Re: [wsn] Use case for double opt-in and other mechanisms for preventingunwanted subscriptions

[Tom Maguire <tmaguire@us.ibm.com>]

Is it not sufficient that security assertions or claims about the sender
handle this?  Why is the 'notify' MEP (as opposed to all the other MEPs the
Notification consumer exposes) given special treatment in this regard?  I
do not understand why composition with WS-Security does not handle the
requirement.

Tom

Problems cannot be solved at the same level of awareness that created
them.  —Albert Einstein
T o m   M a g u i r e

STSM, On Demand Architecture
Poughkeepsie, NY  12601


                                                                           
             David Hull                                                    
             <dmh@tibco.com>                                               
                                                                        To 
             11/22/2004 03:07          wsn@lists.oasis-open.org            
             PM                                                         cc 
                                                                           
                                                                   Subject 
                                       [wsn] Use case for double opt-in    
                                       and other mechanisms for preventing 
                                       unwanted subscriptions              
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




The Use Case:

Because subscriptions may be made by a third party on behalf of the actual
consumer, there must be some means of ensuring that the consumer only
receives notifications it is interested in.  There are many possible
relationships among the subscriber, producer and consumer.  For example
      The subscriber is provably the same entity as the consumer.  The
      producer should accept any subscription from the consumer on its own
      behalf.
      The subscriber, producer and consumer are all in the same isolated
      environment and implicitly trust each other.  Again, there is no need
      to restrict subscription.
      The consumer has supplied the subscriber with a secure token (which
      the NP is able to recognize) authorizing it to subscribe on the
      consumer's behalf.  The NP should reject subscription requests
      without proper authorization.
      The consumer does not know the subscriber even exists, but might be
      interested in some unsolicited subscriptions.  It is thus up to the
      producer to determine interest, generally by sending a test message
      under the double-opt-in pattern.
      Either of the previous cases may apply.  The producer should look for
      the appropriate secure token, and if it's missing, ask the consumer
      via double-opt-in.
      A notification producer may impose a quota on subscriptions directed
      toward a given consumer (perhaps because the consumer asked it to).
      In this case, a given subscription may either succeed or fail
      depending on what other subscriptions are open.
Clearly, many more variants are possible.
Discussion:
In cases where the producer must query the consumer before beginning the
subscription, arbitrarily much time may pass between the subscription
request and the definitive answer.  This asynchronous reply would best be
handled through a callback mechanism, but we would probably rather not
build this into the core subscribe exchange.  In the case of secure tokens,
it might make sense for the subscriber to be able to submit and verify a
token for a particular consumer once (in the context of a secure
connection) instead of passing it with every subscribe request.

It would be desirable to push all such message exchanges out of the core
Subscribe request/response.  This is one driver behind having the
subscriber and producer be able to first negotiate a "destination" cookie
and then use that cookie in the actual subscribe request.  Naturally, this
is not the only way to cover these use cases.