ROM Hack MH4U DLC and savefile encryption

[Arimantha]

Hm, okay. I'm pretty green to this part of it but why do you need NTR CFW?

I'm reading your

They did, kind of. The game first sends a special string to an SSL page which returns the encryption key. Capcom can change this key at any time but that requires them to re-encrypt all the DLC as well. I got the current key by hooking the game's call to http:C AddPostDataRaw. That allowed me to get the special string that the game sends to the SSL page and then I was able to use that to get the key from my computer. I have not yet figured out how that special string is generated so if they change the key I'll have to hook that function again to get it. It must be based on time because the string changes every 1-2 days. This also means I can't get the JPN key because I only have the USA version of the game. And it just so happens that the EUR version is using the same key currently. The encryption itself is just plain Blowfish in ECB mode. It was easy to find that in the code because the save file key literally has the words "blowfish key" in it, haha.
.

post from reddit and it sounds like I could just have something like a sniffer running to log all the communications between my MH4G and Capcom while I access their DLC pages? What am I missing?

Thanks for putting up with all the newbies running around after you released this info

 

[moghedien]

Hm, okay. I'm pretty green to this part of it but why do you need NTR CFW?

I'm reading your



post from reddit and it sounds like I could just have something like a sniffer running to log all the communications between my MH4G and Capcom while I access their DLC pages? What am I missing?

Thanks for putting up with all the newbies running around after you released this info

The first request that actually gets the encryption key is done over SSL. You can't sniff SSL traffic unless you have the server's private key. I used NTR CFW to read/write the game's memory, but if you know another way to do that, that works too.

 

[Arimantha]

It sounds like you have NTR CFW already and just only had the legit USA MH4U cartridge?

Can I just buy you a cartridge of MH4G and ship it to you?

 

[moghedien]

Exactly. But I actually have a copy of the JPN game coming in the mail already it's just slow shipping so I wont have it for another week at least.

 

[Arimantha]

I can probably wait another week

But where did you order it from?? Amazon has it on Prime shipping

 

[moghedien]

play-asia

 

[Bunyan]

Has anyone figured out how to change the name of a quest when you download it like Kiranico and TheHR999Bot did? From thehr999bot's post, he included an extra SKFU Proxy rule replacing the txt info of the quest, so I'm wondering how I can do this for myself.

Rule Hr999Bot used for his quest

source: http://goshawk.capcom.co.jp/3ds/mh4g_us_/DLC_EventQuestInfo_eng.txt
destination: http://puu.sh/iOQa8/332eabefe7.txt add rule

 

[moghedien]

Decrypt it and open it in a text editor, the format is pretty straight forward.
Or just use my proxy script. It will build that file automatically with the text from your quest files.

 

[Bunyan]

Thanks, that worked great. Another question, how do I use those offsets from data.db for the monsters, terms, and maps and turn it into something I can use?
I was told the numbers are just offsets which can tell me the structure of the bytes (1, 2, etc bytes) but besides that it doesn't give much information I could use to edit monsters, terms, and maps with the quest.
How can I translate those offsets into what I need to be able to start editing monsters, terms, and maps?

 

[moghedien]

Thanks, that worked great. Another question, how do I use those offsets from data.db for the monsters, terms, and maps and turn it into something I can use?
I was told the numbers are just offsets which can tell me the structure of the bytes (1, 2, etc bytes) but besides that it doesn't give much information I could use to edit monsters, terms, and maps with the quest.
How can I translate those offsets into what I need to be able to start editing monsters, terms, and maps?

First I would recommend reading these two wiki pages:
https://en.wikipedia.org/wiki/Binary_file
https://en.wikipedia.org/wiki/Endianness (mibs are little endian)

Then look at the quest file format here:
https://github.com/svanheulen/mhff/wiki/Monster-Hunter-4-Ultimate-Quests

On another note, someone found the JPN key for me... I could have actually gotten it the whole time but I didn't notice the difference so I assumed it was wrong, haha. Anyway, get/install the new version of mhef to be able to decrypt the Japanese DLC.

 

[Arimantha]

YES I LOVE YOU SVAN

 

[Bunyan]

How do we get the Japanese dlc mibs so we can decrypt it?

 

[moghedien]

How do we get the Japanese dlc mibs so we can decrypt it?

I updated the tools/download_n3ds.py script to allow picking the region you want to download from.

 

[Bunyan]

Am I supposed to be running a command line or something through mhef-master/tools to download this? When I try clicking on the download_n3ds.py it opens and then closes itself. Sorry for me needing so much help, I just started trying to do this and trying to learn stuff as well as have fun with my game.

 

[moghedien]

Am I supposed to be running a command line or something through mhef-master/tools to download this? When I try clicking on the download_n3ds.py it opens and then closes itself. Sorry for me needing so much help, I just started trying to do this and trying to learn stuff as well as have fun with my game.

Yes, it's all command line. I assume you're using Windows? You use something like this:
C:\Python27\python.exe tools/download_n3ds.py ...

 

[Bunyan]

I think I see what I'm supposed to do.. here's a screenshot
http://prntscr.com/7rsakc
I found this command right after making my post by messing around with the download_n3ds.py
I think this is right so far but what would be some examples for the remote and outputfile?
http://prntscr.com/7rsb8o

Also with with command line you posted, I'm guessing I put the download_n3ds.py in the Python27 tools folder?

 

[moghedien]

This will download the file called "DLC_EventQuestInfo_eng.txt" and save it to a file called "test.txt" in the current folder:
download_n3ds.py USA DLC_EventQuestInfo_eng.txt test.txt

 

[Bunyan]

It worked! Only problem is when I open it I get this
http://prntscr.com/7rsebj

 

[moghedien]

Yes, all the files you download with that script are encrypted. You then have to use the examples/n3ds/dlc.py script to decrypt them.
You'll have to have the mhef module installed for that one to work, which is explained in the README file.

 

[Bunyan]

I was just trying to get that to work. I think I'll be good now. Thanks for helping me! I'll hopefully be able to finish this now.

--------------------- MERGED ---------------------------

I tried putting it in the file you said, and then just decrypted it like any other .mib file. However, it either did not recognize the command anymore or something else on my side. On the older version of mhef-master, I could decrypt any mib successfully so would the older version be able to decrypt this text file as well? If that is the case though I would need the older version

I tried running: python dlc.py d test.txt test.txt
http://prntscr.com/7rsjaz
I am also running Python 2.7