ExportSecretKey Method
Exports the private key of the current key.
procedure ExportSecretKey(FileName: String; useAsciiArmor: Boolean);
Remarks
This method exports the private key of the currently selected Key. The FileName parameter specifies the file on disk that the private key will be written to. The UseAsciiArmor parameter determines whether or not ASCII armoring is used when writing the key to disk.