Re: [Uta] Opportunistic encryption and authentication agility

[Eliot Lear <[e-mail]>]

Hi Michael,

On 3/24/14, 6:32 AM, Michael Richardson wrote:
> Keith Moore <[e-mail]> wrote:
>     > Note that as far as I can tell, it will still be possible to implement a
>     > client that supports only OE; it just doesn't bother verifying the cert /
>     > DNSSEC + TLSA record / pinned key / whatever.    Whether that client will
>     > conform to the recommendations that this group produces, is a different
>     > question.   But offhand I don't know of a way to keep such clients from
>     > working (though for new protocols, it might be nice if there were one).
>
> Well, that's not really correct advice.
> The correct advice is that:
>    If the client is unable to verify the cert via (some set of methods,
>    locally determined), that it treats the connection as if it was
>    unencrypted, according the same level of (un)privileges.

Perhaps I misread Keith's note, but I didn't take it as advice.  Rather
he's assessing the current situation. 

Your advice seems reasonably applicable for mail, at least at first
blush.  But different protocols have different anticipated environments,
and I took Trevor's email Keith's replies to be more general
statements.  My favorite example going the other way is SCIM, where you
would have to be crazy not to fully validate both ends.  I don't know if
it's in the UTA charter, but we discussed developing a general guidance
document in the STRINT workshop to at least help sort out the classes of
(at least envisaged) use.

Eliot