Can EXE generated by cx_freeze be completely decompiled back to readable Python code?

Question

I'm new to python, and I'm evaluating developing desktop programs with Python + PySide, and found that cx_freeze works very good in converting my python code into executables, and it's cross-platform.

My question is, can someone else decompile an EXE generated by cx_freeze back to fully readable code , as if my original source code?

Note: I'm not worried about someone cracking my program, but just don't want someone else can take my code and developed base on it.

Thanks.

Answer 1

It seems that the current accepted answer is no longer true.

Here is how to recover the original source code from a project frozen with cx_freeze.

Note: it is done here on a "Hello world" project, but, using the same method, I've been able to decompile a 1000+ lines-of-code source code from a project of mine frozen with cx_freeze, and recover nearly the original source code!

1) Use cx_freeze

Create a test.py file containing

import time
print('hello')
time.sleep(2)
print('world')

Then create the executable with

cxfreeze test.py --target-name=test.exe

Then usually you'll distribute this to the final users:

Now let's try to reverse engineer this!

2) Get the .pyc bytecode

Open dist/lib/library.zip and extract the file test__main__.pyc.

3) Use decompyle6 to get the source code

import uncompyle6
with open('test_main_reverse_eng.py', 'w') as f:
    uncompyle6.decompile_file('test__main__.pyc', f)

4) Surprise!

Here is the original source code!

# uncompyle6 version 3.7.1
# Python bytecode 3.7 (3394)
# Decompiled from: Python 3.7.6 (tags/v3.7.6:43364a7ae0, Dec 19 2019, 00:42:30) [MSC v.1916 64 bit (AMD64)]
# Embedded file name: test.py
# Compiled at: 2020-06-16 21:02:17
# Size of source mod 2**32: 58 bytes
import time
print('hello')
time.sleep(2)
print('world')

Answer 2

In general - no. CX Freeze and py2exe store the PYC version of your code, the bytecode compiled from the PY files. Currently, if I am not mistaken, there are no working viable PYC decompilers. Some give you a more-or-less readable byte code with annotations, but none will give you the actual Python source code. So in that regard - no, it cannot be decompiled. You can also consider going the full native way and use Shed Skin