Jeff & Marcus:
The S/MIME WG has finished work on the CMS compressed data type. This
Interned-Draft is ready for IETF Last Call and approval by the IESG as a
standards-track RFC.
Title : Compressed Data Content Type for S/MIME
Author(s) : P. Gutmann
Filename : draft-ietf-smime-compression-03.txt
Date : 28-Nov-00
RFC 2630 (CMS) doesn't currently contain any provisions for compressing
data before processing it. Compressing data before transmission provides a
number of advantages including the elimination of data redundancy which
could help an attacker, speeding
up processing by reducing the amount of data to be processed by later steps
such as signing or encryption, and reducing overall message size. Although
there have been proposals for adding compression at other levels (for
example at the MIME or SSL level) these don't address the problem of
compression of CMS content unless the
compression is supplied by an external means (for example by intermixing
MIME and CMS). This document defines a format for using compressed data as
a CMS content type.
Russ