RE: New issue on duplicate assertions of a single type in an alternative: 4583

>It does not cover multiple Encryption assertions

It is unclear what 'Encryption' assertion that you are talking about. If the assertion is 'EncryptedParts' then the answer is in Paul's e-mail below.

Regards,

Asir S Vedamuthu
Microsoft Corporation


From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Ashok Malhotra
Sent: Thursday, May 31, 2007 2:41 PM
To: Paul Cotton
Cc: public-ws-policy@w3.org
Subject: RE: New issue on duplicate assertions of a single type in an alternative: 4583

Re. your point 2. this covers duplicate EncryptedParts assertions which indicate which parts of a message should be encrypted.
It does not cover multiple Encryption assertions which indicate whether or not encryption should be applied to a message.
This, to my mind is the more important question.  If this assertion is duplicated, should encryption be applied twice?

All the best, Ashok

________________________________
From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Paul Cotton
Sent: Thursday, May 24, 2007 1:52 PM
To: Ashok Malhotra
Cc: public-ws-policy@w3.org
Subject: RE: New issue on duplicate assertions of a single type in an alternative: 4583

>The framework document indicates that duplicate instances of an assertion type are allowed in a policy alternative.

You are correct.  This is covered by the following two pieces of text in the CR Framework document [1]:

Section 3.2: A policy alternative MAY contain multiple assertions of the same type. Mechanisms for determining the aggregate behavior indicated by the assertions (and their Post-Schema-Validation Infoset (PSVI) (See XML Schema Part 1 [XML Schema Structures]) content, if any) are specific to the assertion type and are outside the scope of this document.
Section 4.5: See Section 3.2 Policy Alternative for mechanisms for determining the aggregate behavior indicated by multiple assertions of the same policy assertion type.
In fact the Section 3.2 text was in the member submission version of WS-Policy [2].

>1. Should duplicate instances of the same type be allowed in a policy alternative before and after intersection.

Yes.  In fact if we want to carry out our Charter which indicates we should be as backwards as compatible as possible [3], then I think we need a very strong reason to change this text.

>2. Do we need to add guidance re. removing duplicate assertions from an alternative.

Personally, I think the Section 3.2 text covers what the Framework needs to say about duplicate assertions.

>2. What is the default semantic re. the resulting behavior if there is more than one instance of an assertion in an alternative.

Section 3.2 says that the semantics for duplicate assertions are covered by domain specific semantics.

For example, during the WG F2F meeting you asked what a WS-SecurityPolicy implementer should do if they encountered duplicate EncryptedPart assertions in a policy.  I believe this is handled by the following text in SecurityPolicy just as suggested in the Ws-Policy Framework text [4]:

There MAY be multiple EncryptedParts assertions present. Multiple EncryptedParts assertions present within a policy alternative are equivalent to a single EncryptedParts assertion containing the union of all specified message parts. Note that this assertion does not require that a given part appear in a message, just that if such a part appears, it requires confidentiality protection.
I hope this helps.

/paulc

[1] http://www.w3.org/TR/2007/CR-ws-policy-20070330/
[2] http://www.w3.org/Submission/WS-Policy/#Policy_Alternative
[3] http://www.w3.org/2006/04/ws-policy-charter.html
[4] http://www.oasis-open.org/apps/org/workgroup/ws-sx/download.php/23821/ws-securitypolicy-1.2-spec-cs.pdf

Paul Cotton, Microsoft Canada
17 Eleanor Drive, Ottawa, Ontario K2E 6A3
Tel: (613) 225-5445 Fax: (425) 936-7329
mailto:Paul.Cotton@microsoft.com

________________________________
From: public-ws-policy-request@w3.org [mailto:public-ws-policy-request@w3.org] On Behalf Of Ashok Malhotra
Sent: May 24, 2007 3:01 PM
To: public-ws-policy@w3.org
Subject: New issue on duplicate assertions of a single type in an alternative: 4583


The framework document indicates that duplicate instances of an assertion type are allowed in a policy alternative.  During yesterday's and today's discussion a number of questions arose about this situation.

1. Should duplicate instances of the same type be allowed in a policy alternative before and after intersection.

2. Do we need to add guidance re. removing duplicate assertions from an alternative.

2. What is the default semantic re. the resulting behavior if there is more than one instance of an assertion in an alternative.

All the best, Ashok