The Fool and his Money

The password needs to follow the format of 3 groups (letters-numbers-letters) of 3 characters each (i.e. ABC-123-XYZ). If left empty, it'll default to 000-000-000. Enter a name and generate the PassKey.txt file; save it into the game folder. Run the game and when prompted, enter the password.

You can read the specifics of the implementation on its dedicated article and GitHub.