Re: "Derivative predicate" of W3C VC WG and "Expression Language" of OIDF ekyc-ida WG

Thanks for your message, Kristina! Directly adding Brent + Dan + Dave + Tobias here, whom I believe have been working on related efforts in this problem space across Aries, DIF, and CCG. I hope there's an opportunity consolidate efforts.

https://w3c-ccg.github.io/vp-request-spec/
https://identity.foundation/presentation-exchange/
https://mattrglobal.github.io/oidc-client-bound-assertions-spec/

Best,
- Wayne

On Wed, Jul 15, 2020, at 7:58 PM, Kristina Yasuda wrote:
> Hi,
> 
> I am reaching out since  there seems to be synergy with 'derived predicate' concept <https://www.w3.org/TR/vc-data-model/#dfn-predicates> of W3C VC spec and  expression language <https://gruposantander.github.io/digital-trust-docs/assertions/claim-assertions-00.html#name-expression-language> concept being discussed in OpenID Foundation(OIDF)'s  ekyc-ida (identity assurance) WG <https://openid.net/wg/ekyc-ida/>  in the context of selective disclosure.
> 
> This part <https://w3c.github.io/vc-imp-guide/#predicates> in the vc-imp-guide is the most detailed implementation of derived predicate that I have seen. Do you know if
>  * there is more specific proposal for how to express the derived predicates
>  * there is anyone actually implementing this feature
> OIDF is discussing the concept of  expression language <https://gruposantander.github.io/digital-trust-docs/assertions/claim-assertions-00.html#name-expression-language> which could be more generic than "ageOver18" property in VC imp-guide and ekyc-ida wg has been wondering if we could work together on this important topic. 
> OIDF's current proposal is outlined here <https://gruposantander.github..io/digital-trust-docs/assertions/claim-assertions-00.html>. For example for the alcohol purchase age, in the US it is ageOver18, but in Japan it is ageOver20. The concept of expression language would allow to express this as {"age" : { "gt" : "18", "lt" : "20" } } where gt is 'greater than' and 'lt' is less than..
> 
> Best,
> Kristina
> *Identity Standards Team, Microsoft Corp.*
> 
>  
>