Decrypt PGP message
$ffi
$input
Private keys used for decryption should be loaded into the FFI object before calling this function. If password encryption was used, then password provider should be set by calling rnp_ffi_set_pass_provider.
ffi
The FFI object returned by rnp_ffi_create.
input
Encrypted message.
Decrypted message on success失敗した場合に false を返します.
false