The IESG has approved the Internet-Draft 'Compressed Data Content Type
for S/MIME' <draft-ietf-smime-compression-07.txt> as a Proposed
Standard. This document is the product of the S/MIME Mail Security
Working Group. The IESG contact persons are Jeffrey Schiller and
The Cryptographic Message Syntax (CMS) data format which is used by
SMIME does not provide for compression of content prior to
encryption. Because encrypted data is incompressible, compression
applied to an enciphered SMIME message will not prove helpful
(whether done at the IP layer, or at a lower layer such as in a
Compressing data prior to encryption provides two important
1) It decreases the size of a message.
2) It makes cryptographic analysis of the contained message more
difficult for compressed data has less redundancy for the
cryptanalyst to exploit.
This document provide a mechanism for adding compression prior to
encryption in SMIME by being applied at the CMS layer.
Working Group Summary
This document has the consensus of the SMIME Working Group.
This document has been reviewed for the IESG by Jeffrey I. Schiller.