mistode 0.1.1

Python and C code obfuscation tool

Mistode

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Mistode (Mist Code, pronounced like "Miss Told") is a lightweight code obfuscation tool supporting Python and C. It focuses on making code difficult to read while maintaining functional integrity.

Features

• Encrypted Token Generator: Highly customizable encrypted token generation supporting various configurations:
  • Random Seed: Supports setting a random seed to ensure reproducibility.
  • Length Control: Custom token length, range [8, 32] characters.
  • Style Configuration: Supports two obfuscation styles:
    • Similar Character Style: Uses visually similar character groups to enhance obfuscation (e.g., Oo0, iIlL1, b6B8, Zz2, Ss5).
    • Random Character Style: Uses random alphanumeric combinations.
  • Smart Deduplication: Automatically maintains a set of generated tokens to avoid duplicates.
• Python Support:
  • AST Parsing: Accurate obfuscation based on Abstract Syntax Trees, ensuring complete preservation of code format.
  • Smart Identifier Classification: Automatically identifies and preserves imported modules, functions, and built-in methods.
  • Docstring Obfuscation: Replaces docstrings with hash values.
  • Fully Reversible: Supports full restoration using generated key files or embedded metadata.
  • Lossless Restoration: Achieves lossless consistency with the original file (preserving all comments and formatting) via distributed annotated injection of source chunks.
• C Support:
  • Fast Tokenization: Uses robust regular expression tokenizers.
  • Comment Obfuscation: Obfuscates // and /* */ comment content.
  • Compilation Safety: Preserves keywords, preprocessor directives, and string literals (ensuring safety).
  • Lossless Restoration: Achieves lossless consistency with the original file via distributed annotated injection of source chunks.

Installation

pip install mistode

Usage

Simple Usage (Default Settings)

# Obfuscate (generates input.obf.py and input.map.json)
mistode o input.py

# Restore (automatically detects input.map.json if naming matches)
# Generates input.res.py
mistode r input.obf.py

Full Usage

# Obfuscate with explicit options
mistode obfuscate input.py --out output.py --key mapping.json

# Restore with explicit options
mistode restore output.py --out restored.py --key mapping.json

Configuration File

You can set default options in pyproject.toml to avoid repeating the same arguments:

[tool.mistode]
style = "similar"    # Default obfuscation style ("similar" or "random")
length = 16          # Default token length (8-32)
stats = true         # Always show statistics
# seed = 42          # Optional: set a default seed for reproducibility

How it works:

• Mistode automatically searches for pyproject.toml in the current directory and parent directories
• If found, settings from [tool.mistode] are used as defaults
• Command-line arguments always override configuration file settings

Example:

# With the config above, these are equivalent:
mistode o input.py
mistode o input.py --style similar --length 16 --stats

# Override config with command-line args:
mistode o input.py --style random --length 20

For a complete guide, see examples/CONFIG_GUIDE.md.

Advanced Features

Smart Identifier Recognition for Python Obfuscation

Mistode intelligently identifies and avoids obfuscating the following types of identifiers:

• Built-in Modules: re, os, sys, json, math, etc.
• Built-in Functions: print, len, range, str, int, etc.
• Imported Functions: Functions imported via import and from ... import statements.
• Built-in Methods: re.sub, str.strip, list.append, etc.

Example

Original Code:

import re
from openpyxl.utils import get_column_letter, column_index_from_string

def shift_column_letter(base_column, offset):
    """Calculate the shifted column letter based on the given column letter and offset"""
    base_idx = column_index_from_string(base_column)
    target_idx = base_idx + offset
    return get_column_letter(target_idx)

Obfuscated Code:

import re
from openpyxl.utils import get_column_letter, column_index_from_string

#@mistode:chunk:eJzjSklNU8hIzcnJ11BQyEvMTVVQ0LTiU...
def Oo0iIlL1b6B8Zz2Ss5(Oo0iIlL1b6B8Zz2Ss6, Oo0iIlL1b6B8Zz2Ss7):
    """Obfuscated docstring: e2d30883ac53"""
#@mistode:chunk:aVaCikKXmAdOkoVEO01SopaCoogFWAiQo...
    Oo0iIlL1b6B8Zz2Ss8 = column_index_from_string(Oo0iIlL1b6B8Zz2Ss6)
    Oo0iIlL1b6B8Zz2Ss9 = Oo0iIlL1b6B8Zz2Ss8 + Oo0iIlL1b6B8Zz2Ss7
    return get_column_letter(Oo0iIlL1b6B8Zz2Ss9)
#@mistode:metadata:eJxVk1Fr3DAMx79K...

Embedded Metadata & Distributed Source

Mistode uses a two-layer restoration mechanism:

1. Distributed Source Chunks (#@mistode:chunk: or // @mistode:chunk:): The original source code is compressed, encoded, and injected as chunks before each line of the obfuscated code. Restoration prioritizes these chunks to reconstruct the original code, achieving lossless restoration (including all comments, empty lines, and formatting).
2. Embedded Metadata (#@mistode:metadata:): Contains the identifier mapping table as a backup restoration method.

This means you can perfectly restore the original code even without keeping the key file.

# ... Obfuscated Code ...
#@mistode:chunk:eJzjSk... (Distributed Source Chunk)
# ...
#@mistode:metadata:eJxVk1... (Base64 Encoded Mapping)

If no key file is provided, the restore command automatically detects and uses this metadata.

Project Structure

mistode/
├── src/
│   └── mistode/
│       ├── __init__.py      # Package Initialization
│       ├── cli.py           # Command Line Interface
│       ├── python.py        # Python Obfuscator (mistode.python)
│       ├── c.py             # C Obfuscator (mistode.c)
│       └── core.py          # Core Functionality (mistode.core)
├── tests/                   # Tests Directory
│   ├── __init__.py
│   ├── test_python.py       # Python Obfuscator Tests
│   ├── test_c.py            # C Obfuscator Tests
│   ├── test_cli.py          # CLI Tests (Integration)
│   ├── test_cli_unit.py     # CLI Tests (Unit)
│   └── test_core.py         # Core Functionality Tests
├── pyproject.toml           # Project Configuration
└── README.md                # Project Documentation

Development

Running Tests

python -m pytest tests/

Building the Package

pip install build
python -m build