mhw-save-editor (Linux version)

This is a simple Monster Hunter: World save file editor.

Status

Please note this editor is discontinued since Monster Hunter World: Iceborne.

Summary

Mostly inspired by AsteriskAmpersand and all the folks he's been inspired from and working with him/her, this editor is mostly a research prototype project.

How to build it

This needs openssl installed to be able building it. On most distributions one just requires to sudo apt install libssl-dev and it would do the trick. Once done, then just invoke make or make release and the executable should be compiled.

How to use it

Usage: ./mhw-save-editor [options] ... [savefile]
Executes mhw-save-editor 0.1.0

-b, --list-basic       lists the basic save information for all the slots or
                       the specified slot
-l, --list-all         lists all known information for a given slot (if
                       no slot specified, lists for all slots)
    --items-list (csv) specify a custom csv file with fir row header, containing
                       at least columns "id" (numerical identifier) and
                       "name" (name) of items. by default tries to load the
                       file named 'items.csv'
    --list-items       lists only the items (using custom csv - see '--items-list'
                       option)
    --list-inv         lists only investigations
    --list-decos       lists all the decorations (both in builds and in inventory)
-a, --add (type:item)  adds a single item of the type specified in appropriate container.
                       Note that now onlt decorations (type 'd') and materials (type 'm')
                       are currently supported, and the item specified will be added to
                       specific inventory slot; item needs to be specified using the numeric
                       identifier - example '-a d:741' will a Vitality decoration (see file
                       items.csv for a numeric list of items). If slot is not specified, the
                       given item will be added in slot 0
    --overwrite        overwrites the input file
-d, --dump (file)      dumps the decrypted information in the specified file
    --mask-dump (file) dumps the decrypted information in the specified file, by masking the
                       know layout with its own description. Usefuly for understanding
                       the file format
-s, --slot (n)         specify which slot to select (0, 1 or 2)
    --help             prints this help and exit

Monster Hunter: World save file description

The savefile are usually located under: ~/.steam/userdata/*/582010/remote and is named: SAVEDATA1000

Binary data

The binary data inside the file shoould be encrypted/decrypted with Blowfish ecb algorithm and using the following key:

xieZjoe#P2134-3zmaghgpqoe0z8$3azeq

It's worth noting that there is a further byte-swapping inside the file, pre and post encryption, such as the first byte of a quartet needs to be swapped with the last, the second with the third. This operation is performed before and after the encryption/decription stage.

When opening a save file, one should do

swapbytes
decrypt
swapbytes

Data layout

Please see the file layout_bin.h containing all the known binary layout.

Why this editor?

I play on Linux (through SteamPlay) and altough the game runs very well, I have two issues:

• I already have ~1000 hours on PS4 and I don't want to grind again
• On Linux movies can't be played, and given that the game engine needs to be able to play the final movie to let you mark a 'playthrough' as complete, then this can't happen With this editor one should be able to amend the basics and skip the grind.

Also I like to tinker with computer science related topic, and understanding non-documented format is usually a welcome challange.