Re: Global PKI on DNS?

[Eric Rescorla <ekr at rtfm.com>]

"RL 'Bob' Morgan" <rlmorgan at washington.edu> writes:

> On 12 Jun 2002, Eric Rescorla wrote:
> 
> > Nearly all of the major IETF security protocols (TLS, IPsec, OpenPGP)
> > already have their own certificate discovery mechanism and therefore
> > have no need to have certificates in the DNS. TLS, in particular,
> > wouldn't know what to do with them if they were there.
> 
> This is missing the point.  Sure, TLS provides the ability for both
> clients and servers to send certificate chains to their peers as part of
> session startup.  But what happens if I'm a client, and the chain the
> server sends me ends in a cert that I don't know about?  I *might* be able
> to construct a path from one of my trusted roots to one of the certs in
> the path it sends me, and hence be able to validate the whole chain and
> hence successfully start the session, instead of failing.  But I can do
> this only if I can discover certs that *aren't* either in the set it hands
> me or in my local set, and TLS says nothing about how to do this. 
Yes, because it's an edge case. TLS certificate chains almost always
end either implicitly or explicitly in self-signed certs, which you
either trust or you don't. Trying to chain to some other root is highly
unlikely to work. 

We barely have any PKI at all, I think it's a little early to start
worrying about cross-certification.

-Ekr

-- 
[Eric Rescorla                                   ekr at rtfm.com]
                http://www.rtfm.com/