[3DS] Monster Hunter 4 Ultimate (MH4U) Save data modification

[didix16]

Well I think the idea of write an encrypt/decrypt application would be great. You say that you have the blowfish key? What about if we try to use that key to decrypt the data using blowfish method. An other question is: How are you sure its really encrypted with blowfish?

Other thing I have in mind is: You say look through ASM of ROM right? So for looking at this you/we must know about ASM ARM11 right? Is the processor that use 3DS right? From what offset what should we start to looking at? Maybe we can find the encryption/decryption algorithm that ROM use when game is saving into file userX.

Could you tell me some info about how it works? At the moment I could try to write the application for test the blowfish.

[cdngrep]

Right, I think at this point there are a couple of options:
1. Write a blowfish decrypt/encrypt application which allows for testing different keys. Ideally knowing what a given value exactly is would be great, the only thing that I can think of at the moment is to take the offset of the character name and try to decrypt that data.

If you think it's blowfish, do we know how the initialization vector is passed? No decryption would be possible without both the IV and key.

[ness151]

If you think it's blowfish, do we know how the initialization vector is passed? No decryption would be possible without both the IV and key.

I hate to necro a really old thread but...

A person has found the encryption scheme for both psp versions and 3ds versions of the Monster Hunter games. It's not very user-friendly, but it works. It does use Blowfish.

https://github.com/svanheulen/mhef he also found a way to decrypt the DLC contents which can then be used to distribute custom content to those games via your own server.

[mccartytorres]

Thanks for your detailed instructions. I created a number of ROM codes for them that may or may not be available on the web.
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