Understanding Obfuscated Scripts

Global Capsule

The .pyarmor_capsule.zip in the HOME path called Global Capsule. It’s created implicitly when executing command pyarmor obfuscate. PyArmor will read data from Global Capsule when obfuscating scripts or generating licenses for obfuscated scripts.

Obfuscated Scripts

After the scripts are obfuscated by PyArmor, in the dist folder you find all the files you distribute to your users:

myscript.py
mymodule.py

_pytransform.so, or _pytransform.dll in Windows, _pytransform.dylib in MacOS
pytransform.py
pytransform.key
license.lic

The obfuscated scripts are normal Python scripts.

The module dist/mymodule.py would be like this:

__pyarmor__(__name__, __file__, b'\x06\x0f...')

The entry script dist/myscript.py would be like this:

from pytransfrom import pyarmor_runtime
pyarmor_runtime()

__pyarmor__(__name__, __file__, b'\x0a\x02...')

Bootstrap Code

The first 2 lines in the entry script called Bootstrap Code. It’s only in the entry script:

from pytransfrom import pyarmor_runtime
pyarmor_runtime()

Runtime Files

Except obfuscated scripts, all the other files are called Runtime Files:

  • pytransform.py, a normal python module
  • _pytransform.so, or _pytransform.dll, or _pytransform.dylib a dynamic library implements core functions
  • pytransform.key, data file
  • license.lic, the license file for obfuscated scripts

All of them are required to run obfuscated scripts.

The license.lic

There is a special runtime file license.lic. The default one, which generated as executing pyarmor obfuscate, allows obfuscated scripts run in any machine and never expired.

To change this behaviour, use command pyarmor licenses to generate new license.lic and overwrite the default one.

Running Obfuscated Scripts

The obfuscated scripts is a normal python script, it can be run by normal python interpreter:

cd dist
python myscript.py

Firt Bootstrap Code is executed:

  • Import pyarmor_runtime from pytransform.py
  • Execute pyarmor_runtime
    • Load dynamic library _pytransform by ctypes
    • Check license.lic in the same path
    • Add there builtin functions __pyarmor__, __enter_armor__, __exit_armor__

After that:

  • Call __pyarmor__ to import the obfuscated module.
  • Call __enter_armor__ to restore code object of function before executing each function
  • Call __exit_armor__ to obfuscate code object of function after each function return

More information, refer to How to Obfuscate Python Scripts and How to Run Obfuscated Script

Key Points to Use Obfuscated Scripts

  • The obfuscated script is a normal python script, so it can be seamless to replace original script.

  • There is only one thing changed, the following code must be run before using any obfuscated script:

    from pytransform import pyarmor_runtime
    pyarmor_runtime()
    

    It must in the obfuscated script and only be called one time in the same Python interpreter. It will create some builtin function to deal with obfuscated code.

  • The extra runtime file pytransform.py must be in any Python path in target machine. pytransform.py need load dynamic library _pytransform by ctypes. It may be

    • _pytransform.so in Linux
    • _pytransform.dll in Windows
    • _pytransform.dylib in MacOS

    This file is dependent-platform, download the right one to the same path of pytransform.py according to target platform. All the prebuilt dynamic libraries list here

    http://pyarmor.dashingsoft.com/downloads/platforms/

  • By default pytransform.py search dynamic library _pytransform in the same path. Check pytransform._load_library to find the details.

  • All the other Runtime Files should in the same path as dynamic library _pytransform

  • If Runtime Files locate in some other path, change Bootstrap Code:

    from pytransform import pyarmor_runtime
    pyarmor_runtime('/path/to/runtime-files')
    

Two types of license.lic

In PyArmor, there are 2 types of license.lic

  • license.lic of PyArmor, which locates in the source path of PyArmor. It’s required to run pyarmor
  • license.lic of Obfuscated Scripts, which is generated as obfuscating scripts by the end user of PyArmor. It’s required to run the obfuscated scripts.

The relation between 2 license.lic is:

license.lic of PyArmor --> .pyarmor_capsule.zip --> license.lic of Obfuscated Scripts

When obfuscating scripts with command pyarmor obfuscate or pyarmor build, the Global Capsule is used implicitly. If there is no Global Capsule, PyArmor will read license.lic of PyArmor as input to generate the Global Capsule.

When runing command pyarmor licenses, it will generate a new license.lic for obfuscated scripts. Here the Global Capsule will be as input file to generate this license.lic of Obfuscated Scripts.