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smiler, posted Sat Aug 05, 2017 6:03 am (25243)

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Hello, I need help with a few file formats. From the game Dai Gyakuten Saiban 2: Naruhodou Ryuunosuke no Kakugo.
They're an encrypted form of .gmd file used for MT Frameworks. I need a way to decrypt them, and re-encrypt them back.
Help would be much appreciated.

Link to the sample file:
https://drive.google.com/file/d/0B_S0wg ... sp=sharing

smiler, posted Sun Aug 06, 2017 12:32 pm (25277)

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Anyone? It seems like some sort of XOR but I'm uneducated on the subject of decryption.

aluigi, posted Mon Aug 07, 2017 3:25 am (25282)

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Upload more gmd files.

smiler, posted Mon Aug 07, 2017 4:53 pm (25294)

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aluigi wrote:

Upload more gmd files.

Here you go. Should be almost all of them.
https://my.mixtape.moe/lzzxie.7z

aluigi, posted Tue Aug 08, 2017 2:32 pm (25317)

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Do you have also the executable of the game?

smiler, posted Wed Aug 09, 2017 5:34 am (25335)

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aluigi wrote:

Do you have also the executable of the game?

I'll give you the .cia of the game.
https://drive.google.com/file/d/0B_S0wg ... sp=sharing

aluigi, posted Wed Aug 09, 2017 3:58 pm (25347)

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ctrtool doesn't extract it

smiler, posted Thu Aug 10, 2017 2:16 am (25358)

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aluigi wrote:

ctrtool doesn't extract it

Packhack worked for it, so I'll just give you the extracted form.
https://drive.google.com/file/d/0B_S0wg ... sp=sharing

aluigi, posted Thu Aug 10, 2017 8:48 pm (25375)

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I have found the key:
http://aluigi.org/bms/3ds_gmd_mt.bms

Long story short: the script simply dumps the decrypted data without handling the GMD format (because they are text strings, not files). You can use the reimport mode to put the edited data back but pay attention to not change the length of the strings (use spaces if yours are shorter)

smiler, posted Fri Aug 11, 2017 3:16 pm (25392)

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aluigi wrote:

I have found the key:
http://aluigi.org/bms/3ds_gmd_mt.bms

Long story short: the script simply dumps the decrypted data without handling the GMD format (because they are text strings, not files). You can use the reimport mode to put the edited data back but pay attention to not change the length of the strings (use spaces if yours are shorter)

Thanks a lot!

smiler, posted Tue Jan 02, 2018 4:08 pm (31225)

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Sorry for the bump, but how do you reimport it back with the two XOR strings using the same script? Reimporting using the same script doesn't work. It gets stuck on the first line of idstring "GMD/0" because the decrypted scripts no longer actually have the GMD magic number.