not large enough to hold the value. In that case `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

### gnutls_x509_crt_get_issuer_alt_name ()

    int
    gnutls_x509_crt_get_issuer_alt_name (gnutls_x509_crt_t cert,
                                         unsigned int seq,
                                         void *ian,
                                         size_t *ian_size,
                                         unsigned int *critical);

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 `GNUTLS_SAN_OTHERNAME` is returned. You may use `gnutls_x509_crt_get_subject_alt_othername_oid()` to get the corresponding OID and the "virtual" SAN types (e.g., `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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
ian | is the place where the alternative name will be copied to |
ian_size | holds the size of ian. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

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

Since: 2.10.0

### gnutls_x509_crt_get_issuer_alt_name2 ()

    int
    gnutls_x509_crt_get_issuer_alt_name2 (gnutls_x509_crt_t cert,
                                          unsigned int seq,
                                          void *ian,
                                          size_t *ian_size,
                                          unsigned int *ian_type,
                                          unsigned int *critical);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
ian | is the place where the alternative name will be copied to |
ian_size | holds the size of ret. |
ian_type | holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t). |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

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

Since: 2.10.0

### gnutls_x509_crt_get_issuer_alt_othername_oid ()

    int
    gnutls_x509_crt_get_issuer_alt_othername_oid
                                   (gnutls_x509_crt_t cert,
                                    unsigned int seq,
                                    void *ret,
                                    size_t *ret_size);

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 `oid` is null then only the size will be filled. The `oid` returned will be null terminated, although `oid_size` will not account for the trailing null.

This function is only useful if `gnutls_x509_crt_get_issuer_alt_name()` returned `GNUTLS_SAN_OTHERNAME`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
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 otherName OID will be copied to |
ret_size | holds the size of ret. |

#### 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. `GNUTLS_SAN_OTHERNAME_XMPP`, and `GNUTLS_SAN_OTHERNAME` for unknown OIDs. It will return `GNUTLS_E_SHORT_MEMORY_BUFFER` if `ret_size` is not large enough to hold the value. In that case `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

Since: 2.10.0

### gnutls_x509_crt_get_ca_status ()

    int
    gnutls_x509_crt_get_ca_status (gnutls_x509_crt_t cert,
                                   unsigned int *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 `gnutls_x509_crt_get_basic_constraints()` if you want to read the pathLenConstraint field too.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
critical | will be non-zero if the extension is marked as critical |

#### 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.

### gnutls_x509_crt_get_basic_constraints ()

    int
    gnutls_x509_crt_get_basic_constraints (gnutls_x509_crt_t cert,
                                           unsigned int *critical,
                                           unsigned int *ca,
                                           int *pathlen);

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).

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
critical | will be non-zero if the extension is marked as critical |
ca | pointer to output integer indicating CA status, may be NULL, value is 1 if the certificate CA flag is set, 0 otherwise. |
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. |

#### 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.

### gnutls_x509_crt_get_key_usage ()

    int
    gnutls_x509_crt_get_key_usage (gnutls_x509_crt_t cert,
                                   unsigned int *key_usage,
                                   unsigned int *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`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
key_usage | where the key usage bits will be stored |
critical | will be non-zero if the extension is marked as critical |

#### Returns

zero on success, or a negative error code in case of parsing error. If the certificate does not contain the keyUsage extension `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crt_set_key_usage ()

    int
    gnutls_x509_crt_set_key_usage (gnutls_x509_crt_t crt,
                                   unsigned int usage);

This function will set the keyUsage certificate extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
usage | an ORed sequence of the GNUTLS_KEY_* elements. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_authority_info_access ()

    int
    gnutls_x509_crt_set_authority_info_access
                                   (gnutls_x509_crt_t crt,
                                    int what,
                                    gnutls_datum_t *data);

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 `data` is specified via `what` which should be gnutls_info_access_what_t values.

If `what` is `GNUTLS_IA_OCSP_URI`, `data` will hold the OCSP URI. If `what` is `GNUTLS_IA_CAISSUERS_URI`, `data` will hold the caIssuers URI.

#### Parameters

crt | Holds the certificate |
what | what data to get, a gnutls_info_access_what_t type. |
data | output data to be freed with `gnutls_free()`. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0

### gnutls_x509_crt_get_inhibit_anypolicy ()

    int
    gnutls_x509_crt_get_inhibit_anypolicy (gnutls_x509_crt_t cert,
                                           unsigned int *skipcerts,
                                           unsigned int *critical);

This function will return certificate's value of the SkipCerts, i.e., the Inhibit anyPolicy X.509 extension (2.5.29.54).

The returned value is the number of additional certificates that may appear in the path before the anyPolicy is no longer acceptable.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
skipcerts | will hold the number of certificates after which anypolicy is no longer acceptable. |
critical | will be non-zero if the extension is marked as critical |

#### Returns

zero on success, or a negative error code in case of parsing error. If the certificate does not contain the Inhibit anyPolicy extension `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

Since: 3.6.0

### gnutls_x509_crt_set_inhibit_anypolicy ()

    int
    gnutls_x509_crt_set_inhibit_anypolicy (gnutls_x509_crt_t crt,
                                           unsigned int skipcerts);

This function will set the Inhibit anyPolicy certificate extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
skipcerts | number of certificates after which anypolicy is no longer acceptable. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_get_proxy ()

    int
    gnutls_x509_crt_get_proxy (gnutls_x509_crt_t cert,
                               unsigned int *critical,
                               int *pathlen,
                               char **policyLanguage,
                               char **policy,
                               size_t *sizeof_policy);

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).

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
critical | will be non-zero if the extension is marked as critical |
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. |
policyLanguage | output variable with OID of policy language |
policy | output variable with policy data |
sizeof_policy | output variable size of policy data |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned.

### gnutls_x509_tlsfeatures_init ()

    int
    gnutls_x509_tlsfeatures_init (gnutls_x509_tlsfeatures_t *features);

This function will initialize a X.509 TLS features extension structure

#### Parameters

f | The TLS features |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_tlsfeatures_deinit ()

    void
    gnutls_x509_tlsfeatures_deinit (gnutls_x509_tlsfeatures_t Param1);

This function will deinitialize a X.509 TLS features extension structure

#### Parameters

f | The TLS features |

Since: 3.5.1

### gnutls_x509_tlsfeatures_get ()

    int
    gnutls_x509_tlsfeatures_get (gnutls_x509_tlsfeatures_t f,
                                 unsigned  idx,
                                 unsigned int *feature);

This function will get a feature from the X.509 TLS features extension structure.

#### Parameters

f | The TLS features |
idx | The index of the feature to get |
feature | If the function succeeds, the feature will be stored in this variable |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_crt_set_tlsfeatures ()

    int
    gnutls_x509_crt_set_tlsfeatures (gnutls_x509_crt_t crt,
                                     gnutls_x509_tlsfeatures_t features);

This function will set the certificates X.509 TLS extension from the given structure.

#### Parameters

crt | A X.509 certificate |
features | If the function succeeds, the features will be added to the certificate. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_crt_get_tlsfeatures ()

    int
    gnutls_x509_crt_get_tlsfeatures (gnutls_x509_crt_t cert,
                                     gnutls_x509_tlsfeatures_t features,
                                     unsigned int flags,
                                     unsigned int *critical);

This function will get the X.509 TLS features extension structure from the certificate. The returned structure needs to be freed using `gnutls_x509_tlsfeatures_deinit()`.

When the `flags` is set to `GNUTLS_EXT_FLAG_APPEND`, then if the `features` structure is empty this function will behave identically as if the flag was not set. Otherwise if there are elements in the `features` structure then they will be merged with.

Note that `features` must be initialized prior to calling this function.

#### Parameters

crt | A X.509 certificate |
features | If the function succeeds, the features will be stored in this variable. |
flags | zero or `GNUTLS_EXT_FLAG_APPEND` |
critical | the extension status |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_tlsfeatures_check_crt ()

    unsigned
    gnutls_x509_tlsfeatures_check_crt (gnutls_x509_tlsfeatures_t feat,
                                       gnutls_x509_crt_t crt);

### gnutls_x509_policy_release ()

    void
    gnutls_x509_policy_release (struct gnutls_x509_policy_st *policy);

This function will deinitialize all memory associated with the provided `policy` . The policy is allocated using `gnutls_x509_crt_get_policy()`.

#### Parameters

policy | a certificate policy |

Since: 3.1.5

### gnutls_x509_crt_get_policy ()

    int
    gnutls_x509_crt_get_policy (gnutls_x509_crt_t crt,
                                unsigned  indx,
                                struct gnutls_x509_policy_st *policy,
                                unsigned int *critical);

This function will extract the certificate policy (extension 2.5.29.32) specified by the given index.

The policy returned by this function must be deinitialized by using `gnutls_x509_policy_release()`.

#### Parameters

crt | should contain a gnutls_x509_crt_t type |
indx | This specifies which policy to return. Use (0) to get the first one. |
policy | A pointer to a policy structure. |
critical | will be non-zero if the extension is marked as critical |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

Since: 3.1.5

### gnutls_x509_crt_set_policy ()

    int
    gnutls_x509_crt_set_policy (gnutls_x509_crt_t crt,
                                const struct gnutls_x509_policy_st *policy,
                                unsigned int critical);

This function will set the certificate policy extension (2.5.29.32). Multiple calls to this function append a new policy.

Note the maximum text size for the qualifier `GNUTLS_X509_QUALIFIER_NOTICE` is 200 characters. This function will fail with `GNUTLS_E_INVALID_REQUEST` if this is exceeded.

#### Parameters

crt | should contain a gnutls_x509_crt_t type |
policy | A pointer to a policy |
critical | use non-zero if the extension is marked as critical |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.1.5

### gnutls_x509_dn_oid_known ()

    int
    gnutls_x509_dn_oid_known (const char *oid);

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.

#### Parameters

oid | holds an Object Identifier in a null terminated string |

#### Returns

1 on known OIDs and 0 otherwise.

### gnutls_x509_dn_oid_name ()

    const char *
    gnutls_x509_dn_oid_name (const char *oid,
                             unsigned int flags);

This function will return the name of a known DN OID. If `GNUTLS_X509_DN_OID_RETURN_OID` is specified this function will return the given OID if no descriptive name has been found.

#### Parameters

oid | holds an Object Identifier in a null terminated string |
flags | 0 or GNUTLS_X509_DN_OID_* |

#### Returns

A null terminated string or NULL otherwise.

Since: 3.0

### gnutls_x509_crt_get_extension_oid ()

    int
    gnutls_x509_crt_get_extension_oid (gnutls_x509_crt_t cert,
                                       unsigned  indx,
                                       void *oid,
                                       size_t *oid_size);

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 `oid` returned will be null terminated, although `oid_size` will not account for the trailing null.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | Specifies which extension OID to send. Use (0) to get the first one. |
oid | a pointer to a structure to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crt_get_extension_by_oid ()

    int
    gnutls_x509_crt_get_extension_by_oid (gnutls_x509_crt_t cert,
                                          const char *oid,
                                          unsigned  indx,
                                          void *buf,
                                          size_t *buf_size,
                                          unsigned int *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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
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 (0) to get the first one. |
buf | a pointer to a structure to hold the name (may be null) |
buf_size | initially holds the size of `buf` |
critical | will be non-zero if the extension is marked as critical |

#### Returns

On success, `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.

### gnutls_x509_crq_get_signature_algorithm ()

    int
    gnutls_x509_crq_get_signature_algorithm
                                   (gnutls_x509_crq_t crq);

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

Since 3.6.0 this function never returns a negative error code. Error cases and unknown/unsupported signature algorithms are mapped to `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

crq | should contain a gnutls_x509_cr_t type |

#### Returns

a gnutls_sign_algorithm_t value

Since: 3.4.0

### gnutls_x509_crq_get_extension_by_oid2 ()

    int
    gnutls_x509_crq_get_extension_by_oid2 (gnutls_x509_crq_t crq,
                                           const char *oid,
                                           unsigned  indx,
                                           gnutls_datum_t *output,
                                           unsigned int *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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in a null terminated string |
indx | In case multiple same OIDs exist in the extensions, this specifies which to get. Use (0) to get the first one. |
output | will hold the allocated extension data |
critical | will be non-zero if the extension is marked as critical |

#### Returns

On success, `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

Since: 3.3.8

### gnutls_x509_crt_get_extension_info ()

    int
    gnutls_x509_crt_get_extension_info (gnutls_x509_crt_t cert,
                                        unsigned  indx,
                                        void *oid,
                                        size_t *oid_size,
                                        unsigned int *critical);

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 `gnutls_x509_crt_get_extension()` to extract the data.

If the buffer provided is not long enough to hold the output, then `oid_size` is updated and `GNUTLS_E_SHORT_MEMORY_BUFFER` will be returned. The `oid` returned will be null terminated, although `oid_size` will not account for the trailing null (the latter is not true for GnuTLS prior to 3.6.0).

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | Specifies which extension OID to send. Use (0) to get the first one. |
oid | a pointer to a structure to hold the OID |
oid_size | initially holds the maximum size of `oid` , on return holds actual size of `oid` . |
critical | output variable with critical flag, may be NULL. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crt_get_extension_data ()

    int
    gnutls_x509_crt_get_extension_data (gnutls_x509_crt_t cert,
                                        unsigned  indx,
                                        void *data,
                                        size_t *sizeof_data);

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

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | Specifies which extension OID to send. Use (0) to get the first one. |
data | a pointer to a structure to hold the data (may be null) |
sizeof_data | initially holds the size of `data` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crt_get_extension_data2 ()

    int
    gnutls_x509_crt_get_extension_data2 (gnutls_x509_crt_t cert,
                                         unsigned  indx,
                                         gnutls_datum_t *data);

This function will return the requested by the index extension data in the certificate. The extension data will be allocated using `gnutls_malloc()`.

Use `gnutls_x509_crt_get_extension_info()` to extract the OID.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | Specifies which extension OID to read. Use (0) to get the first one. |
data | will contain the extension DER-encoded data |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crt_set_extension_by_oid ()

    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);

This function will set an the extension, by the specified OID, in the certificate. The extension data should be binary data DER encoded.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
oid | holds an Object Identifier 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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_dn ()

    int
    gnutls_x509_crt_set_dn (gnutls_x509_crt_t crt,
                            const char *dn,
                            const char **err);

This function will set the DN on the provided certificate. The input string should be plain ASCII or UTF-8 encoded. On DN parsing error `GNUTLS_E_PARSING_ERROR` is returned.

Note that DNs are not expected to hold DNS information, and thus no automatic IDNA conversions are attempted when using this function. If that is required (e.g., store a domain in CN), process the corresponding input with `gnutls_idna_map()`.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
dn | a comma separated DN string (RFC4514) |
err | indicates the error position (if any) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_dn_by_oid ()

    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);

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.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
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` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_issuer_dn_by_oid ()

    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);

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.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
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` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_issuer_dn ()

    int
    gnutls_x509_crt_set_issuer_dn (gnutls_x509_crt_t crt,
                                   const char *dn,
                                   const char **err);

This function will set the DN on the provided certificate. The input string should be plain ASCII or UTF-8 encoded. On DN parsing error `GNUTLS_E_PARSING_ERROR` is returned.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
dn | a comma separated DN string (RFC4514) |
err | indicates the error position (if any) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_version ()

    int
    gnutls_x509_crt_set_version (gnutls_x509_crt_t crt,
                                 unsigned int version);

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 `gnutls_x509_crt_set_subject_alt_name()` or `gnutls_x509_crt_set_key_usage()`.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
version | holds the version number. For X.509v1 certificates must be 1. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_key ()

    int
    gnutls_x509_crt_set_key (gnutls_x509_crt_t crt,
                             gnutls_x509_privkey_t key);

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

To export the public key (i.e., the SubjectPublicKeyInfo part), check `gnutls_pubkey_import_x509()`.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
key | holds a private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_ca_status ()

    int
    gnutls_x509_crt_set_ca_status (gnutls_x509_crt_t crt,
                                   unsigned int ca);

This function will set the basicConstraints certificate extension. Use `gnutls_x509_crt_set_basic_constraints()` if you want to control the pathLenConstraint field too.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
ca | true(1) or false(0). Depending on the Certificate authority status. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_basic_constraints ()

    int
    gnutls_x509_crt_set_basic_constraints (gnutls_x509_crt_t crt,
                                           unsigned int ca,
                                           int pathLenConstraint);

This function will set the basicConstraints certificate extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
ca | true(1) or false(0). Depending on the Certificate authority status. |
pathLenConstraint | non-negative error codes indicate maximum length of path, and negative error codes indicate that the pathLenConstraints field should not be present. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_subject_unique_id ()

    int
    gnutls_x509_crt_set_subject_unique_id (gnutls_x509_crt_t cert,
                                           const void *id,
                                           size_t id_size);

This function will set the X.509 certificate's subject unique ID field.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
id | The unique ID |
id_size | Holds the size of the unique ID. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.7

### gnutls_x509_crt_set_issuer_unique_id ()

    int
    gnutls_x509_crt_set_issuer_unique_id (gnutls_x509_crt_t cert,
                                          const void *id,
                                          size_t id_size);

This function will set the X.509 certificate's issuer unique ID field.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
id | The unique ID |
id_size | Holds the size of the unique ID. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.7

### gnutls_x509_crt_set_subject_alternative_name ()

    int
    gnutls_x509_crt_set_subject_alternative_name
                                   (gnutls_x509_crt_t crt,
                                    gnutls_x509_subject_alt_name_t type,
                                    const char *data_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 inconsistent with `gnutls_x509_crt_get_subject_alt_name()`.

See `gnutls_x509_crt_set_subject_alt_name()` for more information.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
type | is one of the gnutls_x509_subject_alt_name_t enumerations |
data_string | The data to be set, a (0) terminated string |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_subject_alt_name ()

    int
    gnutls_x509_crt_set_subject_alt_name (gnutls_x509_crt_t crt,
                                          gnutls_x509_subject_alt_name_t type,
                                          const void *data,
                                          unsigned int data_size,
                                          unsigned int flags);

This function will set the subject alternative name certificate extension. It can set the following types: `GNUTLS_SAN_DNSNAME` as a text string, `GNUTLS_SAN_RFC822NAME` as a text string, `GNUTLS_SAN_URI` as a text string, `GNUTLS_SAN_IPADDRESS` as a binary IP address (4 or 16 bytes), `GNUTLS_SAN_OTHERNAME_XMPP` as a UTF8 string (since 3.5.0).

Since version 3.5.7 the `GNUTLS_SAN_RFC822NAME`, `GNUTLS_SAN_DNSNAME`, and `GNUTLS_SAN_OTHERNAME_XMPP` are converted to ACE format when necessary.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
type | is one of the gnutls_x509_subject_alt_name_t enumerations |
data | The data to be set |
data_size | The size of data to be set |
flags | GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.6.0

### gnutls_x509_crt_set_subject_alt_othername ()

    int
    gnutls_x509_crt_set_subject_alt_othername
                                   (gnutls_x509_crt_t crt,
                                    const char *oid,
                                    const void *data,
                                    unsigned int data_size,
                                    unsigned int flags);

This function will set an "othername" to the subject alternative name certificate extension.

The values set are set as binary values and are expected to have the proper DER encoding. For convenience the flags `GNUTLS_FSAN_ENCODE_OCTET_STRING` and `GNUTLS_FSAN_ENCODE_UTF8_STRING` can be used to encode the provided data.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
oid | The other name OID |
data | The data to be set |
data_size | The size of data to be set |
flags | GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.0

### gnutls_x509_crt_set_issuer_alt_name ()

    int
    gnutls_x509_crt_set_issuer_alt_name (gnutls_x509_crt_t crt,
                                         gnutls_x509_subject_alt_name_t type,
                                         const void *data,
                                         unsigned int data_size,
                                         unsigned int flags);

This function will set the issuer alternative name certificate extension. It can set the same types as `gnutls_x509_crt_set_subject_alt_name()`.

Since version 3.5.7 the `GNUTLS_SAN_RFC822NAME`, `GNUTLS_SAN_DNSNAME`, and `GNUTLS_SAN_OTHERNAME_XMPP` are converted to ACE format when necessary.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
type | is one of the gnutls_x509_subject_alt_name_t enumerations |
data | The data to be set |
data_size | The size of data to be set |
flags | GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.3.0

### gnutls_x509_crt_set_issuer_alt_othername ()

    int
    gnutls_x509_crt_set_issuer_alt_othername
                                   (gnutls_x509_crt_t crt,
                                    const char *oid,
                                    const void *data,
                                    unsigned int data_size,
                                    unsigned int flags);

This function will set an "othername" to the issuer alternative name certificate extension.

The values set are set as binary values and are expected to have the proper DER encoding. For convenience the flags `GNUTLS_FSAN_ENCODE_OCTET_STRING` and `GNUTLS_FSAN_ENCODE_UTF8_STRING` can be used to encode the provided data.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
oid | The other name OID |
data | The data to be set |
data_size | The size of data to be set |
flags | GNUTLS_FSAN_SET to clear previous data or GNUTLS_FSAN_APPEND to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.0

### gnutls_x509_crt_sign ()

    int
    gnutls_x509_crt_sign (gnutls_x509_crt_t crt,
                          gnutls_x509_crt_t issuer,
                          gnutls_x509_privkey_t issuer_key);

This function is the same a `gnutls_x509_crt_sign2()` with no flags, and an appropriate hash algorithm. The hash algorithm used may vary between versions of GnuTLS, and it is tied to the security level of the issuer's public key.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
issuer | is the certificate of the certificate issuer |
issuer_key | holds the issuer's private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_sign2 ()

    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);

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.

A known limitation of this function is, that a newly-signed certificate will not be fully functional (e.g., for signature verification), until it is exported an re-imported.

After GnuTLS 3.6.1 the value of `dig` may be `GNUTLS_DIG_UNKNOWN`, and in that case, a suitable but reasonable for the key algorithm will be selected.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
issuer | is the certificate of the certificate issuer |
issuer_key | holds the issuer's private key |
dig | The message digest to use, `GNUTLS_DIG_SHA256` is a safe choice |
flags | must be 0 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_activation_time ()

    int
    gnutls_x509_crt_set_activation_time (gnutls_x509_crt_t cert,
                                         time_t act_time);

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

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
act_time | The actual time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_expiration_time ()

    int
    gnutls_x509_crt_set_expiration_time (gnutls_x509_crt_t cert,
                                         time_t exp_time);

This function will set the time this Certificate will expire. Setting an expiration time to (time_t)-1 will set to the no well-defined expiration date value.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
exp_time | The actual time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_serial ()

    int
    gnutls_x509_crt_set_serial (gnutls_x509_crt_t cert,
                                const void *serial,
                                size_t serial_size);

This function will set the X.509 certificate's serial number. While the serial number is an integer, it is often handled as an opaque field by several CAs. For this reason this function accepts any kind of data as a serial number. To be consistent with the X.509/PKIX specifications the provided `serial` should be a big-endian positive number (i.e. its leftmost bit should be zero).

The size of the serial is restricted to 20 bytes maximum by RFC5280. This function allows writing more than 20 bytes but the generated certificates in that case may be rejected by other implementations.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
serial | The serial number |
serial_size | Holds the size of the serial field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_subject_key_id ()

    int
    gnutls_x509_crt_set_subject_key_id (gnutls_x509_crt_t cert,
                                        const void *id,
                                        size_t id_size);

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

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
id | The key ID |
id_size | Holds the size of the subject key ID field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_proxy_dn ()

    int
    gnutls_x509_crt_set_proxy_dn (gnutls_x509_crt_t crt,
                                  gnutls_x509_crt_t eecrt,
                                  unsigned int raw_flag,
                                  const void *name,
                                  unsigned int sizeof_name);

This function will set the subject in `crt` to the end entity's `eecrt` subject name, and add a single Common Name component `name` of size `sizeof_name` . This corresponds to the required proxy certificate naming style. Note that if `name` is `NULL`, you MUST set it later by using `gnutls_x509_crt_set_dn_by_oid()` or similar.

#### Parameters

crt | a gnutls_x509_crt_t type with the new proxy cert |
eecrt | the end entity certificate that will be issuing the proxy |
raw_flag | must be 0, or 1 if the CN is DER encoded |
name | a pointer to the CN name, may be NULL (but MUST then be added later) |
sizeof_name | holds the size of `name` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_proxy ()

    int
    gnutls_x509_crt_set_proxy (gnutls_x509_crt_t crt,
                               int pathLenConstraint,
                               const char *policyLanguage,
                               const char *policy,
                               size_t sizeof_policy);

This function will set the proxyCertInfo extension.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
pathLenConstraint | non-negative error codes indicate maximum length of path, and negative error codes indicate that the pathLenConstraints field should not be present. |
policyLanguage | OID describing the language of `policy` . |
policy | uint8_t byte array with policy language, can be `NULL` |
sizeof_policy | size of `policy` . |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_print ()

    int
    gnutls_x509_crt_print (gnutls_x509_crt_t cert,
                           gnutls_certificate_print_formats_t format,
                           gnutls_datum_t *out);

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

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

The output `out` needs to be deallocated using `gnutls_free()`.

#### Parameters

cert | The data to be printed |
format | Indicate the format to use |
out | Newly allocated datum with null terminated string. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_print ()

    int
    gnutls_x509_crl_print (gnutls_x509_crl_t crl,
                           gnutls_certificate_print_formats_t format,
                           gnutls_datum_t *out);

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

The output `out` needs to be deallocated using `gnutls_free()`.

#### Parameters

crl | The data to be printed |
format | Indicate the format to use |
out | Newly allocated datum with null terminated string. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_get_raw_issuer_dn ()

    int
    gnutls_x509_crt_get_raw_issuer_dn (gnutls_x509_crt_t cert,
                                       gnutls_datum_t *start);

This function will return a pointer to the DER encoded DN structure and the length. This points to allocated data that must be free'd using `gnutls_free()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | will hold the starting point of the DN |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.or a negative error code on error.

### gnutls_x509_crt_get_raw_dn ()

    int
    gnutls_x509_crt_get_raw_dn (gnutls_x509_crt_t cert,
                                gnutls_datum_t *start);

This function will return a pointer to the DER encoded DN structure and the length. This points to allocated data that must be free'd using `gnutls_free()`.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | will hold the starting point of the DN |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value. or a negative error code on error.

### gnutls_x509_rdn_get ()

    int
    gnutls_x509_rdn_get (const gnutls_datum_t *idn,
                         char *buf,
                         size_t *sizeof_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.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_rdn_get2()`.

#### Parameters

idn | should contain a DER encoded RDN sequence |
buf | a pointer to a structure to hold the peer's name |
buf_size | holds the size of `buf` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, or `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned and *`buf_size` is updated if the provided buffer is not long enough, otherwise a negative error value.

### gnutls_x509_rdn_get2 ()

    int
    gnutls_x509_rdn_get2 (const gnutls_datum_t *idn,
                          gnutls_datum_t *str,
                          unsigned  flags);

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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

idn | should contain a DER encoded RDN sequence |
str | a datum that will hold the name |
flags | zero of `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, or `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned and *`buf_size` is updated if the provided buffer is not long enough, otherwise a negative error value.

### gnutls_x509_rdn_get_oid ()

    int
    gnutls_x509_rdn_get_oid (const gnutls_datum_t *idn,
                             unsigned  indx,
                             void *buf,
                             size_t *sizeof_buf);

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

#### Parameters

idn | should contain a DER encoded RDN sequence |
indx | Indicates which OID to return. Use 0 for the first one. |
buf | a pointer to a structure to hold the peer's name OID |
buf_size | holds the size of `buf` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, or `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned and *`buf_size` is updated if the provided buffer is not long enough, otherwise a negative error value.

Since: 2.4.0

### gnutls_x509_rdn_get_by_oid ()

    int
    gnutls_x509_rdn_get_by_oid (const gnutls_datum_t *idn,
                                const char *oid,
                                unsigned  indx,
                                unsigned int raw_flag,
                                void *buf,
                                size_t *sizeof_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.

#### Parameters

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 |
buf_size | holds the size of `buf` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, or `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned and *`buf_size` is updated if the provided buffer is not long enough, otherwise a negative error value.

### gnutls_x509_crt_get_subject ()

    int
    gnutls_x509_crt_get_subject (gnutls_x509_crt_t cert,
                                 gnutls_x509_dn_t *dn);

Return the Certificate's Subject DN as a `gnutls_x509_dn_t` data type, that can be decoded using `gnutls_x509_dn_get_rdn_ava()`.

Note that `dn` should be treated as constant. Because it points into the `cert` object, you should not use `dn` after `cert` is deallocated.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | output variable with pointer to uint8_t DN. |

#### Returns

Returns 0 on success, or an error code.

### gnutls_x509_crt_get_issuer ()

    int
    gnutls_x509_crt_get_issuer (gnutls_x509_crt_t cert,
                                gnutls_x509_dn_t *dn);

Return the Certificate's Issuer DN as a `gnutls_x509_dn_t` data type, that can be decoded using `gnutls_x509_dn_get_rdn_ava()`.

Note that `dn` should be treated as constant. Because it points into the `cert` object, you should not use `dn` after `cert` is deallocated.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
dn | output variable with pointer to uint8_t DN |

#### Returns

Returns 0 on success, or an error code.

### gnutls_x509_dn_get_rdn_ava ()

    int
    gnutls_x509_dn_get_rdn_ava (gnutls_x509_dn_t dn,
                                int irdn,
                                int iava,
                                gnutls_x509_ava_st *ava);

Get pointers to data within the DN. The format of the `ava` structure is shown below.

struct gnutls_x509_ava_st { gnutls_datum_t oid; gnutls_datum_t value; unsigned long value_tag; };

The X.509 distinguished name is a sequence of sequences of strings and this is what the `irdn` and `iava` indexes model.

Note that `ava` will contain pointers into the `dn` structure which in turns points to the original certificate. Thus you should not modify any data or deallocate any of those.

This is a low-level function that requires the caller to do the value conversions when necessary (e.g. from UCS-2).

#### Parameters

dn | a pointer to DN |
irdn | index of RDN |
iava | index of AVA. |
ava | Pointer to structure which will hold output information. |

#### Returns

Returns 0 on success, or an error code.

### gnutls_x509_dn_get_str ()

    int
    gnutls_x509_dn_get_str (gnutls_x509_dn_t dn,
                            gnutls_datum_t *str);

This function will allocate buffer and copy the name in the provided DN. 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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

dn | a pointer to DN |
str | a datum that will hold the name |
flags | zero or `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.7

### gnutls_x509_dn_get_str2 ()

    int
    gnutls_x509_dn_get_str2 (gnutls_x509_dn_t dn,
                             gnutls_datum_t *str,
                             unsigned  flags);

### gnutls_x509_dn_set_str ()

    int
    gnutls_x509_dn_set_str (gnutls_x509_dn_t dn,
                            const char *str,
                            const char **err);

This function will set the DN on the provided DN structure. The input string should be plain ASCII or UTF-8 encoded. On DN parsing error `GNUTLS_E_PARSING_ERROR` is returned.

#### Parameters

dn | a pointer to DN |
str | a comma separated DN string (RFC4514) |
err | indicates the error position (if any) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.3

### gnutls_x509_dn_init ()

    int
    gnutls_x509_dn_init (gnutls_x509_dn_t *dn);

This function initializes a gnutls_x509_dn_t type.

The object returned must be deallocated using `gnutls_x509_dn_deinit()`.

#### Parameters

dn | the object to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.4.0

### gnutls_x509_dn_import ()

    int
    gnutls_x509_dn_import (gnutls_x509_dn_t dn,
                           const gnutls_datum_t *data);

This function parses an RDN sequence and stores the result to a gnutls_x509_dn_t type. The data must have been initialized with `gnutls_x509_dn_init()`. You may use `gnutls_x509_dn_get_rdn_ava()` to decode the DN.

#### Parameters

dn | the structure that will hold the imported DN |
data | should contain a DER encoded RDN sequence |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.4.0

### gnutls_x509_dn_export ()

    int
    gnutls_x509_dn_export (gnutls_x509_dn_t dn,
                           gnutls_x509_crt_fmt_t format,
                           void *output_data,
                           size_t *output_data_size);

This function will export the DN 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 NAME".

#### Parameters

dn | Holds the uint8_t DN object |
format | the format of output params. One of PEM or DER. |
output_data | will contain a DN PEM or DER encoded |
output_data_size | holds the size of output_data (and will be replaced by the actual size of parameters) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_dn_export2 ()

    int
    gnutls_x509_dn_export2 (gnutls_x509_dn_t dn,
                            gnutls_x509_crt_fmt_t format,
                            gnutls_datum_t *out);

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

The output buffer is allocated using `gnutls_malloc()`.

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

#### Parameters

dn | Holds the uint8_t DN object |
format | the format of output params. One of PEM or DER. |
out | will contain a DN PEM or DER encoded |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.1.3

### gnutls_x509_dn_deinit ()

    void
    gnutls_x509_dn_deinit (gnutls_x509_dn_t dn);

This function deallocates the DN object as returned by `gnutls_x509_dn_import()`.

#### Parameters

dn | a DN uint8_t object pointer. |

Since: 2.4.0

### gnutls_x509_crl_init ()

    int
    gnutls_x509_crl_init (gnutls_x509_crl_t *crl);

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.

#### Parameters

crl | A pointer to the type to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_deinit ()

    void
    gnutls_x509_crl_deinit (gnutls_x509_crl_t crl);

This function will deinitialize a CRL structure.

#### Parameters

crl | The data to be deinitialized |

### gnutls_x509_crl_import ()

    int
    gnutls_x509_crl_import (gnutls_x509_crl_t crl,
                            const gnutls_datum_t *data,
                            gnutls_x509_crt_fmt_t format);

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".

#### Parameters

crl | The data to store the parsed CRL. |
data | The DER or PEM encoded CRL. |
format | One of DER or PEM |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_export ()

    int
    gnutls_x509_crl_export (gnutls_x509_crl_t crl,
                            gnutls_x509_crt_fmt_t format,
                            void *output_data,
                            size_t *output_data_size);

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".

#### Parameters

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) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_export2 ()

    int
    gnutls_x509_crl_export2 (gnutls_x509_crl_t crl,
                             gnutls_x509_crt_fmt_t format,
                             gnutls_datum_t *out);

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

The output buffer is allocated using `gnutls_malloc()`.

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

#### Parameters

crl | Holds the revocation list |
format | the format of output params. One of PEM or DER. |
out | will contain a private key PEM or DER encoded |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since 3.1.3

### gnutls_x509_crl_get_raw_issuer_dn ()

    int
    gnutls_x509_crl_get_raw_issuer_dn (gnutls_x509_crl_t crl,
                                       gnutls_datum_t *dn);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
dn | will hold the starting point of the DN |

#### Returns

a negative error code on error, and (0) on success.

Since: 2.12.0

### gnutls_x509_crl_get_issuer_dn ()

    int
    gnutls_x509_crl_get_issuer_dn (gnutls_x509_crl_t crl,
                                   char *buf,
                                   size_t *sizeof_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 `NULL` then only the size will be filled.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crl_get_issuer_dn3()`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
buf | a pointer to a structure to hold the peer's name (may be null) |
sizeof_buf | initially holds the size of `buf` |

#### 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.

### gnutls_x509_crl_get_issuer_dn2 ()

    int
    gnutls_x509_crl_get_issuer_dn2 (gnutls_x509_crl_t crl,
                                    gnutls_datum_t *dn);

This function will allocate buffer and copy the name of the CRL issuer. 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.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crl_get_issuer_dn3()`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.1.10

### gnutls_x509_crl_get_issuer_dn3 ()

    int
    gnutls_x509_crl_get_issuer_dn3 (gnutls_x509_crl_t crl,
                                    gnutls_datum_t *dn,
                                    unsigned  flags);

This function will allocate buffer and copy the name of the CRL issuer. 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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |
flags | zero or `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.7

### gnutls_x509_crl_get_issuer_dn_by_oid ()

    int
    gnutls_x509_crl_get_issuer_dn_by_oid (gnutls_x509_crl_t crl,
                                          const char *oid,
                                          unsigned  indx,
                                          unsigned int raw_flag,
                                          void *buf,
                                          size_t *sizeof_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 `gnutls_x509_dn_oid_known()`.

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
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 (0) 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` |

#### 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.

### gnutls_x509_crl_get_dn_oid ()

    int
    gnutls_x509_crl_get_dn_oid (gnutls_x509_crl_t crl,
                                unsigned  indx,
                                void *oid,
                                size_t *sizeof_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.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
indx | Specifies which DN OID to send. Use (0) to get the first one. |
oid | a pointer to store the OID (may be null) |
sizeof_oid | initially holds the size of 'oid' |

#### 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.

### gnutls_x509_crl_get_signature_algorithm ()

    int
    gnutls_x509_crl_get_signature_algorithm
                                   (gnutls_x509_crl_t crl);

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

Since 3.6.0 this function never returns a negative error code. Error cases and unknown/unsupported signature algorithms are mapped to `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |

#### Returns

a gnutls_sign_algorithm_t value

### gnutls_x509_crl_get_signature ()

    int
    gnutls_x509_crl_get_signature (gnutls_x509_crl_t crl,
                                   char *sig,
                                   size_t *sizeof_sig);

This function will extract the signature field of a CRL.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
sig | a pointer where the signature part will be copied (may be null). |
sizeof_sig | initially holds the size of `sig` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_get_version ()

    int
    gnutls_x509_crl_get_version (gnutls_x509_crl_t crl);

This function will return the version of the specified CRL.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |

#### Returns

The version number, or a negative error code on error.

### gnutls_x509_crl_get_signature_oid ()

    int
    gnutls_x509_crl_get_signature_oid (gnutls_x509_crl_t crl,
                                       char *oid,
                                       size_t *oid_size);

This function will return the OID of the signature algorithm that has been used to sign this CRL. This is function is useful in the case `gnutls_x509_crl_get_signature_algorithm()` returned `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

zero or a negative error code on error.

Since: 3.5.0

### gnutls_x509_crl_get_this_update ()

    time_t
    gnutls_x509_crl_get_this_update (gnutls_x509_crl_t crl);

This function will return the time this CRL was issued.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |

#### Returns

when the CRL was issued, or (time_t)-1 on error.

### gnutls_x509_crl_get_next_update ()

    time_t
    gnutls_x509_crl_get_next_update (gnutls_x509_crl_t crl);

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.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |

#### Returns

when the next CRL will be issued, or (time_t)-1 on error.

### gnutls_x509_crl_get_crt_count ()

    int
    gnutls_x509_crl_get_crt_count (gnutls_x509_crl_t crl);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |

#### Returns

number of certificates, a negative error code on failure.

### gnutls_x509_crl_get_crt_serial ()

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

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

Note that this function will have performance issues in large sequences of revoked certificates. In that case use `gnutls_x509_crl_iter_crt_serial()`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_iter_crt_serial ()

    int
    gnutls_x509_crl_iter_crt_serial (gnutls_x509_crl_t crl,
                                     gnutls_x509_crl_iter_t *Param2,
                                     unsigned char *serial,
                                     size_t *serial_size,
                                     time_t *t);

This function performs the same as `gnutls_x509_crl_get_crt_serial()`, but reads sequentially and keeps state in the iterator between calls. That allows it to provide better performance in sequences with many elements (50000+).

When past the last element is accessed `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned and the iterator is reset.

After use, the iterator must be deinitialized using `gnutls_x509_crl_iter_deinit()`.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
iter | A pointer to an iterator (initially the iterator should be `NULL`) |
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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_iter_deinit ()

    void
    gnutls_x509_crl_iter_deinit (gnutls_x509_crl_iter_t Param1);

This function will deinitialize an iterator type.

#### Parameters

iter | The iterator to be deinitialized |

### gnutls_x509_crl_check_issuer ()

    unsigned
    gnutls_x509_crl_check_issuer (gnutls_x509_crl_t crl,
                                  gnutls_x509_crt_t issuer);

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

#### Parameters

crl | is the CRL to be checked |
issuer | is the certificate of a possible issuer |

#### Returns

true (1) if the given CRL was issued by the given issuer, and false (0) if not.

### gnutls_x509_crl_list_import2 ()

    int
    gnutls_x509_crl_list_import2 (gnutls_x509_crl_t **crls,
                                  unsigned int *size,
                                  const gnutls_datum_t *data,
                                  gnutls_x509_crt_fmt_t format,
                                  unsigned int flags);

This function will convert the given CRL list to the native gnutls_x509_crl_t format. The output will be stored in `crls` . They will be automatically initialized.

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

#### Parameters

crls | Will contain the parsed crl list. |
size | It will contain the size of the list. |
data | The CRL data. |
format | One of DER or PEM. |
flags | must be (0) or an OR'd sequence of gnutls_certificate_import_flags. |

#### Returns

the number of certificates read or a negative error value.

Since: 3.0

### gnutls_x509_crl_list_import ()

    int
    gnutls_x509_crl_list_import (gnutls_x509_crl_t *crls,
                                 unsigned int *crl_max,
                                 const gnutls_datum_t *data,
                                 gnutls_x509_crt_fmt_t format,
                                 unsigned int flags);

This function will convert the given CRL list to the native gnutls_x509_crl_t format. The output will be stored in `crls` . They will be automatically initialized.

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

#### Parameters

crls | Indicates where the parsed CRLs will be copied to. Must not be initialized. |
crl_max | Initially must hold the maximum number of crls. It will be updated with the number of crls available. |
data | The CRL data |
format | One of DER or PEM. |
flags | must be (0) or an OR'd sequence of gnutls_certificate_import_flags. |

#### Returns

the number of certificates read or a negative error value.

Since: 3.0

### gnutls_x509_crl_set_version ()

    int
    gnutls_x509_crl_set_version (gnutls_x509_crl_t crl,
                                 unsigned int version);

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.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
version | holds the version number. For CRLv1 crls must be 1. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_set_this_update ()

    int
    gnutls_x509_crl_set_this_update (gnutls_x509_crl_t crl,
                                     time_t act_time);

This function will set the time this CRL was issued.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
act_time | The actual time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_set_next_update ()

    int
    gnutls_x509_crl_set_next_update (gnutls_x509_crl_t crl,
                                     time_t exp_time);

This function will set the time this CRL will be updated. This is an optional value to be set on a CRL and this call can be omitted when generating a CRL.

Prior to GnuTLS 3.5.7, setting a nextUpdate field was required in order to generate a CRL.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
exp_time | The actual time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_set_crt_serial ()

    int
    gnutls_x509_crl_set_crt_serial (gnutls_x509_crl_t crl,
                                    const void *serial,
                                    size_t serial_size,
                                    time_t revocation_time);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
serial | The revoked certificate's serial number |
serial_size | Holds the size of the serial field. |
revocation_time | The time this certificate was revoked |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_set_crt ()

    int
    gnutls_x509_crl_set_crt (gnutls_x509_crl_t crl,
                             gnutls_x509_crt_t crt,
                             time_t revocation_time);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
crt | a certificate of type gnutls_x509_crt_t with the revoked certificate |
revocation_time | The time this certificate was revoked |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_get_authority_key_id ()

    int
    gnutls_x509_crl_get_authority_key_id (gnutls_x509_crl_t crl,
                                          void *id,
                                          size_t *id_size,
                                          unsigned int *critical);

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 `GNUTLS_E_X509_UNSUPPORTED_EXTENSION`, if the extension contains the name and serial number of the certificate. In that case `gnutls_x509_crl_get_authority_key_gn_serial()` may be used.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
id | The place where the identifier will be copied |
id_size | Holds the size of the result field. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code in case of an error.

Since: 2.8.0

### gnutls_x509_crl_get_authority_key_gn_serial ()

    int
    gnutls_x509_crl_get_authority_key_gn_serial
                                   (gnutls_x509_crl_t crl,
                                    unsigned int seq,
                                    void *alt,
                                    size_t *alt_size,
                                    unsigned int *alt_type,
                                    void *serial,
                                    size_t *serial_size,
                                    unsigned int *critical);

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 `seq` can be used as a counter to request them all until `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
seq | specifies the sequence number of the alt name (0 for the first one, 1 for the second etc.) |
alt | is the place where the alternative name will be copied to |
alt_size | holds the size of alt. |
alt_type | holds the type of the alternative name (one of gnutls_x509_subject_alt_name_t). |
serial | buffer to store the serial number (may be null) |
serial_size | Holds the size of the serial field (may be null) |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

Returns 0 on success, or an error code.

Since: 3.0

### gnutls_x509_crl_get_number ()

    int
    gnutls_x509_crl_get_number (gnutls_x509_crl_t crl,
                                void *ret,
                                size_t *ret_size,
                                unsigned int *critical);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
ret | The place where the number will be copied |
ret_size | Holds the size of the result field. |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code in case of an error.

Since: 2.8.0

### gnutls_x509_crl_get_extension_oid ()

    int
    gnutls_x509_crl_get_extension_oid (gnutls_x509_crl_t crl,
                                       unsigned  indx,
                                       void *oid,
                                       size_t *sizeof_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.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
indx | Specifies which extension OID to send, use (0) to get the first one. |
oid | a pointer to store the OID (may be null) |
sizeof_oid | initially holds the size of `oid` |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crl_get_extension_info ()

    int
    gnutls_x509_crl_get_extension_info (gnutls_x509_crl_t crl,
                                        unsigned  indx,
                                        void *oid,
                                        size_t *sizeof_oid,
                                        unsigned int *critical);

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 `gnutls_x509_crl_get_extension_data()` to extract the data.

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
indx | Specifies which extension OID to send, use (0) to get the first one. |
oid | a pointer to store the OID |
sizeof_oid | initially holds the maximum size of `oid` , on return holds actual size of `oid` . |
critical | output variable with critical flag, may be NULL. |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crl_get_extension_data ()

    int
    gnutls_x509_crl_get_extension_data (gnutls_x509_crl_t crl,
                                        unsigned  indx,
                                        void *data,
                                        size_t *sizeof_data);

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

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
indx | Specifies which extension OID to send. Use (0) to get the first one. |
data | a pointer to a structure to hold the data (may be null) |
sizeof_data | initially holds the size of `oid` |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crl_get_extension_data2 ()

    int
    gnutls_x509_crl_get_extension_data2 (gnutls_x509_crl_t crl,
                                         unsigned  indx,
                                         gnutls_datum_t *data);

This function will return the requested by the index extension data in the certificate revocation list. The extension data will be allocated using `gnutls_malloc()`.

Use `gnutls_x509_crt_get_extension_info()` to extract the OID.

#### Parameters

crl | should contain a gnutls_x509_crl_t type |
indx | Specifies which extension OID to read. Use (0) to get the first one. |
data | will contain the extension DER-encoded data |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

### gnutls_x509_crl_set_authority_key_id ()

    int
    gnutls_x509_crl_set_authority_key_id (gnutls_x509_crl_t crl,
                                          const void *id,
                                          size_t id_size);

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.

#### Parameters

crl | a CRL of type gnutls_x509_crl_t |
id | The key ID |
id_size | Holds the size of the serial field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crl_set_number ()

    int
    gnutls_x509_crl_set_number (gnutls_x509_crl_t crl,
                                const void *nr,
                                size_t nr_size);

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.

#### Parameters

crl | a CRL of type gnutls_x509_crl_t |
nr | The CRL number |
nr_size | Holds the size of the nr field. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### GNUTLS_PROFILE_TO_VFLAGS()

    #define GNUTLS_PROFILE_TO_VFLAGS(x) (((unsigned)x) << 24)

### GNUTLS_VFLAGS_TO_PROFILE()

    #define GNUTLS_VFLAGS_TO_PROFILE(x) ((((unsigned)x) >> 24) & 0xff)

### gnutls_certificate_verification_profile_get_name ()

    const char *
    gnutls_certificate_verification_profile_get_name
                                   ();

Convert a gnutls_certificate_verification_profiles_t value to a string.

#### Parameters

id | is a profile ID |

#### Returns

a string that contains the name of the specified profile or `NULL`.

### gnutls_x509_crt_list_verify ()

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

This function will try to verify the given certificate list and return its status. The details of the verification are the same as in `gnutls_x509_trust_list_verify_crt2()`.

You must 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.

#### Parameters

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. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_verify ()

    int
    gnutls_x509_crt_verify (gnutls_x509_crt_t cert,
                            const gnutls_x509_crt_t *CA_list,
                            unsigned  CA_list_length,
                            unsigned int flags,
                            unsigned int *verify);

This function will try to verify the given certificate and return its status. Note that a verification error does not imply a negative return status. In that case the `verify` status is set.

The details of the verification are the same as in `gnutls_x509_trust_list_verify_crt2()`.

#### Parameters

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. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crl_verify ()

    int
    gnutls_x509_crl_verify (gnutls_x509_crl_t crl,
                            const gnutls_x509_crt_t *CA_list,
                            unsigned  CA_list_length,
                            unsigned int flags,
                            unsigned int *verify);

This function will try to verify the given crl and return its verification status. See `gnutls_x509_crt_list_verify()` for a detailed description of return values. Note that since GnuTLS 3.1.4 this function includes the time checks.

Note that value in `verify` is set only when the return value of this function is success (i.e, failure to trust a CRL a certificate does not imply a negative return value).

Before GnuTLS 3.5.7 this function would return zero or a positive number on success.

#### Parameters

crl | is the crl to be verified |
trusted_cas | is a certificate list that is considered to be trusted one |
tcas_size | 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. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0), otherwise a negative error value.

### gnutls_x509_crt_verify_data2 ()

    int
    gnutls_x509_crt_verify_data2 (gnutls_x509_crt_t crt,
                                  gnutls_sign_algorithm_t algo,
                                  unsigned int flags,
                                  const gnutls_datum_t *data,
                                  const gnutls_datum_t *signature);

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

#### Parameters

crt | Holds the certificate to verify with |
algo | The signature algorithm used |
flags | Zero or an OR list of gnutls_certificate_verify_flags |
data | holds the signed data |
signature | contains the signature |

#### Returns

In case of a verification failure `GNUTLS_E_PK_SIG_VERIFY_FAILED` is returned, `GNUTLS_E_EXPIRED` or `GNUTLS_E_NOT_YET_ACTIVATED` on expired or not yet activated certificate and zero or positive code on success.

Note that since GnuTLS 3.5.6 this function introduces checks in the end certificate (`crt` ), including time checks and key usage checks.

Since: 3.4.0

### gnutls_x509_crt_check_revocation ()

    int
    gnutls_x509_crt_check_revocation (gnutls_x509_crt_t cert,
                                      const gnutls_x509_crl_t *crl_list,
                                      unsigned  crl_list_length);

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
crl_list | should contain a list of gnutls_x509_crl_t types |
crl_list_length | the length of the crl_list |

#### Returns

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

### gnutls_x509_crt_get_fingerprint ()

    int
    gnutls_x509_crt_get_fingerprint (gnutls_x509_crt_t cert,
                                     gnutls_digest_algorithm_t algo,
                                     void *buf,
                                     size_t *buf_size);

This function will calculate and copy the certificate's fingerprint in the provided buffer. The fingerprint is a hash of the DER-encoded data of the certificate.

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

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
algo | is a digest algorithm |
buf | a pointer to a structure to hold the fingerprint (may be null) |
buf_size | initially holds the size of `buf` |

#### Returns

`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.

### gnutls_x509_crt_get_key_purpose_oid ()

    int
    gnutls_x509_crt_get_key_purpose_oid (gnutls_x509_crt_t cert,
                                         unsigned  indx,
                                         void *oid,
                                         size_t *oid_size,
                                         unsigned int *critical);

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. The `oid` returned will be null terminated, although `oid_size` will not account for the trailing null.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
indx | This specifies which OID to return. Use (0) to get the first one. |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |
critical | output flag to indicate criticality of extension |

#### Returns

`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.

### gnutls_x509_crt_set_key_purpose_oid ()

    int
    gnutls_x509_crt_set_key_purpose_oid (gnutls_x509_crt_t cert,
                                         const void *oid,
                                         unsigned int critical);

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.

#### Parameters

cert | a certificate of type gnutls_x509_crt_t |
oid | a pointer to a null terminated string that holds the OID |
critical | Whether this extension will be critical or not |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned.

### gnutls_x509_crt_check_key_purpose ()

    unsigned
    gnutls_x509_crt_check_key_purpose (gnutls_x509_crt_t cert,
                                       const char *purpose,
                                       unsigned  flags);

This function will check whether the given certificate matches the provided key purpose. If `flags` contains `GNUTLS_KP_FLAG_ALLOW_ANY` then it a certificate marked for any purpose will not match.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
purpose | a key purpose OID (e.g., `GNUTLS_KP_CODE_SIGNING`) |
flags | zero or `GNUTLS_KP_FLAG_DISALLOW_ANY` |

#### Returns

zero if the key purpose doesn't match, and non-zero otherwise.

Since: 3.5.6

### GNUTLS_PKCS_CIPHER_MASK()

    #define GNUTLS_PKCS_CIPHER_MASK(x) ((x) & (~(GNUTLS_PKCS_NULL_PASSWORD)))

### gnutls_pkcs_schema_get_name ()

    const char *
    gnutls_pkcs_schema_get_name (unsigned int schema);

This function will return a human readable description of the PKCS12 or PBES2 schema.

#### Parameters

schema | Holds the PKCS 12 or PBES2 schema (`gnutls_pkcs_encrypt_flags_t`) |

#### Returns

a constraint string or `NULL` on error.

Since: 3.4.0

### gnutls_pkcs_schema_get_oid ()

    const char *
    gnutls_pkcs_schema_get_oid (unsigned int schema);

This function will return the object identifier of the PKCS12 or PBES2 schema.

#### Parameters

schema | Holds the PKCS 12 or PBES2 schema (`gnutls_pkcs_encrypt_flags_t`) |

#### Returns

a constraint string or `NULL` on error.

Since: 3.4.0

### gnutls_x509_privkey_init ()

    int
    gnutls_x509_privkey_init (gnutls_x509_privkey_t *key);

This function will initialize a private key type.

#### Parameters

key | A pointer to the type to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_deinit ()

    void
    gnutls_x509_privkey_deinit (gnutls_x509_privkey_t key);

This function will deinitialize a private key structure.

#### Parameters

key | The key to be deinitialized |

### gnutls_x509_privkey_sec_param ()

    gnutls_sec_param_t
    gnutls_x509_privkey_sec_param (gnutls_x509_privkey_t key);

This function will return the security parameter appropriate with this private key.

#### Parameters

key | a key |

#### Returns

On success, a valid security parameter is returned otherwise `GNUTLS_SEC_PARAM_UNKNOWN` is returned.

Since: 2.12.0

### gnutls_x509_privkey_set_pin_function ()

    void
    gnutls_x509_privkey_set_pin_function (gnutls_x509_privkey_t key,
                                          gnutls_pin_callback_t fn,
                                          void *userdata);

This function will set a callback function to be used when it is required to access a protected object. This function overrides the global function set using `gnutls_pkcs11_set_pin_function()`.

Note that this callback is used when decrypting a key.

#### Parameters

privkey | The certificate structure |
fn | the callback |
userdata | data associated with the callback |

Since: 3.4.0

### gnutls_x509_privkey_cpy ()

    int
    gnutls_x509_privkey_cpy (gnutls_x509_privkey_t dst,
                             gnutls_x509_privkey_t src);

This function will copy a private key from source to destination key. Destination has to be initialized.

#### Parameters

dst | The destination key, which should be initialized. |
src | The source key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import ()

    int
    gnutls_x509_privkey_import (gnutls_x509_privkey_t key,
                                const gnutls_datum_t *data,
                                gnutls_x509_crt_fmt_t format);

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 that contains "PRIVATE KEY". Note that this function falls back to PKCS #8 decoding without password, if the default format fails to import.

#### Parameters

key | The data to store the parsed key |
data | The DER or PEM encoded certificate. |
format | One of DER or PEM |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_pkcs8 ()

    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);

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` . Both RSA and DSA 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.

If the `GNUTLS_PKCS_PLAIN` flag is specified and the supplied data are encrypted then `GNUTLS_E_DECRYPTION_FAILED` is returned.

#### Parameters

key | The data 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. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_openssl ()

    int
    gnutls_x509_privkey_import_openssl (gnutls_x509_privkey_t key,
                                        const gnutls_datum_t *data,
                                        const char *password);

This function will convert the given PEM encrypted to the native gnutls_x509_privkey_t format. The output will be stored in `key` .

The `password` should be in ASCII. If the password is not provided or wrong then `GNUTLS_E_DECRYPTION_FAILED` will be returned.

If the Certificate is PEM encoded it should have a header of "PRIVATE KEY" and the "DEK-Info" header.

#### Parameters

key | The data to store the parsed key |
data | The DER or PEM encoded key. |
password | the password to decrypt the key (if it is encrypted). |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_pkcs8_info ()

    int
    gnutls_pkcs8_info (const gnutls_datum_t *data,
                       gnutls_x509_crt_fmt_t format,
                       unsigned int *schema,
                       unsigned int *cipher,
                       void *salt,
                       unsigned int *salt_size,
                       unsigned int *iter_count,
                       char **oid);

This function will provide information on the algorithms used in a particular PKCS #8 structure. If the structure algorithms are unknown the code `GNUTLS_E_UNKNOWN_CIPHER_TYPE` will be returned, and only `oid` , will be set. That is, `oid` will be set on encrypted PKCS #8 structures whether supported or not. It must be deinitialized using `gnutls_free()`. The other variables are only set on supported structures.

#### Parameters

data | Holds the PKCS #8 data |
format | the format of the PKCS #8 data |
schema | indicate the schema as one of `gnutls_pkcs_encrypt_flags_t` |
cipher | the cipher used as `gnutls_cipher_algorithm_t` |
salt | PBKDF2 salt (if non-NULL then `salt_size` initially holds its size) |
salt_size | PBKDF2 salt size |
iter_count | PBKDF2 iteration count |
oid | if non-NULL it will contain an allocated null-terminated variable with the OID |

#### Returns

`GNUTLS_E_INVALID_REQUEST` if the provided structure isn't an encrypted key, `GNUTLS_E_UNKNOWN_CIPHER_TYPE` if the structure's encryption isn't supported, or another negative error code in case of a failure. Zero on success.

Since: 3.4.0

### gnutls_x509_privkey_import2 ()

    int
    gnutls_x509_privkey_import2 (gnutls_x509_privkey_t key,
                                 const gnutls_datum_t *data,
                                 gnutls_x509_crt_fmt_t format,
                                 const char *password,
                                 unsigned int flags);

This function will import the given DER or PEM encoded key, to the native gnutls_x509_privkey_t format, irrespective of the input format. The input format is auto-detected.

The supported formats are basic unencrypted key, PKCS8, PKCS12, and the openssl format.

If the provided key is encrypted but no password was given, then `GNUTLS_E_DECRYPTION_FAILED` is returned. Since GnuTLS 3.4.0 this function will utilize the PIN callbacks if any.

#### Parameters

key | The data to store the parsed key |
data | The DER or PEM encoded key. |
format | One of DER or PEM |
password | A password (optional) |
flags | an ORed sequence of gnutls_pkcs_encrypt_flags_t |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_rsa_raw ()

    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);

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

#### Parameters

key | The data 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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_rsa_raw2 ()

    int
    gnutls_x509_privkey_import_rsa_raw2 (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,
                                         const gnutls_datum_t *e1,
                                         const gnutls_datum_t *e2);

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

#### Parameters

key | The data 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 (optional) |
e1 | holds e1 = d mod (p-1) (optional) |
e2 | holds e2 = d mod (q-1) (optional) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_ecc_raw ()

    int
    gnutls_x509_privkey_import_ecc_raw (gnutls_x509_privkey_t key,
                                        gnutls_ecc_curve_t curve,
                                        const gnutls_datum_t *x,
                                        const gnutls_datum_t *y,
                                        const gnutls_datum_t *k);

This function will convert the given elliptic curve parameters to the native gnutls_x509_privkey_t format. The output will be stored in `key` . For EdDSA keys, the `x` and `k` values must be in the native to curve format.

#### Parameters

key | The data to store the parsed key |
curve | holds the curve |
x | holds the x-coordinate |
y | holds the y-coordinate |
k | holds the k |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0

### gnutls_x509_privkey_import_gost_raw ()

    int
    gnutls_x509_privkey_import_gost_raw (gnutls_x509_privkey_t key,
                                         gnutls_ecc_curve_t curve,
                                         gnutls_digest_algorithm_t digest,
                                         gnutls_gost_paramset_t paramset,
                                         const gnutls_datum_t *x,
                                         const gnutls_datum_t *y,
                                         const gnutls_datum_t *k);

This function will convert the given GOST private key's parameters to the native gnutls_x509_privkey_t format. The output will be stored in `key` . `digest` should be one of GNUTLS_DIG_GOSR_94, GNUTLS_DIG_STREEBOG_256 or GNUTLS_DIG_STREEBOG_512. If `paramset` is set to GNUTLS_GOST_PARAMSET_UNKNOWN default one will be selected depending on `digest` .

Note: parameters should be stored with least significant byte first. On version 3.6.3 big-endian format was used incorrectly.

#### Parameters

key | The data to store the parsed key |
curve | holds the curve |
digest | will hold the digest |
paramset | will hold the GOST parameter set ID |
x | holds the x-coordinate |
y | holds the y-coordinate |
k | holds the k (private key) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.3

### gnutls_x509_privkey_fix ()

    int
    gnutls_x509_privkey_fix (gnutls_x509_privkey_t key);

This function will recalculate the secondary parameters in a key. In RSA keys, this can be the coefficient and exponent1,2.

#### Parameters

key | a key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_export_dsa_raw ()

    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);

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.

#### Parameters

key | a key |
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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_dsa_raw ()

    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);

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

#### Parameters

key | The data to store the parsed key |
p | holds the p |
q | holds the q |
g | holds the g |
y | holds the y (optional) |
x | holds the x |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_import_dh_raw ()

    int
    gnutls_x509_privkey_import_dh_raw (gnutls_x509_privkey_t key,
                                       const gnutls_dh_params_t params,
                                       const gnutls_datum_t *y,
                                       const gnutls_datum_t *x);

This function will convert the given Diffie-Hellman raw parameters to the native gnutls_x509_privkey_t format. The output will be stored in `key` .

#### Parameters

key | The data to store the parsed key |
params | holds the `gnutls_dh_params_t` |
y | holds the y (optional) |
x | holds the x |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_get_pk_algorithm ()

    int
    gnutls_x509_privkey_get_pk_algorithm (gnutls_x509_privkey_t key);

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

#### Parameters

key | should contain a gnutls_x509_privkey_t type |

#### Returns

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

### gnutls_x509_privkey_get_pk_algorithm2 ()

    int
    gnutls_x509_privkey_get_pk_algorithm2 (gnutls_x509_privkey_t key,
                                           unsigned int *bits);

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

#### Parameters

key | should contain a gnutls_x509_privkey_t type |
bits | The number of bits in the public key algorithm |

#### Returns

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

### gnutls_x509_privkey_get_spki ()

    int
    gnutls_x509_privkey_get_spki (gnutls_x509_privkey_t key,
                                  gnutls_x509_spki_t spki,
                                  unsigned int flags);

This function will return the public key information of a private key. The provided `spki` must be initialized.

#### Parameters

key | should contain a gnutls_x509_privkey_t type |
spki | a SubjectPublicKeyInfo structure of type gnutls_x509_spki_t |
flags | must be zero |

#### Returns

Zero on success, or a negative error code on error.

### gnutls_x509_privkey_set_spki ()

    int
    gnutls_x509_privkey_set_spki (gnutls_x509_privkey_t key,
                                  const gnutls_x509_spki_t spki,
                                  unsigned int flags);

This function will return the public key information of a private key. The provided `spki` must be initialized.

#### Parameters

key | should contain a gnutls_x509_privkey_t type |
spki | a SubjectPublicKeyInfo structure of type gnutls_x509_spki_t |
flags | must be zero |

#### Returns

Zero on success, or a negative error code on error.

### gnutls_x509_privkey_get_key_id ()

    int
    gnutls_x509_privkey_get_key_id (gnutls_x509_privkey_t key,
                                    unsigned int flags,
                                    unsigned char *output_data,
                                    size_t *output_data_size);

This function will return a unique ID that 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.

#### Parameters

key | a key |
flags | should be one of the flags from `gnutls_keyid_flags_t` |
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) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_generate ()

    int
    gnutls_x509_privkey_generate (gnutls_x509_privkey_t key,
                                  gnutls_pk_algorithm_t algo,
                                  unsigned int bits,
                                  unsigned int flags);

This function will generate a random private key. Note that this function must be called on an initialized private key.

The flag `GNUTLS_PRIVKEY_FLAG_PROVABLE` instructs the key generation process to use algorithms like Shawe-Taylor (from FIPS PUB186-4) which generate provable parameters out of a seed for RSA and DSA keys. See `gnutls_x509_privkey_generate2()` for more information.

Note that when generating an elliptic curve key, the curve can be substituted in the place of the bits parameter using the `GNUTLS_CURVE_TO_BITS()` macro. The input to the macro is any curve from `gnutls_ecc_curve_t`.

For DSA keys, if the subgroup size needs to be specified check the `GNUTLS_SUBGROUP_TO_BITS()` macro.

It is recommended to do not set the number of `bits` directly, use `gnutls_sec_param_to_pk_bits()` instead .

See also `gnutls_privkey_generate()`, `gnutls_x509_privkey_generate2()`.

#### Parameters

key | an initialized key |
algo | is one of the algorithms in gnutls_pk_algorithm_t. |
bits | the size of the parameters to generate |
flags | Must be zero or flags from gnutls_privkey_flags_t. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_set_flags ()

    void
    gnutls_x509_privkey_set_flags (gnutls_x509_privkey_t key,
                                   unsigned int flags);

This function will set flags for the specified private key, after it is generated. Currently this is useful for the `GNUTLS_PRIVKEY_FLAG_EXPORT_COMPAT` to allow exporting a "provable" private key in backwards compatible way.

#### Parameters

key | A key of type gnutls_x509_privkey_t |
flags | flags from the `gnutls_privkey_flags` |

Since: 3.5.0

### gnutls_x509_privkey_generate2 ()

    int
    gnutls_x509_privkey_generate2 (gnutls_x509_privkey_t key,
                                   gnutls_pk_algorithm_t algo,
                                   unsigned int bits,
                                   unsigned int flags,
                                   const gnutls_keygen_data_st *data,
                                   unsigned  data_size);

This function will generate a random private key. Note that this function must be called on an initialized private key.

The flag `GNUTLS_PRIVKEY_FLAG_PROVABLE` instructs the key generation process to use algorithms like Shawe-Taylor (from FIPS PUB186-4) which generate provable parameters out of a seed for RSA and DSA keys. On DSA keys the PQG parameters are generated using the seed, while on RSA the two primes. To specify an explicit seed (by default a random seed is used), use the `data` with a `GNUTLS_KEYGEN_SEED` type.

Note that when generating an elliptic curve key, the curve can be substituted in the place of the bits parameter using the `GNUTLS_CURVE_TO_BITS()` macro.

To export the generated keys in memory or in files it is recommended to use the PKCS#8 form as it can handle all key types, and can store additional parameters such as the seed, in case of provable RSA or DSA keys. Generated keys can be exported in memory using `gnutls_privkey_export_x509()`, and then with `gnutls_x509_privkey_export2_pkcs8()`.

If key generation is part of your application, avoid setting the number of bits directly, and instead use `gnutls_sec_param_to_pk_bits()`. That way the generated keys will adapt to the security levels of the underlying GnuTLS library.

See also `gnutls_privkey_generate2()`.

#### Parameters

key | a key |
algo | is one of the algorithms in gnutls_pk_algorithm_t. |
bits | the size of the modulus |
flags | Must be zero or flags from gnutls_privkey_flags_t. |
data | Allow specifying `gnutls_keygen_data_st` types such as the seed to be used. |
data_size | The number of `data` available. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_verify_seed ()

    int
    gnutls_x509_privkey_verify_seed (gnutls_x509_privkey_t key,
                                     gnutls_digest_algorithm_t Param2,
                                     const void *seed,
                                     size_t seed_size);

This function will verify that the given private key was generated from the provided seed. If `seed` is `NULL` then the seed stored in the `key` 's structure will be used for verification.

#### Parameters

key | should contain a gnutls_x509_privkey_t type |
digest | it contains the digest algorithm used for key generation (if applicable) |
seed | the seed of the key to be checked with |
seed_size | holds the size of `seed` |

#### Returns

In case of a verification failure `GNUTLS_E_PRIVKEY_VERIFICATION_ERROR` is returned, and zero or positive code on success.

Since: 3.5.0

### gnutls_x509_privkey_get_seed ()

    int
    gnutls_x509_privkey_get_seed (gnutls_x509_privkey_t key,
                                  gnutls_digest_algorithm_t *Param2,
                                  void *seed,
                                  size_t *seed_size);

This function will return the seed that was used to generate the given private key. That function will succeed only if the key was generated as a provable key.

#### Parameters

key | should contain a gnutls_x509_privkey_t type |
digest | if non-NULL it will contain the digest algorithm used for key generation (if applicable) |
seed | where seed will be copied to |
seed_size | originally holds the size of `seed` , will be updated with actual size |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.0

### gnutls_x509_privkey_verify_params ()

    int
    gnutls_x509_privkey_verify_params (gnutls_x509_privkey_t key);

This function will verify the private key parameters.

#### Parameters

key | a key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_export ()

    int
    gnutls_x509_privkey_export (gnutls_x509_privkey_t key,
                                gnutls_x509_crt_fmt_t format,
                                void *output_data,
                                size_t *output_data_size);

This function will export the private key to a PKCS#1 structure for RSA or RSA-PSS keys, and integer sequence for DSA keys. Other keys types will be exported in PKCS#8 form.

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

It is recommended to use `gnutls_x509_privkey_export_pkcs8()` instead of this function, when a consistent output format is required.

#### Parameters

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) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_export2 ()

    int
    gnutls_x509_privkey_export2 (gnutls_x509_privkey_t key,
                                 gnutls_x509_crt_fmt_t format,
                                 gnutls_datum_t *out);

This function will export the private key to a PKCS#1 structure for RSA or RSA-PSS keys, and integer sequence for DSA keys. Other keys types will be exported in PKCS#8 form.

The output buffer is allocated using `gnutls_malloc()`.

It is recommended to use `gnutls_x509_privkey_export2_pkcs8()` instead of this function, when a consistent output format is required.

#### Parameters

key | Holds the key |
format | the format of output params. One of PEM or DER. |
out | will contain a private key PEM or DER encoded |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since 3.1.3

### gnutls_x509_privkey_export_pkcs8 ()

    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);

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 11 definitions. 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.

#### Parameters

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) |

#### Returns

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

### gnutls_x509_privkey_export2_pkcs8 ()

    int
    gnutls_x509_privkey_export2_pkcs8 (gnutls_x509_privkey_t key,
                                       gnutls_x509_crt_fmt_t format,
                                       const char *password,
                                       unsigned int flags,
                                       gnutls_datum_t *out);

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 11 definitions. 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.

The output buffer is allocated using `gnutls_malloc()`.

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.

#### Parameters

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 |
out | will contain a private key PEM or DER encoded |

#### Returns

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

Since 3.1.3

### gnutls_x509_privkey_export_rsa_raw2 ()

    int
    gnutls_x509_privkey_export_rsa_raw2 (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,
                                         gnutls_datum_t *e1,
                                         gnutls_datum_t *e2);

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.

#### Parameters

key | a key |
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 |
e1 | will hold e1 = d mod (p-1) |
e2 | will hold e2 = d mod (q-1) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.12.0

### gnutls_x509_privkey_export_rsa_raw ()

    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);

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.

#### Parameters

key | a key |
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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_privkey_export_ecc_raw ()

    int
    gnutls_x509_privkey_export_ecc_raw (gnutls_x509_privkey_t key,
                                        gnutls_ecc_curve_t *curve,
                                        gnutls_datum_t *x,
                                        gnutls_datum_t *y,
                                        gnutls_datum_t *k);

This function will export the ECC 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.

In EdDSA curves the `y` parameter will be `NULL` and the other parameters will be in the native format for the curve.

#### Parameters

key | a key |
curve | will hold the curve |
x | will hold the x-coordinate |
y | will hold the y-coordinate |
k | will hold the private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0

### gnutls_x509_privkey_export_gost_raw ()

    int
    gnutls_x509_privkey_export_gost_raw (gnutls_x509_privkey_t key,
                                         gnutls_ecc_curve_t *curve,
                                         gnutls_digest_algorithm_t *digest,
                                         gnutls_gost_paramset_t *paramset,
                                         gnutls_datum_t *x,
                                         gnutls_datum_t *y,
                                         gnutls_datum_t *k);

This function will export the GOST 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.

Note: parameters will be stored with least significant byte first. On version 3.6.3 this was incorrectly returned in big-endian format.

#### Parameters

key | a key |
curve | will hold the curve |
digest | will hold the digest |
paramset | will hold the GOST parameter set ID |
x | will hold the x-coordinate |
y | will hold the y-coordinate |
k | will hold the private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.3

### gnutls_x509_privkey_sign_data ()

    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);

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.

Use `gnutls_x509_crt_get_preferred_hash_algorithm()` to determine the hash algorithm.

#### Parameters

key | a key |
digest | should be a digest algorithm |
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) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_sign ()

    int
    gnutls_x509_crq_sign (gnutls_x509_crq_t crq,
                          gnutls_x509_privkey_t key);

This function is the same a `gnutls_x509_crq_sign2()` with no flags, and an appropriate hash algorithm. The hash algorithm used may vary between versions of GnuTLS, and it is tied to the security level of the issuer's public key.

A known limitation of this function is, that a newly-signed request will not be fully functional (e.g., for signature verification), until it is exported an re-imported.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
key | holds a private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_sign2 ()

    int
    gnutls_x509_crq_sign2 (gnutls_x509_crq_t crq,
                           gnutls_x509_privkey_t key,
                           gnutls_digest_algorithm_t dig,
                           unsigned int flags);

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.

A known limitation of this function is, that a newly-signed request will not be fully functional (e.g., for signature verification), until it is exported an re-imported.

After GnuTLS 3.6.1 the value of `dig` may be `GNUTLS_DIG_UNKNOWN`, and in that case, a suitable but reasonable for the key algorithm will be selected.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
key | holds a private key |
dig | The message digest to use, i.e., `GNUTLS_DIG_SHA256` |
flags | must be 0 |

#### Returns

`GNUTLS_E_SUCCESS` on success, otherwise a negative error 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 `gnutls_x509_crq_set_version()`).

### gnutls_x509_crq_print ()

    int
    gnutls_x509_crq_print (gnutls_x509_crq_t crq,
                           gnutls_certificate_print_formats_t format,
                           gnutls_datum_t *out);

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

The output `out` needs to be deallocated using `gnutls_free()`.

#### Parameters

crq | The data to be printed |
format | Indicate the format to use |
out | Newly allocated datum with null terminated string. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_verify ()

    int
    gnutls_x509_crq_verify (gnutls_x509_crq_t crq,
                            unsigned int flags);

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

#### Parameters

crq | is the crq to be verified |
flags | Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations. |

#### Returns

In case of a verification failure `GNUTLS_E_PK_SIG_VERIFY_FAILED` is returned, and zero or positive code on success.

Since 2.12.0

### gnutls_x509_crq_init ()

    int
    gnutls_x509_crq_init (gnutls_x509_crq_t *crq);

This function will initialize a PKCS10 certificate request structure.

#### Parameters

crq | A pointer to the type to be initialized |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_deinit ()

    void
    gnutls_x509_crq_deinit (gnutls_x509_crq_t crq);

This function will deinitialize a PKCS10 certificate request structure.

#### Parameters

crq | the type to be deinitialized |

### gnutls_x509_crq_import ()

    int
    gnutls_x509_crq_import (gnutls_x509_crq_t crq,
                            const gnutls_datum_t *data,
                            gnutls_x509_crt_fmt_t format);

This function will convert the given DER or PEM encoded certificate request to a gnutls_x509_crq_t type. The output will be stored in `crq` .

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

#### Parameters

crq | The data to store the parsed certificate request. |
data | The DER or PEM encoded certificate. |
format | One of DER or PEM |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_get_private_key_usage_period ()

    int
    gnutls_x509_crq_get_private_key_usage_period
                                   (gnutls_x509_crq_t cert,
                                    time_t *activation,
                                    time_t *expiration,
                                    unsigned int *critical);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
activation | The activation time |
expiration | The expiration time |
critical | the extension status |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` if the extension is not present, otherwise a negative error value.

### gnutls_x509_crq_get_dn ()

    int
    gnutls_x509_crq_get_dn (gnutls_x509_crq_t crq,
                            char *buf,
                            size_t *sizeof_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 `buf` will be ASCII or UTF-8 encoded, depending on the certificate data.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crq_get_dn3()`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
buf | a pointer to a structure to hold the name (may be `NULL`) |
buf_size | initially holds the size of `buf` |

#### Returns

`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.

### gnutls_x509_crq_get_dn2 ()

    int
    gnutls_x509_crq_get_dn2 (gnutls_x509_crq_t crq,
                             gnutls_datum_t *dn);

This function will allocate buffer and copy the name of the Certificate request. 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.

This function does not output a fully RFC4514 compliant string, if that is required see `gnutls_x509_crq_get_dn3()`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value. and a negative error code on error.

Since: 3.1.10

### gnutls_x509_crq_get_dn3 ()

    int
    gnutls_x509_crq_get_dn3 (gnutls_x509_crq_t crq,
                             gnutls_datum_t *dn,
                             unsigned  flags);

This function will allocate buffer and copy the name of the Certificate request. 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.

When the flag `GNUTLS_X509_DN_FLAG_COMPAT` is specified, the output format will match the format output by previous to 3.5.6 versions of GnuTLS which was not not fully RFC4514-compliant.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
dn | a pointer to a structure to hold the name; must be freed using `gnutls_free()` |
flags | zero or `GNUTLS_X509_DN_FLAG_COMPAT` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value. and a negative error code on error.

Since: 3.5.7

### gnutls_x509_crq_get_dn_oid ()

    int
    gnutls_x509_crq_get_dn_oid (gnutls_x509_crq_t crq,
                                unsigned  indx,
                                void *oid,
                                size_t *sizeof_oid);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | Specifies which DN OID to get. Use (0) 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` |

#### 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.

### gnutls_x509_crq_get_dn_by_oid ()

    int
    gnutls_x509_crq_get_dn_by_oid (gnutls_x509_crq_t crq,
                                   const char *oid,
                                   unsigned  indx,
                                   unsigned int raw_flag,
                                   void *buf,
                                   size_t *sizeof_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 `gnutls_x509_dn_oid_known()`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in a null terminated string |
indx | In case multiple same OIDs exist in the RDN, this specifies which to get. Use (0) 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`) |
buf_size | initially holds the size of `buf` |

#### Returns

`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.

### gnutls_x509_crq_set_dn ()

    int
    gnutls_x509_crq_set_dn (gnutls_x509_crq_t crq,
                            const char *dn,
                            const char **err);

This function will set the DN on the provided certificate. The input string should be plain ASCII or UTF-8 encoded. On DN parsing error `GNUTLS_E_PARSING_ERROR` is returned.

#### Parameters

crq | a certificate of type gnutls_x509_crq_t |
dn | a comma separated DN string (RFC4514) |
err | indicates the error position (if any) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_dn_by_oid ()

    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);

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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in a (0)-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` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_version ()

    int
    gnutls_x509_crq_set_version (gnutls_x509_crq_t crq,
                                 unsigned int version);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
version | holds the version number, for v1 Requests must be 1 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_get_version ()

    int
    gnutls_x509_crq_get_version (gnutls_x509_crq_t crq);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |

#### Returns

version of certificate request, or a negative error code on error.

### gnutls_x509_crq_set_key ()

    int
    gnutls_x509_crq_set_key (gnutls_x509_crq_t crq,
                             gnutls_x509_privkey_t key);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
key | holds a private key |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_extension_by_oid ()

    int
    gnutls_x509_crq_set_extension_by_oid (gnutls_x509_crq_t crq,
                                          const char *oid,
                                          const void *buf,
                                          size_t sizeof_buf,
                                          unsigned int critical);

This function will set an the extension, by the specified OID, in the certificate request. The extension data should be binary data DER encoded.

#### Parameters

crq | a certificate of type gnutls_x509_crq_t |
oid | holds an Object Identifier 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 |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_challenge_password ()

    int
    gnutls_x509_crq_set_challenge_password
                                   (gnutls_x509_crq_t crq,
                                    const char *pass);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
pass | holds a (0)-terminated password |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_get_challenge_password ()

    int
    gnutls_x509_crq_get_challenge_password
                                   (gnutls_x509_crq_t crq,
                                    char *pass,
                                    size_t *sizeof_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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
pass | will hold a (0)-terminated password string |
pass_size | Initially holds the size of `pass` . |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_attribute_by_oid ()

    int
    gnutls_x509_crq_set_attribute_by_oid (gnutls_x509_crq_t crq,
                                          const char *oid,
                                          void *buf,
                                          size_t sizeof_buf);

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

Attributes in a certificate request is an optional set of data appended to the request. Their interpretation depends on the CA policy.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in a null-terminated string |
buf | a pointer to a structure that holds the attribute data |
buf_size | holds the size of `buf` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_get_attribute_by_oid ()

    int
    gnutls_x509_crq_get_attribute_by_oid (gnutls_x509_crq_t crq,
                                          const char *oid,
                                          unsigned  indx,
                                          void *buf,
                                          size_t *sizeof_buf);

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

Attributes in a certificate request is an optional set of data appended to the request. Their interpretation depends on the CA policy.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in null-terminated string |
indx | In case multiple same OIDs exist in the attribute list, this specifies which to get, use (0) to get the first one |
buf | a pointer to a structure to hold the attribute data (may be `NULL`) |
buf_size | initially holds the size of `buf` |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_export ()

    int
    gnutls_x509_crq_export (gnutls_x509_crq_t crq,
                            gnutls_x509_crt_fmt_t format,
                            void *output_data,
                            size_t *output_data_size);

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 `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".

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
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) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_export2 ()

    int
    gnutls_x509_crq_export2 (gnutls_x509_crq_t crq,
                             gnutls_x509_crt_fmt_t format,
                             gnutls_datum_t *out);

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

The output buffer is allocated using `gnutls_malloc()`.

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
format | the format of output params. One of PEM or DER. |
out | will contain a certificate request PEM or DER encoded |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since 3.1.3

### gnutls_x509_crt_set_crq ()

    int
    gnutls_x509_crt_set_crq (gnutls_x509_crt_t crt,
                             gnutls_x509_crq_t crq);

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.

Note that this function will only set the `crq` if it is self signed and the signature is correct. See `gnutls_x509_crq_sign2()`.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
crq | holds a certificate request |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crt_set_crq_extensions ()

    int
    gnutls_x509_crt_set_crq_extensions (gnutls_x509_crt_t crt,
                                        gnutls_x509_crq_t crq);

This function will set the extensions from the given request to the certificate.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
crq | holds a certificate request |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crt_set_crq_extension_by_oid ()

    int
    gnutls_x509_crt_set_crq_extension_by_oid
                                   (gnutls_x509_crt_t crt,
                                    gnutls_x509_crq_t crq,
                                    const char *oid,
                                    unsigned  flags);

This function will set the extension specify by `oid` from the given request to the certificate.

#### Parameters

crt | a certificate of type gnutls_x509_crt_t |
crq | holds a certificate request |
oid | the object identifier of the OID to copy |
flags | should be zero |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_crq_set_private_key_usage_period ()

    int
    gnutls_x509_crq_set_private_key_usage_period
                                   (gnutls_x509_crq_t crq,
                                    time_t activation,
                                    time_t expiration);

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

#### Parameters

crq | a certificate of type gnutls_x509_crq_t |
activation | The activation time |
expiration | The expiration time |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

### gnutls_x509_crq_set_key_rsa_raw ()

    int
    gnutls_x509_crq_set_key_rsa_raw (gnutls_x509_crq_t crq,
                                     const gnutls_datum_t *m,
                                     const gnutls_datum_t *e);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
m | holds the modulus |
e | holds the public exponent |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.6.0

### gnutls_x509_crq_set_subject_alt_name ()

    int
    gnutls_x509_crq_set_subject_alt_name (gnutls_x509_crq_t crq,
                                          gnutls_x509_subject_alt_name_t nt,
                                          const void *data,
                                          unsigned int data_size,
                                          unsigned int flags);

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

`GNUTLS_SAN_DNSNAME`: as a text string

`GNUTLS_SAN_RFC822NAME`: as a text string

`GNUTLS_SAN_URI`: as a text string

`GNUTLS_SAN_IPADDRESS`: as a binary IP address (4 or 16 bytes)

`GNUTLS_SAN_OTHERNAME_XMPP`: as a UTF8 string

Since version 3.5.7 the `GNUTLS_SAN_RFC822NAME`, `GNUTLS_SAN_DNSNAME`, and `GNUTLS_SAN_OTHERNAME_XMPP` are converted to ACE format when necessary.

#### Parameters

crq | a certificate request of type gnutls_x509_crq_t |
nt | is one of the gnutls_x509_subject_alt_name_t enumerations |
data | The data to be set |
data_size | The size of data to be set |
flags | `GNUTLS_FSAN_SET` to clear previous data or `GNUTLS_FSAN_APPEND` to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_set_subject_alt_othername ()

    int
    gnutls_x509_crq_set_subject_alt_othername
                                   (gnutls_x509_crq_t crq,
                                    const char *oid,
                                    const void *data,
                                    unsigned int data_size,
                                    unsigned int flags);

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

The values set must be binary values and must be properly DER encoded.

#### Parameters

crq | a certificate request of type gnutls_x509_crq_t |
oid | is the othername OID |
data | The data to be set |
data_size | The size of data to be set |
flags | `GNUTLS_FSAN_SET` to clear previous data or `GNUTLS_FSAN_APPEND` to append. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.0

### gnutls_x509_crq_set_key_usage ()

    int
    gnutls_x509_crq_set_key_usage (gnutls_x509_crq_t crq,
                                   unsigned int usage);

This function will set the keyUsage certificate extension.

#### Parameters

crq | a certificate request of type gnutls_x509_crq_t |
usage | an ORed sequence of the GNUTLS_KEY_* elements. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_set_basic_constraints ()

    int
    gnutls_x509_crq_set_basic_constraints (gnutls_x509_crq_t crq,
                                           unsigned int ca,
                                           int pathLenConstraint);

This function will set the basicConstraints certificate extension.

#### Parameters

crq | a certificate request of type gnutls_x509_crq_t |
ca | true(1) or false(0) depending on the Certificate authority status. |
pathLenConstraint | non-negative error codes indicate maximum length of path, and negative error codes indicate that the pathLenConstraints field should not be present. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_set_key_purpose_oid ()

    int
    gnutls_x509_crq_set_key_purpose_oid (gnutls_x509_crq_t crq,
                                         const void *oid,
                                         unsigned int critical);

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.

#### Parameters

crq | a certificate of type gnutls_x509_crq_t |
oid | a pointer to a null-terminated string that holds the OID |
critical | Whether this extension will be critical or not |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_get_key_purpose_oid ()

    int
    gnutls_x509_crq_get_key_purpose_oid (gnutls_x509_crq_t crq,
                                         unsigned  indx,
                                         void *oid,
                                         size_t *sizeof_oid,
                                         unsigned int *critical);

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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | This specifies which OID to return, use (0) to get the first one |
oid | a pointer to store the OID (may be `NULL`) |
sizeof_oid | initially holds the size of `oid` |
critical | output variable with critical flag, may be `NULL`. |

#### 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.

Since: 2.8.0

### gnutls_x509_crq_get_extension_data ()

    int
    gnutls_x509_crq_get_extension_data (gnutls_x509_crq_t crq,
                                        unsigned  indx,
                                        void *data,
                                        size_t *sizeof_data);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | Specifies which extension number to get. Use (0) to get the first one. |
data | a pointer to a structure to hold the data (may be null) |
sizeof_data | initially holds the size of `oid` |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crq_get_extension_data2 ()

    int
    gnutls_x509_crq_get_extension_data2 (gnutls_x509_crq_t crq,
                                         unsigned  indx,
                                         gnutls_datum_t *data);

This function will return the requested extension data in the certificate request. The extension data will be allocated using `gnutls_malloc()`.

Use `gnutls_x509_crq_get_extension_info()` to extract the OID.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
extension_id | An X.509 extension OID. |
indx | Specifies which extension OID to read. Use (0) to get the first one. |
data | will contain the extension DER-encoded data |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error code is returned. If you have reached the last extension available `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

Since: 3.3.0

### gnutls_x509_crq_get_extension_info ()

    int
    gnutls_x509_crq_get_extension_info (gnutls_x509_crq_t crq,
                                        unsigned  indx,
                                        void *oid,
                                        size_t *sizeof_oid,
                                        unsigned int *critical);

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 `gnutls_x509_crq_get_extension_data()` to extract the data.

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | Specifies which extension number to get. Use (0) to get the first one. |
oid | a pointer to store the OID |
sizeof_oid | initially holds the maximum size of `oid` , on return holds actual size of `oid` . |
critical | output variable with critical flag, may be NULL. |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crq_get_attribute_data ()

    int
    gnutls_x509_crq_get_attribute_data (gnutls_x509_crq_t crq,
                                        unsigned  indx,
                                        void *data,
                                        size_t *sizeof_data);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | Specifies which attribute number to get. Use (0) to get the first one. |
data | a pointer to a structure to hold the data (may be null) |
sizeof_data | initially holds the size of `oid` |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crq_get_attribute_info ()

    int
    gnutls_x509_crq_get_attribute_info (gnutls_x509_crq_t crq,
                                        unsigned  indx,
                                        void *oid,
                                        size_t *sizeof_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 `gnutls_x509_crq_get_attribute_data()` to extract the data.

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
indx | Specifies which attribute number to get. Use (0) to get the first one. |
oid | a pointer to a structure to hold the OID |
sizeof_oid | initially holds the maximum size of `oid` , on return holds actual size of `oid` . |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crq_get_pk_algorithm ()

    int
    gnutls_x509_crq_get_pk_algorithm (gnutls_x509_crq_t crq,
                                      unsigned int *bits);

This function will return the public key algorithm of a PKCS10 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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
bits | if bits is non-`NULL` it will hold the size of the parameters' in bits |

#### Returns

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

### gnutls_x509_crq_get_spki ()

    int
    gnutls_x509_crq_get_spki (gnutls_x509_crq_t crq,
                              gnutls_x509_spki_t spki,
                              unsigned int flags);

### gnutls_x509_crq_set_spki ()

    int
    gnutls_x509_crq_set_spki (gnutls_x509_crq_t crq,
                              const gnutls_x509_spki_t spki,
                              unsigned int flags);

This function will set the certificate request's subject public key information explicitly. This is intended to be used in the cases where a single public key (e.g., RSA) can be used for multiple signature algorithms (RSA PKCS1-1.5, and RSA-PSS).

To export the public key (i.e., the SubjectPublicKeyInfo part), check `gnutls_pubkey_import_x509()`.

#### Parameters

crq | a certificate request of type gnutls_x509_crq_t |
spki | a SubjectPublicKeyInfo structure of type gnutls_x509_spki_t |
flags | must be zero |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.6.0

### gnutls_x509_crq_get_signature_oid ()

    int
    gnutls_x509_crq_get_signature_oid (gnutls_x509_crq_t crq,
                                       char *oid,
                                       size_t *oid_size);

This function will return the OID of the signature algorithm that has been used to sign this certificate request. This function is useful in the case `gnutls_x509_crq_get_signature_algorithm()` returned `GNUTLS_SIGN_UNKNOWN`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

zero or a negative error code on error.

Since: 3.5.0

### gnutls_x509_crq_get_pk_oid ()

    int
    gnutls_x509_crq_get_pk_oid (gnutls_x509_crq_t crq,
                                char *oid,
                                size_t *oid_size);

This function will return the OID of the public key algorithm on that certificate request. This function is useful in the case `gnutls_x509_crq_get_pk_algorithm()` returned `GNUTLS_PK_UNKNOWN`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | a pointer to a buffer to hold the OID (may be null) |
oid_size | initially holds the size of `oid` |

#### Returns

zero or a negative error code on error.

Since: 3.5.0

### gnutls_x509_crq_get_key_id ()

    int
    gnutls_x509_crq_get_key_id (gnutls_x509_crq_t crq,
                                unsigned int flags,
                                unsigned char *output_data,
                                size_t *output_data_size);

This function will return a unique ID that 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.

#### Parameters

crq | a certificate of type gnutls_x509_crq_t |
flags | should be one of the flags from `gnutls_keyid_flags_t` |
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) |

#### Returns

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

Since: 2.8.0

### gnutls_x509_crq_get_key_rsa_raw ()

    int
    gnutls_x509_crq_get_key_rsa_raw (gnutls_x509_crq_t crq,
                                     gnutls_datum_t *m,
                                     gnutls_datum_t *e);

This function will export the RSA public 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.

#### Parameters

crq | Holds the certificate |
m | will hold the modulus |
e | will hold the public exponent |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 2.8.0

### gnutls_x509_crq_get_key_usage ()

    int
    gnutls_x509_crq_get_key_usage (gnutls_x509_crq_t crq,
                                   unsigned int *key_usage,
                                   unsigned int *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`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
key_usage | where the key usage bits will be stored |
critical | will be non-zero if the extension is marked as critical |

#### Returns

the certificate key usage, or a negative error code in case of parsing error. If the certificate does not contain the keyUsage extension `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

Since: 2.8.0

### gnutls_x509_crq_get_basic_constraints ()

    int
    gnutls_x509_crq_get_basic_constraints (gnutls_x509_crq_t crq,
                                           unsigned int *critical,
                                           unsigned int *ca,
                                           int *pathlen);

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).

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
critical | will be non-zero if the extension is marked as critical |
ca | pointer to output integer indicating CA status, may be NULL, value is 1 if the certificate CA flag is set, 0 otherwise. |
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. |

#### 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.

Since: 2.8.0

### gnutls_x509_crq_get_subject_alt_name ()

    int
    gnutls_x509_crq_get_subject_alt_name (gnutls_x509_crq_t crq,
                                          unsigned int seq,
                                          void *ret,
                                          size_t *ret_size,
                                          unsigned int *ret_type,
                                          unsigned int *critical);

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

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
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. |
ret_type | holds the gnutls_x509_subject_alt_name_t name type |
critical | will be non-zero if the extension is marked as critical (may be null) |

#### Returns

the alternative subject name type on success, one of the enumerated gnutls_x509_subject_alt_name_t. It will return `GNUTLS_E_SHORT_MEMORY_BUFFER` if `ret_size` is not large enough to hold the value. In that case `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

Since: 2.8.0

### gnutls_x509_crq_get_subject_alt_othername_oid ()

    int
    gnutls_x509_crq_get_subject_alt_othername_oid
                                   (gnutls_x509_crq_t crq,
                                    unsigned int seq,
                                    void *ret,
                                    size_t *ret_size);

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 `gnutls_x509_crq_get_subject_alt_name()` returned `GNUTLS_SAN_OTHERNAME`.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
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 otherName OID will be copied to |
ret_size | holds the size of ret. |

#### 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. `GNUTLS_SAN_OTHERNAME_XMPP`, and `GNUTLS_SAN_OTHERNAME` for unknown OIDs. It will return `GNUTLS_E_SHORT_MEMORY_BUFFER` if `ret_size` is not large enough to hold the value. In that case `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned.

Since: 2.8.0

### gnutls_x509_crq_get_extension_by_oid ()

    int
    gnutls_x509_crq_get_extension_by_oid (gnutls_x509_crq_t crq,
                                          const char *oid,
                                          unsigned  indx,
                                          void *buf,
                                          size_t *sizeof_buf,
                                          unsigned int *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.

#### Parameters

crq | should contain a gnutls_x509_crq_t type |
oid | holds an Object Identifier in a null terminated string |
indx | In case multiple same OIDs exist in the extensions, this specifies which to get. Use (0) to get the first one. |
buf | a pointer to a structure to hold the name (may be null) |
buf_size | initially holds the size of `buf` |
critical | will be non-zero if the extension is marked as critical |

#### Returns

On success, `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 `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned.

Since: 2.8.0

### gnutls_x509_crq_get_tlsfeatures ()

    int
    gnutls_x509_crq_get_tlsfeatures (gnutls_x509_crq_t crq,
                                     gnutls_x509_tlsfeatures_t features,
                                     unsigned  flags,
                                     unsigned int *critical);

This function will get the X.509 TLS features extension structure from the certificate request. The returned structure needs to be freed using `gnutls_x509_tlsfeatures_deinit()`.

When the `flags` is set to `GNUTLS_EXT_FLAG_APPEND`, then if the `features` structure is empty this function will behave identically as if the flag was not set. Otherwise if there are elements in the `features` structure then they will be merged with.

Note that `features` must be initialized prior to calling this function.

#### Parameters

crq | An X.509 certificate request |
features | If the function succeeds, the features will be stored in this variable. |
flags | zero or `GNUTLS_EXT_FLAG_APPEND` |
critical | the extension status |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_crq_set_tlsfeatures ()

    int
    gnutls_x509_crq_set_tlsfeatures (gnutls_x509_crq_t crq,
                                     gnutls_x509_tlsfeatures_t features);

This function will set the certificate request's X.509 TLS extension from the given structure.

#### Parameters

crq | An X.509 certificate request |
features | If the function succeeds, the features will be added to the certificate request. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.5.1

### gnutls_x509_crt_get_extension_by_oid2 ()

    int
    gnutls_x509_crt_get_extension_by_oid2 (gnutls_x509_crt_t cert,
                                           const char *oid,
                                           unsigned  indx,
                                           gnutls_datum_t *output,
                                           unsigned int *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.

#### Parameters

cert | should contain a gnutls_x509_crt_t type |
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 (0) to get the first one. |
output | will hold the allocated extension data |
critical | will be non-zero if the extension is marked as critical |

#### Returns

On success, `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.

Since: 3.3.8

### gnutls_x509_trust_list_init ()

    int
    gnutls_x509_trust_list_init (gnutls_x509_trust_list_t *list,
                                 unsigned int size);

This function will initialize an X.509 trust list structure.

#### Parameters

list | A pointer to the type to be initialized |
size | The size of the internal hash table. Use (0) for default size. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0.0

### gnutls_x509_trust_list_deinit ()

    void
    gnutls_x509_trust_list_deinit (gnutls_x509_trust_list_t list,
                                   unsigned int all);

This function will deinitialize a trust list. Note that the `all` flag should be typically non-zero unless you have specified your certificates using `gnutls_x509_trust_list_add_cas()` and you want to prevent them from being deinitialized by this function.

#### Parameters

list | The list to be deinitialized |
all | if non-zero it will deinitialize all the certificates and CRLs contained in the structure. |

Since: 3.0.0

### gnutls_x509_trust_list_get_issuer ()

    int
    gnutls_x509_trust_list_get_issuer (gnutls_x509_trust_list_t list,
                                       gnutls_x509_crt_t cert,
                                       gnutls_x509_crt_t *issuer,
                                       unsigned int flags);

This function will find the issuer of the given certificate. If the flag `GNUTLS_TL_GET_COPY` is specified a copy of the issuer will be returned which must be freed using `gnutls_x509_crt_deinit()`. In that case the provided `issuer` must not be initialized.

Note that the flag `GNUTLS_TL_GET_COPY` is required for this function to work with PKCS11 trust lists in a thread-safe way.

#### Parameters

list | The list |
cert | is the certificate to find issuer for |
issuer | Will hold the issuer if any. Should be treated as constant unless `GNUTLS_TL_GET_COPY` is set in `flags` . |
flags | flags from `gnutls_trust_list_flags_t` (`GNUTLS_TL_GET_COPY` is applicable) |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0

### gnutls_x509_trust_list_get_issuer_by_dn ()

    int
    gnutls_x509_trust_list_get_issuer_by_dn
                                   (gnutls_x509_trust_list_t list,
                                    const gnutls_datum_t *dn,
                                    gnutls_x509_crt_t *issuer,
                                    unsigned int flags);

This function will find the issuer with the given name, and return a copy of the issuer, which must be freed using `gnutls_x509_crt_deinit()`.

#### Parameters

list | The list |
dn | is the issuer's DN |
issuer | Will hold the issuer if any. Should be deallocated after use. |
flags | Use zero |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.0

### gnutls_x509_trust_list_get_issuer_by_subject_key_id ()

    int
    gnutls_x509_trust_list_get_issuer_by_subject_key_id
                                   (gnutls_x509_trust_list_t list,
                                    const gnutls_datum_t *dn,
                                    const gnutls_datum_t *spki,
                                    gnutls_x509_crt_t *issuer,
                                    unsigned int flags);

This function will find the issuer with the given name and subject key ID, and return a copy of the issuer, which must be freed using `gnutls_x509_crt_deinit()`.

#### Parameters

list | The list |
dn | is the issuer's DN (may be `NULL`) |
spki | is the subject key ID |
issuer | Will hold the issuer if any. Should be deallocated after use. |
flags | Use zero |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.2

### gnutls_x509_trust_list_add_cas ()

    int
    gnutls_x509_trust_list_add_cas (gnutls_x509_trust_list_t list,
                                    const gnutls_x509_crt_t *clist,
                                    unsigned  clist_size,
                                    unsigned int flags);

This function will add the given certificate authorities to the trusted list. The CAs in `clist` must not be deinitialized during the lifetime of `list` .

If the flag `GNUTLS_TL_NO_DUPLICATES` is specified, then this function will ensure that no duplicates will be present in the final trust list.

If the flag `GNUTLS_TL_NO_DUPLICATE_KEY` is specified, then this function will ensure that no certificates with the same key are present in the final trust list.

If either `GNUTLS_TL_NO_DUPLICATE_KEY` or `GNUTLS_TL_NO_DUPLICATES` are given, `gnutls_x509_trust_list_deinit()` must be called with parameter `all` being 1.

#### Parameters

list | The list |
clist | A list of CAs |
clist_size | The length of the CA list |
flags | flags from `gnutls_trust_list_flags_t` |

#### Returns

The number of added elements is returned; that includes duplicate entries.

Since: 3.0.0

### gnutls_x509_trust_list_remove_cas ()

    int
    gnutls_x509_trust_list_remove_cas (gnutls_x509_trust_list_t list,
                                       const gnutls_x509_crt_t *clist,
                                       unsigned  clist_size);

This function will remove the given certificate authorities from the trusted list.

Note that this function can accept certificates and authorities not yet known. In that case they will be kept in a separate block list that will be used during certificate verification. Unlike `gnutls_x509_trust_list_add_cas()` there is no deinitialization restriction for certificate list provided in this function.

#### Parameters

list | The list |
clist | A list of CAs |
clist_size | The length of the CA list |

#### Returns

The number of removed elements is returned.

Since: 3.1.10

### gnutls_x509_trust_list_add_named_crt ()

    int
    gnutls_x509_trust_list_add_named_crt (gnutls_x509_trust_list_t list,
                                          gnutls_x509_crt_t cert,
                                          const void *name,
                                          size_t name_size,
                                          unsigned int flags);

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 `gnutls_x509_trust_list_verify_crt()` but with `gnutls_x509_trust_list_verify_named_crt()` or `gnutls_x509_trust_list_verify_crt2()` - the latter only since GnuTLS 3.4.0 and if a hostname is provided.

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 `cert` must not be deinitialized during the lifetime of the `list` .

#### Parameters

list | The list |
cert | A certificate |
name | An identifier for the certificate |
name_size | The size of the identifier |
flags | should be 0. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0.0

### gnutls_x509_trust_list_add_crls ()

    int
    gnutls_x509_trust_list_add_crls (gnutls_x509_trust_list_t list,
                                     const gnutls_x509_crl_t *crl_list,
                                     unsigned  crl_size,
                                     unsigned int flags,
                                     unsigned int verification_flags);

This function will add the given certificate revocation lists to the trusted list. The CRLs in `crl_list` must not be deinitialized during the lifetime of `list` .

This function must be called after `gnutls_x509_trust_list_add_cas()` to allow verifying the CRLs for validity. If the flag `GNUTLS_TL_NO_DUPLICATES` is given, then the final CRL list will not contain duplicate entries.

If the flag `GNUTLS_TL_NO_DUPLICATES` is given, `gnutls_x509_trust_list_deinit()` must be called with parameter `all` being 1.

If flag `GNUTLS_TL_VERIFY_CRL` is given the CRLs will be verified before being added, and if verification fails, they will be skipped.

#### Parameters

list | The list |
crl_list | A list of CRLs |
crl_size | The length of the CRL list |
flags | flags from `gnutls_trust_list_flags_t` |
verification_flags | gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL |

#### Returns

The number of added elements is returned; that includes duplicate entries.

Since: 3.0

### gnutls_x509_trust_list_iter_get_ca ()

    int
    gnutls_x509_trust_list_iter_get_ca (gnutls_x509_trust_list_t list,
                                        gnutls_x509_trust_list_iter_t *iter,
                                        gnutls_x509_crt_t *crt);

This function obtains a certificate in the trust list and advances the iterator to the next certificate. The certificate returned in `crt` must be deallocated with `gnutls_x509_crt_deinit()`.

When past the last element is accessed `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned and the iterator is reset.

The iterator is deinitialized and reset to `NULL` automatically by this function after iterating through all elements until `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` is returned. If the iteration is aborted early, it must be manually deinitialized using `gnutls_x509_trust_list_iter_deinit()`.

#### Parameters

list | The list |
iter | A pointer to an iterator (initially the iterator should be `NULL`) |
crt | where the certificate will be copied |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.4.0

### gnutls_x509_trust_list_iter_deinit ()

    void
    gnutls_x509_trust_list_iter_deinit (gnutls_x509_trust_list_iter_t iter);

This function will deinitialize an iterator structure.

#### Parameters

iter | The iterator structure to be deinitialized |

Since: 3.4.0

### gnutls_session_set_verify_output_function ()

    void
    gnutls_session_set_verify_output_function
                                   (gnutls_session_t session,
                                    gnutls_verify_output_function *func);

This function sets a callback to be called when the peer's certificate chain has to be verified and full path to the trusted root has to be printed.

The callback's function prototype is defined in `x509.h': int (*callback)( gnutls_x509_crt_t cert, gnutls_x509_crt_t issuer, gnutls_x509_crl_t crl, unsigned int verification_output);

If the callback function is provided then gnutls will call it, in the certificate verification procedure. To verify the certificate chain and print its path uptp the trusted root, functions such as `gnutls_certificate_verify_peers()`, `gnutls_x509_trust_list_verify_crt()`, and `gnutls_x509_trust_list_verify_crt2()` can be used. The callback is set in `_gnutls_verify_crt_status()` and `_gnutls_pkcs11_verify_crt_status()`.

#### Parameters

session | is a gnutls_x509_trust_list_t type. |
func | is the callback function |

Since: 3.7.0

### gnutls_x509_trust_list_verify_named_crt ()

    int
    gnutls_x509_trust_list_verify_named_crt
                                   (gnutls_x509_trust_list_t list,
                                    gnutls_x509_crt_t cert,
                                    const void *name,
                                    size_t name_size,
                                    unsigned int flags,
                                    unsigned int *verify,
                                    gnutls_verify_output_function func);

This function will try to find a certificate that is associated with the provided name --see `gnutls_x509_trust_list_add_named_crt()`. If a match is found the certificate is considered valid. In addition to that this function will also check CRLs. The `voutput` parameter will hold an OR'ed sequence of `gnutls_certificate_status_t` flags.

Additionally a certificate verification profile can be specified from the ones in `gnutls_certificate_verification_profiles_t` by ORing the result of `GNUTLS_PROFILE_TO_VFLAGS()` to the verification flags.

#### Parameters

list | The list |
cert | is the certificate to be verified |
name | is the certificate's name |
name_size | is the certificate's name size |
flags | Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations. |
voutput | will hold the certificate verification output. |
func | If non-null will be called on each chain element verification with the output. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0.0

### gnutls_x509_trust_list_verify_crt2 ()

    int
    gnutls_x509_trust_list_verify_crt2 (gnutls_x509_trust_list_t list,
                                        gnutls_x509_crt_t *cert_list,
                                        unsigned int cert_list_size,
                                        gnutls_typed_vdata_st *data,
                                        unsigned int elements,
                                        unsigned int flags,
                                        unsigned int *voutput,
                                        gnutls_verify_output_function func);

This function will attempt to verify the given certificate chain and return its status. The `voutput` parameter will hold an OR'ed sequence of `gnutls_certificate_status_t` flags.

When a certificate chain of `cert_list_size` with more than one certificates is provided, the verification status will apply to the first certificate in the chain that failed verification. The verification process starts from the end of the chain (from CA to end certificate). The first certificate in the chain must be the end-certificate while the rest of the members may be sorted or not.

Additionally a certificate verification profile can be specified from the ones in `gnutls_certificate_verification_profiles_t` by ORing the result of `GNUTLS_PROFILE_TO_VFLAGS()` to the verification flags.

Additional verification parameters are possible via the `data` types; the acceptable types are `GNUTLS_DT_DNS_HOSTNAME`, `GNUTLS_DT_IP_ADDRESS` and `GNUTLS_DT_KEY_PURPOSE_OID`. The former accepts as data a null-terminated hostname, and the latter a null-terminated object identifier (e.g., `GNUTLS_KP_TLS_WWW_SERVER`). If a DNS hostname is provided then this function will compare the hostname in the end certificate against the given. If names do not match the `GNUTLS_CERT_UNEXPECTED_OWNER` status flag will be set. In addition it will consider certificates provided with `gnutls_x509_trust_list_add_named_crt()`.

If a key purpose OID is provided and the end-certificate contains the extended key usage PKIX extension, it will be required to match the provided OID or be marked for any purpose, otherwise verification will fail with `GNUTLS_CERT_PURPOSE_MISMATCH` status.

#### Parameters

list | The list |
cert_list | is the certificate list to be verified |
cert_list_size | is the certificate list size |
data | an array of typed data |
elements | the number of data elements |
flags | Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations. |
voutput | will hold the certificate verification output. |
func | If non-null will be called on each chain element verification with the output. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value. Note that verification failure will not result to an error code, only `voutput` will be updated.

Since: 3.3.8

### gnutls_x509_trust_list_verify_crt ()

    int
    gnutls_x509_trust_list_verify_crt (gnutls_x509_trust_list_t list,
                                       gnutls_x509_crt_t *cert_list,
                                       unsigned int cert_list_size,
                                       unsigned int flags,
                                       unsigned int *verify,
                                       gnutls_verify_output_function func);

This function will try to verify the given certificate and return its status. The `voutput` parameter will hold an OR'ed sequence of `gnutls_certificate_status_t` flags.

The details of the verification are the same as in `gnutls_x509_trust_list_verify_crt2()`.

#### Parameters

list | The list |
cert_list | is the certificate list to be verified |
cert_list_size | is the certificate list size |
flags | Flags that may be used to change the verification algorithm. Use OR of the gnutls_certificate_verify_flags enumerations. |
voutput | will hold the certificate verification output. |
func | If non-null will be called on each chain element verification with the output. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

Since: 3.0

### gnutls_x509_trust_list_add_trust_mem ()

    int
    gnutls_x509_trust_list_add_trust_mem (gnutls_x509_trust_list_t list,
                                          const gnutls_datum_t *cas,
                                          const gnutls_datum_t *crls,
                                          gnutls_x509_crt_fmt_t type,
                                          unsigned int tl_flags,
                                          unsigned int tl_vflags);

This function will add the given certificate authorities to the trusted list.

If this function is used `gnutls_x509_trust_list_deinit()` must be called with parameter `all` being 1.

#### Parameters

list | The list |
cas | A buffer containing a list of CAs (optional) |
crls | A buffer containing a list of CRLs (optional) |
type | The format of the certificates |
tl_flags | flags from `gnutls_trust_list_flags_t` |
tl_vflags | gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL |

#### Returns

The number of added elements is returned.

Since: 3.1

### gnutls_x509_trust_list_add_trust_file ()

    int
    gnutls_x509_trust_list_add_trust_file (gnutls_x509_trust_list_t list,
                                           const char *ca_file,
                                           const char *crl_file,
                                           gnutls_x509_crt_fmt_t type,
                                           unsigned int tl_flags,
                                           unsigned int tl_vflags);

This function will add the given certificate authorities to the trusted list. PKCS 11 URLs are also accepted, instead of files, by this function. A PKCS 11 URL implies a trust database (a specially marked module in p11-kit); the URL "pkcs11:" implies all trust databases in the system. Only a single URL specifying trust databases can be set; they cannot be stacked with multiple calls.

#### Parameters

list | The list |
ca_file | A file containing a list of CAs (optional) |
crl_file | A file containing a list of CRLs (optional) |
type | The format of the certificates |
tl_flags | flags from `gnutls_trust_list_flags_t` |
tl_vflags | gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL |

#### Returns

The number of added elements is returned.

Since: 3.1

### gnutls_x509_trust_list_add_trust_dir ()

    int
    gnutls_x509_trust_list_add_trust_dir (gnutls_x509_trust_list_t list,
                                          const char *ca_dir,
                                          const char *crl_dir,
                                          gnutls_x509_crt_fmt_t type,
                                          unsigned int tl_flags,
                                          unsigned int tl_vflags);

This function will add the given certificate authorities to the trusted list. Only directories are accepted by this function.

#### Parameters

list | The list |
ca_dir | A directory containing the CAs (optional) |
crl_dir | A directory containing a list of CRLs (optional) |
type | The format of the certificates |
tl_flags | flags from `gnutls_trust_list_flags_t` |
tl_vflags | gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL |

#### Returns

The number of added elements is returned.

Since: 3.3.6

### gnutls_x509_trust_list_remove_trust_file ()

    int
    gnutls_x509_trust_list_remove_trust_file
                                   (gnutls_x509_trust_list_t list,
                                    const char *ca_file,
                                    gnutls_x509_crt_fmt_t type);

This function will remove the given certificate authorities from the trusted list, and add them into a block list when needed. PKCS 11 URLs are also accepted, instead of files, by this function.

See also `gnutls_x509_trust_list_remove_cas()`.

#### Parameters

list | The list |
ca_file | A file containing a list of CAs |
type | The format of the certificates |

#### Returns

The number of added elements is returned.

Since: 3.1.10

### gnutls_x509_trust_list_remove_trust_mem ()

    int
    gnutls_x509_trust_list_remove_trust_mem
                                   (gnutls_x509_trust_list_t list,
                                    const gnutls_datum_t *cas,
                                    gnutls_x509_crt_fmt_t type);

This function will remove the provided certificate authorities from the trusted list, and add them into a block list when needed.

See also `gnutls_x509_trust_list_remove_cas()`.

#### Parameters

list | The list |
cas | A buffer containing a list of CAs (optional) |
type | The format of the certificates |

#### Returns

The number of removed elements is returned.

Since: 3.1.10

### gnutls_x509_trust_list_add_system_trust ()

    int
    gnutls_x509_trust_list_add_system_trust
                                   (gnutls_x509_trust_list_t list,
                                    unsigned int tl_flags,
                                    unsigned int tl_vflags);

This function adds the system's default trusted certificate authorities to the trusted list. Note that on unsupported systems this function returns `GNUTLS_E_UNIMPLEMENTED_FEATURE`.

This function implies the flag `GNUTLS_TL_NO_DUPLICATES`.

#### Parameters

list | The structure of the list |
tl_flags | GNUTLS_TL_* |
tl_vflags | gnutls_certificate_verify_flags if flags specifies GNUTLS_TL_VERIFY_CRL |

#### Returns

The number of added elements or a negative error code on error.

Since: 3.1

### gnutls_x509_trust_list_set_getissuer_function ()

    void
    gnutls_x509_trust_list_set_getissuer_function
                                   (gnutls_x509_trust_list_t tlist,
                                    gnutls_x509_trust_list_getissuer_function *func);

This function sets a callback to be called when the peer's certificate chain is incomplete due a missing intermediate certificate. The callback may provide the missing certificate for use during verification.

The callback's function prototype is defined in gnutls/x509.h as:

int (*callback)(gnutls_x509_trust_list_t list, const gnutls_x509_crt_t cert, gnutls_x509_crt_t **issuers, unsigned int *issuers_size);

If the callback function is provided then gnutls will call it during the certificate verification procedure. The callback may wish to use `gnutls_x509_crt_get_authority_info_access()` to get a URI from which to attempt to download the missing issuer certificate, if available.

On a successful call, the callback shall set '*issuers' and '*issuers_size' even if the result is empty; in that case '*issuers' will point to `NULL` and '*issuers_size' will be 0. Otherwise, the '*issuers' array shall be allocated using `gnutls_x509_crt_list_import2()`. The ownership of both the array and the elements is transferred to the caller and thus the application does not need to maintain the memory after the call.

The callback function should return 0 if the attempt to retrieve the issuer certificates for 'crt' succeeded, or non-zero to indicate any error occurred during the attempt. In the latter case, '*issuers' and '*issuers_size' are not set.

#### Parameters

tlist | is a gnutls_x509_trust_list_t type. |
func | is the callback function |

Since: 3.7.0

### gnutls_x509_trust_list_set_ptr ()

    void
    gnutls_x509_trust_list_set_ptr (gnutls_x509_trust_list_t tlist,
                                    void *ptr);

This function will set (associate) the user given pointer `ptr` to the tlist structure. This pointer can be accessed with `gnutls_x509_trust_list_get_ptr()`. Useful in the callback function gnutls_x509_trust_list_set_getissuer_function.

#### Parameters

tlist | is a gnutls_x509_trust_list_t type. |
ptr | is the user pointer |

Since: 3.7.0

### gnutls_x509_trust_list_get_ptr ()

    void *
    gnutls_x509_trust_list_get_ptr (gnutls_x509_trust_list_t tlist);

Get user pointer for tlist. Useful in callback function gnutls_x509_trust_list_set_getissuer_function. This is the pointer set with `gnutls_x509_trust_list_set_ptr()`.

#### Parameters

tlist | is a gnutls_x509_trust_list_t type. |

#### Returns

the user given pointer from the tlist structure, or `NULL` if it was never set.

Since: 3.7.0

### gnutls_certificate_set_trust_list ()

    void
    gnutls_certificate_set_trust_list (gnutls_certificate_credentials_t res,
                                       gnutls_x509_trust_list_t tlist,
                                       unsigned  flags);

This function sets a trust list in the gnutls_certificate_credentials_t type.

Note that the `tlist` will become part of the credentials structure and must not be deallocated. It will be automatically deallocated when the `res` structure is deinitialized.

#### Parameters

res | is a gnutls_certificate_credentials_t type. |
tlist | is a gnutls_x509_trust_list_t type |
flags | must be zero |

Since: 3.2.2

### gnutls_certificate_get_trust_list ()

    void
    gnutls_certificate_get_trust_list (gnutls_certificate_credentials_t res,
                                       gnutls_x509_trust_list_t *tlist);

Obtains the list of trusted certificates stored in `res` and writes a pointer to it to the location `tlist` . The pointer will point to memory internal to `res` , and must not be deinitialized. It will be automatically deallocated when the `res` structure is deinitialized.

#### Parameters

res | is a gnutls_certificate_credentials_t type. |
tlist | Location where to store the trust list. |

Since: 3.4.0

### gnutls_x509_ext_deinit ()

    void
    gnutls_x509_ext_deinit (gnutls_x509_ext_st *ext);

### gnutls_x509_ext_print ()

    int
    gnutls_x509_ext_print (gnutls_x509_ext_st *exts,
                           unsigned int exts_size,
                           gnutls_certificate_print_formats_t format,
                           gnutls_datum_t *out);

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

The output `out` needs to be deallocated using `gnutls_free()`.

#### Parameters

exts | The data to be printed |
exts_size | the number of available structures |
format | Indicate the format to use |
out | Newly allocated datum with null terminated string. |

#### Returns

On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise a negative error value.

## Types and Values

### GNUTLS_OID_X520_COUNTRY_NAME

    #define GNUTLS_OID_X520_COUNTRY_NAME "2.5.4.6"

### GNUTLS_OID_X520_ORGANIZATION_NAME

    #define GNUTLS_OID_X520_ORGANIZATION_NAME "2.5.4.10"

### GNUTLS_OID_X520_ORGANIZATIONAL_UNIT_NAME

    #define GNUTLS_OID_X520_ORGANIZATIONAL_UNIT_NAME "2.5.4.11"

### GNUTLS_OID_X520_COMMON_NAME

    #define GNUTLS_OID_X520_COMMON_NAME "2.5.4.3"

### GNUTLS_OID_X520_LOCALITY_NAME

    #define GNUTLS_OID_X520_LOCALITY_NAME "2.5.4.7"

### GNUTLS_OID_X520_STATE_OR_PROVINCE_NAME

    #define GNUTLS_OID_X520_STATE_OR_PROVINCE_NAME "2.5.4.8"

### GNUTLS_OID_X520_INITIALS

    #define GNUTLS_OID_X520_INITIALS "2.5.4.43"

### GNUTLS_OID_X520_GENERATION_QUALIFIER

    #define GNUTLS_OID_X520_GENERATION_QUALIFIER "2.5.4.44"

### GNUTLS_OID_X520_SURNAME

    #define GNUTLS_OID_X520_SURNAME "2.5.4.4"

### GNUTLS_OID_X520_GIVEN_NAME

    #define GNUTLS_OID_X520_GIVEN_NAME "2.5.4.42"

### GNUTLS_OID_X520_TITLE

    #define GNUTLS_OID_X520_TITLE "2.5.4.12"

### GNUTLS_OID_X520_DN_QUALIFIER

    #define GNUTLS_OID_X520_DN_QUALIFIER "2.5.4.46"

### GNUTLS_OID_X520_PSEUDONYM

    #define GNUTLS_OID_X520_PSEUDONYM "2.5.4.65"

### GNUTLS_OID_X520_POSTALCODE

    #define GNUTLS_OID_X520_POSTALCODE "2.5.4.17"

### GNUTLS_OID_X520_NAME

    #define GNUTLS_OID_X520_NAME "2.5.4.41"

### GNUTLS_OID_LDAP_DC

    #define GNUTLS_OID_LDAP_DC "0.9.2342.19200300.100.1.25"

### GNUTLS_OID_LDAP_UID

    #define GNUTLS_OID_LDAP_UID "0.9.2342.19200300.100.1.1"

### GNUTLS_OID_PKCS9_EMAIL

    #define GNUTLS_OID_PKCS9_EMAIL "1.2.840.113549.1.9.1"

### GNUTLS_OID_PKIX_DATE_OF_BIRTH

    #define GNUTLS_OID_PKIX_DATE_OF_BIRTH "1.3.6.1.5.5.7.9.1"

### GNUTLS_OID_PKIX_PLACE_OF_BIRTH

    #define GNUTLS_OID_PKIX_PLACE_OF_BIRTH "1.3.6.1.5.5.7.9.2"

### GNUTLS_OID_PKIX_GENDER

    #define GNUTLS_OID_PKIX_GENDER "1.3.6.1.5.5.7.9.3"

### GNUTLS_OID_PKIX_COUNTRY_OF_CITIZENSHIP

    #define GNUTLS_OID_PKIX_COUNTRY_OF_CITIZENSHIP "1.3.6.1.5.5.7.9.4"

### GNUTLS_OID_PKIX_COUNTRY_OF_RESIDENCE

    #define GNUTLS_OID_PKIX_COUNTRY_OF_RESIDENCE "1.3.6.1.5.5.7.9.5"

### GNUTLS_KP_TLS_WWW_SERVER

    #define GNUTLS_KP_TLS_WWW_SERVER "1.3.6.1.5.5.7.3.1"

### GNUTLS_KP_TLS_WWW_CLIENT

    #define GNUTLS_KP_TLS_WWW_CLIENT "1.3.6.1.5.5.7.3.2"

### GNUTLS_KP_CODE_SIGNING

    #define GNUTLS_KP_CODE_SIGNING "1.3.6.1.5.5.7.3.3"

### GNUTLS_KP_MS_SMART_CARD_LOGON

    #define GNUTLS_KP_MS_SMART_CARD_LOGON "1.3.6.1.4.1.311.20.2.2"

### GNUTLS_KP_EMAIL_PROTECTION

    #define GNUTLS_KP_EMAIL_PROTECTION "1.3.6.1.5.5.7.3.4"

### GNUTLS_KP_TIME_STAMPING

    #define GNUTLS_KP_TIME_STAMPING "1.3.6.1.5.5.7.3.8"

### GNUTLS_KP_OCSP_SIGNING

    #define GNUTLS_KP_OCSP_SIGNING "1.3.6.1.5.5.7.3.9"

### GNUTLS_KP_IPSEC_IKE

    #define GNUTLS_KP_IPSEC_IKE "1.3.6.1.5.5.7.3.17"

### GNUTLS_KP_ANY

    #define GNUTLS_KP_ANY "2.5.29.37.0"

### GNUTLS_KP_FLAG_DISALLOW_ANY

    #define GNUTLS_KP_FLAG_DISALLOW_ANY 1

### GNUTLS_OID_AIA

    #define GNUTLS_OID_AIA "1.3.6.1.5.5.7.1.1"

### GNUTLS_OID_AD_OCSP

    #define GNUTLS_OID_AD_OCSP "1.3.6.1.5.5.7.48.1"

### GNUTLS_OID_AD_CAISSUERS

    #define GNUTLS_OID_AD_CAISSUERS "1.3.6.1.5.5.7.48.2"

### GNUTLS_FSAN_SET

    #define GNUTLS_FSAN_SET 0

### GNUTLS_FSAN_APPEND

    #define GNUTLS_FSAN_APPEND 1

### GNUTLS_FSAN_ENCODE_OCTET_STRING

    #define GNUTLS_FSAN_ENCODE_OCTET_STRING (1 << 1)

### GNUTLS_FSAN_ENCODE_UTF8_STRING

    #define GNUTLS_FSAN_ENCODE_UTF8_STRING (1 << 2)

### GNUTLS_X509EXT_OID_SUBJECT_KEY_ID

    #define GNUTLS_X509EXT_OID_SUBJECT_KEY_ID "2.5.29.14"

### GNUTLS_X509EXT_OID_KEY_USAGE

    #define GNUTLS_X509EXT_OID_KEY_USAGE "2.5.29.15"

### GNUTLS_X509EXT_OID_PRIVATE_KEY_USAGE_PERIOD

    #define GNUTLS_X509EXT_OID_PRIVATE_KEY_USAGE_PERIOD "2.5.29.16"

### GNUTLS_X509EXT_OID_SAN

    #define GNUTLS_X509EXT_OID_SAN "2.5.29.17"

### GNUTLS_X509EXT_OID_IAN

    #define GNUTLS_X509EXT_OID_IAN "2.5.29.18"

### GNUTLS_X509EXT_OID_BASIC_CONSTRAINTS

    #define GNUTLS_X509EXT_OID_BASIC_CONSTRAINTS "2.5.29.19"

### GNUTLS_X509EXT_OID_NAME_CONSTRAINTS

    #define GNUTLS_X509EXT_OID_NAME_CONSTRAINTS "2.5.29.30"

### GNUTLS_X509EXT_OID_CRL_DIST_POINTS

    #define GNUTLS_X509EXT_OID_CRL_DIST_POINTS "2.5.29.31"

### GNUTLS_X509EXT_OID_CRT_POLICY

    #define GNUTLS_X509EXT_OID_CRT_POLICY "2.5.29.32"

### GNUTLS_X509EXT_OID_AUTHORITY_KEY_ID

    #define GNUTLS_X509EXT_OID_AUTHORITY_KEY_ID "2.5.29.35"

### GNUTLS_X509EXT_OID_EXTENDED_KEY_USAGE

    #define GNUTLS_X509EXT_OID_EXTENDED_KEY_USAGE "2.5.29.37"

### GNUTLS_X509EXT_OID_INHIBIT_ANYPOLICY

    #define GNUTLS_X509EXT_OID_INHIBIT_ANYPOLICY "2.5.29.52"

### GNUTLS_X509EXT_OID_AUTHORITY_INFO_ACCESS

    #define GNUTLS_X509EXT_OID_AUTHORITY_INFO_ACCESS "1.3.6.1.5.5.7.1.1"

### GNUTLS_X509EXT_OID_PROXY_CRT_INFO

    #define GNUTLS_X509EXT_OID_PROXY_CRT_INFO "1.3.6.1.5.5.7.1.14"

### GNUTLS_X509EXT_OID_TLSFEATURES

    #define GNUTLS_X509EXT_OID_TLSFEATURES "1.3.6.1.5.5.7.1.24"

### GNUTLS_X509EXT_OID_CT_SCT_V1

    #define GNUTLS_X509EXT_OID_CT_SCT_V1 "1.3.6.1.4.1.11129.2.4.2"

### GNUTLS_X509_OID_POLICY_ANY

    #define GNUTLS_X509_OID_POLICY_ANY "2.5.29.54"

### enum gnutls_certificate_import_flags

Enumeration of different certificate flags.

#### Members

GNUTLS_X509_CRT_LIST_IMPORT_FAIL_IF_EXCEED |  |
GNUTLS_X509_CRT_LIST_FAIL_IF_UNSORTED |  |
GNUTLS_X509_CRT_LIST_SORT |  |

### enum gnutls_x509_crt_flags

#### Members

GNUTLS_X509_CRT_FLAG_IGNORE_SANITY |  |

### enum gnutls_keyid_flags_t

Enumeration of different flags for the key ID functions.

#### Members

GNUTLS_KEYID_USE_SHA1 | Use SHA1 as the key ID algorithm (default). |
GNUTLS_KEYID_USE_SHA256 | Use SHA256 as the key ID algorithm. |
GNUTLS_KEYID_USE_SHA512 | Use SHA512 as the key ID algorithm. |
GNUTLS_KEYID_USE_BEST_KNOWN | Use the best known algorithm to calculate key ID. Using that option will make your program behavior depend on the version of gnutls linked with. That option has a cap of 64-bytes key IDs. |

### enum gnutls_info_access_what_t

Enumeration of types for the `what` parameter of `gnutls_x509_crt_get_authority_info_access()`.

#### Members

GNUTLS_IA_ACCESSMETHOD_OID | Get accessMethod OID. |
GNUTLS_IA_ACCESSLOCATION_GENERALNAME_TYPE | Get accessLocation name type. |
GNUTLS_IA_URI | Get accessLocation URI value. |
GNUTLS_IA_UNKNOWN |  |
GNUTLS_IA_OCSP_URI | get accessLocation URI value for OCSP. |
GNUTLS_IA_CAISSUERS_URI | get accessLocation URI value for caIssuers. |

### gnutls_x509_name_constraints_t

    typedef struct gnutls_name_constraints_st *gnutls_x509_name_constraints_t;

### GNUTLS_EXT_FLAG_APPEND

    #define GNUTLS_EXT_FLAG_APPEND 1

### GNUTLS_NAME_CONSTRAINTS_FLAG_APPEND

    #define GNUTLS_NAME_CONSTRAINTS_FLAG_APPEND GNUTLS_EXT_FLAG_APPEND

### GNUTLS_CRL_REASON_SUPERSEEDED

    #define GNUTLS_CRL_REASON_SUPERSEEDED GNUTLS_CRL_REASON_SUPERSEDED,

### enum gnutls_x509_crl_reason_flags_t

Enumeration of types for the CRL revocation reasons.

#### Members

GNUTLS_CRL_REASON_UNSPECIFIED |  |
GNUTLS_CRL_REASON_PRIVILEGE_WITHDRAWN | The privileges were withdrawn from the owner. |
GNUTLS_CRL_REASON_CERTIFICATE_HOLD | The certificate is on hold. |
GNUTLS_CRL_REASON_CESSATION_OF_OPERATION | The end-entity is no longer operating. |
GNUTLS_CRL_REASON_SUPERSEDED | There is a newer certificate of the owner. |
GNUTLS_CRL_REASON_AFFILIATION_CHANGED | The end-entity affiliation has changed. |
GNUTLS_CRL_REASON_CA_COMPROMISE | The CA was compromised. |
GNUTLS_CRL_REASON_KEY_COMPROMISE | The certificate's key was compromised. |
GNUTLS_CRL_REASON_UNUSED | The key was never used. |
GNUTLS_CRL_REASON_AA_COMPROMISE | AA compromised. |

### GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION

    #define GNUTLS_X509_NO_WELL_DEFINED_EXPIRATION ((time_t)4294197631)

### gnutls_x509_spki_t

    typedef struct gnutls_x509_spki_st *gnutls_x509_spki_t;

### gnutls_x509_tlsfeatures_t

    typedef struct gnutls_x509_tlsfeatures_st *gnutls_x509_tlsfeatures_t;

### GNUTLS_MAX_QUALIFIERS

    #define GNUTLS_MAX_QUALIFIERS 8

### enum gnutls_x509_qualifier_t

Enumeration of types for the X.509 qualifiers, of the certificate policy extension.

#### Members

GNUTLS_X509_QUALIFIER_UNKNOWN | Unknown qualifier. |
GNUTLS_X509_QUALIFIER_URI | A URL |
GNUTLS_X509_QUALIFIER_NOTICE |  |

### gnutls_x509_policy_st

    typedef struct {
    	char *oid;
    	unsigned int qualifiers;
    	struct {
    		gnutls_x509_qualifier_t type;
    		char *data;
    		unsigned int size;
    	} qualifier[GNUTLS_MAX_QUALIFIERS];
    } gnutls_x509_policy_st;

### GNUTLS_X509_DN_OID_RETURN_OID

    #define GNUTLS_X509_DN_OID_RETURN_OID 1

### gnutls_x509_dn_t

    typedef struct gnutls_x509_dn_st *gnutls_x509_dn_t;

### gnutls_x509_ava_st

    typedef struct {
    	gnutls_datum_t oid;
    	gnutls_datum_t value;
    	unsigned long value_tag;
    } gnutls_x509_ava_st;

### GNUTLS_X509_DN_FLAG_COMPAT

    #define GNUTLS_X509_DN_FLAG_COMPAT 1

### gnutls_x509_crl_iter_t

    typedef struct gnutls_x509_crl_iter *gnutls_x509_crl_iter_t;

### gnutls_x509_crl_get_certificate_count

    #define gnutls_x509_crl_get_certificate_count gnutls_x509_crl_get_crt_count

### gnutls_x509_crl_get_certificate

    #define gnutls_x509_crl_get_certificate gnutls_x509_crl_get_crt_serial

### enum gnutls_certificate_verify_flags

Enumeration of different certificate verify flags. Additional verification profiles can be set using `GNUTLS_PROFILE_TO_VFLAGS()` and `gnutls_certificate_verification_profiles_t`.

#### Members

GNUTLS_VERIFY_DISABLE_CA_SIGN | If set a signer does not have to be a certificate authority. This flag should normally be disabled, unless you know what this means. |
GNUTLS_VERIFY_DO_NOT_ALLOW_IP_MATCHES | When verifying a hostname prevent textual IP addresses from matching IP addresses in the certificate. Treat the input only as a DNS name. |
GNUTLS_VERIFY_DO_NOT_ALLOW_SAME | If a certificate is not signed by anyone trusted but exists in the trusted CA list do not treat it as trusted. |
GNUTLS_VERIFY_ALLOW_ANY_X509_V1_CA_CRT | Allow CA certificates that have version 1 (both root and intermediate). This might be dangerous since those haven't the basicConstraints extension. |
GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD2 | Allow certificates to be signed using the broken MD2 algorithm. |
GNUTLS_VERIFY_ALLOW_SIGN_RSA_MD5 | Allow certificates to be signed using the broken MD5 algorithm. |
GNUTLS_VERIFY_DISABLE_TIME_CHECKS | Disable checking of activation and expiration validity periods of certificate chains. Don't set this unless you understand the security implications. |
GNUTLS_VERIFY_DISABLE_TRUSTED_TIME_CHECKS | If set a signer in the trusted list is never checked for expiration or activation. |
GNUTLS_VERIFY_DO_NOT_ALLOW_X509_V1_CA_CRT | Do not allow trusted CA certificates that have version 1. This option is to be used to deprecate all certificates of version 1. |
GNUTLS_VERIFY_DISABLE_CRL_CHECKS | Disable checking for validity using certificate revocation lists or the available OCSP data. |
GNUTLS_VERIFY_ALLOW_UNSORTED_CHAIN | A certificate chain is tolerated if unsorted (the case with many TLS servers out there). This is the default since GnuTLS 3.1.4. |
GNUTLS_VERIFY_DO_NOT_ALLOW_UNSORTED_CHAIN | Do not tolerate an unsorted certificate chain. |
GNUTLS_VERIFY_DO_NOT_ALLOW_WILDCARDS | When including a hostname check in the verification, do not consider any wildcards. |
GNUTLS_VERIFY_USE_TLS1_RSA | This indicates that a (raw) RSA signature is provided as in the TLS 1.0 protocol. Not all functions accept this flag. |
GNUTLS_VERIFY_IGNORE_UNKNOWN_CRIT_EXTENSIONS | This signals the verification process, not to fail on unknown critical extensions. |
GNUTLS_VERIFY_ALLOW_SIGN_WITH_SHA1 | Allow certificates to be signed using the broken SHA1 hash algorithm. |
GNUTLS_VERIFY_RSA_PSS_FIXED_SALT_LENGTH | Disallow RSA-PSS signatures made with mismatching salt length with digest length, as mandated in RFC 8446 4.2.3. |

### GNUTLS_VERIFY_ALLOW_BROKEN

    #define             GNUTLS_VERIFY_ALLOW_BROKEN

### enum gnutls_certificate_verification_profiles_t

Enumeration of different certificate verification profiles.

#### Members

GNUTLS_PROFILE_UNKNOWN | An invalid/unknown profile. |
GNUTLS_PROFILE_VERY_WEAK | A verification profile that corresponds to `GNUTLS_SEC_PARAM_VERY_WEAK` (64 bits) |
GNUTLS_PROFILE_LOW | A verification profile that corresponds to `GNUTLS_SEC_PARAM_LOW` (80 bits) |
GNUTLS_PROFILE_LEGACY | A verification profile that corresponds to `GNUTLS_SEC_PARAM_LEGACY` (96 bits) |
GNUTLS_PROFILE_MEDIUM | A verification profile that corresponds to `GNUTLS_SEC_PARAM_MEDIUM` (112 bits) |
GNUTLS_PROFILE_HIGH | A verification profile that corresponds to `GNUTLS_SEC_PARAM_HIGH` (128 bits) |
GNUTLS_PROFILE_ULTRA | A verification profile that corresponds to `GNUTLS_SEC_PARAM_ULTRA` (192 bits) |
GNUTLS_PROFILE_FUTURE | A verification profile that corresponds to `GNUTLS_SEC_PARAM_FUTURE` (256 bits) |
GNUTLS_PROFILE_SUITEB128 | A verification profile that applies the SUITEB128 rules |
GNUTLS_PROFILE_SUITEB192 | A verification profile that applies the SUITEB192 rules |

### GNUTLS_VFLAGS_PROFILE_MASK

    #define GNUTLS_VFLAGS_PROFILE_MASK (0xff000000)

### GNUTLS_PKCS8_PLAIN

    #define GNUTLS_PKCS8_PLAIN GNUTLS_PKCS_PLAIN

### GNUTLS_PKCS8_USE_PKCS12_3DES

    #define GNUTLS_PKCS8_USE_PKCS12_3DES GNUTLS_PKCS_PKCS12_3DES

### GNUTLS_PKCS8_USE_PKCS12_ARCFOUR

    #define GNUTLS_PKCS8_USE_PKCS12_ARCFOUR GNUTLS_PKCS_PKCS12_ARCFOUR

### GNUTLS_PKCS8_USE_PKCS12_RC2_40

    #define GNUTLS_PKCS8_USE_PKCS12_RC2_40 GNUTLS_PKCS_PKCS12_RC2_40

### enum gnutls_pkcs_encrypt_flags_t

Enumeration of different PKCS encryption flags.

#### Members

GNUTLS_PKCS_PLAIN | Unencrypted private key. |
GNUTLS_PKCS_PKCS12_3DES | PKCS-12 3DES. |
GNUTLS_PKCS_PKCS12_ARCFOUR | PKCS-12 ARCFOUR. |
GNUTLS_PKCS_PKCS12_RC2_40 | PKCS-12 RC2-40. |
GNUTLS_PKCS_PBES2_3DES | PBES2 3DES. |
GNUTLS_PKCS_PBES2_AES_128 | PBES2 AES-128. |
GNUTLS_PKCS_PBES2_AES_192 | PBES2 AES-192. |
GNUTLS_PKCS_PBES2_AES_256 | PBES2 AES-256. |
GNUTLS_PKCS_NULL_PASSWORD | Some schemas distinguish between an empty and a NULL password. |
GNUTLS_PKCS_PBES2_DES | PBES2 single DES. |
GNUTLS_PKCS_PBES1_DES_MD5 | PBES1 with single DES; for compatibility with openssl only. |
GNUTLS_PKCS_PBES2_GOST_TC26Z | PBES2 GOST 28147-89 CFB with TC26-Z S-box. |
GNUTLS_PKCS_PBES2_GOST_CPA | PBES2 GOST 28147-89 CFB with CryptoPro-A S-box. |
GNUTLS_PKCS_PBES2_GOST_CPB | PBES2 GOST 28147-89 CFB with CryptoPro-B S-box. |
GNUTLS_PKCS_PBES2_GOST_CPC | PBES2 GOST 28147-89 CFB with CryptoPro-C S-box. |
GNUTLS_PKCS_PBES2_GOST_CPD | PBES2 GOST 28147-89 CFB with CryptoPro-D S-box. |

### GNUTLS_PKCS_USE_PKCS12_3DES

    #define GNUTLS_PKCS_USE_PKCS12_3DES GNUTLS_PKCS_PKCS12_3DES

### GNUTLS_PKCS_USE_PKCS12_ARCFOUR

    #define GNUTLS_PKCS_USE_PKCS12_ARCFOUR GNUTLS_PKCS_PKCS12_ARCFOUR

### GNUTLS_PKCS_USE_PKCS12_RC2_40

    #define GNUTLS_PKCS_USE_PKCS12_RC2_40 GNUTLS_PKCS_PKCS12_RC2_40

### GNUTLS_PKCS_USE_PBES2_3DES

    #define GNUTLS_PKCS_USE_PBES2_3DES GNUTLS_PKCS_PBES2_3DES

### GNUTLS_PKCS_USE_PBES2_AES_128

    #define GNUTLS_PKCS_USE_PBES2_AES_128 GNUTLS_PKCS_PBES2_AES_128

### GNUTLS_PKCS_USE_PBES2_AES_192

    #define GNUTLS_PKCS_USE_PBES2_AES_192 GNUTLS_PKCS_PBES2_AES_192

### GNUTLS_PKCS_USE_PBES2_AES_256

    #define GNUTLS_PKCS_USE_PBES2_AES_256 GNUTLS_PKCS_PBES2_AES_256

### GNUTLS_PKCS_USE_PBES2_GOST_TC26Z

    #define GNUTLS_PKCS_USE_PBES2_GOST_TC26Z GNUTLS_PKCS_PBES2_GOST_TC26Z

### GNUTLS_PKCS_USE_PBES2_GOST_CPA

    #define GNUTLS_PKCS_USE_PBES2_GOST_CPA GNUTLS_PKCS_PBES2_GOST_CPA

### GNUTLS_PKCS_USE_PBES2_GOST_CPB

    #define GNUTLS_PKCS_USE_PBES2_GOST_CPB GNUTLS_PKCS_PBES2_GOST_CPB

### GNUTLS_PKCS_USE_PBES2_GOST_CPC

    #define GNUTLS_PKCS_USE_PBES2_GOST_CPC GNUTLS_PKCS_PBES2_GOST_CPC

### GNUTLS_PKCS_USE_PBES2_GOST_CPD

    #define GNUTLS_PKCS_USE_PBES2_GOST_CPD GNUTLS_PKCS_PBES2_GOST_CPD

### enum gnutls_keygen_types_t

Enumeration of different key generation data options.

#### Members

GNUTLS_KEYGEN_SEED | Specifies the seed to be used in key generation. |
GNUTLS_KEYGEN_DIGEST | The size field specifies the hash algorithm to be used in key generation. |
GNUTLS_KEYGEN_SPKI | data points to a `gnutls_x509_spki_t` structure; it is not used after the key generation call. |
GNUTLS_KEYGEN_DH | data points to a `gnutls_dh_params_t` structure; it is not used after the key generation call. |

### gnutls_keygen_data_st

    typedef struct {
    	gnutls_keygen_types_t type;
    	unsigned char *data;
    	unsigned int size;
    } gnutls_keygen_data_st;

### gnutls_x509_trust_list_t

    typedef struct gnutls_x509_trust_list_st *gnutls_x509_trust_list_t;

### gnutls_x509_trust_list_iter_t

    typedef struct gnutls_x509_trust_list_iter *gnutls_x509_trust_list_iter_t;

### enum gnutls_trust_list_flags_t

Enumeration of different certificate trust list flags.

#### Members

GNUTLS_TL_VERIFY_CRL | If any CRLs are provided they will be verified for validity prior to be added. The CA certificates that will be used for verification are the ones already added in the trusted list. |
GNUTLS_TL_USE_IN_TLS | Internal flag used by GnuTLS. If provided the trust list structure will cache a copy of CA DNs to be used in the certificate request TLS message. |
GNUTLS_TL_NO_DUPLICATES | If this flag is specified, a function adding certificates will check and eliminate any duplicates. |
GNUTLS_TL_NO_DUPLICATE_KEY | If this flag is specified, a certificate sharing the same key as a previously added on will not be added. |
GNUTLS_TL_GET_COPY | The semantics of this flag are documented to the functions which are applicable. In general, on returned value, the function will provide a copy if this flag is provided, rather than a pointer to internal data. |
GNUTLS_TL_FAIL_ON_INVALID_CRL | If an CRL is added which cannot be validated return an error instead of ignoring (must be used with `GNUTLS_TL_VERIFY_CRL`). |

### gnutls_x509_ext_st

    typedef struct {
    	char *oid;
    	unsigned int critical;
    	gnutls_datum_t data;
    } gnutls_x509_ext_st;