Make sure to parse the big int into a byte string

data/users.py

@@ -3,6 +3,7 @@ import logging
 import json
 import itertools
 import uuid
+import struct
 
 from util.aes import AESCipher
 from util.validation import generate_valid_usernames
@@ -150,7 +151,8 @@ class UserAuthentication(object):
 
     # First try parsing the key as an int.
     try:
-      secret_key = int(app_secret_key)
+      big_int = int(app_secret_key)
+      secret_key = bytearray.fromhex('{:02x}'.format(big_int))
     except ValueError:
       secret_key = app_secret_key