Subject: RE: Comments on draft-ietf-pkix-ac509prof-05.txt

From: "Linn, John" <[email-masked]>
Date: Fri, 27 Oct 2000 16:38:23 -0400

Dale wrote:

> Hi Anders,
> 
> Actually, I'm hopeful but not sure.
> 
> Had you asked me three or four years ago to predict when I 
> could routinely exchange secure email with others or login to 
> a commercial web server using a private key / certificate 
> rather than a simple user name and password, I would have 
> guessed a year, maybe 18 months at the outside.  That hasn't 
> happened yet and we have to wait for that to be put into 
> place before subsequent elements, like Timestamp servers and 
> ACs, can come into play.
> 
> So, we appear to be in a similar position to the people who 
> worked on x.509 v1 certificates back before SSL and S/MIME 
> were proposed then standardized -- they may have felt that 
> good things were likely to happen but they must have been 
> taking quite a lot on faith early on.

Recalling those pre-PKIX days, when PEM was the motivating driver for
considering PKI's application to the Internet, makes me conclude that faith
should be carefully measured.  As experiences suggest, infrastructures
usually take longer to deploy than is first anticipated; the "inevitable"
can spend a long time "just around the corner" and may or may not still be
inevitable if and when it emerges, depending on how the world has changed in
the interim.  PKI is now increasingly mainstream in the Internet (yes!!),
but this result follows more than a decade's worth of activity.  

I believe that a separate PMI can afford powerful generality and that
specification of ACs should be pursued. Against the historic backdrop,
however, I'm also concerned that such a PMI may take a long time to become
pervasive.  Given this concern, the prospect of placing attributes in PKCs
and thereby leveraging the now-existing PKI directly and incrementally seems
attractive, where consistent with organizational responsibilities and
attribute lifetimes. 

--jl

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From: Polar Humenn <[email-masked]>
Date: Fri, 27 Oct 2000 17:02:24 -0400 (EDT)

> attractive, where consistent with organizational responsibilities and

I agree. A public key can be cross certified by an "attribute authority"
merely by issuing another PKC hand it back to the Holder. The holder can
then use that certificate to certify that he indeed does have those
privileges should he have the capability, such as in SSL, to deliver the
Relying Party the certificate which only defines the privilege context in
which the user is using its authentication. Granted the CA/RA of the
original public key would be different, but that information may be
included in the PKC as an extension should that matter to the Relying
Party (it might and it might not, depending on RP's belief in the
attribute authority's due diligence).

I also agree with Bob Jeuneman that when coming to attribute authorities,
there may need to be certificate chains of authorities constraining, just
as the name constraints work in PKCs, the ability to grant only certian
privileges, and the prevention of granting certian privileges to
constituents. I don't see that working currently with ACs.

However, I imagine if somebody will build some of this stuff, somebody
will buy (or get sold) it somewhere down the line, and spend a lot of time
and money integrating their applications with it. I don't see that as a
bad thing, that's the way we all make money. 

Cheers,
-Polar

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