A .blk decryptor and mhy0 extractor for Genshin Impact that doesn't require hooking into the game. Tested working as of 2.0.
The code isn't very good, but it's meant as more of a reference than an actual tool. Any efforts to rewrite the project are highly appreciated.
Also, you'll need a modified AssetStudio to load these files. Since I didn't write it, I won't distribute it here. Sorry.
I finished my own AssetStudio fork that can load .blk files directly, which can be found here. If you're simply interested in datamining or something, you may want to download this instead.