[OpenID] Signing method for XRD

Tue Jun 16 11:52:02 UTC 2009

Peter,

The Resource or RP/STS is part of the RP's trust domain not the users,  
or the OP's in IMI (the protocol formerly known as infocard) or WS-Fed.

I think you are proposing the user having a second Resource OP that is  
delegated to from the users XRD.

That is possible but the second OP will still ned to authenticate the  
user in some way.

In the WS-Fed case the RP asks the RP/STS for a token and the RP/STS  
asks the user to select a card that gets a token from the users IP/STS.
The sequence unwinds in reverse order for the reply.    This can work  
because the RP and RP/STS have pre established trust.

I suspect oAuth might be more appropriate for this second OP than  
openID.

If I remember correctly Sxip's protocol supported something like what  
you are proposing.

John B.

On 16-Jun-09, at 6:03 AM, Peter Williams wrote:

> how far do folks intend to go?
>
> I was watching the mix09 video from microsoft, in which an openid  
> relying party happens to ping an STS to convert a subject name into  
> a role (using the microsoft attribute/claim mapping rule system).  
> Embodied in ACS, the STS is their multi-tenant resource STS - in the  
> cloud (presumably engineered for stateful management of 10,000s of  
> tenants, each with thousands of outstanding wsfed/SAML2 sessions).   
> Some library code implements ws-trust - as the medium to get the  
> inbound token from IDP_OP translated into a transformed token with  
> roles/permissions, providing developers with a simple object API  
> rather than access to the details of the ws-trust protocol.
>
> There seems little reason why the same RP could not be pinging a  
> second "resource" OP using openid auth , rather than an STS via ws- 
> trust  - particularly if its AX support has a role-mapper and  
> permissioning engine rather than an attribute store. But presumably  
> (i) there would be have to be "domain-delegation" from the RP to  
> such a resource-OP allow the OP to do attribute mapping for a given  
> subject name for which it is not the provisioning/controlling/ 
> registering/authenticating/etc authority, (ii) the OP could have to  
> be interacting with the Resource-OP using the user's delegated name  
> (rather than pseudonym name released by the IDP-OP).
>
> Do folks see a role in openid land for a domain-tenant powered OP in  
> the cloud, supporting RPs needs for transformation? where signed XRD  
> conveys the trust between RP and resource STS/OP (rather than trust  
> in certs as in the microsoft example of the relationship between an  
> RP and its ACS-delivered resource STS)?
>
>
> ________________________________
> From: general-bounces at openid.net [general-bounces at openid.net] On  
> Behalf Of John Bradley [john.bradley at wingaa.com]
> Sent: Sunday, June 14, 2009 7:50 AM
> To: general at openid.net
> Subject: Re: [OpenID] Signing method for XRD
>
> Peter,
>
> Yes some of us see the possibility of XRD as signed meta-data being  
> a useful alternative to X.509 eventually.
>
> If we have an signature method that supports enveloping signatures,   
> XRD will be more useful for those applications.
>
> We can opt for the simplest signing, that of signing the binary  
> representation of the XRD and keeping the signature in a detached  
> file.
> This may make life simpler for scripting languages dealing with  
> cannonicalization  but at the cost of making it awkward to deal with  
> in other environments where having the signature in the same  
> document is very useful.
>
> Full XMLDsig is ugly because of qnames and other issues.   We are  
> proposing a constrained implementation that eliminates most of the  
> cannonicalization complexities,  but is still compatible with  
> existing libraries.
>
> John B.
> On 10-Jun-09, at 12:10 PM, general-request at openid.net<mailto:general-request at openid.net 
> > wrote:
>
> Date: Wed, 10 Jun 2009 09:10:44 -0700
> From: Peter Williams <pwilliams at rapattoni.com<mailto:pwilliams at rapattoni.com 
> >>
> Subject: Re: [OpenID] Signing method for XRD
> To: Santosh Rajan <santrajan at gmail.com<mailto:santrajan at gmail.com>>,  
> "general at openid.net<mailto:general at openid.net>"
> <general at openid.net<mailto:general at openid.net>>
> Message-ID:
> <BFBC0F17A99938458360C863B716FE46398DCE8FDD at simmbox01.rapnt.com<mailto:BFBC0F17A99938458360C863B716FE46398DCE8FDD at simmbox01.rapnt.com 
> >>
> Content-Type: text/plain; charset="us-ascii"
>
>
> my first reaction was ugh - xml-dsig has its own inband mechanism  
> for referencing keying material - and here is openid/xrd doing yet  
> another standard for verifying signatures and validating the  
> supporting keying material (probably poorly).
>
> My second reaction on reflection was that xml-dsig is rarely used to  
> its full potential. Its typically used as a PKCS7 signing and  
> sealing emulation modes, with an XML centric view of the world -  
> with no particular benefit. But, if xml dsig fully uses its external  
> references, and the references are to a world of XRD files which are  
> TRUSTED to act as a key distribution mechanism, things get rather  
> more interesting. In that world, the XRD is becoming a certificate,  
> as we know it - and one whose format and semantics would enable it  
> to go beyond the staid ol X.509 cert chains and benefit the full  
> expression power of xri queries and XRI resolution.
>
> What the X.509 v3 format work took part (divorcing asymmetric key  
> management from dap/ldap resolution), XRI/XRD may be putting back  
> together: query-based named-key resolution supporting trust fabric  
> meshes.
>
>