de.py

#!/usr/bin/env python3
import sys
 import zlib
 from base64 import b64decode
 from flask.sessions import session_json_serializer
 from itsdangerous import base64_decode
 
 def decryption(payload):
     payload, sig = payload.rsplit(b'.', 1)
     payload, timestamp = payload.rsplit(b'.', 1)
 
     decompress = False
     if payload.startswith(b'.'):
         payload = payload[1:]
         decompress = True
 
     try:
         payload = base64_decode(payload)
     except Exception as e:
         raise Exception('Could not base64 decode the payload because of '
                          'an exception')
 
     if decompress:
         try:
             payload = zlib.decompress(payload)
         except Exception as e:
             raise Exception('Could not zlib decompress the payload before '
                              'decoding the payload')
 
     return session_json_serializer.loads(payload)
 
 if name == '__main__':
     print(decryption(sys.argv[1].encode()))