vroid web view vrm decrypt

aes.cs

using System;
using System.Security.Cryptography;
using System.IO;
using System.IO.Compression;
namespace Vroid
{
    class Vroiddec
    {
        static void Main(string[] args)
        {
        	using (FileStream fs = new FileStream(args[0],FileMode.Open)) {
        		using (BinaryReader bs = new BinaryReader(fs)) {
        			int buff_size=(int)(fs.Length)-48;
        			RijndaelManaged rDel=new RijndaelManaged();
        			rDel.IV=bs.ReadBytes(16);
        			rDel.Key=bs.ReadBytes(32);
        			rDel.Mode=CipherMode.CBC;
        			byte[] resultarray=rDel.CreateDecryptor().TransformFinalBlock(bs.ReadBytes(buff_size),0,buff_size);
        			using(MemoryStream ms =new MemoryStream(resultarray)){
	        			using(GZipStream gzs=new GZipStream(ms,CompressionMode.Decompress)){
	        				using(FileStream df=new FileStream(args[0]+".dec",FileMode.OpenOrCreate,FileAccess.Write))
	        				{
			        			int data;
			        			while((data=gzs.ReadByte())!=-1)
			        			{
			        				df.WriteByte((byte)data);
			        			}
	        				}
	        			}
        			}
				}
			}
            log_msg("Done!");
        }
		static void log_msg(string msg)
		{
			Console.WriteLine(msg);
		}
    }
}

I checked the differences between the downloaded VRM and the VRM in the browser, and found that the vertex coordinate data had undergone some transformations

VRoid Hub obfuscates the mesh of the preview models. You can read more on this here: https://toon.link/blog/1740863435/borrowing-intellectual-property.

Nice post!

I checked the differences between the downloaded VRM and the VRM in the browser, and found that the vertex coordinate data had undergone some transformations

true dude, I hope this will shows how it works:
https://toon.link/blog/1740863435/borrowing-intellectual-property

Just think this will be helpful? https://inside.pixiv.blog/2024/02/05/120000

now i get a decrypted .bin file. it seems that this .bin file contains a pmx model and its textures and meshes. but i cannnot read this file. hope somebody could give me some suggestions. https://github.com/TenjoinWai/symphony-miku

bumping on this, wondering how the older models are handled