Subject: RE: I-D ACTION:draft-ietf-smime-x400transport-00.txt

From: Graeme Lunt <[email-masked]>
Date: Fri, 10 Nov 2000 08:49:39 -0000

Hi, 

Here are some comments on the following draft:
> 	Title		: Transporting S/MIME Objects in X.400

The comments relate to section 2.2, and in particular to the
OID for CMS objects than are MIME encoded.

The proposal is to use a CMS-defined OID to indicate an 
S/MIME content type. However, would it not be better to use 
an OID that indicate MIME (rather than S/MIME)?

The actual MIME type (and additional parameters) will be contained
within the MIME headers, so that it is not essential to carry the
actual type in the P1 envelope. There is very little an X.400 MTA
would be able to deduce from the P1 content type alone, without
examining the MIME headers.

However, with the more generic approach I can carry arbitrary MIME
types, including multipart/signed. Obviously, a more generic approach
is not necessarily within the scope of the S/MIME group.

Comments?

Graeme

---

From: Graeme Lunt <[email-masked]>
Date: Thu, 16 Nov 2000 16:03:49 -0000

> Graeme,
> 
> I think that 'id-data' covers any MIME object, not just 
> CMS.  Since it's defined in the S/MIME standards, the door 
> is certainly open for somebody to question the scope of its 
> use as a generally applicable identifier for all
> MIME.  However, since (to my knowledge) nothing like this 
> exists elsewhere, it's the best choice available.
 
OK - that's good - that's clarified it for me. 

I'm not sure if this could be commented on in the draft, maybe 
in the context of carrying multipart/signed? 

If so, something like:

"If a multipart/signed message is to be transported in X.400, the
CMS-defined
value id-data SHOULD be used in the content-type field of the P1 envelope."

after the definition of id-data in section 2.2?

However, you may not want to do this if the draft is just looking
at transporting CMS objects, or do want start down the road of 
addressing transporting generic MIME in this draft.

Graeme