[OpenID] Too many providers... and here's one reason

Tue Sep 16 15:22:57 UTC 2008

I just love a good topic to get the creative juices flowing from so many
brainy people.  Thanks all for your ideas.
Regarding George's OP identity assertion w/ AX membership attribute... How
could Org XYZ sign the attribute so that coming from some OP it would be a
verifiable?  Regarding this loose trust relationship between the OP and Org
XYZ, what would that constitute?

The few RPs that would be interested in my membership can have specially
crafted AX fetch requests, no problem.  But these RPs need to be able to
work against whatever OP the authenticating user happens to choose.  If only
a few OPs might support these signed AX attributes that's fine, as long as
the user has a choice and there is no strong affiliation between OP, RP and
Org.

I wonder if Org could assert my membership with a signed, encoded string,
including my claimed id whatever that may be, and I take that encoded string
and AX-store it myself to my arbitrary OP.  Then any AX-fetch (with my
permission) would retrieve that and the RP could check the signature.  The
only thing remaining in my mind is how the RP could verify the signature.
 Can an ordinary public HTTPS server cert on Org.com be used to verify a
signature if it is signed the right way?  Or is there some other way to do
that?

On Tue, Sep 16, 2008 at 6:26 AM, George Fletcher <gffletch at aol.com> wrote:

> Per Dick's response earlier in the thread, I don't see why using an OP of
> my choice with a third party asserted attribute of my membership in org XYZ
> isn't sufficient to meet this use case.
>
> Basically, I'd use my preferred OP and request the organization to provide
> a signed attribute of my membership in org XYZ. Then when I log into the RP
> (with the OP of my choice), it can request this attribute and I can choose
> to provide it (or not) at time of authentication.
>
> This should be completely doable with the existing OpenID 2.0 and Attribute
> Exchange specs. Is the issue what Peter mentioned that there aren't many AX
> supporters right now?
>
> Of course, there will have to be a "trust relationship" between org XYZ and
> my preferred OP, but I don't see that trust as any deeper than the "trust
> relationship" between and RP and an OP.
>
> Thanks,
> George
>
> Andrew Arnott wrote:
>
>> You're affirmative action example is well taken.  Obviously if an OP is
>> the best solution we should go with it.  But just imagine what all these
>> spoons of sugar are going to do to me...
>>
>> Suppose I'm a member of 15 organizations (that's conservative) between my
>> professional, social, personal lives.  Some RP could be interested in
>> providing specialized services if I am a member of Org XYZ.  Another RP may
>> offer premium services if I am a member of Org ABC.
>>
>> Now if every org I am a member of became an OP, then my identity XRDS file
>> now has at least 15 providers listed.  Powerful, perhaps.  Dangerous: yes!!!
>>  If OpenID's weakness already was that if an OP was compromised then all
>> Identifiers that allow that OP's assertions are now compromised, then that
>> weakness is proportional to the number of OPs that are listed in my XRDS
>> file.  I for one do NOT want 15 Providers listed in my XRDS file.  There was
>> a time I thought more was better, and to date I have some 5-6 OPs listed,
>> but I've considered narrowing that down to just 2-3 to decrease my risk
>> surface area.
>>
>> Using OAuth as a post-authentication step of confirming membership is an
>> interesting idea and should work.  In the end, whether we use OpenID or
>> OAuth, it seems we're mixing authentication and membership, or authorization
>> and membership, in order to just get membership.  Too bad there's not just a
>> way to get "membership".
>>
>> Yes, InfoCard managed cards solve this problem, although not as implicitly
>> as I'd like.  I'm hoping OpenID can have a solution of its own.
>>
>> On Mon, Sep 15, 2008 at 5:12 PM, Eran Hammer-Lahav <eran at hueniverse.com<mailto:
>> eran at hueniverse.com>> wrote:
>>
>>    This is like applying affirmative action to cooking. "This cake
>>    calls for two spoons of sugar but we don't have enough people
>>    using lard in cakes, so I am going to use it instead..."
>>
>>    Looks like they want to use OpenID as an assertion verification
>>    protocol, allowing them to confirm that a given user is in fact a
>>    member of their organization. If all they want to do is assert the
>>    claim, they can use both OAuth and OpenID, each with a different
>>    set of extra features. If they use OpenID, a side-effect of this
>>    will turn them into an Identity Provider, but if this is not their
>>    intention, they should not use that identifier internally, but
>>    instead accept OpenID.
>>
>>    In other words, they should be an OP for assertion verification,
>>    and RP for site login.
>>
>>    EHL
>>
>>
>>
>>    On 9/15/08 4:45 PM, "Andrew Arnott" <andrewarnott at gmail.com
>>    <http://andrewarnott@gmail.com>> wrote:
>>
>>        I just spoke with an organization that wants to become a
>>        Provider so that other RP web sites can specifically tell if
>>        the logging in user is a member of this organization by
>>        whether their OpenID Identifier was asserted by that org's OP.
>>        Ideally, I'd like this org to choose to be an RP instead of an
>>        OP because there are already too many OPs out there and not
>>        enough RPs, IMO.
>>        How can an RP accept an OpenID Identifier from arbitrary OPs,
>>        but at each login determine whether the Identifier represents
>>        a user who belongs to a particular Organization?  Basically
>>        the Organization needs to send an assertion about the
>>        Identifier's membership, but only be willing to do so if that
>>        identifier is confirmed as having logged in successfully to
>>        that RP.  This would be easy to do if that Org was an OP, but
>>        I'm trying to reduce the # of reasons to be an OP.
>>
>>
>> ------------------------------------------------------------------------
>>
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