Re: RqP presenting W3C Verifiable Credentials to an UMA Authorization Server

Continuing the cross-posting to make sure David's excellent analysis is
seen by all...

HIE of One Trustee is a self-sovereign technology use-case designed to work
where federations are faltering or distorting the market.

*Analog      VC          UMA          Trustee Example               Eve's
Example                   *

Patient     Subject     RO           Patient                       Bank
Customer

HIV Titer   Issuer      RS           Institution (e.g. Labcorp)    State
License Bureau (digital)

Wallet      Holder      AS           Trustee (an UMA AS)           AS
(customer's digital agent)

HIV Report  VC          Resource     FHIR Resource                 Digital
Driver's License

Blood Bank  Verifier    RqP          Licensed Physician            Bank
Clerk or Loan Officer


*Trust relationships:*
(1) The Verifier / RqP trusts that the Issuer / RS properly identified the
Subject / RO - Liability may rest with the Issuer, the Verifier, or the
Subject depending on the use-case.

(2) The Verifier / RqP trusts that the Holder / AS has not tampered with
the credential.

(3) The Verifier / RqP trusts that the Holder / AS operator will not misuse
the claims they present in order to gain authorization to the resource.

(4) The Verifier / RqP can, acting as an Issuer / RS, issue a secondary
credential (e.g. a prescription) to the Holder / AS that some downstream
Verifier / RqP will trust.

Are 1-4 the only trust issues under consideration?

Are the pairings  Subject / RO,  Issuer / RS, Holder / AS, Verifier / RqP
universal enough to be helpful in our standards efforts?

Adrian



On Fri, Oct 19, 2018 at 5:22 PM David Chadwick <D.W.Chadwick@kent.ac.uk>
wrote:

> Hi Adrian
>
> in the VC work the verifier trusts the issuer(s) of the VCs, not the
> holder.
>
> Translating the VC model into UMA language, the VC verifier is the UMA
> requesting party, the UMA protected resource would be the VC holder's
> wallet holding his/her VCs. The UMA resource owner is the VC holder. The
> VC issuer is not in the UMA diagram in Figure 1: Federated Authorization
> Enhancements to UMA Grant Flow.
>
> If you add this missing entity(ies), namely the VC issuer(s) into your
> diagram, and indicate that the requesting party trusts the VC issuer(s),
> then the requesting party can determine whether the resource owner can
> be trusted or not after validating the VCs.
>
> Note that VCs do not generally use bearer tokens, and the holder has to
> prove that he/she is the genuine holder of the issued VCs. This PoP
> might mean you need an enhancement to the UMA protocol (I dont know the
> UMA protocol in detail. You may already have PoP). One way is for the AS
> or RS to hold the RO's private keys and to sign the response message to
> the requesting party.
>
> regards
>
> David
>
> On 19/10/2018 19:20, Adrian Gropper wrote:
> > I'm cross posting this for the obvious reason and will try to act as
> > relay if a discussion ensues.
> >
> > On today’s UMA standards call, the following came up:
> >
> >
> >         180 degrees use case / decoupled use case discussion
> >
> > Nancy has written up some "180 degrees" use cases, which she'll share
> > more widely soon. These got Eve thinking.
> >
> > We briefly discussed use cases where the requesting party needs to trust
> > the resource owner before taking some action (potentially against
> > resources shared), e.g. a loan officer needing to trust that the
> > putative resource owner is who they say they are so that the (e.g.)
> > personal attributes (resource) shared can be trusted to be associated
> > with that resource owner "bearer". This way, the loan officer can
> > approve a loan (which might be a second resource that the same resource
> > owner could later share with others).
> >
> > The current UMA model allows the RO and their AS to match RqP claims
> > (not just a plain authenticated identity) against policy, and the RO can
> > be decoupled (asynchronous) from that process. The client that the RqP
> > uses is explicitly accounted for in the protocol, and UMA has a
> > framework for this matching and for the RO's delegation / access
> > granting to the RqP. But it only accounts for the client that the RO
> > uses to interact with the RS and AS through the OAuth authorization
> > endpoint (resulting in a PAT), and otherwise the client handling on the
> > RO side is implicit.
> >
> > The notion of the RqP needing to trust the RO and the RO needing to
> > grant resource access to the RqP seems similar to the "decoupled" use
> > cases, where a CSR or bank teller needs to know that Alice is really
> > Alice before getting access to her account.
> >
> > What would make sense for ensuring that the RqP could come to trust the
> > RO "binding"? Alec will describe some work they've done along these
> > lines in our next meeting.
> >
> >
> > For the UMA folks, check out Figure 2 at
> > https://www.w3.org/TR/verifiable-claims-data-model/ to get oriented. For
> > the VC folks, check out
> >
> https://docs.kantarainitiative.org/uma/wg/rec-oauth-uma-federated-authz-2.0.html
> > by way of orientation.
> >
> > Our HIE of One Trustee implementation would not be practical without
> > _both_ UMA authorization and self-sovereign identifier standards.
> > Federation in healthcare is not deployed widely enough to serve a
> > patient-centric health record application. I hope this email inspires
> > our group’s to harmonize or at least to produce a brief paper describing
> > why or why not.
> >
> > Adrian
> >
> >
> >
> > --
> >
> > Adrian Gropper MD
> >
> > PROTECT YOUR FUTURE - RESTORE Health Privacy!
> > HELP us fight for the right to control personal health data.
> > DONATE: https://patientprivacyrights.org/donate-3/
>


-- 

Adrian Gropper MD

PROTECT YOUR FUTURE - RESTORE Health Privacy!
HELP us fight for the right to control personal health data.
DONATE: https://patientprivacyrights.org/donate-3/