RE: Ordering between assertions

the security policy authors have included this in their specification.
if others chose to, they can also specify ordering properties.

Maryann

6.3 [Protection Order] Property
This property indicates the order in which integrity and confidentiality 
are applied to the message, in cases where both integrity and 
confidentiality are required:

EncryptBeforeSigning
Signature MUST computed over ciphertext. Encryption key and signing key 
MUST be derived from the same source key unless distinct keys are 
provided, see Section 7.5 on the AsymmetricBinding.
SignBeforeEncrypting
Signature MUST be computed over plaintext. The resulting signature SHOULD 
be encrypted. Supporting signatures MUST be over the plain text signature.

The default value for this property is 'SignBeforeEncrypting'.



"Rogers, Tony" <Tony.Rogers@ca.com> 
Sent by: public-ws-policy-request@w3.org
08/14/2007 09:12 PM

To
Christopher B Ferris/Waltham/IBM@IBMUS, <ashok.malhotra@oracle.com>
cc
"Anish Karmarkar" <Anish.Karmarkar@oracle.com>, <public-ws-policy@w3.org>, 
<public-ws-policy-request@w3.org>
Subject
RE: Ordering between assertions






I would suggest that Ashok open an issue for this.
 
I do agree that the effects / behaviours corresponding to some assertions 
will be applied in some order (and indeed, I would require that order to 
be specifiable by the originator of the message - I have had requests for 
"sign then encrypt" as well as "encrypt then sign" - so the order must not 
be specified by fiat outside the message). 
 
While I can appreciate the desire to avoid specifying the order of 
applying the behaviours, I think the line has been crossed when suggesting 
the possibility of an ordering assertion. By suggesting it, I believe the 
WG is obligated to provide an example of a possible form :-)
 
Tony Rogers
tony.rogers@ca.com
 

From: public-ws-policy-request@w3.org 
[mailto:public-ws-policy-request@w3.org] On Behalf Of Christopher B Ferris
Sent: Wednesday, 15 August 2007 10:42
To: ashok.malhotra@oracle.com
Cc: Anish Karmarkar; public-ws-policy@w3.org; 
public-ws-policy-request@w3.org
Subject: Re: Ordering between assertions


Ashok, 

Are you opening a new issue? or simply making an observation? 

If the former, please create a bugzilla issue for this so that we can 
track it. 

Cheers, 

Christopher Ferris
STSM, Software Group Standards Strategy
email: chrisfer@us.ibm.com
blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
phone: +1 508 234 2986 

public-ws-policy-request@w3.org wrote on 08/13/2007 06:39:12 PM:

> 
> Consider a policy that includes Reliable Messaging, Header Encryption 
> and Signing.
> It seems clear that the Reliable Messaging headers should be added 
> first, the headers encrypted next that finally the signature created and 

> affixed.  At the receiving end, the signature should be checked first, 
> the headers decrypted next and finally the Reliable Messaging headers 
> processed.  This implies that the Policy assertions be processed in a 
> definite sequence.
> 
> The framework document says:
> "Assertions within an alternative are not ordered, and thus aspects such 

> as the order in which behaviors (indicated by assertions) are applied to 

> a subject 
> <http://www.w3.org/TR/2007/PR-ws-policy-20070706/#policy_subject> are 
> beyond the scope of this specification. However, authors can write 
> assertions that control the order in which behaviors are applied."
> 
> It seems to me that this is a fairly common scenario and it may be good 
> to show an example, in the Guidelines document,.of how such an ordering 
> assertion may be authored.
> -- 
> All the best, Ashok
>