Specify Custom Obfuscators for Protected Models

When creating a protected model, you can specify your own postprocessing function for files that the protected model creation process generates. Before packaging the protected model files, this function is called by the Simulink.ModelReference.protect function. You can use this functionality to run your own custom obfuscator on the generated files by following these steps:

1. Create your postprocessing function. Use this function to call your custom obfuscator. The function must be on the MATLAB^® path and accept a Simulink.ModelReference.ProtectedModel.HookInfo object as an input variable.

2. In your function, get the files and exported symbol information that your custom obfuscator requires to process the protected model files. To get the files and information, access the properties of your function input variable. The variable is a Simulink.ModelReference.ProtectedModel.HookInfo object with the following properties:

   • SourceFiles

   • NonSourceFiles

   • ExportedSymbols

3. Pass the protected model file information to your custom obfuscator. The following is an example of a postprocessing function for custom obfuscation:

   function myHook(protectedModelInfo)
   
       % Get source file list information.
       srcFileList = protectedModelInfo.SourceFiles;
       disp('### Obfuscating...');
       for i=1:length(srcFileList)
           disp(['### Obfuscator: Processing ' srcFileList{i} '...']);
           % call to custom obfuscator
           customObfuscator(srcFileList{i});
       end
   end

4. Specify your postprocessing function when creating the protected model:

   Simulink.ModelReference.protect('myModel, ...
       'Mode', ...
       'CodeGeneration', ...
       'CustomPostProcessingHook', ... 
       @(protectedModelInfo)myHook(protectedModelInfo))

The protected model creator can also enable obfuscation of simulation target code and generated code through the ‘ObfuscateCode’ option of the Simulink.ModelReference.protect function. Your custom obfuscator runs only on the generated code and not on the simulation target code or the generated HDL code. If both obfuscators are in use, the custom obfuscator is the last to run on the generated code before the files are packaged.