Re: Content-Digest: Digesting raw vs MIME encoded data

[Thomas Roessler <tlr@xxxxxx>]

On 2005-07-20 17:53:43 -0700, william(at)elan.net wrote:

> DKIM works on entire message. EDigest always treats the data as
> MIME part (or collection of MIME parts). There is quite a bit of 
> difference in what this means.
> 
> >* OpenPGP (RFC-3156) does signing over the MIME encoded entity
> > (see Section 5), and not the original raw form.
> >
> >* S/MIME (RFC-2633) does signing over the MIME encoded entity
> > (see Section 3), and not the original raw form.
> 
> In both of the above cases, both the original and the signature are
> then enclosed in new entity and this new entity is what is transported
> and may have its own different CTE.

Actually, no.  RFC 2045, section 6.4:

   Certain Content-Transfer-Encoding values may only be used on
   certain media types.  In particular, it is EXPRESSLY FORBIDDEN to
   use any encodings other than "7bit", "8bit", or "binary" with any
   composite media type, i.e. one that recursively includes other
   Content-Type fields.  Currently the only composite media types
   are "multipart" and "message".  All encodings that are desired
   for bodies of type multipart or message must be done at the
   innermost level, by encoding the actual body that needs to be
   encoded.

Regards,
-- 
Thomas Roessler, W3C   <tlr@xxxxxx>