diff --git a/pywidevine/cdm.py b/pywidevine/cdm.py
index 758c459..256cedf 100644
--- a/pywidevine/cdm.py
+++ b/pywidevine/cdm.py
@@ -222,13 +222,10 @@ class Cdm:
 
         try:
             signed_message.ParseFromString(certificate)
-            if (
-                signed_message.SerializeToString() == certificate or
+            if all(
                 # See https://github.com/devine-dl/pywidevine/issues/41
-                all(
-                    bytes(chunk) == signed_message.SerializeToString()
-                    for chunk in zip(*[iter(certificate)] * len(signed_message.SerializeToString()))
-                )
+                bytes(chunk) == signed_message.SerializeToString()
+                for chunk in zip(*[iter(certificate)] * len(signed_message.SerializeToString()))
             ):
                 signed_drm_certificate.ParseFromString(signed_message.msg)
             else: