gnutls

## gnutls gnutls |

## Synopsis

    #define             HAVE_SSIZE_T
    #define             GNUTLS_VERSION
    #define             GNUTLS_VERSION_MAJOR
    #define             GNUTLS_VERSION_MINOR
    #define             GNUTLS_VERSION_PATCH
    #define             GNUTLS_VERSION_NUMBER
    #define             GNUTLS_CIPHER_RIJNDAEL_128_CBC
    #define             GNUTLS_CIPHER_RIJNDAEL_256_CBC
    #define             GNUTLS_CIPHER_RIJNDAEL_CBC
    #define             GNUTLS_CIPHER_ARCFOUR
    enum                gnutls_cipher_algorithm_t;
    enum                gnutls_kx_algorithm_t;
    enum                gnutls_params_type_t;
    enum                gnutls_credentials_type_t;
    #define             GNUTLS_MAC_SHA
    #define             GNUTLS_DIG_SHA
    enum                gnutls_mac_algorithm_t;
    enum                gnutls_digest_algorithm_t;
    #define             GNUTLS_MAX_ALGORITHM_NUM
    enum                gnutls_compression_method_t;
    enum                gnutls_connection_end_t;
    enum                gnutls_alert_level_t;
    enum                gnutls_alert_description_t;
    enum                gnutls_handshake_description_t;
    enum                gnutls_certificate_status_t;
    enum                gnutls_certificate_request_t;
    enum                gnutls_openpgp_crt_status_t;
    enum                gnutls_close_request_t;
    enum                gnutls_protocol_t;
    enum                gnutls_certificate_type_t;
    enum                gnutls_x509_crt_fmt_t;
    enum                gnutls_certificate_print_formats_t;
    enum                gnutls_pk_algorithm_t;
    const char *        gnutls_pk_algorithm_get_name        (gnutls_pk_algorithm_t algorithm);
    enum                gnutls_sign_algorithm_t;
    const char *        gnutls_sign_algorithm_get_name      (gnutls_sign_algorithm_t sign);
    enum                gnutls_sec_param_t;
    enum                gnutls_channel_binding_t;
    typedef             gnutls_transport_ptr_t;
    struct              gnutls_session_int;
    typedef             gnutls_session_t;
    struct              gnutls_dh_params_int;
    typedef             gnutls_dh_params_t;
    struct              gnutls_x509_privkey_int;
    typedef             gnutls_rsa_params_t;
    struct              gnutls_priority_st;
    typedef             gnutls_priority_t;
    int                 gnutls_init                         (gnutls_session_t *session,
                                                             gnutls_connection_end_t con_end);
    void                gnutls_deinit                       (gnutls_session_t session);
    int                 gnutls_bye                          (gnutls_session_t session,
                                                             gnutls_close_request_t how);
    int                 gnutls_handshake                    (gnutls_session_t session);
    int                 gnutls_rehandshake                  (gnutls_session_t session);
    gnutls_alert_description_t gnutls_alert_get             (gnutls_session_t session);
    int                 gnutls_alert_send                   (gnutls_session_t session,
                                                             gnutls_alert_level_t level,
                                                             gnutls_alert_description_t desc);
    int                 gnutls_alert_send_appropriate       (gnutls_session_t session,
                                                             int err);
    const char *        gnutls_alert_get_name               (gnutls_alert_description_t alert);
    gnutls_sec_param_t  gnutls_pk_bits_to_sec_param         (gnutls_pk_algorithm_t algo,
                                                             unsigned int bits);
    const char *        gnutls_sec_param_get_name           (gnutls_sec_param_t param);
    unsigned int        gnutls_sec_param_to_pk_bits         (gnutls_pk_algorithm_t algo,
                                                             gnutls_sec_param_t param);
    gnutls_cipher_algorithm_t gnutls_cipher_get             (gnutls_session_t session);
    gnutls_kx_algorithm_t gnutls_kx_get                     (gnutls_session_t session);
    gnutls_mac_algorithm_t gnutls_mac_get                   (gnutls_session_t session);
    gnutls_compression_method_t gnutls_compression_get      (gnutls_session_t session);
    gnutls_certificate_type_t gnutls_certificate_type_get   (gnutls_session_t session);
    int                 gnutls_sign_algorithm_get_requested (gnutls_session_t session,
                                                             size_t indx,
                                                             gnutls_sign_algorithm_t *algo);
    size_t              gnutls_cipher_get_key_size          (gnutls_cipher_algorithm_t algorithm);
    size_t              gnutls_mac_get_key_size             (gnutls_mac_algorithm_t algorithm);
    const char *        gnutls_cipher_get_name              (gnutls_cipher_algorithm_t algorithm);
    const char *        gnutls_mac_get_name                 (gnutls_mac_algorithm_t algorithm);
    const char *        gnutls_compression_get_name         (gnutls_compression_method_t algorithm);
    const char *        gnutls_kx_get_name                  (gnutls_kx_algorithm_t algorithm);
    const char *        gnutls_certificate_type_get_name    (gnutls_certificate_type_t type);
    const char *        gnutls_pk_get_name                  (gnutls_pk_algorithm_t algorithm);
    const char *        gnutls_sign_get_name                (gnutls_sign_algorithm_t algorithm);
    gnutls_mac_algorithm_t gnutls_mac_get_id                (const char *name);
    gnutls_compression_method_t gnutls_compression_get_id   (const char *name);
    gnutls_cipher_algorithm_t gnutls_cipher_get_id          (const char *name);
    gnutls_kx_algorithm_t gnutls_kx_get_id                  (const char *name);
    gnutls_protocol_t   gnutls_protocol_get_id              (const char *name);
    gnutls_certificate_type_t gnutls_certificate_type_get_id
                                                            (const char *name);
    gnutls_pk_algorithm_t gnutls_pk_get_id                  (const char *name);
    gnutls_sign_algorithm_t gnutls_sign_get_id              (const char *name);
    const gnutls_cipher_algorithm_t * gnutls_cipher_list    (void);
    const gnutls_mac_algorithm_t * gnutls_mac_list          (void);
    const gnutls_compression_method_t * gnutls_compression_list
                                                            (void);
    const gnutls_protocol_t * gnutls_protocol_list          (void);
    const gnutls_certificate_type_t * gnutls_certificate_type_list
                                                            (void);
    const gnutls_kx_algorithm_t * gnutls_kx_list            (void);
    const gnutls_pk_algorithm_t * gnutls_pk_list            (void);
    const gnutls_sign_algorithm_t * gnutls_sign_list        (void);
    const char *        gnutls_cipher_suite_info            (size_t idx,
                                                             char *cs_id,
                                                             gnutls_kx_algorithm_t *kx,
                                                             gnutls_cipher_algorithm_t *cipher,
                                                             gnutls_mac_algorithm_t *mac,
                                                             gnutls_protocol_t *version);
    int                 gnutls_error_is_fatal               (int error);
    int                 gnutls_error_to_alert               (int err,
                                                             int *level);
    void                gnutls_perror                       (int error);
    const char *        gnutls_strerror                     (int error);
    const char *        gnutls_strerror_name                (int error);
    void                gnutls_handshake_set_private_extensions
                                                            (gnutls_session_t session,
                                                             int allow);
    gnutls_handshake_description_t gnutls_handshake_get_last_out
                                                            (gnutls_session_t session);
    gnutls_handshake_description_t gnutls_handshake_get_last_in
                                                            (gnutls_session_t session);
    ssize_t             gnutls_record_send                  (gnutls_session_t session,
                                                             const void *data,
                                                             size_t sizeofdata);
    ssize_t             gnutls_record_recv                  (gnutls_session_t session,
                                                             void *data,
                                                             size_t sizeofdata);
    #define             gnutls_read
    #define             gnutls_write
    void                gnutls_session_enable_compatibility_mode
                                                            (gnutls_session_t session);
    void                gnutls_record_disable_padding       (gnutls_session_t session);
    int                 gnutls_record_get_direction         (gnutls_session_t session);
    size_t              gnutls_record_get_max_size          (gnutls_session_t session);
    ssize_t             gnutls_record_set_max_size          (gnutls_session_t session,
                                                             size_t size);
    size_t              gnutls_record_check_pending         (gnutls_session_t session);
    int                 gnutls_prf                          (gnutls_session_t session,
                                                             size_t label_size,
                                                             const char *label,
                                                             int server_random_first,
                                                             size_t extra_size,
                                                             const char *extra,
                                                             size_t outsize,
                                                             char *out);
    int                 gnutls_prf_raw                      (gnutls_session_t session,
                                                             size_t label_size,
                                                             const char *label,
                                                             size_t seed_size,
                                                             const char *seed,
                                                             size_t outsize,
                                                             char *out);
    int                 (*gnutls_ext_recv_func)             (gnutls_session_t session,
                                                             const unsigned char *data,
                                                             size_t len);
    int                 (*gnutls_ext_send_func)             (gnutls_session_t session,
                                                             unsigned char *data,
                                                             size_t len);
    enum                gnutls_ext_parse_type_t;
    enum                gnutls_server_name_type_t;
    int                 gnutls_server_name_set              (gnutls_session_t session,
                                                             gnutls_server_name_type_t type,
                                                             const void *name,
                                                             size_t name_length);
    int                 gnutls_server_name_get              (gnutls_session_t session,
                                                             void *data,
                                                             size_t *data_length,
                                                             unsigned int *type,
                                                             unsigned int indx);
    int                 gnutls_safe_renegotiation_status    (gnutls_session_t session);
    enum                gnutls_supplemental_data_format_type_t;
    int                 gnutls_session_ticket_key_generate  (gnutls_datum_t *key);
    int                 gnutls_session_ticket_enable_client (gnutls_session_t session);
    int                 gnutls_session_ticket_enable_server (gnutls_session_t session,
                                                             const gnutls_datum_t *key);
    int                 gnutls_priority_init                (gnutls_priority_t *priority_cache,
                                                             const char *priorities,
                                                             const char **err_pos);
    void                gnutls_priority_deinit              (gnutls_priority_t priority_cache);
    int                 gnutls_priority_set                 (gnutls_session_t session,
                                                             gnutls_priority_t priority);
    int                 gnutls_priority_set_direct          (gnutls_session_t session,
                                                             const char *priorities,
                                                             const char **err_pos);
    int                 gnutls_set_default_priority         (gnutls_session_t session);
    int                 gnutls_set_default_export_priority  (gnutls_session_t session);
    const char *        gnutls_cipher_suite_get_name        (gnutls_kx_algorithm_t kx_algorithm,
                                                             gnutls_cipher_algorithm_t cipher_algorithm,
                                                             gnutls_mac_algorithm_t mac_algorithm);
    gnutls_protocol_t   gnutls_protocol_get_version         (gnutls_session_t session);
    const char *        gnutls_protocol_get_name            (gnutls_protocol_t version);
    int                 gnutls_session_set_data             (gnutls_session_t session,
                                                             const void *session_data,
                                                             size_t session_data_size);
    int                 gnutls_session_get_data             (gnutls_session_t session,
                                                             void *session_data,
                                                             size_t *session_data_size);
    int                 gnutls_session_get_data2            (gnutls_session_t session,
                                                             gnutls_datum_t *data);
    #define             GNUTLS_MAX_SESSION_ID
    int                 gnutls_session_get_id               (gnutls_session_t session,
                                                             void *session_id,
                                                             size_t *session_id_size);
    int                 gnutls_session_channel_binding      (gnutls_session_t session,
                                                             gnutls_channel_binding_t cbtype,
                                                             gnutls_datum_t *cb);
    int                 gnutls_session_is_resumed           (gnutls_session_t session);
    int                 (*gnutls_db_store_func)             (void *Param1,
                                                             gnutls_datum_t key,
                                                             gnutls_datum_t data);
    int                 (*gnutls_db_remove_func)            (void *Param1,
                                                             gnutls_datum_t key);
    gnutls_datum_t      (*gnutls_db_retr_func)              (void *Param1,
                                                             gnutls_datum_t key);
    void                gnutls_db_set_cache_expiration      (gnutls_session_t session,
                                                             int seconds);
    void                gnutls_db_remove_session            (gnutls_session_t session);
    void                gnutls_db_set_retrieve_function     (gnutls_session_t session,
                                                             gnutls_db_retr_func retr_func);
    void                gnutls_db_set_remove_function       (gnutls_session_t session,
                                                             gnutls_db_remove_func rem_func);
    void                gnutls_db_set_store_function        (gnutls_session_t session,
                                                             gnutls_db_store_func store_func);
    void                gnutls_db_set_ptr                   (gnutls_session_t session,
                                                             void *ptr);
    void *              gnutls_db_get_ptr                   (gnutls_session_t session);
    int                 gnutls_db_check_entry               (gnutls_session_t session,
                                                             gnutls_datum_t session_entry);
    int                 (*gnutls_handshake_post_client_hello_func)
                                                            (gnutls_session_t Param1);
    void                gnutls_handshake_set_post_client_hello_function
                                                            (gnutls_session_t session,
                                                             gnutls_handshake_post_client_hello_func func);
    void                gnutls_handshake_set_max_packet_length
                                                            (gnutls_session_t session,
                                                             size_t max);
    const char *        gnutls_check_version                (const char *req_version);
    void                gnutls_credentials_clear            (gnutls_session_t session);
    int                 gnutls_credentials_set              (gnutls_session_t session,
                                                             gnutls_credentials_type_t type,
                                                             void *cred);
    #define             gnutls_cred_set
    struct              gnutls_certificate_credentials_st;
    void                gnutls_anon_free_server_credentials (gnutls_anon_server_credentials_t sc);
    int                 gnutls_anon_allocate_server_credentials
                                                            (gnutls_anon_server_credentials_t *sc);
    void                gnutls_anon_set_server_dh_params    (gnutls_anon_server_credentials_t res,
                                                             gnutls_dh_params_t dh_params);
    void                gnutls_anon_set_server_params_function
                                                            (gnutls_anon_server_credentials_t res,
                                                             gnutls_params_function *func);
    void                gnutls_anon_free_client_credentials (gnutls_anon_client_credentials_t sc);
    int                 gnutls_anon_allocate_client_credentials
                                                            (gnutls_anon_client_credentials_t *sc);
    void                gnutls_certificate_free_credentials (gnutls_certificate_credentials_t sc);
    int                 gnutls_certificate_allocate_credentials
                                                            (gnutls_certificate_credentials_t *res);
    void                gnutls_certificate_free_keys        (gnutls_certificate_credentials_t sc);
    void                gnutls_certificate_free_cas         (gnutls_certificate_credentials_t sc);
    void                gnutls_certificate_free_ca_names    (gnutls_certificate_credentials_t sc);
    void                gnutls_certificate_free_crls        (gnutls_certificate_credentials_t sc);
    void                gnutls_certificate_set_dh_params    (gnutls_certificate_credentials_t res,
                                                             gnutls_dh_params_t dh_params);
    void                gnutls_certificate_set_rsa_export_params
                                                            (gnutls_certificate_credentials_t res,
                                                             gnutls_rsa_params_t rsa_params);
    void                gnutls_certificate_set_verify_flags (gnutls_certificate_credentials_t res,
                                                             unsigned int flags);
    void                gnutls_certificate_set_verify_limits
                                                            (gnutls_certificate_credentials_t res,
                                                             unsigned int max_bits,
                                                             unsigned int max_depth);
    int                 gnutls_certificate_set_x509_trust_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *cafile,
                                                             gnutls_x509_crt_fmt_t type);
    int                 gnutls_certificate_set_x509_trust_mem
                                                            (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *ca,
                                                             gnutls_x509_crt_fmt_t type);
    int                 gnutls_certificate_set_x509_crl_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *crlfile,
                                                             gnutls_x509_crt_fmt_t type);
    int                 gnutls_certificate_set_x509_crl_mem (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *CRL,
                                                             gnutls_x509_crt_fmt_t type);
    int                 gnutls_certificate_set_x509_key_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *certfile,
                                                             const char *keyfile,
                                                             gnutls_x509_crt_fmt_t type);
    int                 gnutls_certificate_set_x509_key_mem (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *cert,
                                                             const gnutls_datum_t *key,
                                                             gnutls_x509_crt_fmt_t type);
    void                gnutls_certificate_send_x509_rdn_sequence
                                                            (gnutls_session_t session,
                                                             int status);
    int                 gnutls_certificate_set_x509_simple_pkcs12_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *pkcs12file,
                                                             gnutls_x509_crt_fmt_t type,
                                                             const char *password);
    int                 gnutls_certificate_set_x509_simple_pkcs12_mem
                                                            (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *p12blob,
                                                             gnutls_x509_crt_fmt_t type,
                                                             const char *password);
    typedef             gnutls_x509_privkey_t;
    struct              gnutls_x509_crl_int;
    typedef             gnutls_x509_crl_t;
    struct              gnutls_x509_crt_int;
    typedef             gnutls_x509_crt_t;
    struct              gnutls_x509_crq_int;
    typedef             gnutls_x509_crq_t;
    struct              gnutls_openpgp_keyring_int;
    typedef             gnutls_openpgp_keyring_t;
    int                 gnutls_certificate_set_x509_key     (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crt_t *cert_list,
                                                             int cert_list_size,
                                                             gnutls_x509_privkey_t key);
    int                 gnutls_certificate_set_x509_trust   (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crt_t *ca_list,
                                                             int ca_list_size);
    int                 gnutls_certificate_set_x509_crl     (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crl_t *crl_list,
                                                             int crl_list_size);
    int                 gnutls_global_init                  (void);
    void                gnutls_global_deinit                (void);
    int                 (*mutex_init_func)                  (void **mutex);
    int                 (*mutex_lock_func)                  (void **mutex);
    int                 (*mutex_unlock_func)                (void **mutex);
    int                 (*mutex_deinit_func)                (void **mutex);
    void                gnutls_global_set_mutex             (mutex_init_func init,
                                                             mutex_deinit_func deinit,
                                                             mutex_lock_func lock,
                                                             mutex_unlock_func unlock);
    void *              (*gnutls_alloc_function)            (size_t Param1);
    void *              (*gnutls_calloc_function)           (size_t Param1,
                                                             size_t Param2);
    int                 (*gnutls_is_secure_function)        (const void *Param1);
    void                (*gnutls_free_function)             (void *Param1);
    void *              (*gnutls_realloc_function)          (void *Param1,
                                                             size_t Param2);
    void                gnutls_global_set_mem_functions     (gnutls_alloc_function alloc_func,
                                                             gnutls_alloc_function secure_alloc_func,
                                                             gnutls_is_secure_function is_secure_func,
                                                             gnutls_realloc_function realloc_func,
                                                             gnutls_free_function free_func);
    extern gnutls_alloc_function gnutls_malloc;
    extern gnutls_alloc_function gnutls_secure_malloc;
    extern gnutls_realloc_function gnutls_realloc;
    extern gnutls_calloc_function gnutls_calloc;
    extern gnutls_free_function gnutls_free;
    char *              (*gnutls_strdup)                    (const char *Param1);
    void                (*gnutls_log_func)                  (int Param1,
                                                             const char *Param2);
    void                gnutls_global_set_log_function      (gnutls_log_func log_func);
    void                gnutls_global_set_log_level         (int level);
    int                 gnutls_dh_params_init               (gnutls_dh_params_t *dh_params);
    void                gnutls_dh_params_deinit             (gnutls_dh_params_t dh_params);
    int                 gnutls_dh_params_import_raw         (gnutls_dh_params_t dh_params,
                                                             const gnutls_datum_t *prime,
                                                             const gnutls_datum_t *generator);
    int                 gnutls_dh_params_import_pkcs3       (gnutls_dh_params_t params,
                                                             const gnutls_datum_t *pkcs3_params,
                                                             gnutls_x509_crt_fmt_t format);
    int                 gnutls_dh_params_generate2          (gnutls_dh_params_t params,
                                                             unsigned int bits);
    int                 gnutls_dh_params_export_pkcs3       (gnutls_dh_params_t params,
                                                             gnutls_x509_crt_fmt_t format,
                                                             unsigned char *params_data,
                                                             size_t *params_data_size);
    int                 gnutls_dh_params_export_raw         (gnutls_dh_params_t params,
                                                             gnutls_datum_t *prime,
                                                             gnutls_datum_t *generator,
                                                             unsigned int *bits);
    int                 gnutls_dh_params_cpy                (gnutls_dh_params_t dst,
                                                             gnutls_dh_params_t src);
    int                 gnutls_rsa_params_init              (gnutls_rsa_params_t *rsa_params);
    void                gnutls_rsa_params_deinit            (gnutls_rsa_params_t rsa_params);
    int                 gnutls_rsa_params_cpy               (gnutls_rsa_params_t dst,
                                                             gnutls_rsa_params_t src);
    int                 gnutls_rsa_params_import_raw        (gnutls_rsa_params_t rsa_params,
                                                             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);
    int                 gnutls_rsa_params_generate2         (gnutls_rsa_params_t params,
                                                             unsigned int bits);
    int                 gnutls_rsa_params_export_raw        (gnutls_rsa_params_t params,
                                                             gnutls_datum_t *m,
                                                             gnutls_datum_t *e,
                                                             gnutls_datum_t *d,
                                                             gnutls_datum_t *p,
                                                             gnutls_datum_t *q,
                                                             gnutls_datum_t *u,
                                                             unsigned int *bits);
    int                 gnutls_rsa_params_export_pkcs1      (gnutls_rsa_params_t params,
                                                             gnutls_x509_crt_fmt_t format,
                                                             unsigned char *params_data,
                                                             size_t *params_data_size);
    int                 gnutls_rsa_params_import_pkcs1      (gnutls_rsa_params_t params,
                                                             const gnutls_datum_t *pkcs1_params,
                                                             gnutls_x509_crt_fmt_t format);
    ssize_t             (*gnutls_pull_func)                 (gnutls_transport_ptr_t Param1,
                                                             void *Param2,
                                                             size_t Param3);
    ssize_t             (*gnutls_push_func)                 (gnutls_transport_ptr_t Param1,
                                                             const void *Param2,
                                                             size_t Param3);
    ssize_t             (*gnutls_vec_push_func)             (gnutls_transport_ptr_t Param1,
                                                             const giovec_t *iov,
                                                             int iovcnt);
    int                 (*gnutls_errno_func)                (gnutls_transport_ptr_t Param1);
    void                gnutls_transport_set_ptr            (gnutls_session_t session,
                                                             gnutls_transport_ptr_t ptr);
    void                gnutls_transport_set_ptr2           (gnutls_session_t session,
                                                             gnutls_transport_ptr_t recv_ptr,
                                                             gnutls_transport_ptr_t send_ptr);
    gnutls_transport_ptr_t gnutls_transport_get_ptr         (gnutls_session_t session);
    void                gnutls_transport_get_ptr2           (gnutls_session_t session,
                                                             gnutls_transport_ptr_t *recv_ptr,
                                                             gnutls_transport_ptr_t *send_ptr);
    void                gnutls_transport_set_vec_push_function
                                                            (gnutls_session_t session,
                                                             gnutls_vec_push_func vec_func);
    void                gnutls_transport_set_push_function  (gnutls_session_t session,
                                                             gnutls_push_func push_func);
    void                gnutls_transport_set_pull_function  (gnutls_session_t session,
                                                             gnutls_pull_func pull_func);
    void                gnutls_transport_set_errno_function (gnutls_session_t session,
                                                             gnutls_errno_func errno_func);
    void                gnutls_transport_set_errno          (gnutls_session_t session,
                                                             int err);
    void                gnutls_session_set_ptr              (gnutls_session_t session,
                                                             void *ptr);
    void *              gnutls_session_get_ptr              (gnutls_session_t session);
    void                gnutls_openpgp_send_cert            (gnutls_session_t session,
                                                             gnutls_openpgp_crt_status_t status);
    int                 gnutls_fingerprint                  (gnutls_digest_algorithm_t algo,
                                                             const gnutls_datum_t *data,
                                                             void *result,
                                                             size_t *result_size);
    void                gnutls_srp_free_client_credentials  (gnutls_srp_client_credentials_t sc);
    int                 gnutls_srp_allocate_client_credentials
                                                            (gnutls_srp_client_credentials_t *sc);
    int                 gnutls_srp_set_client_credentials   (gnutls_srp_client_credentials_t res,
                                                             const char *username,
                                                             const char *password);
    void                gnutls_srp_free_server_credentials  (gnutls_srp_server_credentials_t sc);
    int                 gnutls_srp_allocate_server_credentials
                                                            (gnutls_srp_server_credentials_t *sc);
    int                 gnutls_srp_set_server_credentials_file
                                                            (gnutls_srp_server_credentials_t res,
                                                             const char *password_file,
                                                             const char *password_conf_file);
    const char *        gnutls_srp_server_get_username      (gnutls_session_t session);
    void                gnutls_srp_set_prime_bits           (gnutls_session_t session,
                                                             unsigned int bits);
    int                 gnutls_srp_verifier                 (const char *username,
                                                             const char *password,
                                                             const gnutls_datum_t *salt,
                                                             const gnutls_datum_t *generator,
                                                             const gnutls_datum_t *prime,
                                                             gnutls_datum_t *res);
    extern const gnutls_datum_t gnutls_srp_2048_group_prime;
    extern const gnutls_datum_t gnutls_srp_2048_group_generator;
    extern const gnutls_datum_t gnutls_srp_1536_group_prime;
    extern const gnutls_datum_t gnutls_srp_1536_group_generator;
    extern const gnutls_datum_t gnutls_srp_1024_group_prime;
    extern const gnutls_datum_t gnutls_srp_1024_group_generator;
    void                gnutls_srp_set_server_credentials_function
                                                            (gnutls_srp_server_credentials_t cred,
                                                             gnutls_srp_server_credentials_function *func);
    void                gnutls_srp_set_client_credentials_function
                                                            (gnutls_srp_client_credentials_t cred,
                                                             gnutls_srp_client_credentials_function *func);
    int                 gnutls_srp_base64_encode            (const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);
    int                 gnutls_srp_base64_encode_alloc      (const gnutls_datum_t *data,
                                                             gnutls_datum_t *result);
    int                 gnutls_srp_base64_decode            (const gnutls_datum_t *b64_data,
                                                             char *result,
                                                             size_t *result_size);
    int                 gnutls_srp_base64_decode_alloc      (const gnutls_datum_t *b64_data,
                                                             gnutls_datum_t *result);
    enum                gnutls_psk_key_flags;
    void                gnutls_psk_free_client_credentials  (gnutls_psk_client_credentials_t sc);
    int                 gnutls_psk_allocate_client_credentials
                                                            (gnutls_psk_client_credentials_t *sc);
    int                 gnutls_psk_set_client_credentials   (gnutls_psk_client_credentials_t res,
                                                             const char *username,
                                                             const gnutls_datum_t *key,
                                                             gnutls_psk_key_flags format);
    void                gnutls_psk_free_server_credentials  (gnutls_psk_server_credentials_t sc);
    int                 gnutls_psk_allocate_server_credentials
                                                            (gnutls_psk_server_credentials_t *sc);
    int                 gnutls_psk_set_server_credentials_file
                                                            (gnutls_psk_server_credentials_t res,
                                                             const char *password_file);
    int                 gnutls_psk_set_server_credentials_hint
                                                            (gnutls_psk_server_credentials_t res,
                                                             const char *hint);
    const char *        gnutls_psk_server_get_username      (gnutls_session_t session);
    const char *        gnutls_psk_client_get_hint          (gnutls_session_t session);
    void                gnutls_psk_set_server_credentials_function
                                                            (gnutls_psk_server_credentials_t cred,
                                                             gnutls_psk_server_credentials_function *func);
    void                gnutls_psk_set_client_credentials_function
                                                            (gnutls_psk_client_credentials_t cred,
                                                             gnutls_psk_client_credentials_function *func);
    int                 gnutls_hex_encode                   (const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);
    int                 gnutls_hex_decode                   (const gnutls_datum_t *hex_data,
                                                             char *result,
                                                             size_t *result_size);
    void                gnutls_psk_set_server_dh_params     (gnutls_psk_server_credentials_t res,
                                                             gnutls_dh_params_t dh_params);
    void                gnutls_psk_set_server_params_function
                                                            (gnutls_psk_server_credentials_t res,
                                                             gnutls_params_function *func);
    enum                gnutls_x509_subject_alt_name_t;
    struct              gnutls_openpgp_crt_int;
    typedef             gnutls_openpgp_crt_t;
    struct              gnutls_openpgp_privkey_int;
    typedef             gnutls_openpgp_privkey_t;
    struct              gnutls_pkcs11_privkey_st;
    typedef             gnutls_pkcs11_privkey_t;
    enum                gnutls_privkey_type_t;
    gnutls_credentials_type_t gnutls_auth_get_type          (gnutls_session_t session);
    gnutls_credentials_type_t gnutls_auth_server_get_type   (gnutls_session_t session);
    gnutls_credentials_type_t gnutls_auth_client_get_type   (gnutls_session_t session);
    void                gnutls_dh_set_prime_bits            (gnutls_session_t session,
                                                             unsigned int bits);
    int                 gnutls_dh_get_secret_bits           (gnutls_session_t session);
    int                 gnutls_dh_get_peers_public_bits     (gnutls_session_t session);
    int                 gnutls_dh_get_prime_bits            (gnutls_session_t session);
    int                 gnutls_dh_get_group                 (gnutls_session_t session,
                                                             gnutls_datum_t *raw_gen,
                                                             gnutls_datum_t *raw_prime);
    int                 gnutls_dh_get_pubkey                (gnutls_session_t session,
                                                             gnutls_datum_t *raw_key);
    int                 gnutls_rsa_export_get_pubkey        (gnutls_session_t session,
                                                             gnutls_datum_t *exponent,
                                                             gnutls_datum_t *modulus);
    int                 gnutls_rsa_export_get_modulus_bits  (gnutls_session_t session);
    void                gnutls_certificate_set_retrieve_function
                                                            (gnutls_certificate_credentials_t cred,
                                                             gnutls_certificate_retrieve_function *func);
    void                gnutls_certificate_set_verify_function
                                                            (gnutls_certificate_credentials_t cred,
                                                             gnutls_certificate_verify_function *func);
    void                gnutls_certificate_server_set_request
                                                            (gnutls_session_t session,
                                                             gnutls_certificate_request_t req);
    const gnutls_datum_t * gnutls_certificate_get_peers     (gnutls_session_t session,
                                                             unsigned int *list_size);
    const gnutls_datum_t * gnutls_certificate_get_ours      (gnutls_session_t session);
    time_t              gnutls_certificate_activation_time_peers
                                                            (gnutls_session_t session);
    time_t              gnutls_certificate_expiration_time_peers
                                                            (gnutls_session_t session);
    int                 gnutls_certificate_client_get_request_status
                                                            (gnutls_session_t session);
    int                 gnutls_certificate_verify_peers2    (gnutls_session_t session,
                                                             unsigned int *status);
    int                 gnutls_pem_base64_encode            (const char *msg,
                                                             const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);
    int                 gnutls_pem_base64_decode            (const char *header,
                                                             const gnutls_datum_t *b64_data,
                                                             unsigned char *result,
                                                             size_t *result_size);
    int                 gnutls_pem_base64_encode_alloc      (const char *msg,
                                                             const gnutls_datum_t *data,
                                                             gnutls_datum_t *result);
    int                 gnutls_pem_base64_decode_alloc      (const char *header,
                                                             const gnutls_datum_t *b64_data,
                                                             gnutls_datum_t *result);
    #define             GNUTLS_KEY_DIGITAL_SIGNATURE
    #define             GNUTLS_KEY_NON_REPUDIATION
    #define             GNUTLS_KEY_KEY_ENCIPHERMENT
    #define             GNUTLS_KEY_DATA_ENCIPHERMENT
    #define             GNUTLS_KEY_KEY_AGREEMENT
    #define             GNUTLS_KEY_KEY_CERT_SIGN
    #define             GNUTLS_KEY_CRL_SIGN
    #define             GNUTLS_KEY_ENCIPHER_ONLY
    #define             GNUTLS_KEY_DECIPHER_ONLY
    void                gnutls_certificate_set_params_function
                                                            (gnutls_certificate_credentials_t res,
                                                             gnutls_params_function *func);
    void                gnutls_anon_set_params_function     (gnutls_anon_server_credentials_t res,
                                                             gnutls_params_function *func);
    void                gnutls_psk_set_params_function      (gnutls_psk_server_credentials_t res,
                                                             gnutls_params_function *func);
    int                 gnutls_hex2bin                      (const char *hex_data,
                                                             size_t hex_size,
                                                             char *bin_data,
                                                             size_t *bin_size);
    #define             GNUTLS_E_SUCCESS
    #define             GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM
    #define             GNUTLS_E_UNKNOWN_CIPHER_TYPE
    #define             GNUTLS_E_LARGE_PACKET
    #define             GNUTLS_E_UNSUPPORTED_VERSION_PACKET
    #define             GNUTLS_E_UNEXPECTED_PACKET_LENGTH
    #define             GNUTLS_E_INVALID_SESSION
    #define             GNUTLS_E_FATAL_ALERT_RECEIVED
    #define             GNUTLS_E_UNEXPECTED_PACKET
    #define             GNUTLS_E_WARNING_ALERT_RECEIVED
    #define             GNUTLS_E_ERROR_IN_FINISHED_PACKET
    #define             GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET
    #define             GNUTLS_E_UNKNOWN_CIPHER_SUITE
    #define             GNUTLS_E_UNWANTED_ALGORITHM
    #define             GNUTLS_E_MPI_SCAN_FAILED
    #define             GNUTLS_E_DECRYPTION_FAILED
    #define             GNUTLS_E_MEMORY_ERROR
    #define             GNUTLS_E_DECOMPRESSION_FAILED
    #define             GNUTLS_E_COMPRESSION_FAILED
    #define             GNUTLS_E_AGAIN
    #define             GNUTLS_E_EXPIRED
    #define             GNUTLS_E_DB_ERROR
    #define             GNUTLS_E_SRP_PWD_ERROR
    #define             GNUTLS_E_INSUFFICIENT_CREDENTIALS
    #define             GNUTLS_E_INSUFICIENT_CREDENTIALS
    #define             GNUTLS_E_INSUFFICIENT_CRED
    #define             GNUTLS_E_INSUFICIENT_CRED
    #define             GNUTLS_E_HASH_FAILED
    #define             GNUTLS_E_BASE64_DECODING_ERROR
    #define             GNUTLS_E_MPI_PRINT_FAILED
    #define             GNUTLS_E_REHANDSHAKE
    #define             GNUTLS_E_GOT_APPLICATION_DATA
    #define             GNUTLS_E_RECORD_LIMIT_REACHED
    #define             GNUTLS_E_ENCRYPTION_FAILED
    #define             GNUTLS_E_PK_ENCRYPTION_FAILED
    #define             GNUTLS_E_PK_DECRYPTION_FAILED
    #define             GNUTLS_E_PK_SIGN_FAILED
    #define             GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION
    #define             GNUTLS_E_KEY_USAGE_VIOLATION
    #define             GNUTLS_E_NO_CERTIFICATE_FOUND
    #define             GNUTLS_E_INVALID_REQUEST
    #define             GNUTLS_E_SHORT_MEMORY_BUFFER
    #define             GNUTLS_E_INTERRUPTED
    #define             GNUTLS_E_PUSH_ERROR
    #define             GNUTLS_E_PULL_ERROR
    #define             GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER
    #define             GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
    #define             GNUTLS_E_PKCS1_WRONG_PAD
    #define             GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION
    #define             GNUTLS_E_INTERNAL_ERROR
    #define             GNUTLS_E_DH_PRIME_UNACCEPTABLE
    #define             GNUTLS_E_FILE_ERROR
    #define             GNUTLS_E_TOO_MANY_EMPTY_PACKETS
    #define             GNUTLS_E_UNKNOWN_PK_ALGORITHM
    #define             GNUTLS_E_INIT_LIBEXTRA
    #define             GNUTLS_E_LIBRARY_VERSION_MISMATCH
    #define             GNUTLS_E_NO_TEMPORARY_RSA_PARAMS
    #define             GNUTLS_E_LZO_INIT_FAILED
    #define             GNUTLS_E_NO_COMPRESSION_ALGORITHMS
    #define             GNUTLS_E_NO_CIPHER_SUITES
    #define             GNUTLS_E_OPENPGP_GETKEY_FAILED
    #define             GNUTLS_E_PK_SIG_VERIFY_FAILED
    #define             GNUTLS_E_ILLEGAL_SRP_USERNAME
    #define             GNUTLS_E_SRP_PWD_PARSING_ERROR
    #define             GNUTLS_E_NO_TEMPORARY_DH_PARAMS
    #define             GNUTLS_E_ASN1_ELEMENT_NOT_FOUND
    #define             GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND
    #define             GNUTLS_E_ASN1_DER_ERROR
    #define             GNUTLS_E_ASN1_VALUE_NOT_FOUND
    #define             GNUTLS_E_ASN1_GENERIC_ERROR
    #define             GNUTLS_E_ASN1_VALUE_NOT_VALID
    #define             GNUTLS_E_ASN1_TAG_ERROR
    #define             GNUTLS_E_ASN1_TAG_IMPLICIT
    #define             GNUTLS_E_ASN1_TYPE_ANY_ERROR
    #define             GNUTLS_E_ASN1_SYNTAX_ERROR
    #define             GNUTLS_E_ASN1_DER_OVERFLOW
    #define             GNUTLS_E_OPENPGP_UID_REVOKED
    #define             GNUTLS_E_CERTIFICATE_ERROR
    #define             GNUTLS_E_X509_CERTIFICATE_ERROR
    #define             GNUTLS_E_CERTIFICATE_KEY_MISMATCH
    #define             GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE
    #define             GNUTLS_E_X509_UNKNOWN_SAN
    #define             GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED
    #define             GNUTLS_E_X509_UNSUPPORTED_ATTRIBUTE
    #define             GNUTLS_E_UNKNOWN_HASH_ALGORITHM
    #define             GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE
    #define             GNUTLS_E_UNKNOWN_PKCS_BAG_TYPE
    #define             GNUTLS_E_INVALID_PASSWORD
    #define             GNUTLS_E_MAC_VERIFY_FAILED
    #define             GNUTLS_E_CONSTRAINT_ERROR
    #define             GNUTLS_E_WARNING_IA_IPHF_RECEIVED
    #define             GNUTLS_E_WARNING_IA_FPHF_RECEIVED
    #define             GNUTLS_E_IA_VERIFY_FAILED
    #define             GNUTLS_E_UNKNOWN_ALGORITHM
    #define             GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM
    #define             GNUTLS_E_SAFE_RENEGOTIATION_FAILED
    #define             GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED
    #define             GNUTLS_E_UNKNOWN_SRP_USERNAME
    #define             GNUTLS_E_BASE64_ENCODING_ERROR
    #define             GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY
    #define             GNUTLS_E_INCOMPATIBLE_CRYPTO_LIBRARY
    #define             GNUTLS_E_INCOMPATIBLE_LIBTASN1_LIBRARY
    #define             GNUTLS_E_OPENPGP_KEYRING_ERROR
    #define             GNUTLS_E_X509_UNSUPPORTED_OID
    #define             GNUTLS_E_RANDOM_FAILED
    #define             GNUTLS_E_BASE64_UNEXPECTED_HEADER_ERROR
    #define             GNUTLS_E_OPENPGP_SUBKEY_ERROR
    #define             GNUTLS_E_CRYPTO_ALREADY_REGISTERED
    #define             GNUTLS_E_HANDSHAKE_TOO_LARGE
    #define             GNUTLS_E_CRYPTODEV_IOCTL_ERROR
    #define             GNUTLS_E_CRYPTODEV_DEVICE_ERROR
    #define             GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE
    #define             GNUTLS_E_OPENPGP_PREFERRED_KEY_ERROR
    #define             GNUTLS_E_INCOMPAT_DSA_KEY_WITH_TLS_PROTOCOL
    #define             GNUTLS_E_PKCS11_ERROR
    #define             GNUTLS_E_PKCS11_LOAD_ERROR
    #define             GNUTLS_E_PARSING_ERROR
    #define             GNUTLS_E_PKCS11_PIN_ERROR
    #define             GNUTLS_E_PKCS11_SLOT_ERROR
    #define             GNUTLS_E_LOCKING_ERROR
    #define             GNUTLS_E_PKCS11_ATTRIBUTE_ERROR
    #define             GNUTLS_E_PKCS11_DEVICE_ERROR
    #define             GNUTLS_E_PKCS11_DATA_ERROR
    #define             GNUTLS_E_PKCS11_UNSUPPORTED_FEATURE_ERROR
    #define             GNUTLS_E_PKCS11_KEY_ERROR
    #define             GNUTLS_E_PKCS11_PIN_EXPIRED
    #define             GNUTLS_E_PKCS11_PIN_LOCKED
    #define             GNUTLS_E_PKCS11_SESSION_ERROR
    #define             GNUTLS_E_PKCS11_SIGNATURE_ERROR
    #define             GNUTLS_E_PKCS11_TOKEN_ERROR
    #define             GNUTLS_E_PKCS11_USER_ERROR
    #define             GNUTLS_E_CRYPTO_INIT_FAILED
    #define             GNUTLS_E_UNIMPLEMENTED_FEATURE
    #define             GNUTLS_E_APPLICATION_ERROR_MAX
    #define             GNUTLS_E_APPLICATION_ERROR_MIN

## Description

## Details

### HAVE_SSIZE_T

    #define HAVE_SSIZE_T

### GNUTLS_VERSION

    #define GNUTLS_VERSION "2.12.23"

### GNUTLS_VERSION_MAJOR

    #define GNUTLS_VERSION_MAJOR 2

### GNUTLS_VERSION_MINOR

    #define GNUTLS_VERSION_MINOR 12

### GNUTLS_VERSION_PATCH

    #define GNUTLS_VERSION_PATCH 23

### GNUTLS_VERSION_NUMBER

    #define GNUTLS_VERSION_NUMBER 0x020c17

### GNUTLS_CIPHER_RIJNDAEL_128_CBC

    #define GNUTLS_CIPHER_RIJNDAEL_128_CBC GNUTLS_CIPHER_AES_128_CBC

### GNUTLS_CIPHER_RIJNDAEL_256_CBC

    #define GNUTLS_CIPHER_RIJNDAEL_256_CBC GNUTLS_CIPHER_AES_256_CBC

### GNUTLS_CIPHER_RIJNDAEL_CBC

    #define GNUTLS_CIPHER_RIJNDAEL_CBC GNUTLS_CIPHER_AES_128_CBC

### GNUTLS_CIPHER_ARCFOUR

    #define GNUTLS_CIPHER_ARCFOUR GNUTLS_CIPHER_ARCFOUR_128

### enum gnutls_cipher_algorithm_t

    typedef enum {
        GNUTLS_CIPHER_UNKNOWN = 0,
        GNUTLS_CIPHER_NULL = 1,
        GNUTLS_CIPHER_ARCFOUR_128 = 2,
        GNUTLS_CIPHER_3DES_CBC = 3,
        GNUTLS_CIPHER_AES_128_CBC = 4,
        GNUTLS_CIPHER_AES_256_CBC = 5,
        GNUTLS_CIPHER_ARCFOUR_40 = 6,
        GNUTLS_CIPHER_CAMELLIA_128_CBC = 7,
        GNUTLS_CIPHER_CAMELLIA_256_CBC = 8,
        GNUTLS_CIPHER_RC2_40_CBC = 90,
        GNUTLS_CIPHER_DES_CBC = 91,
        GNUTLS_CIPHER_AES_192_CBC = 92,

        /* used only for PGP internals. Ignored in TLS/SSL
         */
        GNUTLS_CIPHER_IDEA_PGP_CFB = 200,
        GNUTLS_CIPHER_3DES_PGP_CFB = 201,
        GNUTLS_CIPHER_CAST5_PGP_CFB = 202,
        GNUTLS_CIPHER_BLOWFISH_PGP_CFB = 203,
        GNUTLS_CIPHER_SAFER_SK128_PGP_CFB = 204,
        GNUTLS_CIPHER_AES128_PGP_CFB = 205,
        GNUTLS_CIPHER_AES192_PGP_CFB = 206,
        GNUTLS_CIPHER_AES256_PGP_CFB = 207,
        GNUTLS_CIPHER_TWOFISH_PGP_CFB = 208
    } gnutls_cipher_algorithm_t;

Enumeration of different symmetric encryption algorithms.

`GNUTLS_CIPHER_UNKNOWN` | Unknown algorithm.
`GNUTLS_CIPHER_NULL` | NULL algorithm.
`GNUTLS_CIPHER_ARCFOUR_128` | ARCFOUR stream cipher with 128-bit keys.
`GNUTLS_CIPHER_3DES_CBC` | 3DES in CBC mode.
`GNUTLS_CIPHER_AES_128_CBC` | AES in CBC mode with 128-bit keys.
`GNUTLS_CIPHER_AES_256_CBC` | AES in CBC mode with 256-bit keys.
`GNUTLS_CIPHER_ARCFOUR_40` | ARCFOUR stream cipher with 40-bit keys.
`GNUTLS_CIPHER_CAMELLIA_128_CBC` | Camellia in CBC mode with 128-bit keys.
`GNUTLS_CIPHER_CAMELLIA_256_CBC` | Camellia in CBC mode with 256-bit keys.
`GNUTLS_CIPHER_RC2_40_CBC` | RC2 in CBC mode with 40-bit keys.
`GNUTLS_CIPHER_DES_CBC` | DES in CBC mode (56-bit keys).
`GNUTLS_CIPHER_AES_192_CBC` | AES in CBC mode with 192-bit keys.
`GNUTLS_CIPHER_IDEA_PGP_CFB` | IDEA in CFB mode.
`GNUTLS_CIPHER_3DES_PGP_CFB` | 3DES in CFB mode.
`GNUTLS_CIPHER_CAST5_PGP_CFB` | CAST5 in CFB mode.
`GNUTLS_CIPHER_BLOWFISH_PGP_CFB` | Blowfish in CFB mode.
`GNUTLS_CIPHER_SAFER_SK128_PGP_CFB` | Safer-SK in CFB mode with 128-bit keys.
`GNUTLS_CIPHER_AES128_PGP_CFB` | AES in CFB mode with 128-bit keys.
`GNUTLS_CIPHER_AES192_PGP_CFB` | AES in CFB mode with 192-bit keys.
`GNUTLS_CIPHER_AES256_PGP_CFB` | AES in CFB mode with 256-bit keys.
`GNUTLS_CIPHER_TWOFISH_PGP_CFB` | Twofish in CFB mode.

### enum gnutls_kx_algorithm_t

    typedef enum {
        GNUTLS_KX_UNKNOWN = 0,
        GNUTLS_KX_RSA = 1,
        GNUTLS_KX_DHE_DSS = 2,
        GNUTLS_KX_DHE_RSA = 3,
        GNUTLS_KX_ANON_DH = 4,
        GNUTLS_KX_SRP = 5,
        GNUTLS_KX_RSA_EXPORT = 6,
        GNUTLS_KX_SRP_RSA = 7,
        GNUTLS_KX_SRP_DSS = 8,
        GNUTLS_KX_PSK = 9,
        GNUTLS_KX_DHE_PSK = 10
    } gnutls_kx_algorithm_t;

Enumeration of different key exchange algorithms.

`GNUTLS_KX_UNKNOWN` | Unknown key-exchange algorithm.
`GNUTLS_KX_RSA` | RSA key-exchange algorithm.
`GNUTLS_KX_DHE_DSS` | DHE-DSS key-exchange algorithm.
`GNUTLS_KX_DHE_RSA` | DHE-RSA key-exchange algorithm.
`GNUTLS_KX_ANON_DH` | Anon-DH key-exchange algorithm.
`GNUTLS_KX_SRP` | SRP key-exchange algorithm.
`GNUTLS_KX_RSA_EXPORT` | RSA-EXPORT key-exchange algorithm.
`GNUTLS_KX_SRP_RSA` | SRP-RSA key-exchange algorithm.
`GNUTLS_KX_SRP_DSS` | SRP-DSS key-exchange algorithm.
`GNUTLS_KX_PSK` | PSK key-exchange algorithm.
`GNUTLS_KX_DHE_PSK` | DHE-PSK key-exchange algorithm.

### enum gnutls_params_type_t

    typedef enum {
        GNUTLS_PARAMS_RSA_EXPORT = 1,
        GNUTLS_PARAMS_DH = 2
    } gnutls_params_type_t;

Enumeration of different TLS session parameter types.

`GNUTLS_PARAMS_RSA_EXPORT` | Session RSA-EXPORT parameters.
`GNUTLS_PARAMS_DH` | Session Diffie-Hellman parameters.

### enum gnutls_credentials_type_t

    typedef enum {
        GNUTLS_CRD_CERTIFICATE = 1,
        GNUTLS_CRD_ANON,
        GNUTLS_CRD_SRP,
        GNUTLS_CRD_PSK,
        GNUTLS_CRD_IA
    } gnutls_credentials_type_t;

Enumeration of different credential types.

`GNUTLS_CRD_CERTIFICATE` | Certificate credential.
`GNUTLS_CRD_ANON` | Anonymous credential.
`GNUTLS_CRD_SRP` | SRP credential.
`GNUTLS_CRD_PSK` | PSK credential.
`GNUTLS_CRD_IA` | IA credential.

### GNUTLS_MAC_SHA

    #define GNUTLS_MAC_SHA GNUTLS_MAC_SHA1

### GNUTLS_DIG_SHA

    #define GNUTLS_DIG_SHA GNUTLS_DIG_SHA1

### enum gnutls_mac_algorithm_t

    typedef enum {
        GNUTLS_MAC_UNKNOWN = 0,
        GNUTLS_MAC_NULL = 1,
        GNUTLS_MAC_MD5 = 2,
        GNUTLS_MAC_SHA1 = 3,
        GNUTLS_MAC_RMD160 = 4,
        GNUTLS_MAC_MD2 = 5,
        GNUTLS_MAC_SHA256 = 6,
        GNUTLS_MAC_SHA384 = 7,
        GNUTLS_MAC_SHA512 = 8,
        GNUTLS_MAC_SHA224 = 9
          /* If you add anything here, make sure you align with
             gnutls_digest_algorithm_t. */
    } gnutls_mac_algorithm_t;

Enumeration of different Message Authentication Code (MAC) algorithms.

`GNUTLS_MAC_UNKNOWN` | Unknown MAC algorithm.
`GNUTLS_MAC_NULL` | NULL MAC algorithm (empty output).
`GNUTLS_MAC_MD5` | HMAC-MD5 algorithm.
`GNUTLS_MAC_SHA1` | HMAC-SHA-1 algorithm.
`GNUTLS_MAC_RMD160` | HMAC-RMD160 algorithm.
`GNUTLS_MAC_MD2` | HMAC-MD2 algorithm.
`GNUTLS_MAC_SHA256` | HMAC-SHA-256 algorithm.
`GNUTLS_MAC_SHA384` | HMAC-SHA-384 algorithm.
`GNUTLS_MAC_SHA512` | HMAC-SHA-512 algorithm.
`GNUTLS_MAC_SHA224` | HMAC-SHA-224 algorithm.

### enum gnutls_digest_algorithm_t

    typedef enum {
        GNUTLS_DIG_UNKNOWN = GNUTLS_MAC_UNKNOWN,
        GNUTLS_DIG_NULL = GNUTLS_MAC_NULL,
        GNUTLS_DIG_MD5 = GNUTLS_MAC_MD5,
        GNUTLS_DIG_SHA1 = GNUTLS_MAC_SHA1,
        GNUTLS_DIG_RMD160 = GNUTLS_MAC_RMD160,
        GNUTLS_DIG_MD2 = GNUTLS_MAC_MD2,
        GNUTLS_DIG_SHA256 = GNUTLS_MAC_SHA256,
        GNUTLS_DIG_SHA384 = GNUTLS_MAC_SHA384,
        GNUTLS_DIG_SHA512 = GNUTLS_MAC_SHA512,
        GNUTLS_DIG_SHA224 = GNUTLS_MAC_SHA224
          /* If you add anything here, make sure you align with
             gnutls_mac_algorithm_t. */
    } gnutls_digest_algorithm_t;

Enumeration of different digest (hash) algorithms.

`GNUTLS_DIG_UNKNOWN` | Unknown hash algorithm.
`GNUTLS_DIG_NULL` | NULL hash algorithm (empty output).
`GNUTLS_DIG_MD5` | MD5 algorithm.
`GNUTLS_DIG_SHA1` | SHA-1 algorithm.
`GNUTLS_DIG_RMD160` | RMD160 algorithm.
`GNUTLS_DIG_MD2` | MD2 algorithm.
`GNUTLS_DIG_SHA256` | SHA-256 algorithm.
`GNUTLS_DIG_SHA384` | SHA-384 algorithm.
`GNUTLS_DIG_SHA512` | SHA-512 algorithm.
`GNUTLS_DIG_SHA224` | SHA-224 algorithm.

### GNUTLS_MAX_ALGORITHM_NUM

    #define GNUTLS_MAX_ALGORITHM_NUM 16

### enum gnutls_compression_method_t

    typedef enum {
        GNUTLS_COMP_UNKNOWN = 0,
        GNUTLS_COMP_NULL = 1,
        GNUTLS_COMP_DEFLATE = 2,
        GNUTLS_COMP_ZLIB = GNUTLS_COMP_DEFLATE,
        GNUTLS_COMP_LZO = 3         /* only available if gnutls-extra has
                                       been initialized
                                     */
    } gnutls_compression_method_t;

Enumeration of different TLS compression methods.

`GNUTLS_COMP_UNKNOWN` | Unknown compression method.
`GNUTLS_COMP_NULL` | The NULL compression method (uncompressed).
`GNUTLS_COMP_DEFLATE` | The deflate/zlib compression method.
`GNUTLS_COMP_ZLIB` | Same as `GNUTLS_COMP_DEFLATE`.
`GNUTLS_COMP_LZO` | The non-standard LZO compression method.

### enum gnutls_connection_end_t

    typedef enum {
        GNUTLS_SERVER = 1,
        GNUTLS_CLIENT
    } gnutls_connection_end_t;

Enumeration of different TLS connection end types.

`GNUTLS_SERVER` | Connection end is a server.
`GNUTLS_CLIENT` | Connection end is a client.

### enum gnutls_alert_level_t

    typedef enum {
        GNUTLS_AL_WARNING = 1,
        GNUTLS_AL_FATAL
    } gnutls_alert_level_t;

Enumeration of different TLS alert severities.

`GNUTLS_AL_WARNING` | Alert of warning severity.
`GNUTLS_AL_FATAL` | Alert of fatal severity.

### enum gnutls_alert_description_t

    typedef enum {
        GNUTLS_A_CLOSE_NOTIFY,
        GNUTLS_A_UNEXPECTED_MESSAGE = 10,
        GNUTLS_A_BAD_RECORD_MAC = 20,
        GNUTLS_A_DECRYPTION_FAILED,
        GNUTLS_A_RECORD_OVERFLOW,
        GNUTLS_A_DECOMPRESSION_FAILURE = 30,
        GNUTLS_A_HANDSHAKE_FAILURE = 40,
        GNUTLS_A_SSL3_NO_CERTIFICATE = 41,
        GNUTLS_A_BAD_CERTIFICATE = 42,
        GNUTLS_A_UNSUPPORTED_CERTIFICATE,
        GNUTLS_A_CERTIFICATE_REVOKED,
        GNUTLS_A_CERTIFICATE_EXPIRED,
        GNUTLS_A_CERTIFICATE_UNKNOWN,
        GNUTLS_A_ILLEGAL_PARAMETER,
        GNUTLS_A_UNKNOWN_CA,
        GNUTLS_A_ACCESS_DENIED,
        GNUTLS_A_DECODE_ERROR = 50,
        GNUTLS_A_DECRYPT_ERROR,
        GNUTLS_A_EXPORT_RESTRICTION = 60,
        GNUTLS_A_PROTOCOL_VERSION = 70,
        GNUTLS_A_INSUFFICIENT_SECURITY,
        GNUTLS_A_INTERNAL_ERROR = 80,
        GNUTLS_A_USER_CANCELED = 90,
        GNUTLS_A_NO_RENEGOTIATION = 100,
        GNUTLS_A_UNSUPPORTED_EXTENSION = 110,
        GNUTLS_A_CERTIFICATE_UNOBTAINABLE = 111,
        GNUTLS_A_UNRECOGNIZED_NAME = 112,
        GNUTLS_A_UNKNOWN_PSK_IDENTITY = 115,
        GNUTLS_A_INNER_APPLICATION_FAILURE = 208,
        GNUTLS_A_INNER_APPLICATION_VERIFICATION = 209
    } gnutls_alert_description_t;

Enumeration of different TLS alerts.

`GNUTLS_A_CLOSE_NOTIFY` | Close notify.
`GNUTLS_A_UNEXPECTED_MESSAGE` | Unexpected message.
`GNUTLS_A_BAD_RECORD_MAC` | Bad record MAC.
`GNUTLS_A_DECRYPTION_FAILED` | Decryption failed.
`GNUTLS_A_RECORD_OVERFLOW` | Record overflow.
`GNUTLS_A_DECOMPRESSION_FAILURE` | Decompression failed.
`GNUTLS_A_HANDSHAKE_FAILURE` | Handshake failed.
`GNUTLS_A_SSL3_NO_CERTIFICATE` | No certificate.
`GNUTLS_A_BAD_CERTIFICATE` | Certificate is bad.
`GNUTLS_A_UNSUPPORTED_CERTIFICATE` | Certificate is not supported.
`GNUTLS_A_CERTIFICATE_REVOKED` | Certificate was revoked.
`GNUTLS_A_CERTIFICATE_EXPIRED` | Certificate is expired.
`GNUTLS_A_CERTIFICATE_UNKNOWN` | Unknown certificate.
`GNUTLS_A_ILLEGAL_PARAMETER` | Illegal parameter.
`GNUTLS_A_UNKNOWN_CA` | CA is unknown.
`GNUTLS_A_ACCESS_DENIED` | Access was denied.
`GNUTLS_A_DECODE_ERROR` | Decode error.
`GNUTLS_A_DECRYPT_ERROR` | Decrypt error.
`GNUTLS_A_EXPORT_RESTRICTION` | Export restriction.
`GNUTLS_A_PROTOCOL_VERSION` | Error in protocol version.
`GNUTLS_A_INSUFFICIENT_SECURITY` | Insufficient security.
`GNUTLS_A_INTERNAL_ERROR` | Internal error.
`GNUTLS_A_USER_CANCELED` | User canceled.
`GNUTLS_A_NO_RENEGOTIATION` | No renegotiation is allowed.
`GNUTLS_A_UNSUPPORTED_EXTENSION` | An unsupported extension was sent.
`GNUTLS_A_CERTIFICATE_UNOBTAINABLE` | Could not retrieve the specified certificate.
`GNUTLS_A_UNRECOGNIZED_NAME` | The server name sent was not recognized.
`GNUTLS_A_UNKNOWN_PSK_IDENTITY` | The SRP/PSK username is missing or not known.
`GNUTLS_A_INNER_APPLICATION_FAILURE` | Inner application negotiation failed.
`GNUTLS_A_INNER_APPLICATION_VERIFICATION` | Inner application verification failed.

### enum gnutls_handshake_description_t

    typedef enum {
        GNUTLS_HANDSHAKE_HELLO_REQUEST = 0,
        GNUTLS_HANDSHAKE_CLIENT_HELLO = 1,
        GNUTLS_HANDSHAKE_SERVER_HELLO = 2,
        GNUTLS_HANDSHAKE_NEW_SESSION_TICKET = 4,
        GNUTLS_HANDSHAKE_CERTIFICATE_PKT = 11,
        GNUTLS_HANDSHAKE_SERVER_KEY_EXCHANGE = 12,
        GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST = 13,
        GNUTLS_HANDSHAKE_SERVER_HELLO_DONE = 14,
        GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY = 15,
        GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE = 16,
        GNUTLS_HANDSHAKE_FINISHED = 20,
        GNUTLS_HANDSHAKE_SUPPLEMENTAL = 23
    } gnutls_handshake_description_t;

Enumeration of different TLS handshake packets.

`GNUTLS_HANDSHAKE_HELLO_REQUEST` | Hello request.
`GNUTLS_HANDSHAKE_CLIENT_HELLO` | Client hello.
`GNUTLS_HANDSHAKE_SERVER_HELLO` | Server hello.
`GNUTLS_HANDSHAKE_NEW_SESSION_TICKET` | New session ticket.
`GNUTLS_HANDSHAKE_CERTIFICATE_PKT` | Certificate packet.
`GNUTLS_HANDSHAKE_SERVER_KEY_EXCHANGE` | Server key exchange.
`GNUTLS_HANDSHAKE_CERTIFICATE_REQUEST` | Certificate request.
`GNUTLS_HANDSHAKE_SERVER_HELLO_DONE` | Server hello done.
`GNUTLS_HANDSHAKE_CERTIFICATE_VERIFY` | Certificate verify.
`GNUTLS_HANDSHAKE_CLIENT_KEY_EXCHANGE` | Client key exchange.
`GNUTLS_HANDSHAKE_FINISHED` | Finished.
`GNUTLS_HANDSHAKE_SUPPLEMENTAL` | Supplemental.

### enum gnutls_certificate_status_t

    typedef enum {
        GNUTLS_CERT_INVALID = 2,
        GNUTLS_CERT_REVOKED = 32,
        GNUTLS_CERT_SIGNER_NOT_FOUND = 64,
        GNUTLS_CERT_SIGNER_NOT_CA = 128,
        GNUTLS_CERT_INSECURE_ALGORITHM = 256,
        GNUTLS_CERT_NOT_ACTIVATED = 512,
        GNUTLS_CERT_EXPIRED = 1024
    } gnutls_certificate_status_t;

Enumeration of certificate status codes. Note that the status bits have different meanings in OpenPGP keys and X.509 certificate verification.

`GNUTLS_CERT_INVALID` | Will be set if the certificate was not verified.
`GNUTLS_CERT_REVOKED` | Certificate revoked. In X.509 this will be set only if CRLs are checked.
`GNUTLS_CERT_SIGNER_NOT_FOUND` | Certificate not verified. Signer not found.
`GNUTLS_CERT_SIGNER_NOT_CA` | Certificate not verified. Signer not a CA certificate.
`GNUTLS_CERT_INSECURE_ALGORITHM` | Certificate not verified, insecure algorithm.
`GNUTLS_CERT_NOT_ACTIVATED` | Certificate not yet activated.
`GNUTLS_CERT_EXPIRED` | Certificate expired.

### enum gnutls_certificate_request_t

    typedef enum {
        GNUTLS_CERT_IGNORE = 0,
        GNUTLS_CERT_REQUEST = 1,
        GNUTLS_CERT_REQUIRE = 2
    } gnutls_certificate_request_t;

Enumeration of certificate request types.

`GNUTLS_CERT_IGNORE` | Ignore certificate.
`GNUTLS_CERT_REQUEST` | Request certificate.
`GNUTLS_CERT_REQUIRE` | Require certificate.

### enum gnutls_openpgp_crt_status_t

    typedef enum {
        GNUTLS_OPENPGP_CERT = 0,
        GNUTLS_OPENPGP_CERT_FINGERPRINT = 1
    } gnutls_openpgp_crt_status_t;

Enumeration of ways to send OpenPGP certificate.

`GNUTLS_OPENPGP_CERT` | Send entire certificate.
`GNUTLS_OPENPGP_CERT_FINGERPRINT` | Send only certificate fingerprint.

### enum gnutls_close_request_t

    typedef enum {
        GNUTLS_SHUT_RDWR = 0,
        GNUTLS_SHUT_WR = 1
    } gnutls_close_request_t;

Enumeration of how TLS session should be terminated. See `gnutls_bye()`.

`GNUTLS_SHUT_RDWR` | Disallow further receives/sends.
`GNUTLS_SHUT_WR` | Disallow further sends.

### enum gnutls_protocol_t

    typedef enum {
        GNUTLS_SSL3 = 1,
        GNUTLS_TLS1_0 = 2,
        GNUTLS_TLS1 = GNUTLS_TLS1_0,
        GNUTLS_TLS1_1 = 3,
        GNUTLS_TLS1_2 = 4,
        GNUTLS_VERSION_MAX = GNUTLS_TLS1_2,
        GNUTLS_VERSION_UNKNOWN = 0xff
    } gnutls_protocol_t;

Enumeration of different SSL/TLS protocol versions.

`GNUTLS_SSL3` | SSL version 3.0.
`GNUTLS_TLS1_0` | TLS version 1.0.
`GNUTLS_TLS1` | Same as `GNUTLS_TLS1_0`.
`GNUTLS_TLS1_1` | TLS version 1.1.
`GNUTLS_TLS1_2` | TLS version 1.2.
`GNUTLS_VERSION_MAX` | Maps to the highest supported TLS version.
`GNUTLS_VERSION_UNKNOWN` | Unknown SSL/TLS version.

### enum gnutls_certificate_type_t

    typedef enum {
        GNUTLS_CRT_UNKNOWN = 0,
        GNUTLS_CRT_X509 = 1,
        GNUTLS_CRT_OPENPGP = 2
    } gnutls_certificate_type_t;

Enumeration of different certificate types.

`GNUTLS_CRT_UNKNOWN` | Unknown certificate type.
`GNUTLS_CRT_X509` | X.509 Certificate.
`GNUTLS_CRT_OPENPGP` | OpenPGP certificate.

### enum gnutls_x509_crt_fmt_t

    typedef enum {
        GNUTLS_X509_FMT_DER = 0,
        GNUTLS_X509_FMT_PEM = 1
    } gnutls_x509_crt_fmt_t;

Enumeration of different certificate encoding formats.

`GNUTLS_X509_FMT_DER` | X.509 certificate in DER format (binary).
`GNUTLS_X509_FMT_PEM` | X.509 certificate in PEM format (text).

### enum gnutls_certificate_print_formats_t

    typedef enum {
        GNUTLS_CRT_PRINT_FULL = 0,
        GNUTLS_CRT_PRINT_ONELINE = 1,
        GNUTLS_CRT_PRINT_UNSIGNED_FULL = 2
    } gnutls_certificate_print_formats_t;

Enumeration of different certificate printing variants.

`GNUTLS_CRT_PRINT_FULL` | Full information about certificate.
`GNUTLS_CRT_PRINT_ONELINE` | Information about certificate in one line.
`GNUTLS_CRT_PRINT_UNSIGNED_FULL` | All info for an unsigned certificate.

### enum gnutls_pk_algorithm_t

    typedef enum {
        GNUTLS_PK_UNKNOWN = 0,
        GNUTLS_PK_RSA = 1,
        GNUTLS_PK_DSA = 2,
        GNUTLS_PK_DH = 3
    } gnutls_pk_algorithm_t;

Enumeration of different public-key algorithms.

`GNUTLS_PK_UNKNOWN` | Unknown public-key algorithm.
`GNUTLS_PK_RSA` | RSA public-key algorithm.
`GNUTLS_PK_DSA` | DSA public-key algorithm.
`GNUTLS_PK_DH` | Diffie-Hellman algorithm. Used to generate parameters.

### gnutls_pk_algorithm_get_name ()

    const char *        gnutls_pk_algorithm_get_name        (gnutls_pk_algorithm_t algorithm);

Convert a gnutls_pk_algorithm_t value to a string.

`algorithm` : | is a pk algorithm
Returns : | a string that contains the name of the specified public key algorithm, or `NULL`.

### enum gnutls_sign_algorithm_t

    typedef enum {
        GNUTLS_SIGN_UNKNOWN = 0,
        GNUTLS_SIGN_RSA_SHA1 = 1,
        GNUTLS_SIGN_RSA_SHA = GNUTLS_SIGN_RSA_SHA1,
        GNUTLS_SIGN_DSA_SHA1 = 2,
        GNUTLS_SIGN_DSA_SHA = GNUTLS_SIGN_DSA_SHA1,
        GNUTLS_SIGN_RSA_MD5 = 3,
        GNUTLS_SIGN_RSA_MD2 = 4,
        GNUTLS_SIGN_RSA_RMD160 = 5,
        GNUTLS_SIGN_RSA_SHA256 = 6,
        GNUTLS_SIGN_RSA_SHA384 = 7,
        GNUTLS_SIGN_RSA_SHA512 = 8,
        GNUTLS_SIGN_RSA_SHA224 = 9,
        GNUTLS_SIGN_DSA_SHA224 = 10,
        GNUTLS_SIGN_DSA_SHA256 = 11
    } gnutls_sign_algorithm_t;

Enumeration of different digital signature algorithms.

`GNUTLS_SIGN_UNKNOWN` | Unknown signature algorithm.
`GNUTLS_SIGN_RSA_SHA1` | Digital signature algorithm RSA with SHA-1
`GNUTLS_SIGN_RSA_SHA` | Same as `GNUTLS_SIGN_RSA_SHA1`.
`GNUTLS_SIGN_DSA_SHA1` | Digital signature algorithm DSA with SHA-1
`GNUTLS_SIGN_DSA_SHA` | Same as `GNUTLS_SIGN_DSA_SHA1`.
`GNUTLS_SIGN_RSA_MD5` | Digital signature algorithm RSA with MD5.
`GNUTLS_SIGN_RSA_MD2` | Digital signature algorithm RSA with MD2.
`GNUTLS_SIGN_RSA_RMD160` | Digital signature algorithm RSA with RMD-160.
`GNUTLS_SIGN_RSA_SHA256` | Digital signature algorithm RSA with SHA-256.
`GNUTLS_SIGN_RSA_SHA384` | Digital signature algorithm RSA with SHA-384.
`GNUTLS_SIGN_RSA_SHA512` | Digital signature algorithm RSA with SHA-512.
`GNUTLS_SIGN_RSA_SHA224` | Digital signature algorithm RSA with SHA-224.
`GNUTLS_SIGN_DSA_SHA224` | Digital signature algorithm DSA with SHA-224
`GNUTLS_SIGN_DSA_SHA256` | Digital signature algorithm DSA with SHA-256

### gnutls_sign_algorithm_get_name ()

    const char *        gnutls_sign_algorithm_get_name      (gnutls_sign_algorithm_t sign);

Convert a gnutls_sign_algorithm_t value to a string.

`sign` : | is a sign algorithm
Returns : | a string that contains the name of the specified sign algorithm, or `NULL`.

### enum gnutls_sec_param_t

    typedef enum {
        GNUTLS_SEC_PARAM_UNKNOWN,
        GNUTLS_SEC_PARAM_WEAK,
        GNUTLS_SEC_PARAM_LOW,
        GNUTLS_SEC_PARAM_NORMAL,
        GNUTLS_SEC_PARAM_HIGH,
        GNUTLS_SEC_PARAM_ULTRA
    } gnutls_sec_param_t;

Enumeration of security parameters for passive attacks

`GNUTLS_SEC_PARAM_UNKNOWN` | Cannot be known
`GNUTLS_SEC_PARAM_WEAK` | 50 or less bits of security
`GNUTLS_SEC_PARAM_LOW` | 80 bits of security
`GNUTLS_SEC_PARAM_NORMAL` | 112 bits of security
`GNUTLS_SEC_PARAM_HIGH` | 128 bits of security
`GNUTLS_SEC_PARAM_ULTRA` | 192 bits of security

### enum gnutls_channel_binding_t

    typedef enum {
        GNUTLS_CB_TLS_UNIQUE
    } gnutls_channel_binding_t;

Enumeration of support channel binding types.

`GNUTLS_CB_TLS_UNIQUE` | "tls-unique" (RFC 5929) channel binding

### gnutls_transport_ptr_t

      typedef void *gnutls_transport_ptr_t;

### struct gnutls_session_int

    struct gnutls_session_int;

### gnutls_session_t

      typedef struct gnutls_session_int *gnutls_session_t;

### struct gnutls_dh_params_int

    struct gnutls_dh_params_int;

### gnutls_dh_params_t

      typedef struct gnutls_dh_params_int *gnutls_dh_params_t;

### struct gnutls_x509_privkey_int

    struct gnutls_x509_privkey_int;

### gnutls_rsa_params_t

      typedef struct gnutls_x509_privkey_int *gnutls_rsa_params_t;

### struct gnutls_priority_st

    struct gnutls_priority_st;

### gnutls_priority_t

      typedef struct gnutls_priority_st *gnutls_priority_t;

### gnutls_init ()

    int                 gnutls_init                         (gnutls_session_t *session,
                                                             gnutls_connection_end_t con_end);

This function initializes the current session to null. Every session must be initialized before use, so internal structures can be allocated. This function allocates structures which can only be free'd by calling `gnutls_deinit()`. Returns zero on success.

`con_end` can be one of `GNUTLS_CLIENT` and `GNUTLS_SERVER`.

`session` : | is a pointer to a gnutls_session_t structure.
`con_end` : | indicate if this session is to be used for server or client.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_deinit ()

    void                gnutls_deinit                       (gnutls_session_t session);

This function clears all buffers associated with the `session`. This function will also remove session data from the session database if the session was terminated abnormally.

`session` : | is a gnutls_session_t structure.

### gnutls_bye ()

    int                 gnutls_bye                          (gnutls_session_t session,
                                                             gnutls_close_request_t how);

Terminates the current TLS/SSL connection. The connection should have been initiated using `gnutls_handshake()`. `how` should be one of `GNUTLS_SHUT_RDWR`, `GNUTLS_SHUT_WR`.

In case of `GNUTLS_SHUT_RDWR` then the TLS connection gets terminated and further receives and sends will be disallowed. If the return value is zero you may continue using the connection. `GNUTLS_SHUT_RDWR` actually sends an alert containing a close request and waits for the peer to reply with the same message.

In case of `GNUTLS_SHUT_WR` then the TLS connection gets terminated and further sends will be disallowed. In order to reuse the connection you should wait for an EOF from the peer. `GNUTLS_SHUT_WR` sends an alert containing a close request.

Note that not all implementations will properly terminate a TLS connection. Some of them, usually for performance reasons, will terminate only the underlying transport layer, thus causing a transmission error to the peer. This error cannot be distinguished from a malicious party prematurely terminating the session, thus this behavior is not recommended.

This function may also return `GNUTLS_E_AGAIN` or `GNUTLS_E_INTERRUPTED`; cf. `gnutls_record_get_direction()`.

`session` : | is a gnutls_session_t structure.
`how` : | is an integer
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code, see function documentation for entire semantics.

### gnutls_handshake ()

    int                 gnutls_handshake                    (gnutls_session_t session);

This function does the handshake of the TLS/SSL protocol, and initializes the TLS connection.

This function will fail if any problem is encountered, and will return a negative error code. In case of a client, if the client has asked to resume a session, but the server couldn't, then a full handshake will be performed.

The non-fatal errors such as `GNUTLS_E_AGAIN` and `GNUTLS_E_INTERRUPTED` interrupt the handshake procedure, which should be later be resumed. Call this function again, until it returns 0; cf. `gnutls_record_get_direction()` and `gnutls_error_is_fatal()`.

If this function is called by a server after a rehandshake request then `GNUTLS_E_GOT_APPLICATION_DATA` or `GNUTLS_E_WARNING_ALERT_RECEIVED` may be returned. Note that these are non fatal errors, only in the specific case of a rehandshake. Their meaning is that the client rejected the rehandshake request or in the case of `GNUTLS_E_GOT_APPLICATION_DATA` it might also mean that some data were pending.

`session` : | is a gnutls_session_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, otherwise an error.

### gnutls_rehandshake ()

    int                 gnutls_rehandshake                  (gnutls_session_t session);

This function will renegotiate security parameters with the client. This should only be called in case of a server.

This message informs the peer that we want to renegotiate parameters (perform a handshake).

If this function succeeds (returns 0), you must call the `gnutls_handshake()` function in order to negotiate the new parameters.

Since TLS is full duplex some application data might have been sent during peer's processing of this message. In that case one should call `gnutls_record_recv()` until GNUTLS_E_REHANDSHAKE is returned to clear any pending data. Care must be taken if rehandshake is mandatory to terminate if it does not start after some threshold.

If the client does not wish to renegotiate parameters he will should with an alert message, thus the return code will be `GNUTLS_E_WARNING_ALERT_RECEIVED` and the alert will be `GNUTLS_A_NO_RENEGOTIATION`. A client may also choose to ignore this message.

`session` : | is a gnutls_session_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, otherwise an error.

### gnutls_alert_get ()

    gnutls_alert_description_t gnutls_alert_get             (gnutls_session_t session);

This function will return the last alert number received. This function should be called if `GNUTLS_E_WARNING_ALERT_RECEIVED` or `GNUTLS_E_FATAL_ALERT_RECEIVED` has been returned by a gnutls function. The peer may send alerts if he thinks some things were not right. Check gnutls.h for the available alert descriptions.

If no alert has been received the returned value is undefined.

`session` : | is a gnutls_session_t structure.
Returns : | returns the last alert received, a gnutls_alert_description_t value.

### gnutls_alert_send ()

    int                 gnutls_alert_send                   (gnutls_session_t session,
                                                             gnutls_alert_level_t level,
                                                             gnutls_alert_description_t desc);

This function will send an alert to the peer in order to inform him of something important (eg. his Certificate could not be verified). If the alert level is Fatal then the peer is expected to close the connection, otherwise he may ignore the alert and continue.

The error code of the underlying record send function will be returned, so you may also receive `GNUTLS_E_INTERRUPTED` or `GNUTLS_E_AGAIN` as well.

`session` : | is a gnutls_session_t structure.
`level` : | is the level of the alert
`desc` : | is the alert description
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_alert_send_appropriate ()

    int                 gnutls_alert_send_appropriate       (gnutls_session_t session,
                                                             int err);

Sends an alert to the peer depending on the error code returned by a gnutls function. This function will call `gnutls_error_to_alert()` to determine the appropriate alert to send.

This function may also return `GNUTLS_E_AGAIN`, or `GNUTLS_E_INTERRUPTED`.

If the return value is `GNUTLS_E_INVALID_REQUEST`, then no alert has been sent to the peer.

`session` : | is a gnutls_session_t structure.
`err` : | is an integer
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_alert_get_name ()

    const char *        gnutls_alert_get_name               (gnutls_alert_description_t alert);

This function will return a string that describes the given alert number, or `NULL`. See `gnutls_alert_get()`.

`alert` : | is an alert number gnutls_session_t structure.
Returns : | string corresponding to gnutls_alert_description_t value.

### gnutls_pk_bits_to_sec_param ()

    gnutls_sec_param_t  gnutls_pk_bits_to_sec_param         (gnutls_pk_algorithm_t algo,
                                                             unsigned int bits);

This is the inverse of `gnutls_sec_param_to_pk_bits()`. Given an algorithm and the number of bits, it will return the security parameter. This is a rough indication.

`algo` : | is a public key algorithm
`bits` : | is the number of bits
Returns : | The security parameter.

### gnutls_sec_param_get_name ()

    const char *        gnutls_sec_param_get_name           (gnutls_sec_param_t param);

Convert a gnutls_sec_param_t value to a string.

`param` : | is a security parameter
Returns : | a pointer to a string that contains the name of the specified public key algorithm, or `NULL`.

### gnutls_sec_param_to_pk_bits ()

    unsigned int        gnutls_sec_param_to_pk_bits         (gnutls_pk_algorithm_t algo,
                                                             gnutls_sec_param_t param);

When generating private and public key pairs a difficult question is which size of "bits" the modulus will be in RSA and the group size in DSA. The easy answer is 1024, which is also wrong. This function will convert a human understandable security parameter to an appropriate size for the specific algorithm.

`algo` : | is a public key algorithm
`param` : | is a security parameter
Returns : | The number of bits, or zero.

### gnutls_cipher_get ()

    gnutls_cipher_algorithm_t gnutls_cipher_get             (gnutls_session_t session);

Get currently used cipher.

`session` : | is a gnutls_session_t structure.
Returns : | the currently used cipher, a gnutls_cipher_algorithm_t type.

### gnutls_kx_get ()

    gnutls_kx_algorithm_t gnutls_kx_get                     (gnutls_session_t session);

Get currently used key exchange algorithm.

`session` : | is a gnutls_session_t structure.
Returns : | the key exchange algorithm used in the last handshake, a gnutls_kx_algorithm_t value.

### gnutls_mac_get ()

    gnutls_mac_algorithm_t gnutls_mac_get                   (gnutls_session_t session);

Get currently used MAC algorithm.

`session` : | is a gnutls_session_t structure.
Returns : | the currently used mac algorithm, a gnutls_mac_algorithm_t value.

### gnutls_compression_get ()

    gnutls_compression_method_t gnutls_compression_get      (gnutls_session_t session);

Get currently used compression algorithm.

`session` : | is a gnutls_session_t structure.
Returns : | the currently used compression method, a gnutls_compression_method_t value.

### gnutls_certificate_type_get ()

    gnutls_certificate_type_t gnutls_certificate_type_get   (gnutls_session_t session);

The certificate type is by default X.509, unless it is negotiated as a TLS extension.

`session` : | is a gnutls_session_t structure.
Returns : | the currently used gnutls_certificate_type_t certificate type.

### gnutls_sign_algorithm_get_requested ()

    int                 gnutls_sign_algorithm_get_requested (gnutls_session_t session,
                                                             size_t indx,
                                                             gnutls_sign_algorithm_t *algo);

Returns the signature algorithm specified by index that was requested by the peer. If the specified index has no data available this function returns `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE`. If the negotiated TLS version does not support signature algorithms then `GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE` will be returned even for the first index. The first index is 0.

This function is useful in the certificate callback functions to assist in selecting the correct certificate.

`session` : | is a gnutls_session_t structure.
`indx` : | is an index of the signature algorithm to return
`algo` : | the returned certificate type will be stored there
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

Since 2.10.0

### gnutls_cipher_get_key_size ()

    size_t              gnutls_cipher_get_key_size          (gnutls_cipher_algorithm_t algorithm);

Get key size for cipher.

`algorithm` : | is an encryption algorithm
Returns : | length (in bytes) of the given cipher's key size, or 0 if the given cipher is invalid.

### gnutls_mac_get_key_size ()

    size_t              gnutls_mac_get_key_size             (gnutls_mac_algorithm_t algorithm);

Get size of MAC key.

`algorithm` : | is an encryption algorithm
Returns : | length (in bytes) of the given MAC key size, or 0 if the given MAC algorithm is invalid.

### gnutls_cipher_get_name ()

    const char *        gnutls_cipher_get_name              (gnutls_cipher_algorithm_t algorithm);

Convert a gnutls_cipher_algorithm_t type to a string.

`algorithm` : | is an encryption algorithm
Returns : | a pointer to a string that contains the name of the specified cipher, or `NULL`.

### gnutls_mac_get_name ()

    const char *        gnutls_mac_get_name                 (gnutls_mac_algorithm_t algorithm);

Convert a gnutls_mac_algorithm_t value to a string.

`algorithm` : | is a MAC algorithm
Returns : | a string that contains the name of the specified MAC algorithm, or `NULL`.

### gnutls_compression_get_name ()

    const char *        gnutls_compression_get_name         (gnutls_compression_method_t algorithm);

Convert a gnutls_compression_method_t value to a string.

`algorithm` : | is a Compression algorithm
Returns : | a pointer to a string that contains the name of the specified compression algorithm, or `NULL`.

### gnutls_kx_get_name ()

    const char *        gnutls_kx_get_name                  (gnutls_kx_algorithm_t algorithm);

Convert a gnutls_kx_algorithm_t value to a string.

`algorithm` : | is a key exchange algorithm
Returns : | a pointer to a string that contains the name of the specified key exchange algorithm, or `NULL`.

### gnutls_certificate_type_get_name ()

    const char *        gnutls_certificate_type_get_name    (gnutls_certificate_type_t type);

Convert a gnutls_certificate_type_t type to a string.

`type` : | is a certificate type
Returns : | a string that contains the name of the specified certificate type, or `NULL` in case of unknown types.

### gnutls_pk_get_name ()

    const char *        gnutls_pk_get_name                  (gnutls_pk_algorithm_t algorithm);

Convert a gnutls_pk_algorithm_t value to a string.

`algorithm` : | is a public key algorithm
Returns : | a pointer to a string that contains the name of the specified public key algorithm, or `NULL`.

Since 2.6.0

### gnutls_sign_get_name ()

    const char *        gnutls_sign_get_name                (gnutls_sign_algorithm_t algorithm);

Convert a gnutls_sign_algorithm_t value to a string.

`algorithm` : | is a public key signature algorithm
Returns : | a pointer to a string that contains the name of the specified public key signature algorithm, or `NULL`.

Since 2.6.0

### gnutls_mac_get_id ()

    gnutls_mac_algorithm_t gnutls_mac_get_id                (const char *name);

Convert a string to a gnutls_mac_algorithm_t value. The names are compared in a case insensitive way.

`name` : | is a MAC algorithm name
Returns : | a gnutls_mac_algorithm_t id of the specified MAC algorithm string, or `GNUTLS_MAC_UNKNOWN` on failures.

### gnutls_compression_get_id ()

    gnutls_compression_method_t gnutls_compression_get_id   (const char *name);

The names are compared in a case insensitive way.

`name` : | is a compression method name
Returns : | an id of the specified in a string compression method, or `GNUTLS_COMP_UNKNOWN` on error.

### gnutls_cipher_get_id ()

    gnutls_cipher_algorithm_t gnutls_cipher_get_id          (const char *name);

The names are compared in a case insensitive way.

`name` : | is a MAC algorithm name
Returns : | return a gnutls_cipher_algorithm_t value corresponding to the specified cipher, or `GNUTLS_CIPHER_UNKNOWN` on error.

### gnutls_kx_get_id ()

    gnutls_kx_algorithm_t gnutls_kx_get_id                  (const char *name);

Convert a string to a gnutls_kx_algorithm_t value. The names are compared in a case insensitive way.

`name` : | is a KX name
Returns : | an id of the specified KX algorithm, or `GNUTLS_KX_UNKNOWN` on error.

### gnutls_protocol_get_id ()

    gnutls_protocol_t   gnutls_protocol_get_id              (const char *name);

The names are compared in a case insensitive way.

`name` : | is a protocol name
Returns : | an id of the specified protocol, or `GNUTLS_VERSION_UNKNOWN` on error.

### gnutls_certificate_type_get_id ()

    gnutls_certificate_type_t gnutls_certificate_type_get_id
                                                            (const char *name);

The names are compared in a case insensitive way.

`name` : | is a certificate type name
Returns : | a gnutls_certificate_type_t for the specified in a string certificate type, or `GNUTLS_CRT_UNKNOWN` on error.

### gnutls_pk_get_id ()

    gnutls_pk_algorithm_t gnutls_pk_get_id                  (const char *name);

Convert a string to a gnutls_pk_algorithm_t value. The names are compared in a case insensitive way. For example, gnutls_pk_get_id("RSA") will return `GNUTLS_PK_RSA`.

`name` : | is a string containing a public key algorithm name.
Returns : | a gnutls_pk_algorithm_t id of the specified public key algorithm string, or `GNUTLS_PK_UNKNOWN` on failures.

Since 2.6.0

### gnutls_sign_get_id ()

    gnutls_sign_algorithm_t gnutls_sign_get_id              (const char *name);

The names are compared in a case insensitive way.

`name` : | is a MAC algorithm name
Returns : | return a gnutls_sign_algorithm_t value corresponding to the specified cipher, or `GNUTLS_SIGN_UNKNOWN` on error.

### gnutls_cipher_list ()

    const gnutls_cipher_algorithm_t * gnutls_cipher_list    (void);

Get a list of supported cipher algorithms. Note that not necessarily all ciphers are supported as TLS cipher suites. For example, DES is not supported as a cipher suite, but is supported for other purposes (e.g., PKCS#8 or similar).

Returns : | a zero-terminated list of gnutls_cipher_algorithm_t integers indicating the available ciphers.

### gnutls_mac_list ()

    const gnutls_mac_algorithm_t * gnutls_mac_list          (void);

Get a list of hash algorithms for use as MACs. Note that not necessarily all MACs are supported in TLS cipher suites. For example, MD2 is not supported as a cipher suite, but is supported for other purposes (e.g., X.509 signature verification or similar).

Returns : | Return a zero-terminated list of gnutls_mac_algorithm_t integers indicating the available MACs.

### gnutls_compression_list ()

    const gnutls_compression_method_t * gnutls_compression_list
                                                            (void);

Get a list of compression methods. Note that to be able to use LZO compression, you must link to libgnutls-extra and call `gnutls_global_init_extra()`.

Returns : | a zero-terminated list of gnutls_compression_method_t integers indicating the available compression methods.

### gnutls_protocol_list ()

    const gnutls_protocol_t * gnutls_protocol_list          (void);

Get a list of supported protocols, e.g. SSL 3.0, TLS 1.0 etc.

Returns : | a zero-terminated list of gnutls_protocol_t integers indicating the available protocols.

### gnutls_certificate_type_list ()

    const gnutls_certificate_type_t * gnutls_certificate_type_list
                                                            (void);

Get a list of certificate types. Note that to be able to use OpenPGP certificates, you must link to libgnutls-extra and call `gnutls_global_init_extra()`.

Returns : | a zero-terminated list of gnutls_certificate_type_t integers indicating the available certificate types.

### gnutls_kx_list ()

    const gnutls_kx_algorithm_t * gnutls_kx_list            (void);

Get a list of supported key exchange algorithms.

Returns : | a zero-terminated list of gnutls_kx_algorithm_t integers indicating the available key exchange algorithms.

### gnutls_pk_list ()

    const gnutls_pk_algorithm_t * gnutls_pk_list            (void);

Get a list of supported public key algorithms.

Returns : | a zero-terminated list of gnutls_pk_algorithm_t integers indicating the available ciphers.

Since 2.6.0

### gnutls_sign_list ()

    const gnutls_sign_algorithm_t * gnutls_sign_list        (void);

Get a list of supported public key signature algorithms.

Returns : | a zero-terminated list of gnutls_sign_algorithm_t integers indicating the available ciphers.

### gnutls_cipher_suite_info ()

    const char *        gnutls_cipher_suite_info            (size_t idx,
                                                             char *cs_id,
                                                             gnutls_kx_algorithm_t *kx,
                                                             gnutls_cipher_algorithm_t *cipher,
                                                             gnutls_mac_algorithm_t *mac,
                                                             gnutls_protocol_t *version);

Get information about supported cipher suites. Use the function iteratively to get information about all supported cipher suites. Call with idx=0 to get information about first cipher suite, then idx=1 and so on until the function returns NULL.

`idx` : | index of cipher suite to get information about, starts on 0.
`cs_id` : | output buffer with room for 2 bytes, indicating cipher suite value
`kx` : | output variable indicating key exchange algorithm, or `NULL`.
`cipher` : | output variable indicating cipher, or `NULL`.
`mac` : | output variable indicating MAC algorithm, or `NULL`.
`version` : | output variable indicating TLS protocol version, or `NULL`.
Returns : | the name of `idx` cipher suite, and set the information about the cipher suite in the output variables. If `idx` is out of bounds, `NULL` is returned.

### gnutls_error_is_fatal ()

    int                 gnutls_error_is_fatal               (int error);

If a GnuTLS function returns a negative value you may feed that value to this function to see if the error condition is fatal.

Note that you may want to check the error code manually, since some non-fatal errors to the protocol may be fatal for you program.

This function is only useful if you are dealing with errors from the record layer or the handshake layer.

`error` : | is a GnuTLS error code, a negative value
Returns : | 1 if the error code is fatal, for positive `error` values, 0 is returned. For unknown `error` values, -1 is returned.

### gnutls_error_to_alert ()

    int                 gnutls_error_to_alert               (int err,
                                                             int *level);

Get an alert depending on the error code returned by a gnutls function. All alerts sent by this function should be considered fatal. The only exception is when `err` is `GNUTLS_E_REHANDSHAKE`, where a warning alert should be sent to the peer indicating that no renegotiation will be performed.

If there is no mapping to a valid alert the alert to indicate internal error is returned.

`err` : | is a negative integer
`level` : | the alert level will be stored there
Returns : | the alert code to use for a particular error code.

### gnutls_perror ()

    void                gnutls_perror                       (int error);

This function is like `perror()`. The only difference is that it accepts an error number returned by a gnutls function.

`error` : | is a GnuTLS error code, a negative value

### gnutls_strerror ()

    const char *        gnutls_strerror                     (int error);

This function is similar to strerror. The difference is that it accepts an error number returned by a gnutls function; In case of an unknown error a descriptive string is sent instead of `NULL`.

Error codes are always a negative value.

`error` : | is a GnuTLS error code, a negative value
Returns : | A string explaining the GnuTLS error message.

### gnutls_strerror_name ()

    const char *        gnutls_strerror_name                (int error);

Return the GnuTLS error code define as a string. For example, gnutls_strerror_name (GNUTLS_E_DH_PRIME_UNACCEPTABLE) will return the string "GNUTLS_E_DH_PRIME_UNACCEPTABLE".

`error` : | is an error returned by a gnutls function.
Returns : | A string corresponding to the symbol name of the error code.

Since 2.6.0

### gnutls_handshake_set_private_extensions ()

    void                gnutls_handshake_set_private_extensions
                                                            (gnutls_session_t session,
                                                             int allow);

This function will enable or disable the use of private cipher suites (the ones that start with 0xFF). By default or if `allow` is 0 then these cipher suites will not be advertized nor used.

Unless this function is called with the option to allow (1), then no compression algorithms, like LZO. That is because these algorithms are not yet defined in any RFC or even internet draft.

Enabling the private ciphersuites when talking to other than gnutls servers and clients may cause interoperability problems.

`session` : | is a gnutls_session_t structure.
`allow` : | is an integer (0 or 1)

### gnutls_handshake_get_last_out ()

    gnutls_handshake_description_t gnutls_handshake_get_last_out
                                                            (gnutls_session_t session);

This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.

Check `gnutls_handshake_description_t` in gnutls.h for the available handshake descriptions.

`session` : | is a gnutls_session_t structure.
Returns : | the last handshake message type sent, a `gnutls_handshake_description_t`.

### gnutls_handshake_get_last_in ()

    gnutls_handshake_description_t gnutls_handshake_get_last_in
                                                            (gnutls_session_t session);

This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.

Check `gnutls_handshake_description_t` in gnutls.h for the available handshake descriptions.

`session` : | is a gnutls_session_t structure.
Returns : | the last handshake message type received, a `gnutls_handshake_description_t`.

### gnutls_record_send ()

    ssize_t             gnutls_record_send                  (gnutls_session_t session,
                                                             const void *data,
                                                             size_t sizeofdata);

This function has the similar semantics with `send()`. The only difference is that it accepts a GnuTLS session, and uses different error codes.

Note that if the send buffer is full, `send()` will block this function. See the `send()` documentation for full information. You can replace the default push function by using `gnutls_transport_set_ptr2()` with a call to `send()` with a MSG_DONTWAIT flag if blocking is a problem.

If the EINTR is returned by the internal push function (the default is `send()`} then `GNUTLS_E_INTERRUPTED` will be returned. If `GNUTLS_E_INTERRUPTED` or `GNUTLS_E_AGAIN` is returned, you must call this function again, with the same parameters; alternatively you could provide a `NULL` pointer for data, and 0 for size. cf. `gnutls_record_get_direction()`.

`session` : | is a gnutls_session_t structure.
`data` : | contains the data to send
`sizeofdata` : | is the length of the data
Returns : | the number of bytes sent, or a negative error code. The number of bytes sent might be less than `sizeofdata`. The maximum number of bytes this function can send in a single call depends on the negotiated maximum record size.

### gnutls_record_recv ()

    ssize_t             gnutls_record_recv                  (gnutls_session_t session,
                                                             void *data,
                                                             size_t sizeofdata);

This function has the similar semantics with `recv()`. The only difference is that it accepts a GnuTLS session, and uses different error codes.

In the special case that a server requests a renegotiation, the client may receive an error code of `GNUTLS_E_REHANDSHAKE`. This message may be simply ignored, replied with an alert `GNUTLS_A_NO_RENEGOTIATION`, or replied with a new handshake, depending on the client's will.

If `EINTR` is returned by the internal push function (the default is `recv()`) then `GNUTLS_E_INTERRUPTED` will be returned. If `GNUTLS_E_INTERRUPTED` or `GNUTLS_E_AGAIN` is returned, you must call this function again to get the data. See also `gnutls_record_get_direction()`.

A server may also receive `GNUTLS_E_REHANDSHAKE` when a client has initiated a handshake. In that case the server can only initiate a handshake or terminate the connection.

`session` : | is a gnutls_session_t structure.
`data` : | the buffer that the data will be read into
`sizeofdata` : | the number of requested bytes
Returns : | the number of bytes received and zero on EOF. A negative error code is returned in case of an error. The number of bytes received might be less than `sizeofdata`.

### gnutls_read

    #define gnutls_read gnutls_record_recv

### gnutls_write

    #define gnutls_write gnutls_record_send

### gnutls_session_enable_compatibility_mode ()

    void                gnutls_session_enable_compatibility_mode
                                                            (gnutls_session_t session);

This function can be used to disable certain (security) features in TLS in order to maintain maximum compatibility with buggy clients. It is equivalent to calling: `gnutls_record_disable_padding()`

Normally only servers that require maximum compatibility with everything out there, need to call this function.

`session` : | is a gnutls_session_t structure.

### gnutls_record_disable_padding ()

    void                gnutls_record_disable_padding       (gnutls_session_t session);

Used to disabled padding in TLS 1.0 and above. Normally you do not need to use this function, but there are buggy clients that complain if a server pads the encrypted data. This of course will disable protection against statistical attacks on the data.

Normally only servers that require maximum compatibility with everything out there, need to call this function.

`session` : | is a gnutls_session_t structure.

### gnutls_record_get_direction ()

    int                 gnutls_record_get_direction         (gnutls_session_t session);

This function provides information about the internals of the record protocol and is only useful if a prior gnutls function call (e.g. `gnutls_handshake()`) was interrupted for some reason, that is, if a function returned `GNUTLS_E_INTERRUPTED` or `GNUTLS_E_AGAIN`. In such a case, you might want to call `select()` or `poll()` before calling the interrupted gnutls function again. To tell you whether a file descriptor should be selected for either reading or writing, `gnutls_record_get_direction()` returns 0 if the interrupted function was trying to read data, and 1 if it was trying to write data.

`session` : | is a gnutls_session_t structure.
Returns : | 0 if trying to read data, 1 if trying to write data.

### gnutls_record_get_max_size ()

    size_t              gnutls_record_get_max_size          (gnutls_session_t session);

Get the record size. The maximum record size is negotiated by the client after the first handshake message.

`session` : | is a gnutls_session_t structure.
Returns : | The maximum record packet size in this connection.

### gnutls_record_set_max_size ()

    ssize_t             gnutls_record_set_max_size          (gnutls_session_t session,
                                                             size_t size);

This function sets the maximum record packet size in this connection. This property can only be set to clients. The server may choose not to accept the requested size.

Acceptable values are 512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12). The requested record size does get in effect immediately only while sending data. The receive part will take effect after a successful handshake.

This function uses a TLS extension called 'max record size'. Not all TLS implementations use or even understand this extension.

`session` : | is a gnutls_session_t structure.
`size` : | is the new size
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_record_check_pending ()

    size_t              gnutls_record_check_pending         (gnutls_session_t session);

This function checks if there are any data to receive in the gnutls buffers.

`session` : | is a gnutls_session_t structure.
Returns : | the size of that data or 0.

### gnutls_prf ()

    int                 gnutls_prf                          (gnutls_session_t session,
                                                             size_t label_size,
                                                             const char *label,
                                                             int server_random_first,
                                                             size_t extra_size,
                                                             const char *extra,
                                                             size_t outsize,
                                                             char *out);

Apply the TLS Pseudo-Random-Function (PRF) using the master secret on some data, seeded with the client and server random fields.

The `label` variable usually contain a string denoting the purpose for the generated data. The `server_random_first` indicate whether the client random field or the server random field should be first in the seed. Non-0 indicate that the server random field is first, 0 that the client random field is first.

The `extra` variable can be used to add more data to the seed, after the random variables. It can be used to tie make sure the generated output is strongly connected to some additional data (e.g., a string used in user authentication).

The output is placed in *`OUT`, which must be pre-allocated.

`session` : | is a gnutls_session_t structure.
`label_size` : | length of the `label` variable.
`label` : | label used in PRF computation, typically a short string.
`server_random_first` : | non-0 if server random field should be first in seed
`extra_size` : | length of the `extra` variable.
`extra` : | optional extra data to seed the PRF with.
`outsize` : | size of pre-allocated output buffer to hold the output.
`out` : | pre-allocate buffer to hold the generated data.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_prf_raw ()

    int                 gnutls_prf_raw                      (gnutls_session_t session,
                                                             size_t label_size,
                                                             const char *label,
                                                             size_t seed_size,
                                                             const char *seed,
                                                             size_t outsize,
                                                             char *out);

Apply the TLS Pseudo-Random-Function (PRF) using the master secret on some data.

The `label` variable usually contain a string denoting the purpose for the generated data. The `seed` usually contain data such as the client and server random, perhaps together with some additional data that is added to guarantee uniqueness of the output for a particular purpose.

Because the output is not guaranteed to be unique for a particular session unless `seed` include the client random and server random fields (the PRF would output the same data on another connection resumed from the first one), it is not recommended to use this function directly. The `gnutls_prf()` function seed the PRF with the client and server random fields directly, and is recommended if you want to generate pseudo random data unique for each session.

`session` : | is a gnutls_session_t structure.
`label_size` : | length of the `label` variable.
`label` : | label used in PRF computation, typically a short string.
`seed_size` : | length of the `seed` variable.
`seed` : | optional extra data to seed the PRF with.
`outsize` : | size of pre-allocated output buffer to hold the output.
`out` : | pre-allocate buffer to hold the generated data.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_ext_recv_func ()

    int                 (*gnutls_ext_recv_func)             (gnutls_session_t session,
                                                             const unsigned char *data,
                                                             size_t len);

### gnutls_ext_send_func ()

    int                 (*gnutls_ext_send_func)             (gnutls_session_t session,
                                                             unsigned char *data,
                                                             size_t len);

### enum gnutls_ext_parse_type_t

    typedef enum {
        GNUTLS_EXT_ANY = 0,
        GNUTLS_EXT_APPLICATION = 1,
        GNUTLS_EXT_TLS = 2,
        GNUTLS_EXT_MANDATORY = 3,
        GNUTLS_EXT_NONE = 4
    } gnutls_ext_parse_type_t;

Enumeration of different TLS extension types. This flag indicates for an extension whether it is useful to application level or TLS level only. This is (only) used to parse the application level extensions before the "client_hello" callback is called.

`GNUTLS_EXT_ANY` | Any extension type.
`GNUTLS_EXT_APPLICATION` | Application extension.
`GNUTLS_EXT_TLS` | TLS-internal extension.
`GNUTLS_EXT_MANDATORY` | Extension parsed even if resuming (or extensions are disabled).
`GNUTLS_EXT_NONE` | Never parsed

### enum gnutls_server_name_type_t

    typedef enum {
        GNUTLS_NAME_DNS = 1
    } gnutls_server_name_type_t;

Enumeration of different server name types.

`GNUTLS_NAME_DNS` | Domain Name System name type.

### gnutls_server_name_set ()

    int                 gnutls_server_name_set              (gnutls_session_t session,
                                                             gnutls_server_name_type_t type,
                                                             const void *name,
                                                             size_t name_length);

This function is to be used by clients that want to inform (via a TLS extension mechanism) the server of the name they connected to. This should be used by clients that connect to servers that do virtual hosting.

The value of `name` depends on the `type` type. In case of `GNUTLS_NAME_DNS`, an ASCII zero-terminated domain name string, without the trailing dot, is expected. IPv4 or IPv6 addresses are not permitted.

`session` : | is a gnutls_session_t structure.
`type` : | specifies the indicator type
`name` : | is a string that contains the server name.
`name_length` : | holds the length of name
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_server_name_get ()

    int                 gnutls_server_name_get              (gnutls_session_t session,
                                                             void *data,
                                                             size_t *data_length,
                                                             unsigned int *type,
                                                             unsigned int indx);

This function will allow you to get the name indication (if any), a client has sent. The name indication may be any of the enumeration gnutls_server_name_type_t.

If `type` is GNUTLS_NAME_DNS, then this function is to be used by servers that support virtual hosting, and the data will be a null terminated UTF-8 string.

If `data` has not enough size to hold the server name GNUTLS_E_SHORT_MEMORY_BUFFER is returned, and `data_length` will hold the required size.

`index` is used to retrieve more than one server names (if sent by the client). The first server name has an index of 0, the second 1 and so on. If no name with the given index exists GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.

`session` : | is a gnutls_session_t structure.
`data` : | will hold the data
`data_length` : | will hold the data length. Must hold the maximum size of data.
`type` : | will hold the server name indicator type
`indx` : | is the index of the server_name
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_safe_renegotiation_status ()

    int                 gnutls_safe_renegotiation_status    (gnutls_session_t session);

Can be used to check whether safe renegotiation is being used in the current session.

`session` : | is a gnutls_session_t structure.
Returns : | 0 when safe renegotiation is not used and non zero when safe renegotiation is used.

Since 2.10.0

### enum gnutls_supplemental_data_format_type_t

    typedef enum {
        GNUTLS_SUPPLEMENTAL_USER_MAPPING_DATA = 0
    } gnutls_supplemental_data_format_type_t;

Enumeration of different supplemental data types (RFC 4680).

`GNUTLS_SUPPLEMENTAL_USER_MAPPING_DATA` | Supplemental user mapping data.

### gnutls_session_ticket_key_generate ()

    int                 gnutls_session_ticket_key_generate  (gnutls_datum_t *key);

Generate a random key to encrypt security parameters within SessionTicket.

`key` : | is a pointer to a gnutls_datum_t which will contain a newly created key.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

Since 2.10.0

### gnutls_session_ticket_enable_client ()

    int                 gnutls_session_ticket_enable_client (gnutls_session_t session);

Request that the client should attempt session resumption using SessionTicket.

`session` : | is a gnutls_session_t structure.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

Since 2.10.0

### gnutls_session_ticket_enable_server ()

    int                 gnutls_session_ticket_enable_server (gnutls_session_t session,
                                                             const gnutls_datum_t *key);

Request that the server should attempt session resumption using SessionTicket. `key` must be initialized with `gnutls_session_ticket_key_generate()`.

`session` : | is a gnutls_session_t structure.
`key` : | key to encrypt session parameters.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

Since 2.10.0

### gnutls_priority_init ()

    int                 gnutls_priority_init                (gnutls_priority_t *priority_cache,
                                                             const char *priorities,
                                                             const char **err_pos);

Sets priorities for the ciphers, key exchange methods, macs and compression methods.

The priorities option allows you to specify a colon separated list of the cipher priorities to enable.

Common keywords: Some keywords are defined to provide quick access to common preferences.

"PERFORMANCE" means all the "secure" ciphersuites are enabled, limited to 128 bit ciphers and sorted by terms of speed performance.

"NORMAL" means all "secure" ciphersuites. The 256-bit ciphers are included as a fallback only. The ciphers are sorted by security margin.

"SECURE128" means all "secure" ciphersuites with ciphers up to 128 bits, sorted by security margin.

"SECURE256" means all "secure" ciphersuites including the 256 bit ciphers, sorted by security margin.

"EXPORT" means all ciphersuites are enabled, including the low-security 40 bit ciphers.

"NONE" means nothing is enabled. This disables even protocols and compression methods.

Special keywords: "!" or "-" appended with an algorithm will remove this algorithm.

"+" appended with an algorithm will add this algorithm.

Check the GnuTLS manual section "Priority strings" for detailed information.

Examples:

"NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL"

"NORMAL:-ARCFOUR-128" means normal ciphers except for ARCFOUR-128.

"SECURE:-VERS-SSL3.0:+COMP-DEFLATE" means that only secure ciphers are enabled, SSL3.0 is disabled, and libz compression enabled.

"NONE:+VERS-TLS-ALL:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1",

"NORMAL:`COMPAT`" is the most compatible mode.

`priority_cache` : | is a gnutls_prioritity_t structure.
`priorities` : | is a string describing priorities
`err_pos` : | In case of an error this will have the position in the string the error occured
Returns : | On syntax error `GNUTLS_E_INVALID_REQUEST` is returned, `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_priority_deinit ()

    void                gnutls_priority_deinit              (gnutls_priority_t priority_cache);

Deinitializes the priority cache.

`priority_cache` : | is a gnutls_prioritity_t structure.

### gnutls_priority_set ()

    int                 gnutls_priority_set                 (gnutls_session_t session,
                                                             gnutls_priority_t priority);

Sets the priorities to use on the ciphers, key exchange methods, macs and compression methods.

`session` : | is a gnutls_session_t structure.
`priority` : | is a gnutls_priority_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_priority_set_direct ()

    int                 gnutls_priority_set_direct          (gnutls_session_t session,
                                                             const char *priorities,
                                                             const char **err_pos);

Sets the priorities to use on the ciphers, key exchange methods, macs and compression methods. This function avoids keeping a priority cache and is used to directly set string priorities to a TLS session. For documentation check the `gnutls_priority_init()`.

`session` : | is a gnutls_session_t structure.
`priorities` : | is a string describing priorities
`err_pos` : | In case of an error this will have the position in the string the error occured
Returns : | On syntax error `GNUTLS_E_INVALID_REQUEST` is returned, `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_set_default_priority ()

    int                 gnutls_set_default_priority         (gnutls_session_t session);

Sets some default priority on the ciphers, key exchange methods, macs and compression methods.

This is the same as calling:

gnutls_priority_set_direct (session, "NORMAL", NULL);

This function is kept around for backwards compatibility, but because of its wide use it is still fully supported. If you wish to allow users to provide a string that specify which ciphers to use (which is recommended), you should use `gnutls_priority_set_direct()` or `gnutls_priority_set()` instead.

`session` : | is a gnutls_session_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_set_default_export_priority ()

    int                 gnutls_set_default_export_priority  (gnutls_session_t session);

Sets some default priority on the ciphers, key exchange methods, macs and compression methods. This function also includes weak algorithms.

This is the same as calling:

gnutls_priority_set_direct (session, "EXPORT", NULL);

This function is kept around for backwards compatibility, but because of its wide use it is still fully supported. If you wish to allow users to provide a string that specify which ciphers to use (which is recommended), you should use `gnutls_priority_set_direct()` or `gnutls_priority_set()` instead.

`session` : | is a gnutls_session_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_cipher_suite_get_name ()

    const char *        gnutls_cipher_suite_get_name        (gnutls_kx_algorithm_t kx_algorithm,
                                                             gnutls_cipher_algorithm_t cipher_algorithm,
                                                             gnutls_mac_algorithm_t mac_algorithm);

Note that the full cipher suite name must be prepended by TLS or SSL depending of the protocol in use.

`kx_algorithm` : | is a Key exchange algorithm
`cipher_algorithm` : | is a cipher algorithm
`mac_algorithm` : | is a MAC algorithm
Returns : | a string that contains the name of a TLS cipher suite, specified by the given algorithms, or `NULL`.

### gnutls_protocol_get_version ()

    gnutls_protocol_t   gnutls_protocol_get_version         (gnutls_session_t session);

Get TLS version, a gnutls_protocol_t value.

`session` : | is a gnutls_session_t structure.
Returns : | the version of the currently used protocol.

### gnutls_protocol_get_name ()

    const char *        gnutls_protocol_get_name            (gnutls_protocol_t version);

Convert a gnutls_protocol_t value to a string.

`version` : | is a (gnutls) version number
Returns : | a string that contains the name of the specified TLS version (e.g., "TLS1.0"), or `NULL`.

### gnutls_session_set_data ()

    int                 gnutls_session_set_data             (gnutls_session_t session,
                                                             const void *session_data,
                                                             size_t session_data_size);

Sets all session parameters, in order to resume a previously established session. The session data given must be the one returned by `gnutls_session_get_data()`. This function should be called before `gnutls_handshake()`.

Keep in mind that session resuming is advisory. The server may choose not to resume the session, thus a full handshake will be performed.

`session` : | is a gnutls_session_t structure.
`session_data` : | is a pointer to space to hold the session.
`session_data_size` : | is the session's size
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_session_get_data ()

    int                 gnutls_session_get_data             (gnutls_session_t session,
                                                             void *session_data,
                                                             size_t *session_data_size);

Returns all session parameters, in order to support resuming. The client should call this, and keep the returned session, if he wants to resume that current version later by calling `gnutls_session_set_data()` This function must be called after a successful handshake.

Resuming sessions is really useful and speedups connections after a successful one.

`session` : | is a gnutls_session_t structure.
`session_data` : | is a pointer to space to hold the session.
`session_data_size` : | is the session_data's size, or it will be set by the function.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_session_get_data2 ()

    int                 gnutls_session_get_data2            (gnutls_session_t session,
                                                             gnutls_datum_t *data);

Returns all session parameters, in order to support resuming. The client should call this, and keep the returned session, if he wants to resume that current version later by calling `gnutls_session_set_data()`. This function must be called after a successful handshake. The returned datum must be freed with `gnutls_free()`.

Resuming sessions is really useful and speedups connections after a successful one.

`session` : | is a gnutls_session_t structure.
`data` : | is a pointer to a datum that will hold the session.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### GNUTLS_MAX_SESSION_ID

    #define GNUTLS_MAX_SESSION_ID 32

### gnutls_session_get_id ()

    int                 gnutls_session_get_id               (gnutls_session_t session,
                                                             void *session_id,
                                                             size_t *session_id_size);

Returns the current session id. This can be used if you want to check if the next session you tried to resume was actually resumed. This is because resumed sessions have the same sessionID with the original session.

Session id is some data set by the server, that identify the current session. In TLS 1.0 and SSL 3.0 session id is always less than 32 bytes.

`session` : | is a gnutls_session_t structure.
`session_id` : | is a pointer to space to hold the session id.
`session_id_size` : | is the session id's size, or it will be set by the function.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_session_channel_binding ()

    int                 gnutls_session_channel_binding      (gnutls_session_t session,
                                                             gnutls_channel_binding_t cbtype,
                                                             gnutls_datum_t *cb);

Extract given channel binding data of the `cbtype` (e.g., `GNUTLS_CB_TLS_UNIQUE`) type.

`session` : | is a gnutls_session_t structure.
`cbtype` : | an gnutls_channel_binding_t enumeration type
`cb` : | output buffer array with data
Returns : | `GNUTLS_E_SUCCESS` on success, `GNUTLS_E_UNIMPLEMENTED_FEATURE` if the `cbtype` is unsupported, `GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE` if the data is not currently available, or an error code.

Since 2.12.0

### gnutls_session_is_resumed ()

    int                 gnutls_session_is_resumed           (gnutls_session_t session);

Check whether session is resumed or not.

`session` : | is a gnutls_session_t structure.
Returns : | non zero if this session is resumed, or a zero if this is a new session.

### gnutls_db_store_func ()

    int                 (*gnutls_db_store_func)             (void *Param1,
                                                             gnutls_datum_t key,
                                                             gnutls_datum_t data);

### gnutls_db_remove_func ()

    int                 (*gnutls_db_remove_func)            (void *Param1,
                                                             gnutls_datum_t key);

### gnutls_db_retr_func ()

    gnutls_datum_t      (*gnutls_db_retr_func)              (void *Param1,
                                                             gnutls_datum_t key);

### gnutls_db_set_cache_expiration ()

    void                gnutls_db_set_cache_expiration      (gnutls_session_t session,
                                                             int seconds);

Set the expiration time for resumed sessions. The default is 3600 (one hour) at the time writing this.

`session` : | is a gnutls_session_t structure.
`seconds` : | is the number of seconds.

### gnutls_db_remove_session ()

    void                gnutls_db_remove_session            (gnutls_session_t session);

This function will remove the current session data from the session database. This will prevent future handshakes reusing these session data. This function should be called if a session was terminated abnormally, and before `gnutls_deinit()` is called.

Normally `gnutls_deinit()` will remove abnormally terminated sessions.

`session` : | is a gnutls_session_t structure.

### gnutls_db_set_retrieve_function ()

    void                gnutls_db_set_retrieve_function     (gnutls_session_t session,
                                                             gnutls_db_retr_func retr_func);

Sets the function that will be used to retrieve data from the resumed sessions database. This function must return a gnutls_datum_t containing the data on success, or a gnutls_datum_t containing null and 0 on failure.

The datum's data must be allocated using the function `gnutls_malloc()`.

The first argument to `retr_func` will be null unless `gnutls_db_set_ptr()` has been called.

`session` : | is a gnutls_session_t structure.
`retr_func` : | is the function.

### gnutls_db_set_remove_function ()

    void                gnutls_db_set_remove_function       (gnutls_session_t session,
                                                             gnutls_db_remove_func rem_func);

Sets the function that will be used to remove data from the resumed sessions database. This function must return 0 on success.

The first argument to `rem_func` will be null unless `gnutls_db_set_ptr()` has been called.

`session` : | is a gnutls_session_t structure.
`rem_func` : | is the function.

### gnutls_db_set_store_function ()

    void                gnutls_db_set_store_function        (gnutls_session_t session,
                                                             gnutls_db_store_func store_func);

Sets the function that will be used to store data from the resumed sessions database. This function must remove 0 on success.

The first argument to `store_func()` will be null unless `gnutls_db_set_ptr()` has been called.

`session` : | is a gnutls_session_t structure.
`store_func` : | is the function

### gnutls_db_set_ptr ()

    void                gnutls_db_set_ptr                   (gnutls_session_t session,
                                                             void *ptr);

Sets the pointer that will be provided to db store, retrieve and delete functions, as the first argument.

`session` : | is a gnutls_session_t structure.
`ptr` : | is the pointer

### gnutls_db_get_ptr ()

    void *              gnutls_db_get_ptr                   (gnutls_session_t session);

Get db function pointer.

`session` : | is a gnutls_session_t structure.
Returns : | the pointer that will be sent to db store, retrieve and delete functions, as the first argument.

### gnutls_db_check_entry ()

    int                 gnutls_db_check_entry               (gnutls_session_t session,
                                                             gnutls_datum_t session_entry);

Check if database entry has expired. This function is to be used when you want to clear unnesessary session which occupy space in your backend.

`session` : | is a gnutls_session_t structure.
`session_entry` : | is the session data (not key)
Returns : | Returns `GNUTLS_E_EXPIRED`, if the database entry has expired or 0 otherwise.

### gnutls_handshake_post_client_hello_func ()

    int                 (*gnutls_handshake_post_client_hello_func)
                                                            (gnutls_session_t Param1);

### gnutls_handshake_set_post_client_hello_function ()

    void                gnutls_handshake_set_post_client_hello_function
                                                            (gnutls_session_t session,
                                                             gnutls_handshake_post_client_hello_func func);

This function will set a callback to be called after the client hello has been received (callback valid in server side only). This allows the server to adjust settings based on received extensions.

Those settings could be ciphersuites, requesting certificate, or anything else except for version negotiation (this is done before the hello message is parsed).

This callback must return 0 on success or a gnutls error code to terminate the handshake.

Warning: You should not use this function to terminate the handshake based on client input unless you know what you are doing. Before the handshake is finished there is no way to know if there is a man-in-the-middle attack being performed.

`session` : | is a gnutls_session_t structure.
`func` : | is the function to be called

### gnutls_handshake_set_max_packet_length ()

    void                gnutls_handshake_set_max_packet_length
                                                            (gnutls_session_t session,
                                                             size_t max);

This function will set the maximum size of all handshake messages. Handshakes over this size are rejected with `GNUTLS_E_HANDSHAKE_TOO_LARGE` error code. The default value is 48kb which is typically large enough. Set this to 0 if you do not want to set an upper limit.

The reason for restricting the handshake message sizes are to limit Denial of Service attacks.

`session` : | is a gnutls_session_t structure.
`max` : | is the maximum number.

### gnutls_check_version ()

    const char *        gnutls_check_version                (const char *req_version);

Check GnuTLS Library version.

See `GNUTLS_VERSION` for a suitable `req_version` string.

`req_version` : | version string to compare with, or `NULL`.
Returns : | Check that the version of the library is at minimum the one given as a string in `req_version` and return the actual version string of the library; return `NULL` if the condition is not met. If `NULL` is passed to this function no check is done and only the version string is returned.

### gnutls_credentials_clear ()

    void                gnutls_credentials_clear            (gnutls_session_t session);

Clears all the credentials previously set in this session.

`session` : | is a gnutls_session_t structure.

### gnutls_credentials_set ()

    int                 gnutls_credentials_set              (gnutls_session_t session,
                                                             gnutls_credentials_type_t type,
                                                             void *cred);

Sets the needed credentials for the specified type. Eg username, password - or public and private keys etc. The `cred` parameter is a structure that depends on the specified type and on the current session (client or server).

In order to minimize memory usage, and share credentials between several threads gnutls keeps a pointer to cred, and not the whole cred structure. Thus you will have to keep the structure allocated until you call `gnutls_deinit()`.

For `GNUTLS_CRD_ANON`, `cred` should be gnutls_anon_client_credentials_t in case of a client. In case of a server it should be gnutls_anon_server_credentials_t.

For `GNUTLS_CRD_SRP`, `cred` should be gnutls_srp_client_credentials_t in case of a client, and gnutls_srp_server_credentials_t, in case of a server.

For `GNUTLS_CRD_CERTIFICATE`, `cred` should be gnutls_certificate_credentials_t.

`session` : | is a gnutls_session_t structure.
`type` : | is the type of the credentials
`cred` : | is a pointer to a structure.
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_cred_set

    #define gnutls_cred_set gnutls_credentials_set

### struct gnutls_certificate_credentials_st

    struct gnutls_certificate_credentials_st;

### gnutls_anon_free_server_credentials ()

    void                gnutls_anon_free_server_credentials (gnutls_anon_server_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_anon_server_credentials_t structure.

### gnutls_anon_allocate_server_credentials ()

    int                 gnutls_anon_allocate_server_credentials
                                                            (gnutls_anon_server_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_anon_server_credentials_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_anon_set_server_dh_params ()

    void                gnutls_anon_set_server_dh_params    (gnutls_anon_server_credentials_t res,
                                                             gnutls_dh_params_t dh_params);

This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Anonymous Diffie-Hellman cipher suites.

`res` : | is a gnutls_anon_server_credentials_t structure
`dh_params` : | is a structure that holds Diffie-Hellman parameters.

### gnutls_anon_set_server_params_function ()

    void                gnutls_anon_set_server_params_function
                                                            (gnutls_anon_server_credentials_t res,
                                                             gnutls_params_function *func);

This function will set a callback in order for the server to get the Diffie-Hellman parameters for anonymous authentication. The callback should return zero on success.

`res` : | is a gnutls_certificate_credentials_t structure
`func` : | is the function to be called

### gnutls_anon_free_client_credentials ()

    void                gnutls_anon_free_client_credentials (gnutls_anon_client_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_anon_client_credentials_t structure.

### gnutls_anon_allocate_client_credentials ()

    int                 gnutls_anon_allocate_client_credentials
                                                            (gnutls_anon_client_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_anon_client_credentials_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_certificate_free_credentials ()

    void                gnutls_certificate_free_credentials (gnutls_certificate_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

This function does not free any temporary parameters associated with this structure (ie RSA and DH parameters are not freed by this function).

`sc` : | is a gnutls_certificate_credentials_t structure.

### gnutls_certificate_allocate_credentials ()

    int                 gnutls_certificate_allocate_credentials
                                                            (gnutls_certificate_credentials_t *res);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`res` : | is a pointer to a gnutls_certificate_credentials_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_certificate_free_keys ()

    void                gnutls_certificate_free_keys        (gnutls_certificate_credentials_t sc);

This function will delete all the keys and the certificates associated with the given credentials. This function must not be called when a TLS negotiation that uses the credentials is in progress.

`sc` : | is a gnutls_certificate_credentials_t structure.

### gnutls_certificate_free_cas ()

    void                gnutls_certificate_free_cas         (gnutls_certificate_credentials_t sc);

This function will delete all the CAs associated with the given credentials. Servers that do not use `gnutls_certificate_verify_peers2()` may call this to save some memory.

`sc` : | is a gnutls_certificate_credentials_t structure.

### gnutls_certificate_free_ca_names ()

    void                gnutls_certificate_free_ca_names    (gnutls_certificate_credentials_t sc);

This function will delete all the CA name in the given credentials. Clients may call this to save some memory since in client side the CA names are not used. Servers might want to use this function if a large list of trusted CAs is present and sending the names of it would just consume bandwidth without providing information to client.

CA names are used by servers to advertize the CAs they support to clients.

`sc` : | is a gnutls_certificate_credentials_t structure.

### gnutls_certificate_free_crls ()

    void                gnutls_certificate_free_crls        (gnutls_certificate_credentials_t sc);

This function will delete all the CRLs associated with the given credentials.

`sc` : | is a gnutls_certificate_credentials_t structure.

### gnutls_certificate_set_dh_params ()

    void                gnutls_certificate_set_dh_params    (gnutls_certificate_credentials_t res,
                                                             gnutls_dh_params_t dh_params);

This function will set the Diffie-Hellman parameters for a certificate server to use. These parameters will be used in Ephemeral Diffie-Hellman cipher suites. Note that only a pointer to the parameters are stored in the certificate handle, so if you deallocate the parameters before the certificate is deallocated, you must change the parameters stored in the certificate first.

`res` : | is a gnutls_certificate_credentials_t structure
`dh_params` : | is a structure that holds Diffie-Hellman parameters.

### gnutls_certificate_set_rsa_export_params ()

    void                gnutls_certificate_set_rsa_export_params
                                                            (gnutls_certificate_credentials_t res,
                                                             gnutls_rsa_params_t rsa_params);

This function will set the temporary RSA parameters for a certificate server to use. These parameters will be used in RSA-EXPORT cipher suites.

`res` : | is a gnutls_certificate_credentials_t structure
`rsa_params` : | is a structure that holds temporary RSA parameters.

### gnutls_certificate_set_verify_flags ()

    void                gnutls_certificate_set_verify_flags (gnutls_certificate_credentials_t res,
                                                             unsigned int flags);

This function will set the flags to be used at verification of the certificates. Flags must be OR of the gnutls_certificate_verify_flags enumerations.

`res` : | is a gnutls_certificate_credentials_t structure
`flags` : | are the flags

### gnutls_certificate_set_verify_limits ()

    void                gnutls_certificate_set_verify_limits
                                                            (gnutls_certificate_credentials_t res,
                                                             unsigned int max_bits,
                                                             unsigned int max_depth);

This function will set some upper limits for the default verification function, `gnutls_certificate_verify_peers2()`, to avoid denial of service attacks. You can set them to zero to disable limits.

`res` : | is a gnutls_certificate_credentials structure
`max_bits` : | is the number of bits of an acceptable certificate (default 8200)
`max_depth` : | is maximum depth of the verification of a certificate chain (default 5)

### gnutls_certificate_set_x509_trust_file ()

    int                 gnutls_certificate_set_x509_trust_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *cafile,
                                                             gnutls_x509_crt_fmt_t type);

This function adds the trusted CAs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

In case of a server the names of the CAs set here will be sent to the client if a certificate request is sent. This can be disabled using `gnutls_certificate_send_x509_rdn_sequence()`.

This function can also accept PKCS 11 URLs. In that case it will import all certificates that are marked as trusted.

`res` : | is a gnutls_certificate_credentials_t structure.
`cafile` : | is a file containing the list of trusted CAs (DER or PEM list)
`type` : | is PEM or DER
Returns : | number of certificates processed, or a negative value on error.

### gnutls_certificate_set_x509_trust_mem ()

    int                 gnutls_certificate_set_x509_trust_mem
                                                            (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *ca,
                                                             gnutls_x509_crt_fmt_t type);

This function adds the trusted CAs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

In case of a server the CAs set here will be sent to the client if a certificate request is sent. This can be disabled using `gnutls_certificate_send_x509_rdn_sequence()`.

`res` : | is a gnutls_certificate_credentials_t structure.
`ca` : | is a list of trusted CAs or a DER certificate
`type` : | is DER or PEM
Returns : | the number of certificates processed or a negative value on error.

### gnutls_certificate_set_x509_crl_file ()

    int                 gnutls_certificate_set_x509_crl_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *crlfile,
                                                             gnutls_x509_crt_fmt_t type);

This function adds the trusted CRLs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

`res` : | is a gnutls_certificate_credentials_t structure.
`crlfile` : | is a file containing the list of verified CRLs (DER or PEM list)
`type` : | is PEM or DER
Returns : | number of CRLs processed or a negative value on error.

### gnutls_certificate_set_x509_crl_mem ()

    int                 gnutls_certificate_set_x509_crl_mem (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *CRL,
                                                             gnutls_x509_crt_fmt_t type);

This function adds the trusted CRLs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

`res` : | is a gnutls_certificate_credentials_t structure.
`CRL` : | is a list of trusted CRLs. They should have been verified before.
`type` : | is DER or PEM
Returns : | number of CRLs processed, or a negative value on error.

### gnutls_certificate_set_x509_key_file ()

    int                 gnutls_certificate_set_x509_key_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *certfile,
                                                             const char *keyfile,
                                                             gnutls_x509_crt_fmt_t type);

This function sets a certificate/private key pair in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server). For clients that wants to send more than its own end entity certificate (e.g., also an intermediate CA cert) then put the certificate chain in `certfile`.

Currently only PKCS-1 encoded RSA and DSA private keys are accepted by this function.

This function can also accept PKCS 11 URLs. In that case it will import the private key and certificate indicated by the urls.

`res` : | is a gnutls_certificate_credentials_t structure.
`certfile` : | is a file that containing the certificate list (path) for the specified private key, in PKCS7 format, or a list of certificates
`keyfile` : | is a file that contains the private key
`type` : | is PEM or DER
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_certificate_set_x509_key_mem ()

    int                 gnutls_certificate_set_x509_key_mem (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *cert,
                                                             const gnutls_datum_t *key,
                                                             gnutls_x509_crt_fmt_t type);

This function sets a certificate/private key pair in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).

Currently are supported: RSA PKCS-1 encoded private keys, DSA private keys.

DSA private keys are encoded the OpenSSL way, which is an ASN.1 DER sequence of 6 INTEGERs - version, p, q, g, pub, priv.

Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates is supported. This means that certificates intended for signing cannot be used for ciphersuites that require encryption.

If the certificate and the private key are given in PEM encoding then the strings that hold their values must be null terminated.

The `key` may be `NULL` if you are using a sign callback, see `gnutls_sign_callback_set()`.

`res` : | is a gnutls_certificate_credentials_t structure.
`cert` : | contains a certificate list (path) for the specified private key
`key` : | is the private key, or `NULL`
`type` : | is PEM or DER
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_certificate_send_x509_rdn_sequence ()

    void                gnutls_certificate_send_x509_rdn_sequence
                                                            (gnutls_session_t session,
                                                             int status);

If status is non zero, this function will order gnutls not to send the rdnSequence in the certificate request message. That is the server will not advertize it's trusted CAs to the peer. If status is zero then the default behaviour will take effect, which is to advertize the server's trusted CAs.

This function has no effect in clients, and in authentication methods other than certificate with X.509 certificates.

`session` : | is a pointer to a gnutls_session_t structure.
`status` : | is 0 or 1

### gnutls_certificate_set_x509_simple_pkcs12_file ()

    int                 gnutls_certificate_set_x509_simple_pkcs12_file
                                                            (gnutls_certificate_credentials_t res,
                                                             const char *pkcs12file,
                                                             gnutls_x509_crt_fmt_t type,
                                                             const char *password);

This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).

MAC:ed PKCS12 files are supported. Encrypted PKCS12 bags are supported. Encrypted PKCS#8 private keys are supported. However, only password based security, and the same password for all operations, are supported.

The private keys may be RSA PKCS#1 or DSA private keys encoded in the OpenSSL way.

PKCS12 file may contain many keys and/or certificates, and there is no way to identify which key/certificate pair you want. You should make sure the PKCS12 file only contain one key/certificate pair and/or one CRL.

It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.

`res` : | is a gnutls_certificate_credentials_t structure.
`pkcs12file` : | filename of file containing PKCS12 blob.
`type` : | is PEM or DER of the `pkcs12file`.
`password` : | optional password used to decrypt PKCS12 file, bags and keys.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_certificate_set_x509_simple_pkcs12_mem ()

    int                 gnutls_certificate_set_x509_simple_pkcs12_mem
                                                            (gnutls_certificate_credentials_t res,
                                                             const gnutls_datum_t *p12blob,
                                                             gnutls_x509_crt_fmt_t type,
                                                             const char *password);

This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).

MAC:ed PKCS12 files are supported. Encrypted PKCS12 bags are supported. Encrypted PKCS#8 private keys are supported. However, only password based security, and the same password for all operations, are supported.

The private keys may be RSA PKCS#1 or DSA private keys encoded in the OpenSSL way.

PKCS12 file may contain many keys and/or certificates, and there is no way to identify which key/certificate pair you want. You should make sure the PKCS12 file only contain one key/certificate pair and/or one CRL.

It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.

`res` : | is a gnutls_certificate_credentials_t structure.
`p12blob` : | the PKCS12 blob.
`type` : | is PEM or DER of the `pkcs12file`.
`password` : | optional password used to decrypt PKCS12 file, bags and keys.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

Since 2.8.0

### gnutls_x509_privkey_t

      typedef struct gnutls_x509_privkey_int *gnutls_x509_privkey_t;

### struct gnutls_x509_crl_int

    struct gnutls_x509_crl_int;

### gnutls_x509_crl_t

      typedef struct gnutls_x509_crl_int *gnutls_x509_crl_t;

### struct gnutls_x509_crt_int

    struct gnutls_x509_crt_int;

### gnutls_x509_crt_t

      typedef struct gnutls_x509_crt_int *gnutls_x509_crt_t;

### struct gnutls_x509_crq_int

    struct gnutls_x509_crq_int;

### gnutls_x509_crq_t

      typedef struct gnutls_x509_crq_int *gnutls_x509_crq_t;

### struct gnutls_openpgp_keyring_int

    struct gnutls_openpgp_keyring_int;

### gnutls_openpgp_keyring_t

      typedef struct gnutls_openpgp_keyring_int *gnutls_openpgp_keyring_t;

### gnutls_certificate_set_x509_key ()

    int                 gnutls_certificate_set_x509_key     (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crt_t *cert_list,
                                                             int cert_list_size,
                                                             gnutls_x509_privkey_t key);

This function sets a certificate/private key pair in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server). For clients that wants to send more than its own end entity certificate (e.g., also an intermediate CA cert) then put the certificate chain in `cert_list`.

`res` : | is a gnutls_certificate_credentials_t structure.
`cert_list` : | contains a certificate list (path) for the specified private key
`cert_list_size` : | holds the size of the certificate list
`key` : | is a gnutls_x509_privkey_t key
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

Since 2.4.0

### gnutls_certificate_set_x509_trust ()

    int                 gnutls_certificate_set_x509_trust   (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crt_t *ca_list,
                                                             int ca_list_size);

This function adds the trusted CAs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

In case of a server the CAs set here will be sent to the client if a certificate request is sent. This can be disabled using `gnutls_certificate_send_x509_rdn_sequence()`.

`res` : | is a gnutls_certificate_credentials_t structure.
`ca_list` : | is a list of trusted CAs
`ca_list_size` : | holds the size of the CA list
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

Since 2.4.0

### gnutls_certificate_set_x509_crl ()

    int                 gnutls_certificate_set_x509_crl     (gnutls_certificate_credentials_t res,
                                                             gnutls_x509_crl_t *crl_list,
                                                             int crl_list_size);

This function adds the trusted CRLs in order to verify client or server certificates. In case of a client this is not required to be called if the certificates are not verified using `gnutls_certificate_verify_peers2()`. This function may be called multiple times.

`res` : | is a gnutls_certificate_credentials_t structure.
`crl_list` : | is a list of trusted CRLs. They should have been verified before.
`crl_list_size` : | holds the size of the crl_list
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

Since 2.4.0

### gnutls_global_init ()

    int                 gnutls_global_init                  (void);

This function initializes the global data to defaults. Every gnutls application has a global data which holds common parameters shared by gnutls session structures. You should call `gnutls_global_deinit()` when gnutls usage is no longer needed

Note that this function will also initialize the underlying crypto backend, if it has not been initialized before.

This function increment a global counter, so that `gnutls_global_deinit()` only releases resources when it has been called as many times as `gnutls_global_init()`. This is useful when GnuTLS is used by more than one library in an application. This function can be called many times, but will only do something the first time.

Note! This function is not thread safe. If two threads call this function simultaneously, they can cause a race between checking the global counter and incrementing it, causing both threads to execute the library initialization code. That would lead to a memory leak. To handle this, your application could invoke this function after aquiring a thread mutex. To ignore the potential memory leak is also an option.

Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_global_deinit ()

    void                gnutls_global_deinit                (void);

This function deinitializes the global data, that were initialized using `gnutls_global_init()`.

Note! This function is not thread safe. See the discussion for `gnutls_global_init()` for more information.

### mutex_init_func ()

    int                 (*mutex_init_func)                  (void **mutex);

### mutex_lock_func ()

    int                 (*mutex_lock_func)                  (void **mutex);

### mutex_unlock_func ()

    int                 (*mutex_unlock_func)                (void **mutex);

### mutex_deinit_func ()

    int                 (*mutex_deinit_func)                (void **mutex);

### gnutls_global_set_mutex ()

    void                gnutls_global_set_mutex             (mutex_init_func init,
                                                             mutex_deinit_func deinit,
                                                             mutex_lock_func lock,
                                                             mutex_unlock_func unlock);

With this function you are allowed to override the default mutex locks used in some parts of gnutls and dependent libraries. This function should be used if you have complete control of your program and libraries. Do not call this function from a library. Instead only initialize gnutls and the default OS mutex locks will be used.

This function must be called before `gnutls_global_init()`.

`init` : | mutex initialization function
`deinit` : | mutex deinitialization function
`lock` : | mutex locking function
`unlock` : | mutex unlocking function

### gnutls_alloc_function ()

    void *              (*gnutls_alloc_function)            (size_t Param1);

### gnutls_calloc_function ()

    void *              (*gnutls_calloc_function)           (size_t Param1,
                                                             size_t Param2);

### gnutls_is_secure_function ()

    int                 (*gnutls_is_secure_function)        (const void *Param1);

### gnutls_free_function ()

    void                (*gnutls_free_function)             (void *Param1);

### gnutls_realloc_function ()

    void *              (*gnutls_realloc_function)          (void *Param1,
                                                             size_t Param2);

### gnutls_global_set_mem_functions ()

    void                gnutls_global_set_mem_functions     (gnutls_alloc_function alloc_func,
                                                             gnutls_alloc_function secure_alloc_func,
                                                             gnutls_is_secure_function is_secure_func,
                                                             gnutls_realloc_function realloc_func,
                                                             gnutls_free_function free_func);

This is the function were you set the memory allocation functions gnutls is going to use. By default the libc's allocation functions (`malloc()`, `free()`), are used by gnutls, to allocate both sensitive and not sensitive data. This function is provided to set the memory allocation functions to something other than the defaults

This function must be called before `gnutls_global_init()` is called. This function is not thread safe.

`alloc_func` : | it's the default memory allocation function. Like `malloc()`.
`secure_alloc_func` : | This is the memory allocation function that will be used for sensitive data.
`is_secure_func` : | a function that returns 0 if the memory given is not secure. May be NULL.
`realloc_func` : | A realloc function
`free_func` : | The function that frees allocated data. Must accept a NULL pointer.

### gnutls_malloc

      extern gnutls_alloc_function gnutls_malloc;

This function will allocate 's' bytes data, and return a pointer to memory. This function is supposed to be used by callbacks.

The allocation function used is the one set by `gnutls_global_set_mem_functions()`.

### gnutls_secure_malloc

      extern gnutls_alloc_function gnutls_secure_malloc;

### gnutls_realloc

      extern gnutls_realloc_function gnutls_realloc;

### gnutls_calloc

      extern gnutls_calloc_function gnutls_calloc;

### gnutls_free

      extern gnutls_free_function gnutls_free;

This function will free data pointed by ptr.

The deallocation function used is the one set by `gnutls_global_set_mem_functions()`.

### gnutls_strdup ()

    char *              (*gnutls_strdup)                    (const char *Param1);

### gnutls_log_func ()

    void                (*gnutls_log_func)                  (int Param1,
                                                             const char *Param2);

### gnutls_global_set_log_function ()

    void                gnutls_global_set_log_function      (gnutls_log_func log_func);

This is the function where you set the logging function gnutls is going to use. This function only accepts a character array. Normally you may not use this function since it is only used for debugging purposes.

gnutls_log_func is of the form, void (*gnutls_log_func)( int level, const char*);

`log_func` : | it's a log function

### gnutls_global_set_log_level ()

    void                gnutls_global_set_log_level         (int level);

This is the function that allows you to set the log level. The level is an integer between 0 and 9. Higher values mean more verbosity. The default value is 0. Larger values should only be used with care, since they may reveal sensitive information.

Use a log level over 10 to enable all debugging options.

`level` : | it's an integer from 0 to 9.

### gnutls_dh_params_init ()

    int                 gnutls_dh_params_init               (gnutls_dh_params_t *dh_params);

This function will initialize the DH parameters structure.

`dh_params` : | Is a structure that will hold the prime numbers
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_deinit ()

    void                gnutls_dh_params_deinit             (gnutls_dh_params_t dh_params);

This function will deinitialize the DH parameters structure.

`dh_params` : | Is a structure that holds the prime numbers

### gnutls_dh_params_import_raw ()

    int                 gnutls_dh_params_import_raw         (gnutls_dh_params_t dh_params,
                                                             const gnutls_datum_t *prime,
                                                             const gnutls_datum_t *generator);

This function will replace the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters should be stored in the appropriate gnutls_datum.

`dh_params` : | Is a structure that will hold the prime numbers
`prime` : | holds the new prime
`generator` : | holds the new generator
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_import_pkcs3 ()

    int                 gnutls_dh_params_import_pkcs3       (gnutls_dh_params_t params,
                                                             const gnutls_datum_t *pkcs3_params,
                                                             gnutls_x509_crt_fmt_t format);

This function will extract the DHParams found in a PKCS3 formatted structure. This is the format generated by "openssl dhparam" tool.

If the structure is PEM encoded, it should have a header of "BEGIN DH PARAMETERS".

`params` : | A structure where the parameters will be copied to
`pkcs3_params` : | should contain a PKCS3 DHParams structure PEM or DER encoded
`format` : | the format of params. PEM or DER.
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_generate2 ()

    int                 gnutls_dh_params_generate2          (gnutls_dh_params_t params,
                                                             unsigned int bits);

This function will generate a new pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters will be allocated using `gnutls_malloc()` and will be stored in the appropriate datum. This function is normally slow.

Do not set the number of bits directly, use `gnutls_sec_param_to_pk_bits()` to get bits for `GNUTLS_PK_DSA`. Also note that the DH parameters are only useful to servers. Since clients use the parameters sent by the server, it's of no use to call this in client side.

`params` : | Is the structure that the DH parameters will be stored
`bits` : | is the prime's number of bits
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_export_pkcs3 ()

    int                 gnutls_dh_params_export_pkcs3       (gnutls_dh_params_t params,
                                                             gnutls_x509_crt_fmt_t format,
                                                             unsigned char *params_data,
                                                             size_t *params_data_size);

This function will export the given dh parameters to a PKCS3 DHParams structure. This is the format generated by "openssl dhparam" tool. 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 DH PARAMETERS".

`params` : | Holds the DH parameters
`format` : | the format of output params. One of PEM or DER.
`params_data` : | will contain a PKCS3 DHParams structure PEM or DER encoded
`params_data_size` : | holds the size of params_data (and will be replaced by the actual size of parameters)
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_export_raw ()

    int                 gnutls_dh_params_export_raw         (gnutls_dh_params_t params,
                                                             gnutls_datum_t *prime,
                                                             gnutls_datum_t *generator,
                                                             unsigned int *bits);

This function will export the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters will be allocated using `gnutls_malloc()` and will be stored in the appropriate datum.

`params` : | Holds the DH parameters
`prime` : | will hold the new prime
`generator` : | will hold the new generator
`bits` : | if non null will hold is the prime's number of bits
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_dh_params_cpy ()

    int                 gnutls_dh_params_cpy                (gnutls_dh_params_t dst,
                                                             gnutls_dh_params_t src);

This function will copy the DH parameters structure from source to destination.

`dst` : | Is the destination structure, which should be initialized.
`src` : | Is the source structure
Returns : | On success, `GNUTLS_E_SUCCESS` (zero) is returned, otherwise an error code is returned.

### gnutls_rsa_params_init ()

    int                 gnutls_rsa_params_init              (gnutls_rsa_params_t *rsa_params);

This function will initialize the temporary RSA parameters structure.

`rsa_params` : | Is a structure that will hold the parameters
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_deinit ()

    void                gnutls_rsa_params_deinit            (gnutls_rsa_params_t rsa_params);

This function will deinitialize the RSA parameters structure.

`rsa_params` : | Is a structure that holds the parameters

### gnutls_rsa_params_cpy ()

    int                 gnutls_rsa_params_cpy               (gnutls_rsa_params_t dst,
                                                             gnutls_rsa_params_t src);

This function will copy the RSA parameters structure from source to destination.

`dst` : | Is the destination structure, which should be initialized.
`src` : | Is the source structure
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_import_raw ()

    int                 gnutls_rsa_params_import_raw        (gnutls_rsa_params_t rsa_params,
                                                             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 replace the parameters in the given structure. The new parameters should be stored in the appropriate gnutls_datum.

`rsa_params` : | Is a structure will hold the parameters
`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 : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_generate2 ()

    int                 gnutls_rsa_params_generate2         (gnutls_rsa_params_t params,
                                                             unsigned int bits);

This function will generate new temporary RSA parameters for use in RSA-EXPORT ciphersuites. This function is normally slow.

Note that if the parameters are to be used in export cipher suites the bits value should be 512 or less. Also note that the generation of new RSA parameters is only useful to servers. Clients use the parameters sent by the server, thus it's no use calling this in client side.

`params` : | The structure where the parameters will be stored
`bits` : | is the prime's number of bits
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_export_raw ()

    int                 gnutls_rsa_params_export_raw        (gnutls_rsa_params_t params,
                                                             gnutls_datum_t *m,
                                                             gnutls_datum_t *e,
                                                             gnutls_datum_t *d,
                                                             gnutls_datum_t *p,
                                                             gnutls_datum_t *q,
                                                             gnutls_datum_t *u,
                                                             unsigned int *bits);

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

`params` : | a structure that holds the rsa parameters
`m` : | will hold the modulus
`e` : | will hold the public exponent
`d` : | will hold the private exponent
`p` : | will hold the first prime (p)
`q` : | will hold the second prime (q)
`u` : | will hold the coefficient
`bits` : | if non null will hold the prime's number of bits
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_export_pkcs1 ()

    int                 gnutls_rsa_params_export_pkcs1      (gnutls_rsa_params_t params,
                                                             gnutls_x509_crt_fmt_t format,
                                                             unsigned char *params_data,
                                                             size_t *params_data_size);

This function will export the given RSA parameters to a PKCS1 RSAPublicKey structure. 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 RSA PRIVATE KEY".

`params` : | Holds the RSA parameters
`format` : | the format of output params. One of PEM or DER.
`params_data` : | will contain a PKCS1 RSAPublicKey structure PEM or DER encoded
`params_data_size` : | holds the size of params_data (and will be replaced by the actual size of parameters)
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_rsa_params_import_pkcs1 ()

    int                 gnutls_rsa_params_import_pkcs1      (gnutls_rsa_params_t params,
                                                             const gnutls_datum_t *pkcs1_params,
                                                             gnutls_x509_crt_fmt_t format);

This function will extract the RSAPublicKey found in a PKCS1 formatted structure.

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

`params` : | A structure where the parameters will be copied to
`pkcs1_params` : | should contain a PKCS1 RSAPublicKey structure PEM or DER encoded
`format` : | the format of params. PEM or DER.
Returns : | `GNUTLS_E_SUCCESS` on success, or an negative error code.

### gnutls_pull_func ()

    ssize_t             (*gnutls_pull_func)                 (gnutls_transport_ptr_t Param1,
                                                             void *Param2,
                                                             size_t Param3);

### gnutls_push_func ()

    ssize_t             (*gnutls_push_func)                 (gnutls_transport_ptr_t Param1,
                                                             const void *Param2,
                                                             size_t Param3);

### gnutls_vec_push_func ()

    ssize_t             (*gnutls_vec_push_func)             (gnutls_transport_ptr_t Param1,
                                                             const giovec_t *iov,
                                                             int iovcnt);

### gnutls_errno_func ()

    int                 (*gnutls_errno_func)                (gnutls_transport_ptr_t Param1);

### gnutls_transport_set_ptr ()

    void                gnutls_transport_set_ptr            (gnutls_session_t session,
                                                             gnutls_transport_ptr_t ptr);

Used to set the first argument of the transport function (like PUSH and PULL). In berkeley style sockets this function will set the connection handle.

`session` : | is a gnutls_session_t structure.
`ptr` : | is the value.

### gnutls_transport_set_ptr2 ()

    void                gnutls_transport_set_ptr2           (gnutls_session_t session,
                                                             gnutls_transport_ptr_t recv_ptr,
                                                             gnutls_transport_ptr_t send_ptr);

Used to set the first argument of the transport function (like PUSH and PULL). In berkeley style sockets this function will set the connection handle. With this function you can use two different pointers for receiving and sending.

`session` : | is a gnutls_session_t structure.
`recv_ptr` : | is the value for the pull function
`send_ptr` : | is the value for the push function

### gnutls_transport_get_ptr ()

    gnutls_transport_ptr_t gnutls_transport_get_ptr         (gnutls_session_t session);

Used to get the first argument of the transport function (like PUSH and PULL). This must have been set using `gnutls_transport_set_ptr()`.

`session` : | is a gnutls_session_t structure.
Returns : | first argument of the transport function.

### gnutls_transport_get_ptr2 ()

    void                gnutls_transport_get_ptr2           (gnutls_session_t session,
                                                             gnutls_transport_ptr_t *recv_ptr,
                                                             gnutls_transport_ptr_t *send_ptr);

Used to get the arguments of the transport functions (like PUSH and PULL). These should have been set using `gnutls_transport_set_ptr2()`.

`session` : | is a gnutls_session_t structure.
`recv_ptr` : | will hold the value for the pull function
`send_ptr` : | will hold the value for the push function

### gnutls_transport_set_vec_push_function ()

    void                gnutls_transport_set_vec_push_function
                                                            (gnutls_session_t session,
                                                             gnutls_vec_push_func vec_func);

This is the function where you set a push function for gnutls to use in order to send data. If you are going to use berkeley style sockets, you do not need to use this function since the default (send(2)) will probably be ok. Otherwise you should specify this function for gnutls to be able to send data.

PUSH_FUNC is of the form, ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);

`session` : | is a gnutls_session_t structure.
`vec_func` : | a callback function similar to `writev()`

### gnutls_transport_set_push_function ()

    void                gnutls_transport_set_push_function  (gnutls_session_t session,
                                                             gnutls_push_func push_func);

This is the function where you set a push function for gnutls to use in order to send data. If you are going to use berkeley style sockets, you do not need to use this function since the default (send(2)) will probably be ok. Otherwise you should specify this function for gnutls to be able to send data.

PUSH_FUNC is of the form, ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);

`session` : | is a gnutls_session_t structure.
`push_func` : | a callback function similar to `write()`

### gnutls_transport_set_pull_function ()

    void                gnutls_transport_set_pull_function  (gnutls_session_t session,
                                                             gnutls_pull_func pull_func);

This is the function where you set a function for gnutls to receive data. Normally, if you use berkeley style sockets, do not need to use this function since the default (recv(2)) will probably be ok.

PULL_FUNC is of the form, ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);

`session` : | is a gnutls_session_t structure.
`pull_func` : | a callback function similar to `read()`

### gnutls_transport_set_errno_function ()

    void                gnutls_transport_set_errno_function (gnutls_session_t session,
                                                             gnutls_errno_func errno_func);

This is the function where you set a function to retrieve errno after a failed push or pull operation.

errno_func is of the form, int (*gnutls_errno_func)(gnutls_transport_ptr_t); and should return the errno.

`session` : | is a gnutls_session_t structure.
`errno_func` : | a callback function similar to `write()`

### gnutls_transport_set_errno ()

    void                gnutls_transport_set_errno          (gnutls_session_t session,
                                                             int err);

Store `err` in the session-specific errno variable. Useful values for `err` is EAGAIN and EINTR, other values are treated will be treated as real errors in the push/pull function.

This function is useful in replacement push/pull functions set by gnutls_transport_set_push_function and gnutls_transport_set_pullpush_function under Windows, where the replacement push/pull may not have access to the same `errno` variable that is used by GnuTLS (e.g., the application is linked to msvcr71.dll and gnutls is linked to msvcrt.dll).

If you don't have the `session` variable easily accessible from the push/pull function, and don't worry about thread conflicts, you can also use `gnutls_transport_set_global_errno()`.

`session` : | is a gnutls_session_t structure.
`err` : | error value to store in session-specific errno variable.

### gnutls_session_set_ptr ()

    void                gnutls_session_set_ptr              (gnutls_session_t session,
                                                             void *ptr);

This function will set (associate) the user given pointer `ptr` to the session structure. This is pointer can be accessed with `gnutls_session_get_ptr()`.

`session` : | is a gnutls_session_t structure.
`ptr` : | is the user pointer

### gnutls_session_get_ptr ()

    void *              gnutls_session_get_ptr              (gnutls_session_t session);

Get user pointer for session. Useful in callbacks. This is the pointer set with `gnutls_session_set_ptr()`.

`session` : | is a gnutls_session_t structure.
Returns : | the user given pointer from the session structure, or `NULL` if it was never set.

### gnutls_openpgp_send_cert ()

    void                gnutls_openpgp_send_cert            (gnutls_session_t session,
                                                             gnutls_openpgp_crt_status_t status);

This function will order gnutls to send the key fingerprint instead of the key in the initial handshake procedure. This should be used with care and only when there is indication or knowledge that the server can obtain the client's key.

`session` : | is a pointer to a gnutls_session_t structure.
`status` : | is one of GNUTLS_OPENPGP_CERT, or GNUTLS_OPENPGP_CERT_FINGERPRINT

### gnutls_fingerprint ()

    int                 gnutls_fingerprint                  (gnutls_digest_algorithm_t algo,
                                                             const gnutls_datum_t *data,
                                                             void *result,
                                                             size_t *result_size);

This function will calculate a fingerprint (actually a hash), of the given data. The result is not printable data. You should convert it to hex, or to something else printable.

This is the usual way to calculate a fingerprint of an X.509 DER encoded certificate. Note however that the fingerprint of an OpenPGP is not just a hash and cannot be calculated with this function.

`algo` : | is a digest algorithm
`data` : | is the data
`result` : | is the place where the result will be copied (may be null).
`result_size` : | should hold the size of the result. The actual size of the returned result will also be copied there.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_srp_free_client_credentials ()

    void                gnutls_srp_free_client_credentials  (gnutls_srp_client_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_srp_client_credentials_t structure.

### gnutls_srp_allocate_client_credentials ()

    int                 gnutls_srp_allocate_client_credentials
                                                            (gnutls_srp_client_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_srp_server_credentials_t structure.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

### gnutls_srp_set_client_credentials ()

    int                 gnutls_srp_set_client_credentials   (gnutls_srp_client_credentials_t res,
                                                             const char *username,
                                                             const char *password);

This function sets the username and password, in a gnutls_srp_client_credentials_t structure. Those will be used in SRP authentication. `username` and `password` should be ASCII strings or UTF-8 strings prepared using the "SASLprep" profile of "stringprep".

`res` : | is a gnutls_srp_client_credentials_t structure.
`username` : | is the user's userid
`password` : | is the user's password
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

### gnutls_srp_free_server_credentials ()

    void                gnutls_srp_free_server_credentials  (gnutls_srp_server_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_srp_server_credentials_t structure.

### gnutls_srp_allocate_server_credentials ()

    int                 gnutls_srp_allocate_server_credentials
                                                            (gnutls_srp_server_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_srp_server_credentials_t structure.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

### gnutls_srp_set_server_credentials_file ()

    int                 gnutls_srp_set_server_credentials_file
                                                            (gnutls_srp_server_credentials_t res,
                                                             const char *password_file,
                                                             const char *password_conf_file);

This function sets the password files, in a gnutls_srp_server_credentials_t structure. Those password files hold usernames and verifiers and will be used for SRP authentication.

`res` : | is a gnutls_srp_server_credentials_t structure.
`password_file` : | is the SRP password file (tpasswd)
`password_conf_file` : | is the SRP password conf file (tpasswd.conf)
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

### gnutls_srp_server_get_username ()

    const char *        gnutls_srp_server_get_username      (gnutls_session_t session);

This function will return the username of the peer. This should only be called in case of SRP authentication and in case of a server. Returns NULL in case of an error.

`session` : | is a gnutls session
Returns : | SRP username of the peer, or NULL in case of error.

### gnutls_srp_set_prime_bits ()

    void                gnutls_srp_set_prime_bits           (gnutls_session_t session,
                                                             unsigned int bits);

This function sets the minimum accepted number of bits, for use in an SRP key exchange. If zero, the default 2048 bits will be used.

In the client side it sets the minimum accepted number of bits. If a server sends a prime with less bits than that `GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER` will be returned by the handshake.

This function has no effect in server side.

`session` : | is a gnutls_session_t structure.
`bits` : | is the number of bits

Since 2.6.0

### gnutls_srp_verifier ()

    int                 gnutls_srp_verifier                 (const char *username,
                                                             const char *password,
                                                             const gnutls_datum_t *salt,
                                                             const gnutls_datum_t *generator,
                                                             const gnutls_datum_t *prime,
                                                             gnutls_datum_t *res);

This function will create an SRP verifier, as specified in RFC2945. The `prime` and `generator` should be one of the static parameters defined in gnutls/extra.h or may be generated using the libgcrypt functions `gcry_prime_generate()` and `gcry_prime_group_generator()`.

The verifier will be allocated with `malloc` and will be stored in `res` using binary format.

`username` : | is the user's name
`password` : | is the user's password
`salt` : | should be some randomly generated bytes
`generator` : | is the generator of the group
`prime` : | is the group's prime
`res` : | where the verifier will be stored.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, or an error code.

### gnutls_srp_2048_group_prime

      extern const gnutls_datum_t gnutls_srp_2048_group_prime;

### gnutls_srp_2048_group_generator

      extern const gnutls_datum_t gnutls_srp_2048_group_generator;

### gnutls_srp_1536_group_prime

      extern const gnutls_datum_t gnutls_srp_1536_group_prime;

### gnutls_srp_1536_group_generator

      extern const gnutls_datum_t gnutls_srp_1536_group_generator;

### gnutls_srp_1024_group_prime

      extern const gnutls_datum_t gnutls_srp_1024_group_prime;

### gnutls_srp_1024_group_generator

      extern const gnutls_datum_t gnutls_srp_1024_group_generator;

### gnutls_srp_set_server_credentials_function ()

    void                gnutls_srp_set_server_credentials_function
                                                            (gnutls_srp_server_credentials_t cred,
                                                             gnutls_srp_server_credentials_function *func);

This function can be used to set a callback to retrieve the user's SRP credentials. The callback's function form is:

int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t* salt, gnutls_datum_t *verifier, gnutls_datum_t* g, gnutls_datum_t* n);

`username` contains the actual username. The `salt`, `verifier`, `generator` and `prime` must be filled in using the `gnutls_malloc()`. For convenience `prime` and `generator` may also be one of the static parameters defined in extra.h.

In case the callback returned a negative number then gnutls will assume that the username does not exist.

In order to prevent attackers from guessing valid usernames, if a user does not exist, g and n values should be filled in using a random user's parameters. In that case the callback must return the special value (1).

The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.

`cred` : | is a gnutls_srp_server_credentials_t structure.
`func` : | is the callback function

### gnutls_srp_set_client_credentials_function ()

    void                gnutls_srp_set_client_credentials_function
                                                            (gnutls_srp_client_credentials_t cred,
                                                             gnutls_srp_client_credentials_function *func);

This function can be used to set a callback to retrieve the username and password for client SRP authentication. The callback's function form is:

int (*callback)(gnutls_session_t, char** username, char**password);

The `username` and `password` must be allocated using `gnutls_malloc()`. `username` and `password` should be ASCII strings or UTF-8 strings prepared using the "SASLprep" profile of "stringprep".

The callback function will be called once per handshake before the initial hello message is sent.

The callback should not return a negative error code the second time called, since the handshake procedure will be aborted.

The callback function should return 0 on success. -1 indicates an error.

`cred` : | is a gnutls_srp_server_credentials_t structure.
`func` : | is the callback function

### gnutls_srp_base64_encode ()

    int                 gnutls_srp_base64_encode            (const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);

This function will convert the given data to printable data, using the base64 encoding, as used in the libsrp. This is the encoding used in SRP password files. If the provided buffer is not long enough GNUTLS_E_SHORT_MEMORY_BUFFER is returned.

Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.

`data` : | contain the raw data
`result` : | the place where base64 data will be copied
`result_size` : | holds the size of the result
Returns : | `GNUTLS_E_SHORT_MEMORY_BUFFER` if the buffer given is not long enough, or 0 on success.

### gnutls_srp_base64_encode_alloc ()

    int                 gnutls_srp_base64_encode_alloc      (const gnutls_datum_t *data,
                                                             gnutls_datum_t *result);

This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in SRP password files. This function will allocate the required memory to hold the encoded data.

You should use `gnutls_free()` to free the returned data.

Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.

`data` : | contains the raw data
`result` : | will hold the newly allocated encoded data
Returns : | 0 on success, or an error code.

### gnutls_srp_base64_decode ()

    int                 gnutls_srp_base64_decode            (const gnutls_datum_t *b64_data,
                                                             char *result,
                                                             size_t *result_size);

This function will decode the given encoded data, using the base64 encoding found in libsrp.

Note that `b64_data` should be null terminated.

Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.

`b64_data` : | contain the encoded data
`result` : | the place where decoded data will be copied
`result_size` : | holds the size of the result
Returns : | `GNUTLS_E_SHORT_MEMORY_BUFFER` if the buffer given is not long enough, or 0 on success.

### gnutls_srp_base64_decode_alloc ()

    int                 gnutls_srp_base64_decode_alloc      (const gnutls_datum_t *b64_data,
                                                             gnutls_datum_t *result);

This function will decode the given encoded data. The decoded data will be allocated, and stored into result. It will decode using the base64 algorithm as used in libsrp.

You should use `gnutls_free()` to free the returned data.

Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.

`b64_data` : | contains the encoded data
`result` : | the place where decoded data lie
Returns : | 0 on success, or an error code.

### enum gnutls_psk_key_flags

    typedef enum {
        GNUTLS_PSK_KEY_RAW = 0,
        GNUTLS_PSK_KEY_HEX
    } gnutls_psk_key_flags;

Enumeration of different PSK key flags.

`GNUTLS_PSK_KEY_RAW` | PSK-key in raw format.
`GNUTLS_PSK_KEY_HEX` | PSK-key in hex format.

### gnutls_psk_free_client_credentials ()

    void                gnutls_psk_free_client_credentials  (gnutls_psk_client_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_psk_client_credentials_t structure.

### gnutls_psk_allocate_client_credentials ()

    int                 gnutls_psk_allocate_client_credentials
                                                            (gnutls_psk_client_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_psk_server_credentials_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_psk_set_client_credentials ()

    int                 gnutls_psk_set_client_credentials   (gnutls_psk_client_credentials_t res,
                                                             const char *username,
                                                             const gnutls_datum_t *key,
                                                             gnutls_psk_key_flags format);

This function sets the username and password, in a gnutls_psk_client_credentials_t structure. Those will be used in PSK authentication. `username` should be an ASCII string or UTF-8 strings prepared using the "SASLprep" profile of "stringprep". The key can be either in raw byte format or in Hex format (without the 0x prefix).

`res` : | is a gnutls_psk_client_credentials_t structure.
`username` : | is the user's zero-terminated userid
`key` : | is the user's key
`format` : | indicate the format of the key, either `GNUTLS_PSK_KEY_RAW` or `GNUTLS_PSK_KEY_HEX`.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_psk_free_server_credentials ()

    void                gnutls_psk_free_server_credentials  (gnutls_psk_server_credentials_t sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.

`sc` : | is a gnutls_psk_server_credentials_t structure.

### gnutls_psk_allocate_server_credentials ()

    int                 gnutls_psk_allocate_server_credentials
                                                            (gnutls_psk_server_credentials_t *sc);

This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.

`sc` : | is a pointer to a gnutls_psk_server_credentials_t structure.
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_psk_set_server_credentials_file ()

    int                 gnutls_psk_set_server_credentials_file
                                                            (gnutls_psk_server_credentials_t res,
                                                             const char *password_file);

This function sets the password file, in a `gnutls_psk_server_credentials_t` structure. This password file holds usernames and keys and will be used for PSK authentication.

`res` : | is a gnutls_psk_server_credentials_t structure.
`password_file` : | is the PSK password file (passwd.psk)
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

### gnutls_psk_set_server_credentials_hint ()

    int                 gnutls_psk_set_server_credentials_hint
                                                            (gnutls_psk_server_credentials_t res,
                                                             const char *hint);

This function sets the identity hint, in a `gnutls_psk_server_credentials_t` structure. This hint is sent to the client to help it chose a good PSK credential (i.e., username and password).

`res` : | is a gnutls_psk_server_credentials_t structure.
`hint` : | is the PSK identity hint string
Returns : | `GNUTLS_E_SUCCESS` on success, or an error code.

Since 2.4.0

### gnutls_psk_server_get_username ()

    const char *        gnutls_psk_server_get_username      (gnutls_session_t session);

This should only be called in case of PSK authentication and in case of a server.

`session` : | is a gnutls session
Returns : | the username of the peer, or `NULL` in case of an error.

### gnutls_psk_client_get_hint ()

    const char *        gnutls_psk_client_get_hint          (gnutls_session_t session);

The PSK identity hint may give the client help in deciding which username to use. This should only be called in case of PSK authentication and in case of a client.

`session` : | is a gnutls session
Returns : | the identity hint of the peer, or `NULL` in case of an error.

Since 2.4.0

### gnutls_psk_set_server_credentials_function ()

    void                gnutls_psk_set_server_credentials_function
                                                            (gnutls_psk_server_credentials_t cred,
                                                             gnutls_psk_server_credentials_function *func);

This function can be used to set a callback to retrieve the user's PSK credentials. The callback's function form is: int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t* key);

`username` contains the actual username. The `key` must be filled in using the `gnutls_malloc()`.

In case the callback returned a negative number then gnutls will assume that the username does not exist.

The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.

`cred` : | is a gnutls_psk_server_credentials_t structure.
`func` : | is the callback function

### gnutls_psk_set_client_credentials_function ()

    void                gnutls_psk_set_client_credentials_function
                                                            (gnutls_psk_client_credentials_t cred,
                                                             gnutls_psk_client_credentials_function *func);

This function can be used to set a callback to retrieve the username and password for client PSK authentication. The callback's function form is: int (*callback)(gnutls_session_t, char** username, gnutls_datum_t* key);

The `username` and `key->data` must be allocated using `gnutls_malloc()`. `username` should be ASCII strings or UTF-8 strings prepared using the "SASLprep" profile of "stringprep".

The callback function will be called once per handshake.

The callback function should return 0 on success. -1 indicates an error.

`cred` : | is a gnutls_psk_server_credentials_t structure.
`func` : | is the callback function

### gnutls_hex_encode ()

    int                 gnutls_hex_encode                   (const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);

This function will convert the given data to printable data, using the hex encoding, as used in the PSK password files.

`data` : | contain the raw data
`result` : | the place where hex data will be copied
`result_size` : | holds the size of the result
Returns : | `GNUTLS_E_SHORT_MEMORY_BUFFER` if the buffer given is not long enough, or 0 on success.

### gnutls_hex_decode ()

    int                 gnutls_hex_decode                   (const gnutls_datum_t *hex_data,
                                                             char *result,
                                                             size_t *result_size);

This function will decode the given encoded data, using the hex encoding used by PSK password files.

Note that hex_data should be null terminated.

`hex_data` : | contain the encoded data
`result` : | the place where decoded data will be copied
`result_size` : | holds the size of the result
Returns : | `GNUTLS_E_SHORT_MEMORY_BUFFER` if the buffer given is not long enough, or 0 on success.

### gnutls_psk_set_server_dh_params ()

    void                gnutls_psk_set_server_dh_params     (gnutls_psk_server_credentials_t res,
                                                             gnutls_dh_params_t dh_params);

This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Diffie-Hellman exchange with PSK cipher suites.

`res` : | is a gnutls_psk_server_credentials_t structure
`dh_params` : | is a structure that holds Diffie-Hellman parameters.

### gnutls_psk_set_server_params_function ()

    void                gnutls_psk_set_server_params_function
                                                            (gnutls_psk_server_credentials_t res,
                                                             gnutls_params_function *func);

This function will set a callback in order for the server to get the Diffie-Hellman parameters for PSK authentication. The callback should return zero on success.

`res` : | is a gnutls_certificate_credentials_t structure
`func` : | is the function to be called

### enum gnutls_x509_subject_alt_name_t

    typedef enum {
        GNUTLS_SAN_DNSNAME = 1,
        GNUTLS_SAN_RFC822NAME = 2,
        GNUTLS_SAN_URI = 3,
        GNUTLS_SAN_IPADDRESS = 4,
        GNUTLS_SAN_OTHERNAME = 5,
        GNUTLS_SAN_DN = 6,
        /* The following are "virtual" subject alternative name types, in
           that they are represented by an otherName value and an OID.
           Used by gnutls_x509_crt_get_subject_alt_othername_oid().  */
        GNUTLS_SAN_OTHERNAME_XMPP = 1000
    } gnutls_x509_subject_alt_name_t;

Enumeration of different subject alternative names types.

`GNUTLS_SAN_DNSNAME` | DNS-name SAN.
`GNUTLS_SAN_RFC822NAME` | E-mail address SAN.
`GNUTLS_SAN_URI` | URI SAN.
`GNUTLS_SAN_IPADDRESS` | IP address SAN.
`GNUTLS_SAN_OTHERNAME` | OtherName SAN.
`GNUTLS_SAN_DN` | DN SAN.
`GNUTLS_SAN_OTHERNAME_XMPP` | Virtual SAN, used by `gnutls_x509_crt_get_subject_alt_othername_oid()`.

### struct gnutls_openpgp_crt_int

    struct gnutls_openpgp_crt_int;

### gnutls_openpgp_crt_t

      typedef struct gnutls_openpgp_crt_int *gnutls_openpgp_crt_t;

### struct gnutls_openpgp_privkey_int

    struct gnutls_openpgp_privkey_int;

### gnutls_openpgp_privkey_t

      typedef struct gnutls_openpgp_privkey_int *gnutls_openpgp_privkey_t;

### struct gnutls_pkcs11_privkey_st

    struct gnutls_pkcs11_privkey_st;

### gnutls_pkcs11_privkey_t

      typedef struct gnutls_pkcs11_privkey_st *gnutls_pkcs11_privkey_t;

### enum gnutls_privkey_type_t

    typedef enum {
        GNUTLS_PRIVKEY_X509,        /* gnutls_x509_privkey_t */
        GNUTLS_PRIVKEY_OPENPGP,     /* gnutls_openpgp_privkey_t */
        GNUTLS_PRIVKEY_PKCS11       /* gnutls_pkcs11_privkey_t */
    } gnutls_privkey_type_t;

### gnutls_auth_get_type ()

    gnutls_credentials_type_t gnutls_auth_get_type          (gnutls_session_t session);

Returns type of credentials for the current authentication schema. The returned information is to be used to distinguish the function used to access authentication data.

Eg. for CERTIFICATE ciphersuites (key exchange algorithms: `GNUTLS_KX_RSA`, `GNUTLS_KX_DHE_RSA`), the same function are to be used to access the authentication data.

`session` : | is a gnutls_session_t structure.
Returns : | The type of credentials for the current authentication schema, a gnutls_credentials_type_t type.

### gnutls_auth_server_get_type ()

    gnutls_credentials_type_t gnutls_auth_server_get_type   (gnutls_session_t session);

Returns the type of credentials that were used for server authentication. The returned information is to be used to distinguish the function used to access authentication data.

`session` : | is a gnutls_session_t structure.
Returns : | The type of credentials for the server authentication schema, a gnutls_credentials_type_t type.

### gnutls_auth_client_get_type ()

    gnutls_credentials_type_t gnutls_auth_client_get_type   (gnutls_session_t session);

Returns the type of credentials that were used for client authentication. The returned information is to be used to distinguish the function used to access authentication data.

`session` : | is a gnutls_session_t structure.
Returns : | The type of credentials for the client authentication schema, a gnutls_credentials_type_t type.

### gnutls_dh_set_prime_bits ()

    void                gnutls_dh_set_prime_bits            (gnutls_session_t session,
                                                             unsigned int bits);

This function sets the number of bits, for use in an Diffie-Hellman key exchange. This is used both in DH ephemeral and DH anonymous cipher suites. This will set the minimum size of the prime that will be used for the handshake.

In the client side it sets the minimum accepted number of bits. If a server sends a prime with less bits than that `GNUTLS_E_DH_PRIME_UNACCEPTABLE` will be returned by the handshake.

This function has no effect in server side.

`session` : | is a gnutls_session_t structure.
`bits` : | is the number of bits

### gnutls_dh_get_secret_bits ()

    int                 gnutls_dh_get_secret_bits           (gnutls_session_t session);

This function will return the bits used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman.

`session` : | is a gnutls session
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_dh_get_peers_public_bits ()

    int                 gnutls_dh_get_peers_public_bits     (gnutls_session_t session);

Get the Diffie-Hellman public key bit size. Can be used for both anonymous and ephemeral Diffie-Hellman.

`session` : | is a gnutls session
Returns : | the public key bit size used in the last Diffie-Hellman key exchange with the peer, or a negative value in case of error.

### gnutls_dh_get_prime_bits ()

    int                 gnutls_dh_get_prime_bits            (gnutls_session_t session);

This function will return the bits of the prime used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman. Note that some ciphers, like RSA and DSA without DHE, does not use a Diffie-Hellman key exchange, and then this function will return 0.

`session` : | is a gnutls session
Returns : | The Diffie-Hellman bit strength is returned, or 0 if no Diffie-Hellman key exchange was done, or a negative error code on failure.

### gnutls_dh_get_group ()

    int                 gnutls_dh_get_group                 (gnutls_session_t session,
                                                             gnutls_datum_t *raw_gen,
                                                             gnutls_datum_t *raw_prime);

This function will return the group parameters used in the last Diffie-Hellman key exchange with the peer. These are the prime and the generator used. This function should be used for both anonymous and ephemeral Diffie-Hellman. The output parameters must be freed with `gnutls_free()`.

`session` : | is a gnutls session
`raw_gen` : | will hold the generator.
`raw_prime` : | will hold the prime.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_dh_get_pubkey ()

    int                 gnutls_dh_get_pubkey                (gnutls_session_t session,
                                                             gnutls_datum_t *raw_key);

This function will return the peer's public key used in the last Diffie-Hellman key exchange. This function should be used for both anonymous and ephemeral Diffie-Hellman. The output parameters must be freed with `gnutls_free()`.

`session` : | is a gnutls session
`raw_key` : | will hold the public key.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_rsa_export_get_pubkey ()

    int                 gnutls_rsa_export_get_pubkey        (gnutls_session_t session,
                                                             gnutls_datum_t *exponent,
                                                             gnutls_datum_t *modulus);

This function will return the peer's public key exponent and modulus used in the last RSA-EXPORT authentication. The output parameters must be freed with `gnutls_free()`.

`session` : | is a gnutls session
`exponent` : | will hold the exponent.
`modulus` : | will hold the modulus.
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_rsa_export_get_modulus_bits ()

    int                 gnutls_rsa_export_get_modulus_bits  (gnutls_session_t session);

Get the export RSA parameter's modulus size.

`session` : | is a gnutls session
Returns : | the bits used in the last RSA-EXPORT key exchange with the peer, or a negative value in case of error.

### gnutls_certificate_set_retrieve_function ()

    void                gnutls_certificate_set_retrieve_function
                                                            (gnutls_certificate_credentials_t cred,
                                                             gnutls_certificate_retrieve_function *func);

This function sets a callback to be called in order to retrieve the certificate to be used in the handshake.

The callback's function prototype is: int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs, const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_retr2_st* st);

`req_ca_cert` is only used in X.509 certificates. Contains a list with the CA names that the server considers trusted. Normally we should send a certificate that is signed by one of these CAs. These names are DER encoded. To get a more meaningful value use the function `gnutls_x509_rdn_get()`.

`pk_algos` contains a list with server's acceptable signature algorithms. The certificate returned should support the server's given algorithms.

`st` should contain the certificates and private keys.

If the callback function is provided then gnutls will call it, in the handshake, after the certificate request message has been received.

In server side pk_algos and req_ca_dn are NULL.

The callback function should set the certificate list to be sent, and return 0 on success. If no certificate was selected then the number of certificates should be set to zero. The value (-1) indicates error and the handshake will be terminated.

`cred` : | is a gnutls_certificate_credentials_t structure.
`func` : | is the callback function

### gnutls_certificate_set_verify_function ()

    void                gnutls_certificate_set_verify_function
                                                            (gnutls_certificate_credentials_t cred,
                                                             gnutls_certificate_verify_function *func);

This function sets a callback to be called when peer's certificate has been received in order to verify it on receipt rather than doing after the handshake is completed.

The callback's function prototype is: int (*callback)(gnutls_session_t);

If the callback function is provided then gnutls will call it, in the handshake, just after the certificate message has been received. To verify or obtain the certificate the `gnutls_certificate_verify_peers2()`, `gnutls_certificate_type_get()`, `gnutls_certificate_get_peers()` functions can be used.

The callback function should return 0 for the handshake to continue or non-zero to terminate.

`cred` : | is a gnutls_certificate_credentials_t structure.
`func` : | is the callback function

Since 2.10.0

### gnutls_certificate_server_set_request ()

    void                gnutls_certificate_server_set_request
                                                            (gnutls_session_t session,
                                                             gnutls_certificate_request_t req);

This function specifies if we (in case of a server) are going to send a certificate request message to the client. If `req` is GNUTLS_CERT_REQUIRE then the server will return an error if the peer does not provide a certificate. If you do not call this function then the client will not be asked to send a certificate.

`session` : | is a gnutls_session_t structure.
`req` : | is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE

### gnutls_certificate_get_peers ()

    const gnutls_datum_t * gnutls_certificate_get_peers     (gnutls_session_t session,
                                                             unsigned int *list_size);

Get the peer's raw certificate (chain) as sent by the peer. These certificates are in raw format (DER encoded for X.509). In case of a X.509 then a certificate list may be present. The first certificate in the list is the peer's certificate, following the issuer's certificate, then the issuer's issuer etc.

In case of OpenPGP keys a single key will be returned in raw format.

`session` : | is a gnutls session
`list_size` : | is the length of the certificate list
Returns : | return a pointer to a gnutls_datum_t containing our certificates, or `NULL` in case of an error or if no certificate was used.

### gnutls_certificate_get_ours ()

    const gnutls_datum_t * gnutls_certificate_get_ours      (gnutls_session_t session);

Get the certificate as sent to the peer, in the last handshake. These certificates are in raw format. In X.509 this is a certificate list. In OpenPGP this is a single certificate.

`session` : | is a gnutls session
Returns : | return a pointer to a gnutls_datum_t containing our certificates, or `NULL` in case of an error or if no certificate was used.

### gnutls_certificate_activation_time_peers ()

    time_t              gnutls_certificate_activation_time_peers
                                                            (gnutls_session_t session);

### Warning

`gnutls_certificate_activation_time_peers` is deprecated and should not be used in newly-written code. `gnutls_certificate_verify_peers2()` now verifies activation times.

This function will return the peer's certificate activation time. This is the creation time for openpgp keys.

`session` : | is a gnutls session
Returns : | (time_t)-1 on error.

### gnutls_certificate_expiration_time_peers ()

    time_t              gnutls_certificate_expiration_time_peers
                                                            (gnutls_session_t session);

### Warning

`gnutls_certificate_expiration_time_peers` is deprecated and should not be used in newly-written code. `gnutls_certificate_verify_peers2()` now verifies expiration times.

This function will return the peer's certificate expiration time.

`session` : | is a gnutls session
Returns : | (time_t)-1 on error.

### gnutls_certificate_client_get_request_status ()

    int                 gnutls_certificate_client_get_request_status
                                                            (gnutls_session_t session);

Get whether client certificate is requested or not.

`session` : | is a gnutls session
Returns : | 0 if the peer (server) did not request client authentication or 1 otherwise, or a negative value in case of error.

### gnutls_certificate_verify_peers2 ()

    int                 gnutls_certificate_verify_peers2    (gnutls_session_t session,
                                                             unsigned int *status);

This function will try to verify the peer's certificate and return its status (trusted, invalid etc.). The value of `status` should be one or more of the gnutls_certificate_status_t enumerated elements bitwise or'd. To avoid denial of service attacks some default upper limits regarding the certificate key size and chain size are set. To override them use `gnutls_certificate_set_verify_limits()`.

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

This function uses `gnutls_x509_crt_list_verify()` with the CAs in the credentials as trusted CAs.

`session` : | is a gnutls session
`status` : | is the output of the verification
Returns : | a negative error code on error and zero on success.

### gnutls_pem_base64_encode ()

    int                 gnutls_pem_base64_encode            (const char *msg,
                                                             const gnutls_datum_t *data,
                                                             char *result,
                                                             size_t *result_size);

This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages.

The output string will be null terminated, although the size will not include the terminating null.

`msg` : | is a message to be put in the header
`data` : | contain the raw data
`result` : | the place where base64 data will be copied
`result_size` : | holds the size of the result
Returns : | On success `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned if the buffer given is not long enough, or 0 on success.

### gnutls_pem_base64_decode ()

    int                 gnutls_pem_base64_decode            (const char *header,
                                                             const gnutls_datum_t *b64_data,
                                                             unsigned char *result,
                                                             size_t *result_size);

This function will decode the given encoded data. If the header given is non null this function will search for "-----BEGIN header" and decode only this part. Otherwise it will decode the first PEM packet found.

`header` : | A null terminated string with the PEM header (eg. CERTIFICATE)
`b64_data` : | contain the encoded data
`result` : | the place where decoded data will be copied
`result_size` : | holds the size of the result
Returns : | On success `GNUTLS_E_SUCCESS` (0) is returned, `GNUTLS_E_SHORT_MEMORY_BUFFER` is returned if the buffer given is not long enough, or 0 on success.

### gnutls_pem_base64_encode_alloc ()

    int                 gnutls_pem_base64_encode_alloc      (const char *msg,
                                                             const gnutls_datum_t *data,
                                                             gnutls_datum_t *result);

This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages. This function will allocate the required memory to hold the encoded data.

You should use `gnutls_free()` to free the returned data.

`msg` : | is a message to be put in the encoded header
`data` : | contains the raw data
`result` : | will hold the newly allocated encoded data
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### gnutls_pem_base64_decode_alloc ()

    int                 gnutls_pem_base64_decode_alloc      (const char *header,
                                                             const gnutls_datum_t *b64_data,
                                                             gnutls_datum_t *result);

This function will decode the given encoded data. The decoded data will be allocated, and stored into result. If the header given is non null this function will search for "-----BEGIN header" and decode only this part. Otherwise it will decode the first PEM packet found.

You should use `gnutls_free()` to free the returned data.

`header` : | The PEM header (eg. CERTIFICATE)
`b64_data` : | contains the encoded data
`result` : | the place where decoded data lie
Returns : | On success, `GNUTLS_E_SUCCESS` (0) is returned, otherwise an error code is returned.

### GNUTLS_KEY_DIGITAL_SIGNATURE

    #define GNUTLS_KEY_DIGITAL_SIGNATURE 128

### GNUTLS_KEY_NON_REPUDIATION

    #define GNUTLS_KEY_NON_REPUDIATION 64

### GNUTLS_KEY_KEY_ENCIPHERMENT

    #define GNUTLS_KEY_KEY_ENCIPHERMENT 32

### GNUTLS_KEY_DATA_ENCIPHERMENT

    #define GNUTLS_KEY_DATA_ENCIPHERMENT 16

### GNUTLS_KEY_KEY_AGREEMENT

    #define GNUTLS_KEY_KEY_AGREEMENT 8

### GNUTLS_KEY_KEY_CERT_SIGN

    #define GNUTLS_KEY_KEY_CERT_SIGN 4

### GNUTLS_KEY_CRL_SIGN

    #define GNUTLS_KEY_CRL_SIGN		2

### GNUTLS_KEY_ENCIPHER_ONLY

    #define GNUTLS_KEY_ENCIPHER_ONLY 1

### GNUTLS_KEY_DECIPHER_ONLY

    #define GNUTLS_KEY_DECIPHER_ONLY 32768

### gnutls_certificate_set_params_function ()

    void                gnutls_certificate_set_params_function
                                                            (gnutls_certificate_credentials_t res,
                                                             gnutls_params_function *func);

This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for certificate authentication. The callback should return zero on success.

`res` : | is a gnutls_certificate_credentials_t structure
`func` : | is the function to be called

### gnutls_anon_set_params_function ()

    void                gnutls_anon_set_params_function     (gnutls_anon_server_credentials_t res,
                                                             gnutls_params_function *func);

This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for anonymous authentication. The callback should return zero on success.

`res` : | is a gnutls_anon_server_credentials_t structure
`func` : | is the function to be called

### gnutls_psk_set_params_function ()

    void                gnutls_psk_set_params_function      (gnutls_psk_server_credentials_t res,
                                                             gnutls_params_function *func);

This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for PSK authentication. The callback should return zero on success.

`res` : | is a gnutls_psk_server_credentials_t structure
`func` : | is the function to be called

### gnutls_hex2bin ()

    int                 gnutls_hex2bin                      (const char *hex_data,
                                                             size_t hex_size,
                                                             char *bin_data,
                                                             size_t *bin_size);

Convert a buffer with hex data to binary data.

`hex_data` : | string with data in hex format
`hex_size` : | size of hex data
`bin_data` : | output array with binary data
`bin_size` : | when calling *`bin_size` should hold size of `bin_data`, on return will hold actual size of `bin_data`.
Returns : | `GNUTLS_E_SUCCESS` on success, otherwise an error.

Since 2.4.0

### GNUTLS_E_SUCCESS

    #define GNUTLS_E_SUCCESS 0

### GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM

    #define GNUTLS_E_UNKNOWN_COMPRESSION_ALGORITHM -3

### GNUTLS_E_UNKNOWN_CIPHER_TYPE

    #define GNUTLS_E_UNKNOWN_CIPHER_TYPE -6

### GNUTLS_E_LARGE_PACKET

    #define GNUTLS_E_LARGE_PACKET -7

### GNUTLS_E_UNSUPPORTED_VERSION_PACKET

    #define GNUTLS_E_UNSUPPORTED_VERSION_PACKET -8  /* GNUTLS_A_PROTOCOL_VERSION */

### GNUTLS_E_UNEXPECTED_PACKET_LENGTH

    #define GNUTLS_E_UNEXPECTED_PACKET_LENGTH -9    /* GNUTLS_A_RECORD_OVERFLOW */

### GNUTLS_E_INVALID_SESSION

    #define GNUTLS_E_INVALID_SESSION -10

### GNUTLS_E_FATAL_ALERT_RECEIVED

    #define GNUTLS_E_FATAL_ALERT_RECEIVED -12

### GNUTLS_E_UNEXPECTED_PACKET

    #define GNUTLS_E_UNEXPECTED_PACKET -15  /* GNUTLS_A_UNEXPECTED_MESSAGE */

### GNUTLS_E_WARNING_ALERT_RECEIVED

    #define GNUTLS_E_WARNING_ALERT_RECEIVED -16

### GNUTLS_E_ERROR_IN_FINISHED_PACKET

    #define GNUTLS_E_ERROR_IN_FINISHED_PACKET -18

### GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET

    #define GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET -19

### GNUTLS_E_UNKNOWN_CIPHER_SUITE

    #define GNUTLS_E_UNKNOWN_CIPHER_SUITE -21       /* GNUTLS_A_HANDSHAKE_FAILURE */

### GNUTLS_E_UNWANTED_ALGORITHM

    #define GNUTLS_E_UNWANTED_ALGORITHM -22

### GNUTLS_E_MPI_SCAN_FAILED

    #define GNUTLS_E_MPI_SCAN_FAILED -23

### GNUTLS_E_DECRYPTION_FAILED

    #define GNUTLS_E_DECRYPTION_FAILED -24  /* GNUTLS_A_DECRYPTION_FAILED, GNUTLS_A_BAD_RECORD_MAC */

### GNUTLS_E_MEMORY_ERROR

    #define GNUTLS_E_MEMORY_ERROR -25

### GNUTLS_E_DECOMPRESSION_FAILED

    #define GNUTLS_E_DECOMPRESSION_FAILED -26       /* GNUTLS_A_DECOMPRESSION_FAILURE */

### GNUTLS_E_COMPRESSION_FAILED

    #define GNUTLS_E_COMPRESSION_FAILED -27

### GNUTLS_E_AGAIN

    #define GNUTLS_E_AGAIN -28

### GNUTLS_E_EXPIRED

    #define GNUTLS_E_EXPIRED -29

### GNUTLS_E_DB_ERROR

    #define GNUTLS_E_DB_ERROR -30

### GNUTLS_E_SRP_PWD_ERROR

    #define GNUTLS_E_SRP_PWD_ERROR -31

### GNUTLS_E_INSUFFICIENT_CREDENTIALS

    #define GNUTLS_E_INSUFFICIENT_CREDENTIALS -32

### GNUTLS_E_INSUFICIENT_CREDENTIALS

    #define GNUTLS_E_INSUFICIENT_CREDENTIALS GNUTLS_E_INSUFFICIENT_CREDENTIALS      /* for backwards compatibility only */

### GNUTLS_E_INSUFFICIENT_CRED

    #define GNUTLS_E_INSUFFICIENT_CRED GNUTLS_E_INSUFFICIENT_CREDENTIALS

### GNUTLS_E_INSUFICIENT_CRED

    #define GNUTLS_E_INSUFICIENT_CRED GNUTLS_E_INSUFFICIENT_CREDENTIALS     /* for backwards compatibility only */

### GNUTLS_E_HASH_FAILED

    #define GNUTLS_E_HASH_FAILED -33

### GNUTLS_E_BASE64_DECODING_ERROR

    #define GNUTLS_E_BASE64_DECODING_ERROR -34

### GNUTLS_E_MPI_PRINT_FAILED

    #define GNUTLS_E_MPI_PRINT_FAILED -35

### GNUTLS_E_REHANDSHAKE

    #define GNUTLS_E_REHANDSHAKE -37        /* GNUTLS_A_NO_RENEGOTIATION */

### GNUTLS_E_GOT_APPLICATION_DATA

    #define GNUTLS_E_GOT_APPLICATION_DATA -38

### GNUTLS_E_RECORD_LIMIT_REACHED

    #define GNUTLS_E_RECORD_LIMIT_REACHED -39

### GNUTLS_E_ENCRYPTION_FAILED

    #define GNUTLS_E_ENCRYPTION_FAILED -40

### GNUTLS_E_PK_ENCRYPTION_FAILED

    #define GNUTLS_E_PK_ENCRYPTION_FAILED -44

### GNUTLS_E_PK_DECRYPTION_FAILED

    #define GNUTLS_E_PK_DECRYPTION_FAILED -45

### GNUTLS_E_PK_SIGN_FAILED

    #define GNUTLS_E_PK_SIGN_FAILED -46

### GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION

    #define GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION -47

### GNUTLS_E_KEY_USAGE_VIOLATION

    #define GNUTLS_E_KEY_USAGE_VIOLATION -48

### GNUTLS_E_NO_CERTIFICATE_FOUND

    #define GNUTLS_E_NO_CERTIFICATE_FOUND -49       /* GNUTLS_A_BAD_CERTIFICATE */

### GNUTLS_E_INVALID_REQUEST

    #define GNUTLS_E_INVALID_REQUEST -50

### GNUTLS_E_SHORT_MEMORY_BUFFER

    #define GNUTLS_E_SHORT_MEMORY_BUFFER -51

### GNUTLS_E_INTERRUPTED

    #define GNUTLS_E_INTERRUPTED -52

### GNUTLS_E_PUSH_ERROR

    #define GNUTLS_E_PUSH_ERROR -53

### GNUTLS_E_PULL_ERROR

    #define GNUTLS_E_PULL_ERROR -54

### GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER

    #define GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER -55 /* GNUTLS_A_ILLEGAL_PARAMETER */

### GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE

    #define GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE -56

### GNUTLS_E_PKCS1_WRONG_PAD

    #define GNUTLS_E_PKCS1_WRONG_PAD -57

### GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION

    #define GNUTLS_E_RECEIVED_ILLEGAL_EXTENSION -58

### GNUTLS_E_INTERNAL_ERROR

    #define GNUTLS_E_INTERNAL_ERROR -59

### GNUTLS_E_DH_PRIME_UNACCEPTABLE

    #define GNUTLS_E_DH_PRIME_UNACCEPTABLE -63

### GNUTLS_E_FILE_ERROR

    #define GNUTLS_E_FILE_ERROR -64

### GNUTLS_E_TOO_MANY_EMPTY_PACKETS

    #define GNUTLS_E_TOO_MANY_EMPTY_PACKETS -78

### GNUTLS_E_UNKNOWN_PK_ALGORITHM

    #define GNUTLS_E_UNKNOWN_PK_ALGORITHM -80

### GNUTLS_E_INIT_LIBEXTRA

    #define GNUTLS_E_INIT_LIBEXTRA -82

### GNUTLS_E_LIBRARY_VERSION_MISMATCH

    #define GNUTLS_E_LIBRARY_VERSION_MISMATCH -83

### GNUTLS_E_NO_TEMPORARY_RSA_PARAMS

    #define GNUTLS_E_NO_TEMPORARY_RSA_PARAMS -84

### GNUTLS_E_LZO_INIT_FAILED

    #define GNUTLS_E_LZO_INIT_FAILED -85

### GNUTLS_E_NO_COMPRESSION_ALGORITHMS

    #define GNUTLS_E_NO_COMPRESSION_ALGORITHMS -86

### GNUTLS_E_NO_CIPHER_SUITES

    #define GNUTLS_E_NO_CIPHER_SUITES -87

### GNUTLS_E_OPENPGP_GETKEY_FAILED

    #define GNUTLS_E_OPENPGP_GETKEY_FAILED -88

### GNUTLS_E_PK_SIG_VERIFY_FAILED

    #define GNUTLS_E_PK_SIG_VERIFY_FAILED -89

### GNUTLS_E_ILLEGAL_SRP_USERNAME

    #define GNUTLS_E_ILLEGAL_SRP_USERNAME -90

### GNUTLS_E_SRP_PWD_PARSING_ERROR

    #define GNUTLS_E_SRP_PWD_PARSING_ERROR -91

### GNUTLS_E_NO_TEMPORARY_DH_PARAMS

    #define GNUTLS_E_NO_TEMPORARY_DH_PARAMS -93

### GNUTLS_E_ASN1_ELEMENT_NOT_FOUND

    #define GNUTLS_E_ASN1_ELEMENT_NOT_FOUND -67

### GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND

    #define GNUTLS_E_ASN1_IDENTIFIER_NOT_FOUND -68

### GNUTLS_E_ASN1_DER_ERROR

    #define GNUTLS_E_ASN1_DER_ERROR -69

### GNUTLS_E_ASN1_VALUE_NOT_FOUND

    #define GNUTLS_E_ASN1_VALUE_NOT_FOUND -70

### GNUTLS_E_ASN1_GENERIC_ERROR

    #define GNUTLS_E_ASN1_GENERIC_ERROR -71

### GNUTLS_E_ASN1_VALUE_NOT_VALID

    #define GNUTLS_E_ASN1_VALUE_NOT_VALID -72

### GNUTLS_E_ASN1_TAG_ERROR

    #define GNUTLS_E_ASN1_TAG_ERROR -73

### GNUTLS_E_ASN1_TAG_IMPLICIT

    #define GNUTLS_E_ASN1_TAG_IMPLICIT -74

### GNUTLS_E_ASN1_TYPE_ANY_ERROR

    #define GNUTLS_E_ASN1_TYPE_ANY_ERROR -75

### GNUTLS_E_ASN1_SYNTAX_ERROR

    #define GNUTLS_E_ASN1_SYNTAX_ERROR -76

### GNUTLS_E_ASN1_DER_OVERFLOW

    #define GNUTLS_E_ASN1_DER_OVERFLOW -77

### GNUTLS_E_OPENPGP_UID_REVOKED

    #define GNUTLS_E_OPENPGP_UID_REVOKED -79

### GNUTLS_E_CERTIFICATE_ERROR

    #define GNUTLS_E_CERTIFICATE_ERROR -43

### GNUTLS_E_X509_CERTIFICATE_ERROR

    #define GNUTLS_E_X509_CERTIFICATE_ERROR GNUTLS_E_CERTIFICATE_ERROR

### GNUTLS_E_CERTIFICATE_KEY_MISMATCH

    #define GNUTLS_E_CERTIFICATE_KEY_MISMATCH -60

### GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE

    #define GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE -61       /* GNUTLS_A_UNSUPPORTED_CERTIFICATE */

### GNUTLS_E_X509_UNKNOWN_SAN

    #define GNUTLS_E_X509_UNKNOWN_SAN -62

### GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED

    #define GNUTLS_E_OPENPGP_FINGERPRINT_UNSUPPORTED -94

### GNUTLS_E_X509_UNSUPPORTED_ATTRIBUTE

    #define GNUTLS_E_X509_UNSUPPORTED_ATTRIBUTE -95

### GNUTLS_E_UNKNOWN_HASH_ALGORITHM

    #define GNUTLS_E_UNKNOWN_HASH_ALGORITHM -96

### GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE

    #define GNUTLS_E_UNKNOWN_PKCS_CONTENT_TYPE -97

### GNUTLS_E_UNKNOWN_PKCS_BAG_TYPE

    #define GNUTLS_E_UNKNOWN_PKCS_BAG_TYPE -98

### GNUTLS_E_INVALID_PASSWORD

    #define GNUTLS_E_INVALID_PASSWORD -99

### GNUTLS_E_MAC_VERIFY_FAILED

    #define GNUTLS_E_MAC_VERIFY_FAILED -100 /* for PKCS #12 MAC */

### GNUTLS_E_CONSTRAINT_ERROR

    #define GNUTLS_E_CONSTRAINT_ERROR -101

### GNUTLS_E_WARNING_IA_IPHF_RECEIVED

    #define GNUTLS_E_WARNING_IA_IPHF_RECEIVED -102

### GNUTLS_E_WARNING_IA_FPHF_RECEIVED

    #define GNUTLS_E_WARNING_IA_FPHF_RECEIVED -103

### GNUTLS_E_IA_VERIFY_FAILED

    #define GNUTLS_E_IA_VERIFY_FAILED -104

### GNUTLS_E_UNKNOWN_ALGORITHM

    #define GNUTLS_E_UNKNOWN_ALGORITHM -105

### GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM

    #define GNUTLS_E_UNSUPPORTED_SIGNATURE_ALGORITHM -106

### GNUTLS_E_SAFE_RENEGOTIATION_FAILED

    #define GNUTLS_E_SAFE_RENEGOTIATION_FAILED -107

### GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED

    #define GNUTLS_E_UNSAFE_RENEGOTIATION_DENIED -108

### GNUTLS_E_UNKNOWN_SRP_USERNAME

    #define GNUTLS_E_UNKNOWN_SRP_USERNAME -109

### GNUTLS_E_BASE64_ENCODING_ERROR

    #define GNUTLS_E_BASE64_ENCODING_ERROR -201

### GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY

    #define GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY -202       /* obsolete */

### GNUTLS_E_INCOMPATIBLE_CRYPTO_LIBRARY

    #define GNUTLS_E_INCOMPATIBLE_CRYPTO_LIBRARY -202

### GNUTLS_E_INCOMPATIBLE_LIBTASN1_LIBRARY

    #define GNUTLS_E_INCOMPATIBLE_LIBTASN1_LIBRARY -203

### GNUTLS_E_OPENPGP_KEYRING_ERROR

    #define GNUTLS_E_OPENPGP_KEYRING_ERROR -204

### GNUTLS_E_X509_UNSUPPORTED_OID

    #define GNUTLS_E_X509_UNSUPPORTED_OID -205

### GNUTLS_E_RANDOM_FAILED

    #define GNUTLS_E_RANDOM_FAILED -206

### GNUTLS_E_BASE64_UNEXPECTED_HEADER_ERROR

    #define GNUTLS_E_BASE64_UNEXPECTED_HEADER_ERROR -207

### GNUTLS_E_OPENPGP_SUBKEY_ERROR

    #define GNUTLS_E_OPENPGP_SUBKEY_ERROR -208

### GNUTLS_E_CRYPTO_ALREADY_REGISTERED

    #define GNUTLS_E_CRYPTO_ALREADY_REGISTERED -209

### GNUTLS_E_HANDSHAKE_TOO_LARGE

    #define GNUTLS_E_HANDSHAKE_TOO_LARGE -210

### GNUTLS_E_CRYPTODEV_IOCTL_ERROR

    #define GNUTLS_E_CRYPTODEV_IOCTL_ERROR -211

### GNUTLS_E_CRYPTODEV_DEVICE_ERROR

    #define GNUTLS_E_CRYPTODEV_DEVICE_ERROR -212

### GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE

    #define GNUTLS_E_CHANNEL_BINDING_NOT_AVAILABLE -213

### GNUTLS_E_OPENPGP_PREFERRED_KEY_ERROR

    #define GNUTLS_E_OPENPGP_PREFERRED_KEY_ERROR -215

### GNUTLS_E_INCOMPAT_DSA_KEY_WITH_TLS_PROTOCOL

    #define GNUTLS_E_INCOMPAT_DSA_KEY_WITH_TLS_PROTOCOL -216

### GNUTLS_E_PKCS11_ERROR

    #define GNUTLS_E_PKCS11_ERROR -300

### GNUTLS_E_PKCS11_LOAD_ERROR

    #define GNUTLS_E_PKCS11_LOAD_ERROR -301

### GNUTLS_E_PARSING_ERROR

    #define GNUTLS_E_PARSING_ERROR -302

### GNUTLS_E_PKCS11_PIN_ERROR

    #define GNUTLS_E_PKCS11_PIN_ERROR -303

### GNUTLS_E_PKCS11_SLOT_ERROR

    #define GNUTLS_E_PKCS11_SLOT_ERROR -305

### GNUTLS_E_LOCKING_ERROR

    #define GNUTLS_E_LOCKING_ERROR -306

### GNUTLS_E_PKCS11_ATTRIBUTE_ERROR

    #define GNUTLS_E_PKCS11_ATTRIBUTE_ERROR -307

### GNUTLS_E_PKCS11_DEVICE_ERROR

    #define GNUTLS_E_PKCS11_DEVICE_ERROR -308

### GNUTLS_E_PKCS11_DATA_ERROR

    #define GNUTLS_E_PKCS11_DATA_ERROR -309

### GNUTLS_E_PKCS11_UNSUPPORTED_FEATURE_ERROR

    #define GNUTLS_E_PKCS11_UNSUPPORTED_FEATURE_ERROR -310

### GNUTLS_E_PKCS11_KEY_ERROR

    #define GNUTLS_E_PKCS11_KEY_ERROR -311

### GNUTLS_E_PKCS11_PIN_EXPIRED

    #define GNUTLS_E_PKCS11_PIN_EXPIRED -312

### GNUTLS_E_PKCS11_PIN_LOCKED

    #define GNUTLS_E_PKCS11_PIN_LOCKED -313

### GNUTLS_E_PKCS11_SESSION_ERROR

    #define GNUTLS_E_PKCS11_SESSION_ERROR -314

### GNUTLS_E_PKCS11_SIGNATURE_ERROR

    #define GNUTLS_E_PKCS11_SIGNATURE_ERROR -315

### GNUTLS_E_PKCS11_TOKEN_ERROR

    #define GNUTLS_E_PKCS11_TOKEN_ERROR -316

### GNUTLS_E_PKCS11_USER_ERROR

    #define GNUTLS_E_PKCS11_USER_ERROR -317

### GNUTLS_E_CRYPTO_INIT_FAILED

    #define GNUTLS_E_CRYPTO_INIT_FAILED -318

### GNUTLS_E_UNIMPLEMENTED_FEATURE

    #define GNUTLS_E_UNIMPLEMENTED_FEATURE -1250

### GNUTLS_E_APPLICATION_ERROR_MAX

    #define GNUTLS_E_APPLICATION_ERROR_MAX -65000

### GNUTLS_E_APPLICATION_ERROR_MIN

    #define GNUTLS_E_APPLICATION_ERROR_MIN -65500