Re: T2 Retry with Delivery Receipt

[Dan Weinreb <dlw@exceloncorp.com>]

   Date: Thu, 20 Sep 2001 22:32:13 -0400
   From: Rich Salz <rsalz@zolera.com>

				     SSL/TLS -- so perhaps saying "use ssl
   if you're worried about tcp bitrot" is the way to go.

Unfortunately, SSL/TLS also requires that key material be generated
and set up.  Also, if we're going to do this at all, it seems like
doing it end-to-end is best for the usual reasons (ref. classic paper
by Saltzer et. al.) and because you'd like to get the benefits of
error-checking even if you go through a path of intermediates in which
some hops aren't done via SSL/TLS.

   It ends up being an awful lot of work.  Are there any other IETF-spec'd
   TCP-based services that do this?

I think the MIME level looks like the right place to put the
error-detecting information.  Unfortunately, the MIME type we want
does not seem to be standardized.  RFC 1847 appears to deal with
signatures and encryption but not just plain message digests.

I didn't look into S/MIME; the whole idea of using both XMLDSIG and
S/MIME in the same protocol boggles my mind...