File: gpgme.info,  Node: Decrypt and Verify,  Next: Sign,  Prev: Verify,  Up: Crypto Operations

7.6.3 Decrypt and Verify
------------------------

 -- Function: gpgme_error_t gpgme_op_decrypt_verify (gpgme_ctx_t CTX,
          gpgme_data_t CIPHER, gpgme_data_t PLAIN)
     The function ‘gpgme_op_decrypt_verify’ decrypts the ciphertext in
     the data object CIPHER and stores it into the data object PLAIN.
     If CIPHER contains signatures, they will be verified.

     After the operation completed, ‘gpgme_op_decrypt_result’ and
     ‘gpgme_op_verify_result’ can be used to retrieve more information
     about the signatures.

     If the error code ‘GPG_ERR_NO_DATA’ is returned, CIPHER does not
     contain any data to decrypt.  However, it might still be signed.
     The information about detected signatures is available with
     ‘gpgme_op_verify_result’ in this case.

     The function returns the error code ‘GPG_ERR_NO_ERROR’ if the
     ciphertext could be decrypted successfully, ‘GPG_ERR_INV_VALUE’ if
     CTX, CIPHER or PLAIN is not a valid pointer, ‘GPG_ERR_NO_DATA’ if
     CIPHER does not contain any data to decrypt,
     ‘GPG_ERR_DECRYPT_FAILED’ if CIPHER is not a valid cipher text,
     ‘GPG_ERR_BAD_PASSPHRASE’ if the passphrase for the secret key could
     not be retrieved, and passes through any errors that are reported
     by the crypto engine support routines.

 -- Function: gpgme_error_t gpgme_op_decrypt_verify_start
          (gpgme_ctx_t CTX, gpgme_data_t CIPHER, gpgme_data_t PLAIN)
     The function ‘gpgme_op_decrypt_verify_start’ initiates a
     ‘gpgme_op_decrypt_verify’ 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, ‘GPG_ERR_INV_VALUE’ if
     CTX, CIPHER, PLAIN or R_STAT is not a valid pointer, and
     ‘GPG_ERR_NO_DATA’ if CIPHER does not contain any data to decrypt.

   When processing mails it is sometimes useful to extract the actual
mail address (the “addr-spec”) from a string.  GPGME provides this
helper function which uses the same semantics as the internal functions
in GPGME and GnuPG:

 -- Function: char * gpgme_addrspec_from_uid (const char *UID)

     SINCE: 1.7.1

     Return the mail address (called “addr-spec” in RFC-5322) from the
     string UID which is assumed to be a user id (called “address” in
     RFC-5322).  All plain ASCII characters (i.e., those with bit 7
     cleared) in the result are converted to lowercase.  Caller must
     free the result using ‘gpgme_free’.  Returns ‘NULL’ if no valid
     address was found (in which case ‘ERRNO’ is set to ‘EINVAL’) or for
     other errors.