diff --git a/slixmpp_omemo/__init__.py b/slixmpp_omemo/__init__.py
index 2f901b3..1bf170b 100644
--- a/slixmpp_omemo/__init__.py
+++ b/slixmpp_omemo/__init__.py
@@ -414,11 +414,16 @@ class XEP_0384(BasePlugin):
     def is_encrypted(self, msg: Message) -> bool:
         return msg.xml.find('{%s}encrypted' % OMEMO_BASE_NS) is not None
 
-    def decrypt_message(self, msg: Message, allow_untrusted: bool = False) -> Optional[str]:
-        header = msg['omemo_encrypted']['header']
-        payload = b64dec(msg['omemo_encrypted']['payload']['value'])
+    def decrypt_message(
+        self,
+        encrypted: Encrypted,
+        sender: JID,
+        allow_untrusted: bool = False,
+    ) -> Optional[str]:
+        header = encrypted['header']
+        payload = b64dec(encrypted['payload']['value'])
 
-        jid = msg['from'].bare
+        jid = sender
         sid = int(header['sid'])
 
         key = header.xml.find("{%s}key[@rid='%s']" % (