Not affiliated with osu! or ppy Pty Ltd ;)
This is a private tool I used to decrypt osu!'s symbol names, allowing me to view osu!'s code as if I got it from the original source. Since peppy changed his encryption key and it can no longer be considered public domain, I believe it is safe to publish this tool publicly.
It has a help menu, you can figure it out. You probably want to run your input through EazFixer first.
As of 26/03/2019 (v3098), peppy has changed away from a (leaked) static encryption key used for encrypting symbol names. This tool will only work on osu! builds with a known encryption key.
You can tell from commit 3d15ab that the source in this repo started from a decompiled program. I was an idiot and just lost the original source a few years ago.