Solutions for Tom's Data Onion riddles from https://www.tomdalling.com/toms-data-onion/

The idea of making a standalone decoding script was "stolen" from nharrer's TomsDataOnion repo.
The other scripts for decoding the individual layers I have written myself. I found nharrer's repo just after I finished solving all the riddles.

Coincidentally, the prerequisites are quite similar:
You'll need Python 3 as well as pycryptdome. Simply install it with pip:

$ pip install pycrptdome

Then you can easily decode the whole Onion by running

$ python decode.py

Note:

I'd advise you to first solve the riddles yourself before running the decode script or having a look into the code.

The contents of each layer will be put into a separate file with the name of the corresponding layer. The last file contains the THE CORE of the Onion.

But be warned: The secret hidden inside the Onion is deeply shocking! Use at your own risk.