1 files changed, 5 insertions, 3 deletions

diff --git a/src/mailman_pgp/pgp/mime.py b/src/mailman_pgp/pgp/mime.py
index 5617c19..26d5ddc 100644
--- a/src/mailman_pgp/pgp/mime.py
+++ b/src/mailman_pgp/pgp/mime.py
@@ -10,8 +10,8 @@ class PGPMIMEWrapper:
     def _is_mime(self):
         is_multipart = self.msg.is_multipart()
         payloads = len(self.msg.get_payload())
-        first_part = self.msg.get_payload(0)
-        return is_multipart and payloads == 2 and 'Version: 1' in first_part
+
+        return is_multipart and payloads == 2
 
     def is_mime_signed(self):
         """
@@ -35,12 +35,14 @@ class PGPMIMEWrapper:
         """
         if not self._is_mime():
             return False
+        first_part = str(self.msg.get_payload(0))
         first_type = self.msg.get_payload(0).get_content_type()
         second_type = self.msg.get_payload(1).get_content_type()
         content_subtype = self.msg.get_content_subtype()
         protocol_param = collapse_rfc2231_value(self.msg.get_param('protocol'))
 
-        return first_type == 'application/pgp-encrypted' and \
+        return 'Version: 1' in first_part and \
+               first_type == 'application/pgp-encrypted' and \
                second_type == 'application/octet-stream' and \
                content_subtype == 'encrypted' and \
                protocol_param == 'application/pgp-encrypted'