Network bandwidth is one relevant consideration, but storage consumption may
be even more strongly motivating for messaging-oriented protocols like CMS.
It's quite possible that some CMS-encapsulated objects (including, but not
limited to, S/MIME messages) will be stored for long-term reference by
recipients. It could be convenient for them to be sent and received in a
compressed form, to avoid the need to reprocess them for efficient storage.
--jl
-----Original Message-----
From: Darren Harter [mailto:darren(_dot_)harter(_at_)entegrity(_dot_)com]
Sent: Thursday, July 29, 1999 4:41 AM
To: ietf-smime(_at_)imc(_dot_)org
Subject: RE: Compressed data type for S/MIME
All,
I've been watching this thread with interest and I'd like to
raise a few observations/questions/issues. I'd like to make
the point first though that what follows is not intended to
contradict or counter any of the messages that proceed this
one - I'd just like to widen the debate a little and firm up
my understanding of the relative merits of performing
compression or not.
1. Are we really concerned with saving network bandwidth
these days? If we are then clearly compression is essential.
If we're not, why are we discussing it at all?
2. If we need compression, how does the algorithm complexity
of zlib compression algorithm compare with 3DES encryption?
What's its average compression rate?
e.g. How does the time to process the data compare in the following:
a. Encrypt 10Mb of plaintext with 3DES
b. Compress 10Mb to (say) 5Mb using zlib and then
encrypt using 3DES.
3. If b. takes longer than a. and we're not that concerned
with network bandwidth why bother compressing?
I think my bottom line questions here are: how important is
processing speed compared to network bandwidth? and how much
time does this aspect of the processing take compared with
all those cert/crl processes going on in S/MIME and/or CMS?
Regards,
Darren
--------------------------------------------------------------
----------
Darren Harter B.Sc (Hons) CEng MBCS
Application Development Group, UK
Entegrity Solutions Corp.
Tel: +44 1452 371383
Fax: +44 1452 371384
Cell: +44 7801 812850
Email: mailto:darren(_dot_)harter(_at_)entegrity(_dot_)com
http://www.entegrity.com
http://www.entegrity.co.uk