Re: Any drafts for IMAP4/TLS and/or POP3/TLS

On Sat, 30 Aug 1997, David Brownell wrote:
> First, I'd like an explicit statement that when the TLS connection
> ends, so does the IMAP4 or POP3 connection.  You don't now have a
> STOPTLS command, which would be necessary to do that securely; and
> I think it's fine (and desirable!) that there be no such command.

The TLS session layer includes an "end TLS" message which doesn't
explicitly end the underlying TCP connection.  If you think it should,
please suggest wording.  I'll note that LDAPv3 group has decided that it
shouldn't end the TCP connection.

> Third, I think some language is necessary with respect to X.509
> certificate profiling.  Probably these five things would suffice:
>
> One could argue that TLS or PKIX should address this fourth set
> of issues, but I'd say otherwise.  All of them are cert policy
> issues which affect interop for this application, but perhaps
> not for others.

My general inclination is that most of this stuff really belongs in the
TLS specification, as part of the definition of the
TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA cipher suite.  Otherwise this would have
to be duplicated in every profile, which seems silly to me.  Is there
really a reason to use TLS without binding the certs to the hostname, or
using the same algorithm to certify the key that the key uses to sign
values?  I'm not trying to brush these issues under the carpet because I
agree they're very important, but I'd prefer these issues were addressed
in one place, as the vast majority of TLS profiles will have exactly the
same requirements.

In addition, I know very little about X.509 certs (I'm an IMAP/POP guy --
not an OSI/ASN.1 guy), so I don't believe I could write good text to
address the issues you've raised.  If you would be willing to write text
describing a TCP/TLS profile for the TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA
cipher suite, I'm sure we'll be able to find a home for it.  If the TLS
group doesn't want it, it could either be a standalone document which TLS
profiles can reference or I'll drop it in this profile if people think
that's a good idea.

> Arguably such a set of parameters should be in the TLS spec.
> But, it's not there now, and not looking to be.  Perhaps it'd
> be approprate as a separate informational RFC, rather than as
> part of either the IETF's TLS or {IMAP4,POP3}/TLS specs.

It sounds like the sort of thing that would make a useful informational
RFC.  In fact, why not go a bit futher and include a suggested file format
for storing them.  See the section on /etc/tpasswd.conf at
<http://srp.stanford.edu/srp/motivation.html> for want seems like a
reasonable proposal to me. 

		- Chris