Re: [scim] Multiple external id values

[Mark Dobrinic <[e-mail]>]

Hi Phil,

Thanks for the quick response.

The resolution to expose a client specific externalId only works in half
the scenario's, where you have multiple clients all representing one
domain. In the other scenario, where one client representing multiple
domains is using one Scim Service Provider, the client actually relies
on the Service Provider to store multiple identities for its multiple
domains, so in that usecase it is multi-valued by design.

Do I get it right that this particular use case has not yet come up then?

Concerning the privacy cinsideration, given a trust relationship between
the Scim Service Provider and the Scim Client (quite some features are
based on this already), privacy characteristics of the solution are not
of primary concern here. The Scim Client could (should) actually take
over the responsibility for protecting privacy in this one.

Cheers!

Mark




On 05/10/15 17:17, Phil Hunt wrote:
> This was discussed and the consensus was single value. 
>
> What you can do is expose a different single value for each domain
> client your server talks to.  Thus domains cannot see each other's
> ids. The spec already suggests this as a security consideration for
> the id value. 
>
> This would provide much better privacy characteristics and reduces
> propagation of PII. 
>
> Phil
>
> On Oct 5, 2015, at 07:42, Mark Dobrinic
> <[e-mail]
> <mailto:[e-mail]>> wrote:
>
>> Hi Scim people,
>>
>> While incorporating Scim client functionality towards a Scim Service
>> Provider, we've stumbled upon a limitation regarding our desired use
>> of externalId, that doesn't fit the current spec.
>>
>> Our usecase involves managing multiple external id's, so that we can
>> both support multiple externalId's to multiple Scim Clients from one
>> Scim Service Provider, as well as let a Scim Client manage multiple
>> external id's with one Scim Service Provider.  Each external id lives
>> within the domain of a, well, domain. There are plenty of real world
>> examples where domain-scoped id's are used, so it seems no more than
>> natural to consider this with Scim as well.
>>
>> For example, a user with id barbara has an externalId 'babs' in the
>> domain 'home', and externalId 'labarbara' in domain 'work'.
>>
>> As I understand Scim as being as effective and simple as possible,
>> we've been using the extensibility of Scim to make this work. I can
>> imagine this to be a generic problem that more people are (or will
>> be) facing. Therefore, I'd like to propose our solution and would
>> like to discuss whether this could/should be considered a standard
>> solution to a standard problem, either in this form or something better.
>>
>> What we did was introduce an extension "
>> urn:scim:schemas:extensions:external-ids:1.0"
>> that defines an attribute "externalIds",
>> is of type "complex",
>> is multiValued,
>> can be described as "External Identities of a user. Each External
>> Identity is scoped within its domain",
>> is optional,
>> and has the following sub-attributes:
>> - value : string value containing the value of the external id
>> - type : string value containing the domain of the external id
>>
>> In JSON, it would look like this:
>>
>>                 {
>>                 "schemas": [ "urn:scim:schemas:core:1.0",
>> "urn:scim:schemas:extensions:external-ids:1.0" ],
>>                 "id":"2819c223-7f76-453a-919d-413861904646",
>>                 "userName":"bjensen",
>>                 "externalId":"bjensen",
>>                 ....
>>                 "urn:scim:schemas:extensions:external-ids:1.0": {
>>                     "externalIds": [
>>                         {
>>                             "value": "babs",
>>                             "type": "home"
>>                         },
>>                         {
>>                             "value": "labarbara",
>>                             "type": "work"
>>                         }]
>>                     }
>>                 }
>>
>>
>>
>> Note that we are adding to the baseline features of Scim, and not
>> changing anything existing.
>>
>>
>> I would like to hear your feedback on this, and I'm interested
>> whether this could be considered as a standard extension in upcoming
>> Scim versions.
>>
>>
>> Thanks!
>>
>> -- 
>> Regards,
>>
>> Mark Dobrinic
>> Software Engineer and Identity Specialist
>> Twobo Technologies AB
>>
>> [e-mail]
>> www.twobotechnologies.com
>> _______________________________________________
>> scim mailing list
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-- 
Regards,

Mark Dobrinic
Software Engineer and Identity Specialist
Twobo Technologies AB

[e-mail]
www.twobotechnologies.com