Free open-source obfuscator that targeting Mono and whole .NET

BitMono

BitMono is a free, open-source C# obfuscator that was initially designed and intended mainly for Mono, however, now you're feel free to use it for any .NET app, but, be careful some protections work on .NET Framework, some on .NET, some on Mono, some on Unity only.

BitMono uses AsmResolver instead of dnlib (which we used in the past) for handling assemblies. If you have questions or issues, please let us know here. Download the latest version of BitMono here.

You can also use BitMono as an engine to build custom obfuscators. It is built using dependency injection (DI) using Autofac and follows the latest C# best practices.

Usability

BitMono breaks the most popular tools using just one packer, such as:

• dnSpy;
• dnlib;
• AsmResolver;
• MonoCecil;
• ILSpy;
• PEBear;
• DetectItEasy;
• CFF Explorer
• Perhaps, some dumpers?
• and many, many more...

So, if you will add more protection to the file, I think it would seem like total magic. :D

Documentation

Read the docs to read protection, functionality, and more.

How your app will look since BitMono obfuscation - just in a few words

• Looks like C++ application but is an actual C# application;
• Crash of decompilers when analyzing types;
• Broken decompilers;
• Broken IL Code;
• Invisible types;
• No code

Features

• StringsEncryption
• UnmanagedString (based on existing protection)
• BitDotNet (based and improved on existing protection)
• BitMethodDotnet (based and improved on existing protection)
• DotNetHook (based on existing protection)
• CallToCalli
• ObjectReturnType
• NoNamespaces
• FullRenamer
• AntiDebugBreakpoints
• AntiDecompiler
• BitDecompiler (fixed version of BitDotNet for newer Unity Versions)
• BitDateTimeStamp
• BitMono
• BillionNops
• AntiDe4dot
• AntiILdasm
• and you can integrate existing/make own feature ;)

Usage

Download

Go and get Latest BitMono Release and download preferred archive file, and make sure to select the similar or same Target Framework of the app that you are going to protect, for example:

• Your Target File is for .NET 8 then use BitMono for .NET 8 BitMono-v0.25.3+e64e54d3-CLI-net8.0-win-x64.zip
• Your Target File is for .netstandard then use BitMono for .NET Framework or .NET 8 BitMono-v0.25.3+e64e54d3-CLI-net8.0-win-x64.zip
• Your Target File is .NET Framework then use BitMono for .NET Framework BitMono-v0.25.3+e64e54d3-CLI-net462-win-x64.zip

If you select wrong BitMono build you have a risk that your file going to be protected incorrectly, because you use different target framework build.

Pre-Require

Enable one of the protection in protections.json file: Set Enabled to true.

Using CLI

BitMono.CLI <path to file>/drag-and-drop

Always drop dependencies in libs directory in the same path where file for obfuscation is located

Your obfuscation directory structure will look something like this:

specially_created_folder_for_obfuscation/
├─ your_app.exe
└─ libs/
  ├─ ImportantLibrary.dll
  ├─ SuperImportantLibrary.dll
  └─ ...

Copy all libraries (.dll) from the building application folder and paste them into the libs directory (if it doesn't exist yet create it), or even create the libs directory yourself with a custom name for example - myLibs, and then specify it in BitMono, however, if you will use libs then by default BitMono looking for a libs directory, so it will save your time.

Using CLI Commands

  -f, --file         Required. Set file path.

  -l, --libraries    Set libraries path.

  -o, --output       Set output path.

  --help             Display this help screen.

  --version          Display version information.

Basic example

$ BitMono.CLI -f C:\specially_created_folder_for_obfuscation/your_app.exe -l specially_created_folder_for_obfuscation/libs

In case when you already have a directory with the name libs (specially_created_folder_for_obfuscation\libs) BitMono will catch it automatically, so, you don't need to specify it anymore, but you can in case if you made another directory with libs somewhere on the disk or even just for "visibility".

$ BitMono.CLI -f C:\specially_created_folder_for_obfuscation/your_app.exe

Specify custom libs directory

$ BitMono.CLI -f C:\specially_created_folder_for_obfuscation/your_app.exe -l C:\mythings\obfuscation\superLibsDirectory

Specify file, libs and output. If output directory doesn't exist BitMono will create it automatically and even open it on the top of the screen, if you want you can disable opening of the directory on the of top of the screen in obfuscation.json - and set OpenFileDestinationInFileExplorer to false.

$ BitMono.CLI -f C:\specially_created_folder_for_obfuscation/your_app.exe -l C:\mythings\obfuscation\superLibsDirectory -o C:\specially_created_folder_for_obfuscation/output

Want more? Simply read the docs.

Troubleshooting

Having issues? Get more help here.

Building

If you want to build the BitMono by your own - click here for detailed info

Supported Frameworks

Feel free to use BitMono on frameworks which described below. Be careful using some protections because some might work on .NET Framework only, some on .NET (Core) only, some on all frameworks, some on Mono only - if the protection is unique to its platform/framework you will get a notification about that.

Credits

JetBrains has kindly provided licenses for their JetBrains Rider IDE to the contributors of BitMono. This top-tier tool greatly facilitates and enhances the process of software development.

0x59R11 for his acquaintance in big part of BitDotNet that breaks files for mono executables!

Gazzi for his help that me asked a lot!

Elliesaur for her acquaintance in DotNetHook that hooks methods.

Weka for his advices, help and motivation.

MrakDev for the acquaintance in UnmanagedString.

ConfuserEx and their Forks for most things that I watched for the architecture of BitMono and the obfuscator engine as an application and solving plenty of User solutions which I would be knew in the very long future after much fail usage of BitMono and reports by other Users. Day-by-day I'm looking for something interesting there to improve myself in knowledge and BitMono also.

OpenMod Definitely, openmod inspired this project a lot with services and clean code, extensive similar things to openmod.

Kao and his blogs thanks a lot of these blogs.

drakonia for her costura decompressor.