iv = 'asdfasdfasdfasdf'
key = 'asdfasdfasdfasdfasdfasdfasdfasdf'
encoded = b64decode('my_encrypted_string')
dec = AES.new(key=key, mode=AES.MODE_CBC, IV=iv)
AES - Encryption with Crypto (node-js) / decryption with Pycrypto (python)