Presented with a 100 megabyte .Onion file, I didn’t know what to do until I read the description of the challenge which mentioned the famous Shrek quote: Ogres are like Onions, they have layers. The quote hinted that there may be different layers of encryptions. A small part of it is shown below:

4e4755304e7a55314d7a41305a5464684e54557a4d54526b4e3245304d544d774e5745314e4459304e6a67305a5455304e Decoding it by hex to ASCII leads to NGU0NzU1MzA0ZTdhNTUzMTRkN2E0MTMwNWE1NDY0Njg0ZTU0N Which looks like base64, decoing back to ASCII leads to 4e4755304e7a55314d7a41305a5464684e54 Bingo, we have the layers.

I wrote a simple little python script to do exactly just that to the file

Original writeup (https://outwrest.github.io/writeup/2020/04/13/DawgCTF-Writeup.html).