I've released an Alpha-Version of my Project "Java-RPG-Maker-MV-Decrypter", which works with whole Directories and save/renames Files by itself...
May you try it out, it also have a GUI. If you just want to decrypt single-Files, I recommend this Version here (Bec you don't need to download it). But for whole Directories you should try the Java-Version of the Decrypter! =)
Welcome to the RPG-Maker MV & MZ-File Decrypter you can easily decrypt Files from any RPG-MV/RPG-MZ Project that are encrypted with the Build-In encryption. You can also encrypt them back (Mainly used for translation purposes).
Make sure that you don't use this tool to steal assets, if you want to take a look on images (which is okay for private use by most laws), feel free to do, but don't steal them please.
Please select what you want to do:(No-Key) Restore images from a Game En/Decrypt Files to/from a Game
PNG-Files (Images - ".rpgmvp & .png_-Files") don't need the Decryption-Code, except you want to re-encrypt them. Please go here for restoring images without Key.
In this area you can De- and (Re-)Encrypt Files from RPG-Maker MV & MZ Games.
You can get the Decrypt-Code from the File:
Click "Detect" after you selected the System(.json) File. If you know the Key you can also just enter it in the text-box.
In this area you can Restore PNG-Files (Images - ".rpgmvp & .png_-Files") from RPG-Maker Games without the Decryption-Key.
First: Please note, that this Script is just tested and developed on Firefox. You can help me to make it run on all Browsers, by reporting bugs!