chenx221/Light.vnTools
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Fix xor-ing the last 100 bytes and update README

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Using Array.Reverse to automatically reverse KEY and store to
REVERSE_KEY leading to unexpected result to entire decryption process.
When using manually reversed KEY constant (REVERSE_KEY), the problem
is fixed.

Signed-off-by: Bayu Satiyo <itsyuukunz@gmail.com>
This commit is contained in:
Bayu Satiyo 2023-08-14 21:34:35 +07:00
parent 2718391ff5
commit 33848ae084
No known key found for this signature in database
GPG Key ID: 3C98876626C85FE3
2 changed files with 22 additions and 54 deletions
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70
Program.cs
View File

@ -1,10 +1,11 @@
using System.IO.Compression;
using System.Text;
namespace LightvnTools
{
public class Program
{
static readonly string VERSION = "0.0.1";
static readonly string VERSION = "1.0.0";
// PKZip signature
static readonly byte[] PKZIP = { 0x50, 0x4B, 0x03, 0x04 };
@ -12,34 +13,8 @@ namespace LightvnTools
// Key used to decrypt the file header and footer (reverse)
// Text: `d6c5fKI3GgBWpZF3Tz6ia3kF0`
// Source: https://github.com/morkt/GARbro/issues/440
static readonly byte[] KEY =
{
0x64,
0x36,
0x63,
0x35,
0x66,
0x4B,
0x49,
0x33,
0x47,
0x67,
0x42,
0x57,
0x70,
0x5A,
0x46,
0x33,
0x54,
0x7A,
0x36,
0x69,
0x61,
0x33,
0x6B,
0x46,
0x30
};
static readonly byte[] KEY = { 0x64, 0x36, 0x63, 0x35, 0x66, 0x4B, 0x49, 0x33, 0x47, 0x67, 0x42, 0x57, 0x70, 0x5A, 0x46, 0x33, 0x54, 0x7A, 0x36, 0x69, 0x61, 0x33, 0x6B, 0x46, 0x30 };
static readonly byte[] REVERSED_KEY = { 0x30, 0x46, 0x6B, 0x33, 0x61, 0x69, 0x36, 0x7A, 0x54, 0x33, 0x46, 0x5A, 0x70, 0x57, 0x42, 0x67, 0x47, 0x33, 0x49, 0x4B, 0x66, 0x35, 0x63, 0x36, 0x64 };
static void Main(string[] args)
{
@ -155,21 +130,17 @@ namespace LightvnTools
try
{
byte[] buffer;
byte[] REVERSED_KEY = KEY;
Array.Reverse(REVERSED_KEY);
int bufferLength;
using (FileStream inputStream = File.OpenRead(filePath))
{
using MemoryStream outputStream = new();
inputStream.CopyTo(outputStream);
buffer = outputStream.ToArray();
buffer = new byte[bufferLength = (int)inputStream.Length];
inputStream.Read(buffer, 0, bufferLength);
}
int length = buffer.Length;
if (length < 100)
if (bufferLength < 100)
{
if (length == 0)
if (bufferLength == 0)
{
Console.WriteLine($"Skipping {filePath}. File is empty.");
return;
@ -177,24 +148,23 @@ namespace LightvnTools
Console.WriteLine($"File size is smaller than 100 bytes: {filePath}");
// XOR the first 100 bytes
for (int i = 0; i < length; i++)
buffer[i] ^= REVERSED_KEY[i % 25];
// XOR entire bytes
for (int i = 0; i < bufferLength; i++)
buffer[i] ^= REVERSED_KEY[i % KEY.Length];
}
else
{
// XOR the last 100 bytes
for (int i = 0; i < 99; i++)
buffer[length - 99 + i] ^= REVERSED_KEY[i % 25];
// XOR the first 100 bytes
for (int i = 0; i < 100; i++)
buffer[i] ^= KEY[i % 25];
}
using (FileStream outputStream = File.OpenWrite(filePath))
{
outputStream.Write(buffer, 0, length);
buffer[i] ^= KEY[i % KEY.Length];
// XOR the last 100 bytes
for (int i = 0; i < 99; i++)
buffer[bufferLength - 99 + i] ^= REVERSED_KEY[i % KEY.Length];
}
using FileStream outputStream = File.OpenWrite(filePath);
outputStream.Write(buffer, 0, bufferLength);
}
catch (Exception ex)
{

6
README.md
View File

@ -2,9 +2,7 @@
## Overview
**<p align="center">This tool is very unstable and not work on the newer version of Light.vn</p>**
Light.vnTools is a simple unpack and repacking tool for game created using [Light.vn](https://lightvn.net "Light.vn") game engine.
Light.vnTools is an unpack and repacking tool for game created with [Light.vn](https://lightvn.net "Light.vn") game engine.
## Requirements
@ -30,4 +28,4 @@ For more information about the GNU General Public License version 3.0 (GNU GPL 3
## Disclaimer
This tool is intentionally created as a modding tool to translate the visual novel game created with Light.vn game engine. I didn't condone any piracy in any forms such as taking the game visual and sell it illegally which harm the developer. Use the tool at your own risk (DWYOR - Do What You Own Risk).
This tool is intentionally created as a modding tool to translate the visual novel game created with Light.vn game engine. I didn't condone any piracy in any forms such as taking the game visual and sell it illegally which harm the game developer. Use the tool at your own risk (DWYOR - Do What You Own Risk).