This tools will help you to encrypt and decrypt any file. You just need to know the key used on the file.
The source file will be encrypted/decrypted at the destination path. After selecting the two paths, just enter the hex key (without any prefix) and click on "Encrypt" or "Decrypt" button.
Here some keys.
Code:
LevExp: 4D2
Silent: 2537
MapDestination: 2537
ItemType: 2537
Monster: 2537
UserHelpInfo: 2537
N.B. The app will extract a DLL from itself. The C++ DLL contains the COFAC algorithm.
UPDATE. New version in C# (2.0) with the cipher implemented directly in the app. The UI is slightly simplified too. The source code is available.