If you are interested in stronger obfuscation methods, feel free to take a look at my new project masxinlingvonta that further obfuscates java bytecode by compiling it to native code.

A Java bytecode obfuscator supporting

• Flow Obfuscation
• Line Number Removal
• Number Obfuscation
• [Unstable] Name Obfuscation (Classes, methods and fields) with custom dictionaries
• Deobfuscator crasher
• String Encryption
• Inner Class Removal
• HWID Locking
• Invoke Dynamic
• Reference Proxy
• Member Shuffling & Hiding

Feel free to join my discord server:

Luyten + Procyon

Without

public class HelloWorld {
    public HelloWorld() {
        super();
    }
    
    public static void main(final String[] args) {
        System.out.println("Hello World");
        for (int i = 0; i < 10; ++i) {
            System.out.println(i);
        }
    }
}

Obfuscated (short version for full code visit https://pastebin.com/RFHtgPtX)

public class HelloWorld {
    
    public static void main(final String[] array) {
        // invokedynamic(1:(Ljava/io/PrintStream;Ljava/lang/String;)V, invokedynamic(0:()Ljava/io/PrintStream;), HelloWorld.llII[HelloWorld.lllI[0]])
        float lllllllIlIllIII = HelloWorld.lllI[0];
        while (llIll((int)lllllllIlIllIII, HelloWorld.lllI[1])) {
            // invokedynamic(2:(Ljava/io/PrintStream;I)V, invokedynamic(0:()Ljava/io/PrintStream;), lllllllIlIllIII)
            ++lllllllIlIllIII;
            "".length();
            if (" ".length() == (" ".length() << ("   ".length() << " ".length()) & ~(" ".length() << ("   ".length() << " ".length())))) {
                throw null;
            }
        }
    }
    
}

--help Prints the help page on the screen

--version Shows the version of the obfuscator

--jarIn <input> Input JAR

--jarOut <output> Output JAR

--config <configFile> Config File

--cp <classPath> Class Path

--scriptFile <scriptFile> A JS file to script certain parts of the obfuscation

--threads Sets the number of threads the obfuscator should use

--verbose Sets logging to verbose mode

java -jar obfuscator.jar --jarIn helloWorld.jar --jarOut helloWorld-obf.jar

java -jar obfuscator.jar --jarIn helloWorld.jar --jarOut helloWorld-obf.jar --config obfConfig

{
  "input": "D:\\Computing\\HelloWorld\\out\\artifacts\\HelloWorld_jar\\HelloWorld.jar",
  "output": "D:\\Computing\\HelloWorld\\out\\artifacts\\HelloWorld_jar\\HelloWorld-obf.jar",
  "script": "function isRemappingEnabledForClass(node) {\n    return true;\n}\nfunction isObfuscatorEnabledForClass(node) {\n    return true;\n}",
  "libraries": [
    "C:\\Program Files\\Java\\jre1.8.0_211\\lib",
    "D:\\Computing\\backdoored_old\\dependencies",
    "D:\\Computing\\backdoored\\libs"
  ],
  "Crasher": {
    "Enabled": false,
    "Invalid Signatures": true,
    "Empty annotation spam": true
  },
  "InvokeDynamic": {
    "Enabled": true
  },
  "HWIDPRotection": {
    "Enabled": false,
    "HWID": ""
  },
  "Optimizer": {
    "Enabled": true,
    "Replace String.equals()": true,
    "Replace String.equalsIgnoreCase()": true,
    "Optimize static string calls": true
  },
  "LineNumberRemover": {
    "Enabled": true,
    "Rename local variables": true,
    "Remove Line Numbers": true,
    "Remove Debug Names": true,
    "Add Local Variables": true,
    "New SourceFile Name": ""
  },
  "StringEncryption": {
    "Enabled": true,
    "HideStrings": true,
    "AES": true
  },
  "NumberObfuscation": {
    "Enabled": true,
    "Extract to Array": true,
    "Obfuscate Zero": true,
    "Shift": false,
    "And": false,
    "Multiple Instructions": true
  },
  "ReferenceProxy": {
    "Enabled": false
  },
  "ShuffleMembers": {
    "Enabled": true
  },
  "InnerClassRemover": {
    "Enabled": true,
    "Remap": true,
    "Remove Metadata": true
  },
  "NameObfuscation": {
    "Enabled": true,
    "Excluded classes": "HelloWorld",
    "Excluded methods": "",
    "Excluded fields": ""
  },
  "General Settings": {
    "Custom dictionary": true,
    "Name dictionary": "hello,world"
  },
  "Packager": {
    "Enabled": false,
    "Use MainClass from the JAR manifest": true,
    "Main class": "HelloWorld"
  },
  "FlowObfuscator": {
    "Enabled": true,
    "Mangle Comparisons": true,
    "Replace GOTO": true,
    "Replace If": true,
    "Bad POP": true,
    "Bad Concat": true,
    "Mangle Switches": false,
    "Mangle Return": false,
    "Mangle Local Variables": false
  },
  "HideMembers": {
    "Enabled": true
  },
  "Inlining": {
    "Enabled": false
  }
}

In some situations you need to prevent certain classes from being obfuscated, such as dependencies packaged with your jar or mixins in a forge mod.

You will need to exclude in two places.

Here is an example script that will obfuscate and remap all classes except the org.json dependency and mixins.

function isRemappingEnabledForClass(node) {
    var flag1 = !node.name.startsWith("org/json");
    var flag2 = !node.name.startsWith("com/client/mixin");
    return flag1 && flag2;
}
function isObfuscatorEnabledForClass(node) {
    var flag1 = !node.name.startsWith("org/json");
    var flag2 = !node.name.startsWith("com/client/mixin");
    return flag1 && flag2;
}

If you also want to exclude these classes from name obfuscation you will need to go to Transformers -> Name Obfuscation and add these exclusions there.

To Exclude the same classes as we did above, we would need to add the following to Excluded classes, methods and fields.

org.json.**
com.client.mixin.**

If your classes are still being obfuscated after applyinng both of these exclusions please open an issue.

• Click the "Fork" button at the top right hand corner of this page
• Then run git clone https://github.com/[your github username]/obfuscator.git

• File -> New -> Project From Existing Sources
• Select C:\[Path To]\obfuscator\pom.xml
• Set "Search for projects recursively" and "Import Maven projects automatically" to true and click next
• Make sure all maven projects are ticked
• Select the correct Java SDK and go with all the default options for the next pages

• Make any edits
• Package the project to make sure that the project is still functional:
  • java -Dmaven.multiModuleProjectDirectory=D:\Computing\obfuscator\obfuscator-core "-Dmaven.home=C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\plugins\maven\lib\maven3" "-Dclassworlds.conf=C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\plugins\maven\lib\maven3\bin\m2.conf" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\lib\idea_rt.jar=18889:C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\plugins\maven\lib\maven3\boot\plexus-classworlds-2.5.2.jar" org.codehaus.classworlds.Launcher -Didea.version2019.1.3 package (Change any paths to be relevant to your system)

• Run git status to see which files you've changed
• Run git add [file name] for each of the files you want to submit your changes to
• Do git commit -m "[A description of the changes]"
• And finally git push to upload your changes to GitHub

• Go to https://github.com/[your github username]/obfuscator and click "Pull Requests" and then "New Pull Request"
• Make sure all your changes are included then submit the Pull Request.

• MCInjector (FFixer base)
• FFixer (Obfuscator base)
• SmokeObfuscator (Some ideas)
• MarcoMC (Some ideas)
• ItzSomebody (NameUtils.crazyString(), Crasher)