File: gpgme.info, Node: Creating a Signature, Next: Signature_Notation_Data.php">Signature Notation Data, Prev: Signers.php">Selecting Signers, Up: Sign 7.6.4.2 Creating a Signature ............................ -- Data type: enum gpgme_sig_mode_t The ‘gpgme_sig_mode_t’ type is used to specify the desired type of a signature. The following modes are available: ‘GPGME_SIG_MODE_NORMAL’ A normal signature is made, the output includes the plaintext and the signature. ‘GPGME_SIG_MODE_DETACH’ A detached signature is made. ‘GPGME_SIG_MODE_CLEAR’ A clear text signature is made. The ASCII armor and text mode settings of the context are ignored. ‘GPGME_SIG_MODE_ARCHIVE’ SINCE: 1.19.0 A signed archive is created from the given files and directories. This feature is currently only supported for the OpenPGP crypto engine and requires GnuPG 2.4.1. -- Function: gpgme_error_t gpgme_op_sign (gpgme_ctx_t CTX, gpgme_data_t PLAIN, gpgme_data_t SIG, gpgme_sig_mode_t MODE) The function ‘gpgme_op_sign’ creates a signature for the text in the data object PLAIN and returns it in the data object SIG or writes it directly to the file set with ‘gpgme_data_set_file_name’ for the data object SIG. The type of the signature created is determined by the ASCII armor (or, if that is not set, by the encoding specified for SIG), the text mode attributes set for the context CTX and the requested signature mode MODE. If signature mode ‘GPGME_SIG_MODE_ARCHIVE’ is requested, then a signed archive is created from the files and directories given as NUL-separated list in the data object PLAIN and returned in the data object SIG. The paths of the files and directories have to be given as paths relative to the current working directory or relative to the base directory set with ‘gpgme_data_set_file_name’. After the operation completed successfully, the result can be retrieved with ‘gpgme_op_sign_result’. If an S/MIME signed message is created using the CMS crypto engine, the number of certificates to include in the message can be specified with ‘gpgme_set_include_certs’. *Note Included Certificates::. The function returns the error code ‘GPG_ERR_NO_ERROR’ if the signature could be created successfully, ‘GPG_ERR_INV_VALUE’ if CTX, PLAIN or SIG is not a valid pointer, ‘GPG_ERR_NO_DATA’ if the signature could not be created, ‘GPG_ERR_BAD_PASSPHRASE’ if the passphrase for the secret key could not be retrieved, ‘GPG_ERR_UNUSABLE_SECKEY’ if there are invalid signers, and passes through any errors that are reported by the crypto engine support routines. -- Function: gpgme_error_t gpgme_op_sign_start (gpgme_ctx_t CTX, gpgme_data_t PLAIN, gpgme_data_t SIG, gpgme_sig_mode_t MODE) The function ‘gpgme_op_sign_start’ initiates a ‘gpgme_op_sign’ operation. It can be completed by calling ‘gpgme_wait’ on the context. *Note Waiting For Completion::. The function returns the error code ‘GPG_ERR_NO_ERROR’ if the operation could be started successfully, and ‘GPG_ERR_INV_VALUE’ if CTX, PLAIN or SIG is not a valid pointer. -- Data type: gpgme_new_signature_t This is a pointer to a structure used to store a part of the result of a ‘gpgme_op_sign’ operation. The structure contains the following members: ‘gpgme_new_signature_t next’ This is a pointer to the next new signature structure in the linked list, or ‘NULL’ if this is the last element. ‘gpgme_sig_mode_t type’ The type of this signature. ‘gpgme_pubkey_algo_t pubkey_algo’ The public key algorithm used to create this signature. ‘gpgme_hash_algo_t hash_algo’ The hash algorithm used to create this signature. ‘unsigned int sig_class’ The signature class of this signature. Note that only the values 0, 1, and 2 are well-defined. ‘long int timestamp’ The creation timestamp of this signature. ‘char *fpr’ The fingerprint of the key which was used to create this signature. -- Data type: gpgme_sign_result_t This is a pointer to a structure used to store the result of a ‘gpgme_op_sign’ operation. After successfully generating a signature, you can retrieve the pointer to the result with ‘gpgme_op_sign_result’. The structure contains the following members: ‘gpgme_invalid_key_t invalid_signers’ A linked list with information about all invalid keys for which a signature could not be created. ‘gpgme_new_signature_t signatures’ A linked list with information about all signatures created. -- Function: gpgme_sign_result_t gpgme_op_sign_result (gpgme_ctx_t CTX) The function ‘gpgme_op_sign_result’ returns a ‘gpgme_sign_result_t’ pointer to a structure holding the result of a ‘gpgme_op_sign’ operation. The pointer is only valid if the last operation on the context was a ‘gpgme_op_sign’, ‘gpgme_op_sign_start’, ‘gpgme_op_encrypt_sign’ or ‘gpgme_op_encrypt_sign_start’ operation. If that operation failed, the function might return a ‘NULL’ pointer. The returned pointer is only valid until the next operation is started on the context.