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Re: XKMS

From: Yassir Elley <yassir.elley@sun.com>
Date: Tue, 27 Nov 2001 17:15:35 -0500
Message-ID: <3C041086.FA0E64B5@sun.com>
To: stephen.farrell@baltimore.ie
CC: Rich Salz <rsalz@zolera.com>, Blair Dillaway <blaird@microsoft.com>, "Hallam-Baker, Phillip" <pbaker@verisign.com>, Mike Just <Mike.Just@entrust.com>, www-xkms-ws@w3c.org
I want to make sure I understand the proposal.

If the underlying PKI is X.509/PKIX, I am particularly interested in
how the X-KISS Validate service knows which trusted public keys
and certificate policies to use when constructing a certificate chain
on behalf of a certain client.

I think the proposal I am hearing from members
of the list is that a particular XKMS service point URL
(e.g. http://xkms.xmltrustcenter.org/us_gov_bridge_ca_confidential)
would be configured to use particular trusted public keys and certificate
policies (in this case, the bridge CA's public key and a certificate policy
of confidential) and would declare these trust semantics on some web page.

An XKMS client would have to be familiar with the trust semantics
for a particular XKMS service (by going to the web pages of several
XKMS services where the semantics are described) and the client would
invoke the particular service that happened to use the trust anchors and
cert policies he wanted to use.

So, if a client wanted to use three particular trusted roots, they would have to find a service
that would have those three trusted roots. If they wanted to use four trusted roots,
they would have to find a different service that used those four trusted roots. If
they wanted to use four trusted roots and wanted every certificate in the chain
to have a particular certificate policy, they would have to find a third service that
supported that permutation.

Is my understanding of the proposal correct?

-Yassir.

Stephen Farrell wrote:

> All,
>
> I'd tend to agree that the URL level "trust" model is the thing to go
> with for xkms.
>
> Two further questions:-
>
> 1. Is there a specific issue with preventing replay of a reponse from a
> different service URL (but the same responder key etc.), or, is there a
> general issue with correlating requests and responses? That is, is the
> fix likely to be alongs the lines of "include the service URL in a signed
> response" or "include a random value in the request and that same value
> in the corresponding response"
>
> 2. Could anyone who disagrees with using service URLs as "trust selectors"
> or who thinks we *need* to specify a finer-granularity of something (whether
> in request or response) please speak up in the next couple of days?
>
> Stephen.
>
> Rich Salz wrote:
> >
> > > You wouldn't actually need to have a different WSDL description per URL.
> >
> > No, you don't HAVE to have them; I was putting too much on the "private"
> > notation made in the current spec about the service URL.
> >
> > I'd expect someone who was providing an outsourced service would want to
> > keep each binding in a separate file, but that's just a guess.
> >
> > > Either suggested approach for handling multiple trust models would work.
> > > I think the real issue is whether the folks planning to build such
> > > services believe one of them makes their life simpler.  I tend to favor
> > > the URL model, but admit this view is based on fairly limited thinking
> > > about how I might want to deploy such a system.
> >
> > Same here.
> >
> > > I can't imagine clients trying to deal
> > > dynamically with what trust models are supported by a given service.
> > > Going to web page to get info on supported trust models (like current
> > > CPS docs for CAs) seems adequate to me.
> >
> > Agreed.
> >         /r$
> > --
> > Zolera Systems, Your Key to Online Integrity
> > Securing Web services: XML, SOAP, Dig-sig, Encryption
> > http://www.zolera.com
>
> --
> ____________________________________________________________
> Stephen Farrell
> Baltimore Technologies,   tel: (direct line) +353 1 881 6716
> 39 Parkgate Street,                     fax: +353 1 881 7000
> Dublin 8.                mailto:stephen.farrell@baltimore.ie
> Ireland                             http://www.baltimore.com
Received on Tuesday, 27 November 2001 17:19:52 EST

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