CookieCloud Fixed IV Decryption - Python

This is a Python implementation for decrypting CookieCloud's aes-128-cbc-fixed encrypted data using PyCryptodome library.

Requirements

• Python 3.6 or higher
• PyCryptodome library

Installation

cd python
pip install -r requirements.txt

Or install globally:

pip install pycryptodome

Usage

Command Line

python decrypt.py
# or
python3 decrypt.py

As Module

from decrypt import decrypt

uuid = 'your-uuid'
encrypted = 'base64-encrypted-data'
password = 'your-password'

try:
    data = decrypt(uuid, encrypted, password)
    print('Decrypted data:', data)
except Exception as error:
    print(f'Decryption failed: {error}')

Flask API Example

from flask import Flask, request, jsonify
from decrypt import decrypt

app = Flask(__name__)

@app.route('/decrypt', methods=['POST'])
def decrypt_endpoint():
    data = request.json
    
    try:
        result = decrypt(data['uuid'], data['encrypted'], data['password'])
        return jsonify({'success': True, 'data': result})
    except Exception as e:
        return jsonify({'success': False, 'error': str(e)}), 400

if __name__ == '__main__':
    app.run(debug=True)

Django Integration

# views.py
from django.http import JsonResponse
from django.views.decorators.csrf import csrf_exempt
import json
from .decrypt import decrypt

@csrf_exempt
def decrypt_view(request):
    if request.method == 'POST':
        data = json.loads(request.body)
        
        try:
            result = decrypt(data['uuid'], data['encrypted'], data['password'])
            return JsonResponse({'success': True, 'data': result})
        except Exception as e:
            return JsonResponse({'success': False, 'error': str(e)}, status=400)

Dependencies

• PyCryptodome: Modern cryptographic library for Python
  • Provides AES encryption/decryption
  • PKCS7 padding utilities
  • Cross-platform compatibility

Algorithm Details

• Algorithm: AES-128-CBC
• Key: MD5(uuid + "-" + password).substring(0, 16)
• IV: Fixed 16 bytes of zeros
• Padding: PKCS7
• Encoding: Base64

Performance

• Decryption time: ~3-5ms for typical CookieCloud data
• Memory usage: ~10-15MB
• Pure Python implementation with C extensions for crypto operations

Troubleshooting

Installation Issues

If you encounter installation issues with PyCryptodome:

Windows:

pip install pycryptodome

macOS:

pip install pycryptodome
# or if using Homebrew Python
pip3 install pycryptodome

Linux:

pip install pycryptodome
# or
sudo apt-get install python3-pycryptodome  # Debian/Ubuntu

Alternative: PyCrypto

If PyCryptodome is not available, you can use the older PyCrypto library:

pip install pycrypto

The code automatically detects and uses either library.