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);
		}
    }
}

hihihi Everyone I’m glad that everyone pays attention to this code of mine I share some json parsing methods of gltf models for everyone to facilitate extraction and error correction. get block info

import json
import sys
with open(sys.argv[1],encoding='utf-8') as f:
    data = json.load(f)


for i in data.keys():
    a=data[i]
    #print(type(a))

accessors = data["accessors"]
buffer_views = data["bufferViews"]
type_num_dict = {"SCALAR": 1, "VEC2": 2, "VEC3": 3, "VEC4": 4, "MAT4": 16}

type_dict={
    5120: "BYTE",
    5121: "UNSIGNED_BYTE",
    5122: "SHORT",
    5123: "UNSIGNED_SHORT",
    5124: "INT",
    5125: "UNSIGNED_INT",
    5126: "FLOAT"
}

for accessor_index, accessor in enumerate(accessors):
    type_count = type_num_dict[accessor["type"]]
    #ct=accessor["componentType"]
    pos=buffer_views[accessor["bufferView"]]["byteOffset"]
    count=accessor["count"]
    ac=accessor["componentType"]
    print(accessor_index,count,type_dict[ac],type_count==1,pos)

get mesh info

print("mesh")
for n, mesh in enumerate(data["meshes"]):
    #print(n,mesh.keys())
    for j,primive in enumerate(mesh["primitives"]):
        #print(primive)
        if primive["mode"] != 4:
            raise "1"
        dbb=primive["indices"]
        print(dbb)
        
        va=primive["attributes"]
        print(va)

The id in meshinfo corresponds to the id in blockinfo I will provide the complete model extraction code later

Hi, is there any update about the complete model extraction code?

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