a simple utility to enccrypt / decrypt user id's

security_utils.py

from Crypto.Cipher import AES
import base64
import urllib


class SecurityUtils(object):
    
    key = '^&#$SuP3rCR@zy$t%piDSEcu1+yK3Y$%&#'
    mode = AES.MODE_CBC
    pad_character = 'X'
    
    @classmethod
    def encode_user_id(cls, user_id):
        aes = AES.new(cls.key, cls.mode)
        padded_key = str(user_id).ljust(32, cls.pad_character)
        encrypted_key = aes.encrypt(padded_key)
        encoded_key = base64.b64encode(encrypted_key)
        quoted_key = urllib.quote(encoded_key, '')
        return quoted_key
    
    @classmethod
    def decode_user_id(cls, encoded_user_id):
        aes = AES.new(cls.key, cls.mode)
        unquoted_key = urllib.unquote(encoded_user_id)
        unencoded_key = base64.b64decode(unquoted_k)
        user_id = aes.decrypt(unencoded_key)
        user_id = user_id[: user_id.index(cls.pad_character)]
        return int(user_id)