DC.NET Protector
An open source tool to encrypt .NET assembly file, help people protect theirs copyright.
Background
Many .net developers are worry about their software has been cracked,copyright under infringed, so they use some tools to obfuscate IL code.such as PreEmptive dotfuscator.But some times ,it is not enought.
So I write DC.NET Protector can encrypt .NET assembly deeply,help people protect their copyright.and this tool is open source. It is a console .NET application, the UI is :
Features
It has following features.
1 , Encrypt all string values define in assembly.
DC.NET Protector can collect all string values define in assembly,convert they to static readonly fields in a new class,and encrypt theirs value.Make hakers can no search string value direct, crack is more difficulty.
For example , the old code is :
private string GetLicenseMessage()
{
return "This software license to :" + Environment.UserName;
}
After use DC.NET Protector , the new code is :
private string GetLicenseMessage()
{
string text = _0._6 + Environment.UserName;
return text;
}
// also create a new class, contains all string value in assembly in random order.
internal static class _0
{
public static readonly string _0;
public static readonly string _1;
public static readonly string _2;
public static readonly string _3;
public static readonly string _4;
public static readonly string _5;
public static readonly string _6;
public static readonly string _7;
public static readonly string _8;
public static readonly string _9;
public static readonly string _10;
public static readonly string _11;
public static readonly string _12;
public static readonly string _13;
public static readonly string _14;
public static readonly string _15;
public static readonly string _16;
public static readonly string _17;
public static readonly string _18;
public static readonly string _19;
public static readonly string _20;
public static readonly string _21;
static _0()
{
byte[] datas = _BytesContainer__._0();
_11 = GetStringByLong(datas, 151732605047602L);
_20 = GetStringByLong(datas, 450799767951810L);
_7 = GetStringByLong(datas, 101155071172227L);
_4 = GetStringByLong(datas, 47279000500949L);
_15 = GetStringByLong(datas, 415615395474299L);
_5 = GetStringByLong(datas, 54975582493063L);
_2 = GetStringByLong(datas, 17592187197342L);
_14 = GetStringByLong(datas, 206708198516324L);
_8 = GetStringByLong(datas, 124244814685054L);
_21 = GetStringByLong(datas, 459595860893446L);
_6 = GetStringByLong(datas, 72567769190975L);
_13 = GetStringByLong(datas, 182518931688172L);
_18 = GetStringByLong(datas, 433207581847376L);
_16 = GetStringByLong(datas, 417814419099513L);
_3 = GetStringByLong(datas, 36283884381871L);
_1 = GetStringByLong(datas, 9895605165436L);
_9 = GetStringByLong(datas, 136339442622330L);
_19 = GetStringByLong(datas, 440904163377248L);
_17 = GetStringByLong(datas, 426610511995160L);
_0 = GetStringByLong(datas, 598562L);
_10 = GetStringByLong(datas, 148434069970387L);
_12 = GetStringByLong(datas, 158329675868829L);
}
private static string GetStringByLong(byte[] datas, long key)
{
int num = (int)(key & 0xFFFF) ^ 0xEF83;
key >>= 16;
int num2 = (int)(key & 0xFFFFF);
key >>= 24;
int num3 = (int)key;
char[] array = new char[num2];
int num4 = 0;
while (num4 < num2)
{
int num5 = num4 + num3 << 1;
array[num4] = (char)(((datas[num5] << 8) + datas[num5 + 1]) ^ num);
num4++;
num++;
}
return new string(array);
}
}
Additional, this process can avoid a kind of performance problem cause by assembly obfuscation.
For example, use the following code:
public static byte[] ParseUpperHexString(string hexs)
{
var list = new List<byte>();
int Value = -1;
foreach (char c in hexs)
{
int index = "0123456789ABCDEF".IndexOf(c);
if (index >= 0)
{
if (Value < 0)
{
Value = index;
}
else
{
Value = Value * 16 + index;
list.Add((byte)Value);
Value = -1;
}
}
}
return list.ToArray();
}
After dotfuscate the code change to:
public static byte[] z0ZzZzbn(string A_0)
{
int a_ = 15;
List<byte> list = new List<byte>();
int num = -1;
foreach (char value in A_0)
{
int num2 = z0ZzZzbbz.b("\uf0bf\uf3c1\uf6c3\uf5c5\uffc9¨¢?\ue8cf\uebd1¨ºG?e??¨¹a???y", a_).IndexOf(value);
if (num2 >= 0)
{
if (num < 0)
{
num = num2;
continue;
}
num = num * 16 + num2;
list.Add((byte)num);
num = -1;
}
}
return list.ToArray();
}
internal unsafe static string z0ZzZzbbz.b(string A_0, int A_1)
{
char[] array = A_0.ToCharArray();
int num = (int)((long)(IntPtr)(void*)((long)(IntPtr)(void*)((long)(1169192937 + A_1) + 80L) + 78L) + 41L);
int num2 = 0;
if (num2 >= 1)
{
goto IL_0029;
}
goto IL_005c;
IL_005c:
if (num2 >= array.Length)
{
return string.Intern(new string(array));
}
goto IL_0029;
IL_0029:
int num3 = num2;
char num4 = array[num3];
byte b = (byte)((num4 & 0xFFu) ^ (uint)num++);
byte b2 = (byte)(((int)num4 >> 8) ^ num++);
byte num5 = b2;
b2 = b;
b = num5;
array[num3] = (char)((b2 << 8) | b);
num2++;
goto IL_005c;
}
This cause a serious performance problem.To solve the problem, by use DC.NET Proector, this code change to :
private static readonly string _HexChars = _0._11 ;
public static byte[] ParseUpperHexString(string hexs)
{
var list = new List<byte>();
int Value = -1;
foreach (char c in hexs)
{
int index = _HexChars.IndexOf(c);
if (index >= 0)
{
if (Value < 0)
{
Value = index;
}
else
{
Value = Value * 16 + index;
list.Add((byte)Value);
Value = -1;
}
}
}
return list.ToArray();
}
After dotfuscate the code change to:
private static readonly string z0ZzZzbg = z0ZzZzbbz.z0ZzZzbef;
public static byte[] z0ZzZzbu(string A_0)
{
List<byte> list = new List<byte>();
int num = -1;
foreach (char value in A_0)
{
int num2 = DCFormCheckBoxElement.z0ZzZzbg.IndexOf(value);
if (num2 >= 0)
{
if (num < 0)
{
num = num2;
continue;
}
num = num * 16 + num2;
list.Add((byte)num);
num = -1;
}
}
return list.ToArray();
}
This code avoid the performance problem.
2 , Encrypt *.resources file.
Haker can dasm .NET assembly file use ildasm.exe, and get all *.resouces file embed in assembly , change it , maby replace their name or logo image, and use ilasm.exe to rebuild a .NET assembly file.Change your copyright UI to haker's copyright UI.
DC.NET Protector can encrypt *.resouces files and hidden it, It is more hard to modify copyright UI.So it can protect your copyright.
For example, your a define a WinFrom , and the InitializeComponent() function code is :
private void InitializeComponent()
{
System.ComponentModel.ComponentResourceManager resources
= new System.ComponentModel.ComponentResourceManager(typeof(SampleWinApp.frmMain));
pictureBox1 = new System.Windows.Forms.PictureBox();
btnAbout = new System.Windows.Forms.Button();
btnDoWork = new System.Windows.Forms.Button();
label1 = new System.Windows.Forms.Label();
button1 = new System.Windows.Forms.Button();
((System.ComponentModel.ISupportInitialize)pictureBox1).BeginInit();
SuspendLayout();
pictureBox1.Image = (System.Drawing.Image)resources.GetObject("pictureBox1.Image");
pictureBox1.Location = new System.Drawing.Point(150, 21);
pictureBox1.Name = "pictureBox1";
pictureBox1.Size = new System.Drawing.Size(64, 64);
pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.AutoSize;
pictureBox1.TabIndex = 1;
pictureBox1.TabStop = false;
btnAbout.Location = new System.Drawing.Point(21, 188);
btnAbout.Name = "btnAbout";
btnAbout.Size = new System.Drawing.Size(299, 64);
btnAbout.TabIndex = 2;
btnAbout.Text = "About...";
btnAbout.UseVisualStyleBackColor = true;
btnAbout.Click += new System.EventHandler(btnAbout_Click);
btnDoWork.Location = new System.Drawing.Point(21, 109);
btnDoWork.Name = "btnDoWork";
btnDoWork.Size = new System.Drawing.Size(299, 64);
btnDoWork.TabIndex = 3;
btnDoWork.Text = "Do work";
btnDoWork.UseVisualStyleBackColor = true;
btnDoWork.Click += new System.EventHandler(btnDoWork_Click);
label1.AutoSize = true;
label1.Location = new System.Drawing.Point(13, 43);
label1.Name = "label1";
label1.Size = new System.Drawing.Size(131, 12);
label1.TabIndex = 4;
label1.Text = "This is a logo image:";
button1.Location = new System.Drawing.Point(21, 275);
button1.Name = "button1";
button1.Size = new System.Drawing.Size(299, 63);
button1.TabIndex = 5;
button1.Text = "Get string in resource";
button1.UseVisualStyleBackColor = true;
button1.Click += new System.EventHandler(button1_Click);
base.AutoScaleDimensions = new System.Drawing.SizeF(6f, 12f);
base.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
base.ClientSize = new System.Drawing.Size(414, 365);
base.Controls.Add(button1);
base.Controls.Add(label1);
base.Controls.Add(btnDoWork);
base.Controls.Add(btnAbout);
base.Controls.Add(pictureBox1);
base.Name = "frmMain";
Text = "frmMain";
base.Load += new System.EventHandler(frmMain_Load);
((System.ComponentModel.ISupportInitialize)pictureBox1).EndInit();
ResumeLayout(false);
PerformLayout();
}
After use DC.NET Protector, the code change to :
private void InitializeComponent()
{
__DC20210205._Res1 res = new __DC20210205._Res1();
pictureBox1 = new System.Windows.Forms.PictureBox();
btnAbout = new System.Windows.Forms.Button();
btnDoWork = new System.Windows.Forms.Button();
label1 = new System.Windows.Forms.Label();
button1 = new System.Windows.Forms.Button();
((System.ComponentModel.ISupportInitialize)pictureBox1).BeginInit();
SuspendLayout();
pictureBox1.Image = (System.Drawing.Image)res.GetObject(__DC20210205._0._2);
pictureBox1.Location = new System.Drawing.Point(150, 21);
pictureBox1.Name = __DC20210205._0._8;
pictureBox1.Size = new System.Drawing.Size(64, 64);
pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.AutoSize;
pictureBox1.TabIndex = 1;
pictureBox1.TabStop = false;
btnAbout.Location = new System.Drawing.Point(21, 188);
btnAbout.Name = __DC20210205._0._16;
btnAbout.Size = new System.Drawing.Size(299, 64);
btnAbout.TabIndex = 2;
btnAbout.Text = __DC20210205._0._20;
btnAbout.UseVisualStyleBackColor = true;
btnAbout.Click += new System.EventHandler(btnAbout_Click);
btnDoWork.Location = new System.Drawing.Point(21, 109);
btnDoWork.Name = __DC20210205._0._0;
btnDoWork.Size = new System.Drawing.Size(299, 64);
btnDoWork.TabIndex = 3;
btnDoWork.Text = __DC20210205._0._21;
btnDoWork.UseVisualStyleBackColor = true;
btnDoWork.Click += new System.EventHandler(btnDoWork_Click);
label1.AutoSize = true;
label1.Location = new System.Drawing.Point(13, 43);
label1.Name = __DC20210205._0._11;
label1.Size = new System.Drawing.Size(131, 12);
label1.TabIndex = 4;
label1.Text = __DC20210205._0._7;
button1.Location = new System.Drawing.Point(21, 275);
button1.Name = __DC20210205._0._4;
button1.Size = new System.Drawing.Size(299, 63);
button1.TabIndex = 5;
button1.Text = __DC20210205._0._13;
button1.UseVisualStyleBackColor = true;
button1.Click += new System.EventHandler(button1_Click);
base.AutoScaleDimensions = new System.Drawing.SizeF(6f, 12f);
base.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
base.ClientSize = new System.Drawing.Size(414, 365);
base.Controls.Add(button1);
base.Controls.Add(label1);
base.Controls.Add(btnDoWork);
base.Controls.Add(btnAbout);
base.Controls.Add(pictureBox1);
base.Name = __DC20210205._0._18;
Text = __DC20210205._0._18;
base.Load += new System.EventHandler(frmMain_Load);
((System.ComponentModel.ISupportInitialize)pictureBox1).EndInit();
ResumeLayout(false);
PerformLayout();
}
// And auto create a new class:
internal class _Res1 : ComponentResourceManager, IDisposable
{
private ResourceSet _Data;
public _Res1()
{
_Data = InnerAssemblyHelper20210315.LoadResourceSet(
_BytesContainer__._2(), 224, gzip: true);
}
public override ResourceSet GetResourceSet(
CultureInfo culture, bool createIfNotExists, bool tryParents)
{
return _Data;
}
protected override ResourceSet InternalGetResourceSet(
CultureInfo culture, bool createIfNotExists, bool tryParents)
{
return _Data;
}
public void Dispose()
{
if (_Data != null)
{
_Data.Close();
_Data = null;
}
}
}
And remove the embeded resource "SampleWinApp.frmMain.resources". after do these, new code is very difficulty to crack.
Additional,If software is design for globalization with multiple UI language,The software will include specify UI language resource dll files.My tools will prompt operator to select a UI language and merge UI language resource data to IL code .and remove embeded .resources file. This will provide a more fast lanuch speed and without UI language resouce dll.
My tool also can change the resource package class code.
For example, This is a resource package class code:
[GeneratedCode("System.Resources.Tools.StronglyTypedResourceBuilder", "15.0.0.0")]
[DebuggerNonUserCode]
[CompilerGenerated]
internal class Resource1
{
private static ResourceManager resourceMan;
private static CultureInfo resourceCulture;
[EditorBrowsable(EditorBrowsableState.Advanced)]
internal static ResourceManager ResourceManager
{
get
{
if (resourceMan == null)
{
ResourceManager temp = resourceMan = new ResourceManager(
"SampleWinApp.Resource1", typeof(Resource1).Assembly);
}
return resourceMan;
}
}
[EditorBrowsable(EditorBrowsableState.Advanced)]
internal static CultureInfo Culture
{
get
{
return resourceCulture;
}
set
{
resourceCulture = value;
}
}
internal static Bitmap blue96
{
get
{
object obj = ResourceManager.GetObject("blue96", resourceCulture);
return (Bitmap)obj;
}
}
internal static string String2 {
get{ return ResourceManager.GetString("String2", resourceCulture);}
}
internal static string StringValue {
get{ return ResourceManager.GetString("StringValue", resourceCulture);}
}
internal Resource1()
{
}
}
After use my tool , It change to :
internal class Resource1
{
private static readonly byte[] _Datas = _BytesContainer__._1();
private static Bitmap _blue96;
public static Bitmap get_blue96()
{
if (_blue96 == null)
{
_blue96 = InnerAssemblyHelper20210315.GetBitmap(_Datas, 0, 36918, 1807292644);
}
return _blue96;
}
internal static string get_String2()
{
return InnerAssemblyHelper20210315.GetString(_Datas, 37002, 98, 614997590);
}
internal static string get_StringValue()
{
return InnerAssemblyHelper20210315.GetString(_Datas, 36918, 84, 57466195);
}
}
The resouce data aleady has been encrypted, and hard to crack.
3 ,Hidden allocation call stack.
Hackers can search key information by using memory profiler tools , etc. Scitech .NET memory Profiler.but DC.NET Protector can change this stack,puzzle hackers.
For example, I use the follow code to display software license info.
private void btnAbout_Click(object sender, EventArgs e)
{
MessageBox.Show(this, GetLicenseMessage());
}
private string GetLicenseMessage()
{
string msg = "This software license to :" + Environment.UserName;
return msg;
}
When you start application in Scitech .NET memory Profiler, and show the about dialog. the screensnapshort like this. 
In .NET Memory profiler.the UI is 
seach the string "This software license to:Administrator" and double click , then you can see the follow UI: 
There are list the key string value allocation call stack :
mscorlib!System.String.Concat( string,string )
SampleWinApp!SampleWinApp.frmMain.GetLicenseMessage() frmMain.cs
SampleWinApp!SampleWinApp.frmMain.btnAbout_Click( object,EventArgs ) frmMain.cs
System.Windows.Forms!System.Windows.Forms.Control.OnClick( EventArgs )
System.Windows.Forms!System.Windows.Forms.Button.OnMouseUp( MouseEventArgs )
System.Windows.Forms!System.Windows.Forms.Control.WmMouseUp( ref Message,MouseButtons,int )
System.Windows.Forms!System.Windows.Forms.Control.WndProc( ref Message )
System.Windows.Forms!System.Windows.Forms.ButtonBase.WndProc( ref Message )
System.Windows.Forms!System.Windows.Forms.Control.ControlNativeWindow.WndProc( ref Message )
System.Windows.Forms!System.Windows.Forms.NativeWindow.Callback( IntPtr,int,IntPtr,IntPtr )
[Native to managed transition]
[Managed to native transition]
System.Windows.Forms!System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW( ref MSG )
System.Windows.Forms!System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop( int,int,int )
System.Windows.Forms!System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner( int,ApplicationContext )
System.Windows.Forms!System.Windows.Forms.Application.ThreadContext.RunMessageLoop( int,ApplicationContext )
SampleWinApp!SampleWinApp.Program.Main() Program.cs
This call stack maby point out how to crack the software.
Then you can change source to :
private void btnAbout_Click(object sender, EventArgs e)
{
MessageBox.Show(this, GetLicenseMessage());
}
private string GetLicenseMessage()
{
var str = "Yuan_yong_fu_dao_ci_yi_you";// no used,just let DC.NET Protector know the owner method need change.
string msg = "This software license to :" + Environment.UserName;
return msg;
}
At there,the code var str = "Yuan_yong_fu_dao_ci_yi_you"; do nothing, just let DC.NET Protector know this is a key method, need to change, the value is case sensitive.
My tool can change this call stack to this:
mscorlib!System.String.CtorCharArray( char[] )
SampleWinApp2!DCSoft.Common.InnerAssemblyHelper20210315.CloneStringCrossThead_Thread()
mscorlib!System.Threading.ExecutionContext.RunInternal( ExecutionContext,ContextCallback,object,bool )
mscorlib!System.Threading.ExecutionContext.Run( ExecutionContext,ContextCallback,object,bool )
mscorlib!System.Threading.ExecutionContext.Run( ExecutionContext,ContextCallback,object )
mscorlib!System.Threading.ThreadHelper.ThreadStart()
It is more difficuted to find out the key call stack.This feature help you hidden your weakness, protect your software copyright.
4 , Obfuscate class's members order.
When we write a large class's code , usual ,field or method for the same target is very nearby.for example:
private string _RegisterCode = null;
private bool _IsRegisteredFlag = false;
public void SetRegisterCode( string code ){};
pulbic bool IsRegisterdCodeOK( string code ){};
public string GetErrorMessageForRegister();
XXXXXXX other members XXXXXX
When hakers capture one key member,for example _RegisterCode , and analyse other members nearby, maby can get more information.
But DC.NET Protector can obfuscate order of class's members , just like this:
private bool _IsRegisteredFlag = false;
XXXXXXX other members XXXXXX
private string _RegisterCode = null;
XXXXXXX other members XXXXXX
public string GetErrorMessageForRegister();
XXXXXXX other members XXXXXX
pulbic bool IsRegisterdCodeOK( string code ){};
XXXXXXX other members XXXXXX
public void SetRegisterCode( string code ){};
XXXXXXX other members XXXXXX
Other members nearby maby have nothing to do with one key member.this can make carck more difficult.
5 , Easy to use.
My new tool is a .NET framework console application.
It support following command line argument :
input =[required,Full path of input .NET assembly file , can be .exe or .dll, currenttly only support .NET framework 2.0 or later]
output=[optional,Full path of output .NET assmebly file , if it is empty , then use input argument value]
snk =[optional,Full path of snk file. It use to add strong name to output assembly file.]
pause =[optional,pause the console after finish process.]
Example 1, protect d:\a.dll ,this will modify dll file.
DCNETProtector.exe input=d:\a.dll
Exmaple 2, anlyse d:\a.dll , and write result to another dll file with strong name.
DCNETProtector.exe input=d:\a.dll output=d:\publish\a.dll snk=d:\source\company.snk
So many cool features! But DC.NET Protector has no more than 5000 lines C# code!
Exclude
This new tool's finall target is protect all .NET software copyright.Of cause,it does not do all things, it does not support renaming,flow-obfuscate, For those function you can seach other tools.
License
DC.NET Protector use GPL-2.0 License.
