https://github.com/mlgmxyysd/ddlc-plus-asset-decrypter
Doki Doki Literature Club Plus Asset Decrypter
https://github.com/mlgmxyysd/ddlc-plus-asset-decrypter
hacktoberfest php
Last synced: about 1 year ago
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Doki Doki Literature Club Plus Asset Decrypter
- Host: GitHub
- URL: https://github.com/mlgmxyysd/ddlc-plus-asset-decrypter
- Owner: MlgmXyysd
- License: apache-2.0
- Created: 2021-07-10T10:56:16.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2021-10-17T14:56:23.000Z (almost 5 years ago)
- Last Synced: 2025-03-31T08:38:46.998Z (over 1 year ago)
- Topics: hacktoberfest, php
- Language: PHP
- Homepage:
- Size: 22.5 KB
- Stars: 21
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# DDLC Plus Asset Decrypter
Doki Doki Literature Club Plus Asset Decrypter
Used to decrypt encrypted Streaming Asset Bundle files (*.cy) in DDLC-Plus.
## How to use
1. Download and install PHP for your system from the [official website](https://www.php.net/downloads).
2. Open the terminal and use PHP interpreter to execute the [script](ddlcpcydec.php) with the usage.
3. Wait for the script to run.
4. Use [Perfare/AssetStudio](https://github.com/Perfare/AssetStudio/) or other tools to unpack the decrypted asset file.
## Changelog
- v1.1:
- Split file into 10M cache to speed up the decryption process
- v1.0:
- First ver
## TO-DOs
- v1.3:
- Use multiple threads to speed up the decryption process (Requires pthread extension)
- v1.2:
- Iterate through paths to decrypt all files
## Workaround
The game has been cleared and I want to get its wallpaper and new music.
When I got the file, I found that its header is the same, but in an unknown format. By consulting the C# code, the game calls the regular AssetBundles load method. Nothing related to decryption was found in the C# code. I started to disassemble the native PE program and also found no code for decryption.
So I seemed to be stuck in a conundrum. I started to guess the encryption method, and the common ones are AES and XOR. But I didn't find any AES decryption method needed, so I ruled it out. Then I turned to XOR, starting by first guessing the key in a loop from 0 to 100.
Fortunately, the UnityFS file header and the Unity3D engine version were successfully decrypted when the XOR key was 40. By comparing it with StreamingAssets from other Unity3D powered games, I was convinced that this was the normally file.
Unpacked it using AssetStudio, everything worked fine and I got the wallpaper and music I wanted.
There is a saying in Chinese called "暴力出奇迹". Great discoveries require bold guesses, and often they work. :)
## Why do I use PHP
Simply, I hate Python syntax.
As an interpretive language, PHP has a friendly syntax similar to that of other languages and is easy to use.
In addition, ~~PHP is the best language in the world and does not accept any refutation~~. LMAO
## License
The project is open source under [Apache License v2.0](LICENSE). All rights reserved for script author [MlgmXyysd](https://github.com/MlgmXyysd/).