Standard mode is the most common, but if you don't know the mode, you should try both. Note: Auto Solve will try in the mode you select (Standard Mode or Autokey mode). In case a specific letter (for instance X) is used as word separator, set it to Substitute. In most cases it should be set to Automatic. It eliminates the periodic repeats otherwise seen in polyalphabetic ciphers.
If you don't have any key, you can try to auto solve (break) your cipher. You can decode (decrypt) or encode (encrypt) your message with your key.
