RE: [security-services] SAML Authn Ctx Combination Spec

From
Thomas Wisniewski <>
Date
2006-07-07T13:47:40+00:00
ID
Thread
RE: [security-services] SAML Authn Ctx Combination Spec
Title: RE: [security-services] SAML Authn Ctx Combination Spec

Paul, I agree with your sentiments.

Perhaps I'm looking at a diff version (5/18/06), but what you are proposing obviously changes the schema and the example (you indicated that neither would change). The current spec proposes a single element RequestedAuthnContexts that was nested whereas the changes you propose below would indicate a list of RequestedAuthnContext elements inside a single RequestedAuthnContexts element. So the schema would changes as you indicated below and the example would change to

<RequestedAuthnContexts RACComparison="all">

  <RequestedAuthnContext RACComparison="exact"> 

    <saml:AuthnContextClassRef...></..>

  </RequestedAuthnContext>

  <RequestedAuthnContext RACComparison="exact"> 

    <saml:AuthnContextClassRef...></..>

  </RequestedAuthnContext>

</RequestedAuthnContexts>

Tom.

> -----Original Message-----

> From: Paul Madsen [mailto:] 

> Sent: Friday, July 07, 2006 8:27 AM

> To: Thomas Wisniewski

> Cc: OASIS SSTC

> Subject: Re: [security-services] SAML Authn Ctx Combination Spec

> 

> 

> Thomas Wisniewski wrote:

> >

> > It would seem ok, but a bit awkward.

> >

> why?

> >

> > Would your example be changed to

> >

> > <RequestedAuthnContexts RACComparison="all">

> >   <saml:AuthnContexxtClassRef...></..>

> >   <RequestedAuthnContexts RACComparison="exact"> 

> >     <saml:AuthnContexxtClassRef...></..>

> >   </RequestedAuthnContexts>

> > </RequestedAuthnContexts>

> >

> > Is that whay you're trying to say?

> >

> the example wouldn't change. I was proposing leaving the 

> schema as is, 

> merely loosening the text that disallowed multiple 

> <RequestedAuthnContexts> elements in a message

> >

> > Why not just have a top level (maxOccurs="1") RequestedAuthnContext

> > element that then defines an unlimited number of 

> RequestedAuthnContext 

> > elements that have a comparison operator attribute and contain the 

> > saml AuthnContextClassRef element.

> >

> So, something like

> 

> <complexType name="RequestedAuthnContextsType">

>    <sequence>

>         <element ref="RequestedAuthnContext" maxOccurs="unbounded"/> 

>    </sequence>

> </complexType>

> 

> <complexType name="RequestedAuthnContextType">

>    <sequence>

>         <element ref="saml:AuthnContextClassRef" 

> maxOccurs="unbounded"/>

>    </sequence>

>    <attribute name="RACComparison" type="anyURI" 

> use="optional"/> </complexType>

> 

> we wanted the comparison operator on the top-level element as well. 

> Given that, we tried to minimize the number of new elements  by 

> introducing the nesting.

> 

> Additionally, the above forces an SP to insert the 

> <RequestedAuthnContext> element even when all they want to do 

> is give a 

> list of <AuthnContextClassRef>s they want combined.

> >

> > Do I need to satisfy all the RequestedAuthnContext elements in order

> > to satisfy the RequestedAuthnContexts element? I.e., in 

> your example 

> > you say this is an AND -- so I assume the answer is yes. I.e., you 

> > cannot express that you are requesting either AC-1 or AC-2 

> (exactly) 

> > in your schema.

> >

> the 'all' on the outermost <RequestedAuthnContexts> in the example 

> requires you to satisfy both. We don't have an 'either' but 

> neither does 

> core SAML.

> >

> - 

> Paul Madsen             e:paulmadsen @ ntt-at.com

> NTT                     p:613-482-0432

>                         m:613-302-1428

>                         aim:PaulMdsn5

>                         web:connectid.blogspot.com 

>