diff --git a/ipc/ipdl/ipdl/util.py b/ipc/ipdl/ipdl/util.py
index 2fcbf9b4f7048..be50e5fc6dc01 100644
--- a/ipc/ipdl/ipdl/util.py
+++ b/ipc/ipdl/ipdl/util.py
@@ -2,12 +2,11 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-import hashlib
+import zlib
 
 
 # The built-in hash over the str type is non-deterministic, so we need to do
 # this instead.
 def hash_str(s):
     assert isinstance(s, str)
-    return int.from_bytes(hashlib.md5(s.encode('utf-8')).digest(),
-                          byteorder='big')
+    return zlib.adler32(s.encode('utf-8'))