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Locating the responder's public key(s)

From: Stephen Farrell <stephen.farrell@baltimore.ie>
Date: Wed, 27 Nov 2002 13:08:13 +0000
Message-ID: <3DE4C3BD.28370EAD@baltimore.ie>
To: www-xkms@w3.org


I've an action to say how to do this. The idea is to
specify a "magic" KeyName in the locate request which is 
hardcoded into the responder. The locate response will
contain the usual things (depending on the RespondWith
etc.) and in particular can, and most likely will, 
contain a KeyName which is not the "magic" value.
Reponders with >1 key simply give back information about
all of their keys as they wish (i.e. its ok to only give
back info about some of your keys, perhaps only the more
recent ones).

"To find the key(s) with which an XKMS responder protects
messages and/or connections, an XKMS client MAY send a 
special Locate request to the responder which specifies
a fixed QueryKeyBinding containing a single "ds:KeyInfo",
which in turn contains a single "ds:KeyName" with a fixed 
case-sensitive value of "XKMSResponder". Responders MUST
return a Locate response containing the key(s) of the
responder together with whatever other information was
requested in the Locate request (via the normal RespondWith
mechanism). A minimal example request is shown below.

         <?xml version="1.0" encoding="utf-8"?>
         <LocateRequest xmlns:ds="http://www.w3.org/2000/09/xmldsig#" 
               xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" 
               Id="I9f382e970f38be00bf4e40c5c3c54a09" Service="http://test.xmltrustcenter.org/XKMS"
               xmlns="http://www.w3.org/2002/03/xkms#">
           <RespondWith>KeyValue</RespondWith>
           <QueryKeyBinding>
             <KeyInfo>
               <ds:KeyName>XKMSResponder</ds:KeyName>
             </KeyInfo>
           </QueryKeyBinding>
         </LocateRequest>

If the RespondWith field in the request asks
for a KeyName, then the client MUST NOT assume that the
value in the response will be "XKMSResponder", in fact, it
will almost certainly not be that value, though responders
MAY choose to always include such a KeyName value in 
addition to "real" key names like "XKMSRespnder@example.org".

The response to this "special" locate, MUST include a "ds:KeyValue"
but MAY include other forms of the key, e.g. X.509 certificates.

NOTE THAT THIS MECHANISM PROVIDES NO SECURITY, NOR TRUST, VALUE
WHATSOEVER AND IS SIMPLY A STANDARD MECHANISM TO RETRIEVE THE
KEYS USED BY AN XKMS RESPONDER. VALIDATING THAT THOSE KEYS 
ARE "TRUSTWORTHY", FOR ALL DEFINITIONS OF TRUSTWORTHY, IS OUT
OF SCOPE OF THIS SPECIFICATION."

An example response would be good to add, but I haven't got
one handy right now.

I'm not sure where this ought to go in the spec, but maybe
as part of the description of Locate with a pointer to the
section from the introduction to X-KISS (section 1.4). Having
the pointer in section 1.4 is probably the most important 
thing anwyay,

Cheers,
Stephen.

-- 
____________________________________________________________
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 Wednesday, 27 November 2002 08:12:04 GMT

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