diff --git a/voice.py b/voice.py
index d1c3319..3f5dbd9 100644
--- a/voice.py
+++ b/voice.py
@@ -76,7 +76,7 @@ def _build_e2ee_options() -> rtc.E2EEOptions:
     Element Call uses: ratchetWindowSize=16, keyringSize=256, salt="LKFrameEncryptionKey"
     """
     key_opts = rtc.KeyProviderOptions(
-        shared_key=None,
+        shared_key=b"",
         ratchet_window_size=16,
         ratchet_salt=b"LKFrameEncryptionKey",
         failure_tolerance=-1,