1 files changed, 34 insertions, 12 deletions

diff --git a/src/mailman_pgp/pgp/mime.py b/src/mailman_pgp/pgp/mime.py
index fde9d49..3421167 100644
--- a/src/mailman_pgp/pgp/mime.py
+++ b/src/mailman_pgp/pgp/mime.py
@@ -16,10 +16,10 @@
 # this program.  If not, see <http://www.gnu.org/licenses/>.
 
 """RFC1847 and RFC3156 compliant message wrapped."""
-
+from email.iterators import walk
 from email.utils import collapse_rfc2231_value
 
-from pgpy import PGPMessage, PGPSignature
+from pgpy import PGPKey, PGPMessage, PGPSignature
 from public import public
 
 
@@ -29,6 +29,7 @@ class MIMEWrapper:
 
     _signed_subtype = 'application/pgp-signature'
     _encrypted_subtype = 'application/pgp-encrypted'
+    _keys_subtype = 'application/pgp-keys'
 
     def __init__(self, msg):
         """
@@ -58,10 +59,9 @@ class MIMEWrapper:
         protocol_param = collapse_rfc2231_value(self.msg.get_param('protocol'))
         content_subtype = self.msg.get_content_subtype()
 
-        return \
-            second_type == MIMEWrapper._signed_subtype and \
-            content_subtype == 'signed' and \
-            protocol_param == MIMEWrapper._signed_subtype
+        return (second_type == MIMEWrapper._signed_subtype and
+                content_subtype == 'signed' and
+                protocol_param == MIMEWrapper._signed_subtype)
 
     def is_encrypted(self):
         """
@@ -78,12 +78,34 @@ class MIMEWrapper:
         content_subtype = self.msg.get_content_subtype()
         protocol_param = collapse_rfc2231_value(self.msg.get_param('protocol'))
 
-        return \
-            'Version: 1' in first_part and \
-            first_type == MIMEWrapper._encrypted_subtype and \
-            second_type == 'application/octet-stream' and \
-            content_subtype == 'encrypted' and \
-            protocol_param == MIMEWrapper._encrypted_subtype
+        return ('Version: 1' in first_part and
+                first_type == MIMEWrapper._encrypted_subtype and
+                second_type == 'application/octet-stream' and
+                content_subtype == 'encrypted' and
+                protocol_param == MIMEWrapper._encrypted_subtype)
+
+    def has_keys(self):
+        """
+        Whether the message contains keys as per RFC3156 section 7.
+
+        :return: If the message contains keys.
+        :rtype: bool
+        """
+        for part in walk(self.msg):
+            if part.get_content_type() == MIMEWrapper._keys_subtype:
+                return True
+        return False
+
+    def keys(self):
+        """
+        Get the collection of keys in this message.
+
+        :return: A collection of keys.
+        """
+        for part in walk(self.msg):
+            if part.get_content_type() == MIMEWrapper._keys_subtype:
+                key, _ = PGPKey.from_blob(part.get_payload())
+                yield key
 
     def verify(self, key):
         """