ROM Hack Question Decrypting/Decompressing Switch Saves & Files

[SupImBirDy]

Hey everyone so I was just wondering if anyone has had any tutorials, books, or forums laying around with information about reverse engineering switch files... you know to find magic numbers to decompress and decrypt game files to modify and repack. I'm not new to this, just spreading my horizons. I looked into quickbms, but all the tutorials for making scripts for it didnt make any sense so I scrapped that idea. Any help would be appreciated!

 

[Hayato213]

You need access to CFW/Homebrew in order to decrypt and re-encrypt save files.

 

[SupImBirDy]

Well I'm not this new my friend. I'm running atmosphere and reinx on 8.0. I already dumped some games using nxdumper to get the encrypted files off the rom. Some are accessible, some aren't. So I want to access the ones I cant.

 

[masagrator]

There is no one ultimate tutorial. You need to specify game and what you want to do with it.

 

[SupImBirDy]

I thought i was pretty specific with what I wanted to know. I know what I am doing to an extent. I was asking for a tutorial or guidance on finding file magic numbers and headers for the switch so i can access files that are encrypted and view the content inside. I dont want to be game specific because then its not a challenge for me with someone just doing it for me. If someone were to show me how with another game id like that.

 

[masagrator]

I thought i was pretty specific with what I wanted to know. I know what I am doing to an extent. I was asking for a tutorial or guidance on finding file magic numbers and headers for the switch so i can access files that are encrypted and view the content inside. I dont want to be game specific because then its not a challenge for me with someone just doing it for me. If someone were to show me how with another game id like that.

But you know each engine is using different compression, different way for size table, name table, offset table, serializing, etc? If quickbms is too hard for you, then I don't know what you expect. Even quickbms author is not a god and couldn't figure out f.e. vpp_nx64 in Saints Row 3 for Switch. This is like asking how to repair car engine without knowing where to start. F.e. for me one of the hardest parts is finding compression method, because almost none of them are using headers (I'm aware only of zstd and zlib), you need to learn on many files how each compression looks like (Oodle has very easy to recognize data).
Look at quickbms scripts for games like Astral Chain, Xenoblade 2, etc. and learn from it. If you want to go more deeper, you need to learn Python, how to write scripts and implement compression libraries.

 

[SupImBirDy]

But you know each engine is using different compression, different way for size table, name table, offset table, serializing, etc? If quickbms is too hard for you, then I don't know what you expect. Even quickbms author is not a god and couldn't figure out f.e. vpp_nx64 in Saints Row 3 for Switch. This is like asking how to repair car engine without knowing where to start. F.e. for me one of the hardest parts is finding compression method, because almost none of them are using headers (I'm aware only of zstd and zlib), you need to learn on many files how each compression looks like (Oodle has very easy to recognize data).
Look at quickbms scripts for games like Astral Chain, Xenoblade 2, etc. and learn from it. If you want to go more deeper, you need to learn Python, how to write scripts and implement compression libraries.

I can write in C,C++, python, C#, Java so im good there. I know to check the game engines, for what format the coding is in (big indian, little indian etc), but its not that QuickBMS is hard, the only info out on it or any tutorial on it that has educational value is out of date and the pictures applied arent even available anymore so it sucks. But good idea to look at some programs that do what i am looking to learn. I appreciate you taking time out of your day to explain. Like i said i some what know what im doing but some things i need to learn