|Moehrke, John (GE Healthcare)||Jul 14, 2009 10:07 am|
|Davis, John M.||Jul 14, 2009 11:39 am|
|Moehrke, John (GE Healthcare)||Jul 15, 2009 4:03 am|
|Anthony Mallia||Jul 15, 2009 7:11 am|
|Moehrke, John (GE Healthcare)||Jul 15, 2009 2:45 pm|
|Anthony Mallia||Jul 16, 2009 6:46 am|
|Moehrke, John (GE Healthcare)||Jul 16, 2009 12:18 pm|
|Moehrke, John (GE Healthcare)||Jul 16, 2009 12:22 pm|
|steven meyer||Jul 16, 2009 2:01 pm|
|Subject:||RE: [xspa] Policy scope|
|From:||Moehrke, John (GE Healthcare) (John...@med.ge.com)|
|Date:||Jul 15, 2009 4:03:42 am|
Mike, I am glad you expressed how this is handled in the NHIN DURSA world. This is also a good example of how the NHIN DURSA got around the issue. This solution is based on the tools they had available at the time. What I am trying to get discussed is if there is a more flexible way to support this in the XSPA standards future.
The problem I see with the NHIN DURSA solution is that it simply makes the problem the responsibility of ACS requestor. This does not eliminate the problem, it simply moves the problem out of DURSA space and into the hie/hospital/clinic space where, in general, there is little expertise to solve the problem. I am well aware that you personally are happy with this solution as you do have solutions and architects in the VA space. I think we must think of the whole architecture. This is not to say that we must define an internal architecture for the 'participants', but the underlying XACML schema seems should support appropriate metadata coding to support the need.
As you very clearly indicated a policy is not enforced until both parties agree to enforce it. So, how is this 'scope' of the policy encoded? This is my question.
So to be clear. The reason I am asking this question on XSPA is because I see this as an unsolved problem that our 'standards' development should consider. I am well aware of ways that it is handled in the old days, as I also indicated one of these old days as well.
The NHIN DURSA follows the principal of "autonomy", meaning that each participant follows it's own policies in making access control decisions. The NHIN does not gather policies, the participants do, but only from their own policy stores. When a request is made, it is decided upon based upon the participants policy and the consent directives on hand.
In the case of the VA, for example, we would not release information unless there was a consent directive to do so (Opt-In is a minimal consent directive). That means that anyone requesting information must provide the consent directive at the time of the request. There are many ways to do this, for example, by reference to an XDS directory.
Date reuse requires that the patient establish appropriate consent directives at each participant site. The patient consent directive at the responding participant needs to reflect their preferences established with the requesting participant.
Again, the autonomy principal requires that each participant have all policies on hand for their decision, since they are the authoritative source for all policies, including patient ones that they are enforcing. A participant is NOT responsible for enforcing policies not in its policy repository. BTW, Consent directives themselves are not automatically enforced and do not become participant policies until the agency agrees to enforce them. This enforcement agreement is a binding contract between the participant and the patient. That requires an administrative action (since it involves liability on the provider) as part of the process. Finally, participants will not push a consent directive as an obligation.
So what is important are the attributes asserted at the time of the request. These are used to inform the participant policies (whatever they are). Since different participants are under jurisdiction of different laws, there can be no guarantee of a "common" set of enterprise policies, but I believe that might be possible with consent directives which will probably be related to specific law at some point. On the other hand, Federal law (e.g., FISMA) that applies only to federal agencies may require different policies than California does. Since we are not passing policies back and forth, this should be transparent. In other words, the requester only needs to know what authorization attributes need to be asserted, not what policy set is being enforced. Also, there is no burden on a participant to tell another "Why" a decision was revoked, only to respond, e.g. "Data not available".
Here are the core policy assumptions:
* Multi-Party Agreement. Single agreement to which all Participants agree that establishes trust framework and rules of engagement.
* Participants in Production. Assumes the agreement is for those in production and complements end user trust agreements.
* Privacy and Security Obligations. Defers to Applicable Law and establishes HIPAA as contractual standard of performance for other non-HIPAA or non-governmental entities.
* Requests for Data Based on Permitted Purposes. Permits exchange of information among NHIN for certain purposes for the pilots, including treatment, payment, health care operations, public health activities, quality reporting for "meaningful use" and disclosures based on an authorization from the individual (e.g. SSA disability determination).
* Duty to Respond. All Participants have a duty to respond to requests for data for treatment purposes, and may respond to other types of requests.
* Future Use of Data Received Through the NHIN. Data are received and integrated into end-user's system and may be reused or disclosed as any other information in its records, in accordance with Applicable Law and local policy.
* Duties of Requesting and Responding Participants. Each Participant has certain duties when acting as a requesting or responding Participant, including conformance with NHIN requirements.
* Autonomy principle for access - When responding to a request for data, Participants will apply their local policies to determine whether and how to respond to the request.
* Responding Participant's Legal requirements. A Responding Participant must make sure that it has met any legal requirements before disclosing the data including, but not limited to, obtaining consent or authorization for treatment purposes.
* Authorizations. When a request is based on an authorization (e.g. for SSA benefits determination), the requesting Participant must send a copy of the authorization with the request for data.
* Participant Breach Notification. Participants are required to promptly notify the NHIN Coordinating Committee and other impacted Participants of breaches which involve the unauthorized disclosure of data through the NHIN.
* Mandatory Non-Binding Dispute Resolution. Participants will agree to participate in a mandatory, non-binding dispute resolution process that preserves the Participants' rights to seek redress in the courts if not resolved through the dispute resolution process.
* Allocation of Liability Risk. With respect to liability, the DURSA memorializes the Participant's understanding that each Participant is responsible for its own acts or omissions.
Regards, Mike Davis, CISSP
Department of Veterans Affairs
CHIO Emerging Health Technologies
A question came up today in discussion on Access Control white paper in IHE. How is it known when all applicable policies have been gathered? Specifically in an environment like the USA NHIN, how does the NHIN know when they have done sufficient gathering of policies in order to make the specific-access-control-decision?
I have heard discussions where the access control decision logic simply is happy making a positive response based on the knowledge it has, but how does it not know that there is a 'new' policy declaration available that indicates that the patient has revoked authorization?
The same can be said for a decision of NO could have been rather a YES because of a new authorization.
But the most concerning is how does the system understand that there is a policy available to be gathered/retrieved that is simply not applicable.
In the 'old days' under BPPC, this is handled simply because each policy identifier is either understood by the access-control-service (meaning the policy logic was configured into the ACS) or it is NOT. Therefore a query for all policies that have been acknowledged results in a list of unique identifiers to enable, therefore the decision is made based on the cross-section of those that are acknowledged vs those that are understood. This results in a self limited set of policies.
In the XACML world, it is possible for the ACS to pull down the computable policy and make it known to my ACS... so how do I determine which I SHOULD incorporate vs which ones should I continue to ignore?
I presume that much of this is simply encoded into the policy as the scope of the policy. For example which organizations does this policy affect. If a policy indicates that it is scoped to a set of organizations that are not involved in a transaction, then that policy is not applicable. Is this already built into XACML core?
John Moehrke Principal Engineer: Interoperability and Security GE Healthcare
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