I just released version 0.2.0 of the script, which comes with a new option to include shared addressbooks/calendars to the backup. This may be used to provide only one username + password in the credentials-file to whom all addressbooks/calendars (to be backed up) are shared. A just for this purpose created new user would make sense. If the file gets somehow in wrong hands, only the credentials of this single user will be compromised.
Drawback of this approach is: added addressbooks/calendars will not be backed up, unless they are shared with that user. That’s the price for improved security…
Have a look at the section “About the option -i / --include-shares” in the file README.md in the github-repo for a detailed “How to”. There you can also find some usage examples:
Cheers, Bernie_O