[Openid-specs-heart] Resources vs Resource sets

[Justin Richer]

As far as what matters, you're missing a key point: it very much matters 
to HEART that an RS and AS that are both *run* by the same group don't 
have to be *built* by the same group. Runtime choice matters for more 
than just patients.

As far as the patient choice of AS at all times, there are two very real 
consequences to discovery that we need to be aware of as a group. Both 
of these have been discussed here in HEART before (as well as elsewhere, 
particularly in the UMA working group) but to reiterate:

  1) To have the AS selectable at runtime by a client with no token (ie: 
a "dry start" to get to the resource, like we have in UMA), you need to 
limit the type of API you protect. The RS needs to know *which* AS to 
get to without a hint from the security layer. This puts APIs styled 
like OpenID Connect's UserInfo Endpoint out of reach since they use the 
access token to dispatch to the appropriate resource owner and therefore 
appropriate resource. In general, FHIR records are going to have a 
patient or record identifier in the URL, but this of course has privacy 
implications as you're leaking identifying information in an unprotected 
component (the URL itself).

2) The above leads us to an interesting attack. Let's say I get (or 
guess) a patient's record URL, /PXZ-1234. I don't know who it's for and 
I don't have access to it. But I use my generic client to call said URL, 
and the RS dutifully goes and figures out that this is Alice's record 
and it's protected by Alice's AS, alicehealth.org. This is Alice's own 
personal AS and she's the only one that uses it. I can go to 
alicehealth.org and see that stamped right on the front page. What have 
we learned? That /PXZ-1234 belongs to Alice, a real-life person that we 
can probably find now. And we've got her medical record number, she can 
become a target for other attacks, online and off. Remember, all of this 
is required by the current protocols and would be universal if it were 
"patient always gets to choose the AS no matter what" as Adrian suggests 
(though I'll note that this is NOT in the HEART charter or mission).

Protected service discovery is a thorny problem, and not one I've seen 
an elegant solution for yet. Not to say it's intractable but rather to 
get us to be aware of the consequences of our decisions here.


  -- Justin

On 7/31/2016 7:04 PM, Adrian Gropper wrote:
> Debbie,
>
> Thanks for giving me another opportunity to explain what's at stake 
> for all of us.
>
> As far as the substantive point of this interchange, it doesn't matter 
> if only 5% or 10% of the AS are independent - it will be enough to 
> make every authorization service patient-centered and make 
> transparency and longitudinal health records the norm for all of us.
>
> I don't understand why any AS operated by an RS matters in the HEART 
> context. It's entirely captive and not an interoperability issue. The 
> only AS that matters to HEART is the one a patient has a choice over.
>
> Adrian
>
> On Sunday, July 31, 2016, Debbie Bucci <debbucci at gmail.com 
> <mailto:debbucci at gmail.com>> wrote:
>
>
>     Adrian -
>
>     My sincere apologies if I offended you.   I just voiced a personal
>     opinion.  That was not the point of the paragraph though - I
>     failed to state the point I was trying to make - sorry to send you
>     off on a tangent.
>
>     Totally agree with the following statement.
>
>     The degree to which HEART chooses to profile particular subsets of
>     FHIR has nothing to do with whether a person chooses to outsource
>     his / her authorization server. It simply has to do with the
>     person's user experience in setting policies that
>     HIPAA-covered-entities and FTC-covered-entities and
>     42-CFR-covered-entities as resource servers will need to follow.
>     In some cases, the resource servers will voluntarily take
>     advantage of the FHIR standard while in others it will not apply
>     at all.
>
>
>     I do not see the rise of totally independent AS.   I see it more
>     as a federate authorization model (kind of what MIT is thinking
>     about with Datahub - DUMA - PDS).  All RS will have their own AS
>     processes to deal with - even if trusted, most likely the sharing
>     preference/consent/ROI would be replicated to the RA AS to manage
>     ongoing requests.
>
>
>
>
>
> _______________________________________________
> Openid-specs-heart mailing list
> Openid-specs-heart at lists.openid.net
> http://lists.openid.net/mailman/listinfo/openid-specs-heart

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openid.net/pipermail/openid-specs-heart/attachments/20160801/1cec2096/attachment.html>