GARbro-mirror/ArcFormats/Unity/ScriptDSM.cs

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//! \file ScriptDSM.cs
//! \date 2023 Sep 03
//! \brief Decrypt data.dsm script.
//
// Copyright (C) 2023 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System;
using System.ComponentModel.Composition;
using System.IO;
using System.Security.Cryptography;
using System.Text;
namespace GameRes.Formats.NScripter
{
[Export(typeof(ScriptFormat))]
public class DsmConverter : GenericScriptFormat
{
public override string Tag { get => "DSM/UTAGE"; }
public override string Description { get => "UTAGE Unity engine script file"; }
public override uint Signature { get => 0; }
public override bool IsScript (IBinaryStream file)
{
return VFS.IsPathEqualsToFileName (file.Name, "data.dsm");
}
public override Stream ConvertFrom (IBinaryStream file)
{
using (var reader = new StreamReader (file.AsStream))
{
var sourceString = reader.ReadToEnd();
var text = DsmDecryptor.DecryptString (sourceString, "pass");
return new BinMemoryStream (text, file.Name);
}
}
public override Stream ConvertBack (IBinaryStream file)
{
throw new NotSupportedException();
}
}
internal static class DsmDecryptor
{
internal static void GenerateKeyFromPassword (string password, int keySize, out byte[] key, int blockSize, out byte[] iv)
{
var bytes = Encoding.UTF8.GetBytes ("saltは必ず8バイト以上");
var derive = new Rfc2898DeriveBytes (password, bytes);
derive.IterationCount = 1000;
key = derive.GetBytes (keySize / 8);
iv = derive.GetBytes (blockSize / 8);
}
internal static byte[] DecryptString (string sourceString, string password)
{
var rij = new RijndaelManaged();
byte[] key, iv;
GenerateKeyFromPassword (password, rij.KeySize, out key, rij.BlockSize, out iv);
rij.Key = key;
rij.IV = iv;
var array = Convert.FromBase64String (sourceString);
using (var cryptoTransform = rij.CreateDecryptor())
{
return cryptoTransform.TransformFinalBlock (array, 0, array.Length);
}
}
}
}