Pretty neet indeed.
However it failed in my case.
Maybe something’s change since the writing of the script in 2019?
I systematically got a “Unable to extract SecureTar - Maybe your password is wrong or the tar is not password encrypted?” message even on freshly created backups .
Scratch that: I’m an idiot and was using the wrong password. 
The script is fine and useful!
Although I decided to avoid encryption from now on.
you are a life saver. Thanks so much
Anyone who can tell me how to do this in windows?
Have installed python3 but dont know how to use it.
follow the instructions above, but in a cmd indow instead of the nano command use notepad (or your favorite text editor) and use that to create your decrypt.py file
install the cryptography module by doing:
pip install cryptography
then run the same python command above, but your executable might be python or py instead of python3.