The Differences of Obfuscated Scripts

There are something changed after Python scripts are obfuscated:

  • The major version of Python in build machine should be same as in target machine. Because the scripts will be compiled to byte-code before they’re obfuscated, so the obfuscated scripts can’t be run by all the Python versions as the original scripts could. Especially for Python 3.6, it introduces word size instructions, and it’s totally different from Python 3.5 and before. It’s recommeded to run the obfuscated scripts with same major version of Python.

  • If Python interpreter is compiled with Py_TRACE_REFS or Py_DEBUG, it will crash to run obfuscated scripts.

  • The callback function set by sys.settrace, sys.setprofile, threading.settrace and threading.setprofile will be ignored by obfuscated scripts.

  • The attribute __file__ of code object in the obfuscated scripts will be <frozen name> other than real filename. So in the traceback, the filename is shown as <frozen name>.

    Note that __file__ of moudle is still filename. For example, obfuscate the script and run it:

    def hello(msg):
    # The output will be ''
    # The output will be '<frozen foo>'

About Third-Party Interpreter

About third-party interperter, for example Jython, and any embeded Python C/C++ code, they should satisfy the following conditions at least to run the obfuscated scripts:

  • They must be load offical Python dynamic library, which should be built from the soure , and the core source code should not be modified.
  • On Linux, RTLD_GLOBAL must be set as loading by dlopen, otherwise obfuscated scripts couldn’t work.


Boost::python does not load with RTLD_GLOBAL by default, so it will raise error “No PyCode_Type found” as running obfuscated scripts. To solve this problem, try to call the method sys.setdlopenflags(os.RTLD_GLOBAL) as initializing.

  • The module ctypes must be exists and ctypes.pythonapi._handle must be set as the real handle of Python dynamic library, PyArmor will query some Python C APIs by this handle.