Subject: [Simple] Presence Authorization Discussion D: Conflicting Information to Different Watchers

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 11 Oct 2004 03:54:07 -0400

Markus raised an issue quite some time back, about whether or not you 
could give conflicting information to different watchers, and how this 
was done within the framework of the authorization policy. The answer 
was that the privacy model really only allowed you to remove information 
from the document, not set information to appear differently to one user 
vs. another. Thus, if you want to send different information to 
different watchers, you'd have to include both tuples in the document, 
with different class perhaps, and then use the authorization rules to 
send tuples with one class to one set of watchers, and tuples of another 
class to another. If both tuples were in a doc sent to a watcher, well - 
oops.

The data model nicely addresses this. It says that privacy filtering is 
just one step of the overall processing of a presence document. 
Composition is the stage which is really responsible for resolving 
conflicts, producing a document were there is only one instance of each 
service or device. The model is explicit, in fact, that you can only 
have one instance of a service or device (identified by service URI or 
device ID respectively) per document. THis eliminates the possibility of 
conflicting device or service information going out to a watcher.

The implication is that our composition policies will need to allow us 
to create different documents for different watchers, with potentially 
quite different views of my state. That's fine; composition policy is 
NOT privacy filtering, and the fundamental rules of privacy management 
(positive permissions only, privacy safety, etc.) do not apply.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                600 Lanidex Plaza
Chief Technology Officer                    Parsippany, NJ 07054-2711
dynamicsoft
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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From: [email-masked]
Date: Thu, 28 Oct 2004 15:24:09 +0300

We just need to make sure that the composition policy does not merge <person>, <device> or <tuple> elements that were intended to be sent to different watchers.

/Hisham

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]]On Behalf
> Of ext Jonathan Rosenberg
> Sent: 11.October.2004 10:54
> To: Simple WG
> Subject: [Simple] Presence Authorization Discussion D: Conflicting
> Information to Different Watchers
> 
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