diff --git a/lib/sup/crypto.rb b/lib/sup/crypto.rb
index <HASH>..<HASH> 100644
--- a/lib/sup/crypto.rb
+++ b/lib/sup/crypto.rb
@@ -88,7 +88,7 @@ EOS
     control.body = "Version: 1\n"
 
     envelope = RMail::Message.new
-    envelope.header["Content-Type"] = 'multipart/encrypted; protocol="application/pgp-encrypted"'
+    envelope.header["Content-Type"] = 'multipart/encrypted; protocol=application/pgp-encrypted'
 
     envelope.add_part control
     envelope.add_part encrypted_payload
Stop double quoting the protocol when sending encrypted emails

It was the case that when encrypting emails, the content-type
header line would look like:
Content-Type: multipart/encrypted; boundary="=-<I>-<I>-<I>-<I>-1-="; protocol=""application/pgp-encrypted""
It appears that rmail adds the extra quotes, so this change
makes the protocol unquoted to start with, so we end up with
correct quoting.