Partial file coding (C#)

Signed-off-by: JDM170 <30170278+JDM170@users.noreply.github.com>

.gitignore

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+bin/
+obj/

Program.cs

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+/*
+ * Created by SharpDevelop.
+ * User: JDM17
+ * Date: 23.09.2020
+ * Time: 17:48
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+using System;
+using System.IO;
+using Tea;
+using Utils;
+
+namespace ModelCoder
+{
+	class Program
+	{
+		private static readonly int encodeSize = 3000;
+
+		private static bool encodeFile(string path, uint[] key)
+		{
+			Console.WriteLine("[OUTPUT] Reading: " + path);
+			byte[] file_bytes;
+			try {
+				file_bytes = File.ReadAllBytes(path);
+			} catch {
+				Console.WriteLine("[OUTPUT] File '" + path + "' not found");
+				return false;
+			}
+
+			ITeaCoding tea = new TeaCoding();
+			var block = new uint[2];
+			for (uint i = 0; i < encodeSize; i += 2) {
+				Console.WriteLine(i + " start iteration");
+				block[0] = file_bytes[i];
+				block[1] = file_bytes[i + 1];
+				Console.WriteLine(i + " start encoding");
+				tea.code(block, key);
+			}
+
+			return true;
+		}
+		
+		[STAThread]
+		static void Main(string[] args)
+		{
+			IUtil util = new Util();
+
+			string fpath;
+			if (args.Length > 0) {
+				fpath = args[0];
+			} else {
+		        Console.WriteLine("[OUTPUT] You can open file(s) with this program");
+		        Console.WriteLine("[OUTPUT] Or drag'n'drop on it");
+		        Console.Write("[INPUT] Enter filename (without spaces): ");
+		        fpath = Console.ReadLine();
+			}
+
+			Console.Write("[INPUT] Enter key: ");
+			uint[] uKey = util.ConvertKey(Console.ReadLine());
+			
+			Console.WriteLine("[OUTPUT] Reading file(s)...");
+			if (args.Length > 1) {
+				foreach (string i in args)
+					encodeFile(i, uKey);
+			} else {
+				encodeFile(fpath, uKey);
+			}
+
+			Console.Write("Press any key to continue . . . ");
+			Console.ReadKey(true);
+		}
+	}
+}

Properties/AssemblyInfo.cs

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+#region Using directives
+using System;
+using System.Reflection;
+using System.Runtime.InteropServices;
+
+#endregion
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle ("model_coder")]
+[assembly: AssemblyDescription ("")]
+[assembly: AssemblyConfiguration ("")]
+[assembly: AssemblyCompany ("")]
+[assembly: AssemblyProduct ("model_coder")]
+[assembly: AssemblyCopyright ("Copyright 2020")]
+[assembly: AssemblyTrademark ("")]
+[assembly: AssemblyCulture ("")]
+// This sets the default COM visibility of types in the assembly to invisible.
+// If you need to expose a type to COM, use [ComVisible(true)] on that type.
+[assembly: ComVisible (false)]
+// The assembly version has following format :
+//
+// Major.Minor.Build.Revision
+//
+// You can specify all the values or you can use the default the Revision and 
+// Build Numbers by using the '*' as shown below:
+[assembly: AssemblyVersion ("1.0.*")]

README.md

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+#### Thanks [Toliak](https://github.com/Toliak) for his [MTA-TEA-Encoder](https://github.com/Toliak/MTA-TEA-Encoder)

app.config

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+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+	<startup>
+		<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0" />
+	</startup>
+</configuration>

model_coder.Settings

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+<OpenCoverSettings />

model_coder.csproj

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+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" DefaultTargets="Build">
+  <PropertyGroup>
+    <ProjectGuid>{794C3722-03FF-400A-A0EA-DD5FD78AE01D}</ProjectGuid>
+    <ProjectTypeGuids>{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <OutputType>Exe</OutputType>
+    <RootNamespace>model_coder</RootNamespace>
+    <AssemblyName>model_coder</AssemblyName>
+    <TargetFrameworkVersion>v4.0</TargetFrameworkVersion>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <NoWin32Manifest>False</NoWin32Manifest>
+    <SignAssembly>False</SignAssembly>
+    <DelaySign>False</DelaySign>
+    <RunPostBuildEvent>OnBuildSuccess</RunPostBuildEvent>
+    <AllowUnsafeBlocks>False</AllowUnsafeBlocks>
+    <NoStdLib>False</NoStdLib>
+    <TreatWarningsAsErrors>False</TreatWarningsAsErrors>
+    <IntermediateOutputPath>obj\$(Configuration)\</IntermediateOutputPath>
+    <WarningLevel>4</WarningLevel>
+    <RunCodeAnalysis>False</RunCodeAnalysis>
+    <SourceAnalysisOverrideSettingsFile>C:\Users\JDM17\AppData\Roaming\ICSharpCode\SharpDevelop5\Settings.SourceAnalysis</SourceAnalysisOverrideSettingsFile>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Platform)' == 'AnyCPU' ">
+    <PlatformTarget>x86</PlatformTarget>
+    <BaseAddress>4194304</BaseAddress>
+    <RegisterForComInterop>False</RegisterForComInterop>
+    <GenerateSerializationAssemblies>Auto</GenerateSerializationAssemblies>
+    <FileAlignment>4096</FileAlignment>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
+    <OutputPath>bin\Debug\</OutputPath>
+    <DebugSymbols>True</DebugSymbols>
+    <DebugType>Full</DebugType>
+    <Optimize>False</Optimize>
+    <CheckForOverflowUnderflow>True</CheckForOverflowUnderflow>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <BaseIntermediateOutputPath>obj\</BaseIntermediateOutputPath>
+    <StartAction>Project</StartAction>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
+    <OutputPath>bin\Release\</OutputPath>
+    <DebugSymbols>False</DebugSymbols>
+    <DebugType>None</DebugType>
+    <Optimize>True</Optimize>
+    <CheckForOverflowUnderflow>False</CheckForOverflowUnderflow>
+    <DefineConstants>TRACE</DefineConstants>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="Microsoft.CSharp">
+      <RequiredTargetFramework>4.0</RequiredTargetFramework>
+    </Reference>
+    <Reference Include="System" />
+    <Reference Include="System.Core">
+      <RequiredTargetFramework>3.5</RequiredTargetFramework>
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="utils.cs" />
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="tea.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="app.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

model_coder.sdsettings

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+<?xml version="1.0" encoding="utf-8"?>
+<Properties />

model_coder.sln

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+
+Microsoft Visual Studio Solution File, Format Version 11.00
+# Visual Studio 2010
+# SharpDevelop 5.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "model_coder", "model_coder.csproj", "{E7DCB830-5ACF-4B60-A14A-525047F074C0}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{E7DCB830-5ACF-4B60-A14A-525047F074C0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E7DCB830-5ACF-4B60-A14A-525047F074C0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E7DCB830-5ACF-4B60-A14A-525047F074C0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E7DCB830-5ACF-4B60-A14A-525047F074C0}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

tea.cs

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+/*
+ * Created by SharpDevelop.
+ * User: JDM17
+ * Date: 23.09.2020
+ * Time: 17:50
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+using System;
+
+namespace Tea
+{
+	public interface ITeaCoding
+	{
+		void code(uint[] v, uint[] k);
+		//void decode(uint[] v, uint[] k);
+	}
+	public partial class TeaCoding: ITeaCoding
+	{
+		private readonly uint c_delta = 0x9E3779B9;
+
+		/*
+		public void encode(uint[] v, uint[] k) {
+			uint v0 = v[0], v1 = v[1];
+			uint sum = 0;
+			//for(int i = 0; i < 32; i++) {
+			for(uint i = 32; i > 0; i--) {
+				//v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
+				//sum += c_delta;
+				//v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
+
+				//sum += c_delta;
+				//v0 += (v1 << 4) + k[0] ^ v1 + sum ^ (v1 >> 5) + k[1];
+				//v1 += (v0 << 4) + k[2] ^ v0 + sum ^ (v0 >> 5) + k[3];
+
+				v0 += (v1 << 4 ^ v1 >> 5) + v1 ^ sum + k[sum & 3];
+		        sum += c_delta;
+		        v1 += (v0 << 4 ^ v0 >> 5) + v0 ^ sum + k[sum >> 11 & 3];
+			}
+			v[0] = v0;
+			v[1] = v1;
+		}
+		*/
+		public void code(uint[] v, uint[] k)
+		{
+		    uint y = v[0];
+		    uint z = v[1];
+		    uint sum = 0;
+		    uint n = 32;
+
+		    while (n-- > 0)
+		    {
+		        y += (z << 4 ^ z >> 5) + z ^ sum + k[sum & 3];
+		        sum += c_delta;
+		        z += (y << 4 ^ y >> 5) + y ^ sum + k[sum >> 11 & 3];
+		    }
+
+		    v[0] = y;
+		    v[1] = z;
+		}
+
+		/*
+		private readonly uint c_sum = 0xC6EF3720;
+		public void decode(uint[] v, uint[] k) {
+			uint v0 = v[0], v1 = v[1];
+			uint sum = c_sum;
+			for (int i = 0; i < 32; i++) {
+				v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + k[(sum >> 11) & 3]);
+				sum -= c_delta;
+				v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + k[sum & 3]);
+			}
+			v[0] = v0;
+			v[1] = v1;
+		}
+		*/
+	}
+}

test/partial_file_decode.lua

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+
+local key = "1234" -- Model key
+local fileName = "partial_file_encode" -- File name
+local encodeSize = 36000 -- Encoding size (3000*12)
+
+-- Reading crypted file
+local file = fileOpen(fileName .. ".enc")
+local encodedFileData = fileRead(file, encodeSize)
+fileSetPos(file, encodeSize)
+local originalFileData = fileRead(file, fileGetSize(file) - encodeSize)
+fileClose(file)
+
+-- Decoding file data
+local block = ""
+local decoded = ""
+local encodedKey = string.sub(utf8.lower(md5(key)), 1, 16)
+for i = 1, encodeSize, 12 do
+	block = teaDecode(string.sub(encodedFileData, i, i + 12), encodedKey)
+	decoded = decoded .. block
+end
+
+-- Writing uncrypted data to clean file
+file = fileCreate(fileName .. ".dec")
+fileWrite(file, decoded .. originalFileData)
+fileClose(file)
+
+originalFileData = nil
+encodedFileData = nil
+encodedKey = nil
+decoded = nil
+block = nil
+file = nil

utils.cs

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+/*
+ * Created by SharpDevelop.
+ * User: JDM17
+ * Date: 23.09.2020
+ * Time: 20:59
+ * 
+ * To change this template use Tools | Options | Coding | Edit Standard Headers.
+ */
+
+using System;
+using System.Text;
+using System.Security.Cryptography;
+
+namespace Utils
+{
+	public interface IUtil
+	{
+		uint[] ConvertKey(string input);
+		uint ConvertStringToUInt(string input);
+		string ConvertUIntToString(uint input);
+	}
+	public partial class Util: IUtil
+	{
+		public uint[] ConvertKey(string input)
+		{
+			// MD5 Hashing	
+			var md5 = MD5.Create();
+	        byte[] inputBytes = Encoding.ASCII.GetBytes(input);
+	        byte[] hashBytes = md5.ComputeHash(inputBytes);
+	        var sb = new StringBuilder();
+	        for (int i = 0; i < hashBytes.Length; i++)
+	        	sb.Append(hashBytes[i].ToString("X2"));
+	        // Converting to uint[]
+	        string key = sb.ToString().ToLower().Substring(0, 16);
+	        var formattedKey = new uint[4];
+			int j = 0;
+			for (int i = 0; i < key.Length; i += 4)
+				formattedKey[j++] = ConvertStringToUInt(key.Substring(i, 4));
+			return formattedKey;
+		}
+		public uint ConvertStringToUInt(string input)
+		{
+			uint output;
+		    output =  ((uint)input[0]);
+		    output += ((uint)input[1] << 8);
+		    output += ((uint)input[2] << 16);
+		    output += ((uint)input[3] << 24);
+		    return output;
+		}
+		public string ConvertUIntToString(uint input)
+		{
+		    var output = new StringBuilder();
+		    output.Append((char)((input & 0xFF)));
+		    output.Append((char)((input >> 8) & 0xFF));
+		    output.Append((char)((input >> 16) & 0xFF));
+		    output.Append((char)((input >> 24) & 0xFF));
+		    return output.ToString();
+		}
+	}
+}