[Openid-specs-ab] Identifiers and discovery.
Mike Jones
Michael.Jones at microsoft.com
Wed Apr 13 23:40:35 UTC 2011
I agree that uniqueness is only required within the federation. But if you adopt the OpenID Foundation's position that we are trying to build open systems where any party can be a full participant, then one of the things that our architecture needs to support is precisely a global federation. (And yes, of course, being a full participant in any particular context requires that the party is appropriately trusted by the other parties with which it is interacting.) But before trust can be established, the first step is being able to identify and perform discovery on the participants in the global federation to discover their services that you need to interact with.
I obviously agree with you that any TRUST decision based on a claim must be based upon the issuer of that claim. But that's actually independent of whether the IDENTIFIER for a principal (which yes, would be used in a claim signed by an issuer) is globally unique or not.
-- Mike
From: Chuck Mortimore [mailto:cmortimore at salesforce.com]
Sent: Wednesday, April 13, 2011 4:31 PM
To: Mike Jones; Axel.Nennker at telekom.de; breno at google.com
Cc: openid-specs-ab at lists.openid.net
Subject: Re: [Openid-specs-ab] Identifiers and discovery.
On 4/13/11 4:10 PM, "Mike Jones" <Michael.Jones at microsoft.com> wrote:
Taking your viewpoint for a minute, yes, in SWD the principal will of course be interpreted by the site at which discovery is being performed. This somewhat corresponds to it being relative to an issuer, I suppose.
It really must be interpreted in the context of the issuer, else you'd have issuers asserting principals for which they are not authoritative.
As a thought experiment, are you also proposing that an audience value could/should also be similarly scoped in some manner?
In federation deployments, the issuer and audience must be unique within the federation. It's not mandatory that they are globally unique. We could go for a global federation here which would change that, but I suspect that would actually limit some use-cases.
And do you agree with my architectural statement that the same entity could be any of a principal, an issuer, or an audience restriction value? If so, the your statement that an issuer should be unique also implies that so should a principal and an audience restriction value, as they are logically of the same kind.
I agree that an entity may be playing multiple roles, however we always need to interpret a claim in the context of who is making it.
For example, at Salesforce I can act as both a SAML SP and a SAML IDP. If a customer passes me an assertion I create session for the subject relative to the issuer, and check to see if the audience is me. If I turn around and act as an IDP, the entity id I previously used for audience now becomes my issuer, and I may send the exact same subject. However, the receiving service provider needs to interpret that subject as relative to me, and not the original IDP, as I'm the one making the assertion. It would technically be possible to form multi-party claims, or to pass along claims, but in all cases you must consider the subject in the light of who's making the assertion.
Note this isn't yet arguing for or against separating them :-)
-cmort
Thanks for the thoughtful discussion...
-- Mike
From: Chuck Mortimore [mailto:cmortimore at salesforce.com]
Sent: Wednesday, April 13, 2011 4:03 PM
To: Mike Jones; Axel.Nennker at telekom.de; breno at google.com
Cc: openid-specs-ab at lists.openid.net
Subject: Re: [Openid-specs-ab] Identifiers and discovery.
When I said JWT I guess I actually meant JWT bearer token. You are correct that JWT on it's own doesn't contain a principal.
I agree that Issuer should be unique and is in JWT, SAML, etc. In practice, it's pretty difficult to enforce global uniqueness of this without some sort of discovery.
I do not believe that the text of your JWT Bearer Token profile makes "prn" globally unique, nor do I think that it should. The identifier should always be scoped to the issuer. The result may be globally unique, but prn should always be interpreted in context of who's asserting it.
-cmort
On 4/13/11 3:04 PM, "Mike Jones" <Michael.Jones at microsoft.com> wrote:
No, I don't believe that captures it accurately, as JWT <http://self-issued.info/docs/draft-jones-json-web-token.html> does not follow the first model as you wrote below. Both SWD <http://self-issued.info/docs/draft-jones-simple-web-discovery.html> and the OAuth JWT Profile <http://self-issued.info/docs/draft-jones-oauth-jwt-bearer.html> assume that the principal is a globally unique identifier. Likewise, all three of JWT <http://self-issued.info/docs/draft-jones-json-web-token.html> , SWD <http://self-issued.info/docs/draft-jones-simple-web-discovery.html> , and the OAuth JWT Profile <http://self-issued.info/docs/draft-jones-oauth-jwt-bearer.html> assume that issuer is also a globally unique identifier.
Furthermore, architecturally, a principal in one context may be an issuer in another context and an audience restriction value in a third. All need to use the same data representation for the system to architecturally hang together.
I believe that this is a strong architectural argument why https://login.salesforce.com/id/00DD0000000FH8l/005D0000001Az1u is the best choice.
-- Mike
From: openid-specs-ab-bounces at lists.openid.net [mailto:openid-specs-ab-bounces at lists.openid.net] On Behalf Of Chuck Mortimore
Sent: Wednesday, April 13, 2011 2:43 PM
To: Axel.Nennker at telekom.de; breno at google.com
Cc: openid-specs-ab at lists.openid.net
Subject: Re: [Openid-specs-ab] Identifiers and discovery.
I'd be concerned treating either 2 or 3 as an Identitfier.
As I understand it, the main debate is around the persistent identifier, and if the issuer and principal are separate entities or if the issuer is reflected in the principal. For example do we want
issuer: https://login.salesforce.com/id
principal: 00DD0000000FH8l/005D0000001Az1u
Or
principal: https://login.salesforce.com/id/00DD0000000FH8l/005D0000001Az1u
The current ConnectCore uses the first model ( calling them user_id and domain ). JWT and SAML follow the first model. I believe this is Breno's preference as well.
We've currently deployed the second model; our focus was on simplicity and discoverability of the data behind the service. It acts are both our user_info endpoint as well as a discovery service for endpoints authorized for the access_token.
Does this capture it accurately? Is so, let's just hash out the pros/cons of each approach. I'm loathe to starting issuing 3 different types of identifiers.
-cmort
On 4/13/11 1:53 AM, "Axel.Nennker at telekom.de" <Axel.Nennker at telekom.de> wrote:
You say:
1) Persistent Identifier (in the scope of the OP), never reassigned
lasjkflasdflsajfljal02384ß20183lskadjfölsafj
2) UI Identifier
Fullname: Axel Nennker
Profilepicref: https://www.google.com/s2/photos/public/AIbEiAIAAABECOzLpfXm2dn7pAEiC3ZjYXJkX3Bob3RvKihiODRmYjAxMDU0ZjdhYmVmMzI4MGZmN2I0ZWI4NWY1OThlZjQ3MmMxMAH08_TJz4ElY-WIBPBE1pmNuOStyQ (is this persistent?)
3) Contact Identifier
Work: axel.nennker at telekom.de
Private: ignisvulpis at gmail.com
Personal: axel at nennker.de
Tel: +491702275312
Right?
Is https://www.google.com/profiles/ignisvulpis in category 1? Never reassigned?
> -----Original Message-----
> From: Breno de Medeiros [mailto:breno at google.com]
> Sent: Wednesday, April 13, 2011 10:38 AM
> To: Nennker, Axel
> Cc: openid-specs-ab at lists.openid.net
> Subject: Re: [Openid-specs-ab] Identifiers and discovery.
>
> On Wed, Apr 13, 2011 at 01:15, <Axel.Nennker at telekom.de> wrote:
> >
> > Similar for me. I gave up on trying to attend because 4pm
> PT is 1am here, so I went to sleep at 23:30 and could have
> made it for midnight.
> > Anyway.
> >
> > Regarding identifiers: Some people expect that the openid
> is "fancy" and easy to distiguish.
> > Example: @t is much cooler than @AxelNennker or pt at fb.com
> is cooler than user4711 at facebook.com or
> > https://me.google.com/AxelNennker is cooler than
> https://me.google.com/users/lasjkflasdflsajfljal02384ß20183lsk
> adjfölsafj
> >
> > The uglier ones achieve the goal of beeing not reassigned
> much easier than the prettier ones.
> >
> > Display Names are an related issue: I guess that there are
> more than one "Mike Jones" in Microsoft possibly even more
> than one "Michael B. Jones". Each has a unique identifier
> which might be reassigned (after a grace period) to a new
> Michael B. Jones.
> >
> > This is not only a technical problem. People want the
> pretty identifiers.
>
> It is a technical problem. If we label the identifiers in the
> protocol as:
>
> - Identifier 1: This is persistent. Use as index in your DB. E.g: a
> numeric value.
> - Identifier 2: This is what the user wants you to represent him as.
> E.g: a name, photo, business card, etc.
> - Identifier 3: This is what the user thinks you can use to find who
> he is. E.g.: an email address
>
> > The best we can achieve, I think, is that users never see
> the unique, never reassigned (, maybe global) identifiers.
> > And that the UI for the display names is powerfull enough
> to help me to find the Mike Jones I want to reach.
> >
> > Example: Consider a blog post with comments by openid
> users. The blog received a sreg fullname and the
> openid.claimed_id and openid.identity.
> > Now it renders the fullname on the html page giving us
> comment by several Mike Jones. The "social" rendering would
> allow my user agent to render the comments from my friend
> list other than comments from people I don't know.
> >
> > Ok, this moves away from pure protocol issues and issuer
> policy to OC best practices and UI issues.
> > I am not sure how the openid abc wg "protocol" group can
> solve this non technical problems.
> >
>
> No, that's the mistake OpenID2 fell into. We should have different
> identifiers for different purposes so that it's foolproof how to deal
> with this.
>
> My proposal is that the identifier used in auth is number 1. You know
> you can't use to do anything presentational with it.
> Identifier #2 is the easiest: we return attributes at the user info
> endpoint that can be used to personalize the user experience.
> Identifier #3 is missing from the current drafts. I can see two
> sensible approaches:
>
> - Define a discovery protocol that starts by going to the issuer and
> asking what it knows about the asserted user_id. The advantage of
> doing this is that we can support both public and protected (meaning
> that user needs to consent) discovery with the same set of techniques.
>
> - Use the email or profile URL (both which will be returned as user
> attributes) as discovery starting points. This has some advantages in
> that we may be able to re-use some existing ideas and techniques.
>
> Again, what we don't want is an identifier that does all
> three jobs poorly.
>
> > -Axel
> >
> >> -----Original Message-----
> >> From: openid-specs-ab-bounces at lists.openid.net
> >> [mailto:openid-specs-ab-bounces at lists.openid.net] On Behalf
> >> Of Breno de Medeiros
> >> Sent: Tuesday, April 12, 2011 6:18 PM
> >> To: openid-specs-ab at lists.openid.net
> >> Subject: [Openid-specs-ab] Identifiers and discovery.
> >>
> >> I hope Nat's well.
> >>
> >> I was in a meeting at 3:00pm (that I scheduled after
> JBradley asserted
> >> the conference call would take place as usual at 4pm).
> When I joined,
> >> Mike Jones and Nat were dropping off the call.
> >>
> >> That left JBradley and I on the call. We had a discussion on
> >> identifiers and discovery.
> >>
> >> I would like to continue this conversation via email, as it's
> >> an important one.
> >>
> >>
> >> Currently, Google's proposal on identifiers is:
> >>
> >> - Identifiers are unique to the user and non-reassignable
> within the
> >> scope of the issuer. However, they need not be globally unique.
> >>
> >> - Id_tokens attest to the issuer and therefore provide a
> statement of
> >> the globally unique (issuer_id, user_id) pair. If the signature is
> >> based on PK, these tokens are also universally verifiable and fully
> >> portable.
> >>
> >> Looking forward to an interesting discussion,
> >>
> >> --
> >> --Breno
> >> _______________________________________________
> >> Openid-specs-ab mailing list
> >> Openid-specs-ab at lists.openid.net
> >> http://lists.openid.net/mailman/listinfo/openid-specs-ab
> >>
> >
>
>
>
> --
> --Breno
>
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