diff --git a/kepi/bowler_pub/parsers.py b/kepi/bowler_pub/parsers.py
index 843b735..208fa65 100644
--- a/kepi/bowler_pub/parsers.py
+++ b/kepi/bowler_pub/parsers.py
@@ -5,16 +5,29 @@
 # Licensed under the GNU Public License v2.
 
 """
-django-rest-framework provides a JSON parser, which
-does what we need for parsing ActivityPub. However,
-it baulks at the ActivityPub MIME type. So we have a
-subclass here with only the accepted MIME type changed.
+A custom django-rest-framework parser for ActivityPub.
 """
 
-from rest_framework.parsers import JSONParser
+import codecs
+from django.conf import settings
+from rest_framework.parsers import BaseParser
 
-class ActivityParser(JSONParser):
+class ActivityParser(BaseParser):
     """
     django-rest-framework parser for application/activity+json.
     """
     media_type = "application/activity+json"
+
+    def parse(self, stream, media_type=None, parser_context=None):
+
+        """
+        Traditionally, we'd be parsing the JSON here. But despite
+        the name, we don't parse the incoming stream here at all.
+        This is because validate() needs to know the exact content
+        in order to test the signature. So we just pass it back
+        as a bytestring.
+        """
+
+        result = stream.read()
+
+        return result