Sunday, February 3, 2013

Patient Privacy At Web Scale

A study entitled Patients want granular privacy control over health information in electronic medical records by Kelly Caine and Rima Hanania in the current issue of the Journal of the American Medical Informatics Association (JAMIA) clearly indicates that patients want a granular level of control over the sharing of their medical information. Patients also want to control with whom their health information is shared and for what purpose. The study looks at how the presence of sensitive health information in a medical record affects patient privacy preferences. In this post, I discuss how current and emerging standards can be used to enforce patient privacy preferences at web scale.

First, I think the key to achieving patient privacy at web scale is to adopt proven light-weight protocols and standards such as REST, JSON, OAuth2, and OpenID Connect. The RESTful Health Exchange (RHEx) project funded by the Federal Health Archicture (FHA) was a step in the right direction. These protocols have also been embraced by large internet identity providers like Google, Facebook, and Microsoft. To increase the strength of authentication when using these existing online identities in patient-facing healthcare applications, techniques like multi-factor authentication (e.g., two-factor authentication using the user's phone) and adaptive risk authentication can be used. These light-weight standards and protocols contrast with enterprise-centric alternatives like SOAP and SAML which are the foundation for Integrating the Health Enterprise (IHE) standards including XDS.b, XDR, and XUA.

An emerging approach that could really help put patients in control of the privacy of their electronic medical record is the User-Managed Access (UMA) Protocol of the Kantara Initiative. According to the UMA Core specification:
User-Managed Access (UMA) is a profile of OAuth 2.0. UMA defines how resource owners can control protected-resource access by clients operated by arbitrary requesting parties, where the resources reside on any number of resource servers, and where a centralized authorization server governs access based on resource owner policy.
That sounds a lot like a healthcare environment where a typical patient has her health information residing in the Electronic Health Record (EHR) systems of multiple healthcare providers. A frequent use case is when the patient's health information is shared among providers during primary care physicians' referrals to specialist outpatient clinics. The following are the benefits for the patient privacy of a centralized authorization server as defined in UMA:

  • The ability to manage her consent directives (scope of access in UMA parlance) from a central location (ideally in the cloud) as opposed to the current paper-based environment where the patient signs a consent form for each provider and has no visibility into how the consent is being used and enforced.
  • It facilitates the update and revocation of the consent directives by the patient. 
  • It would give the patient a full audit trail of requests and access events related to her health information.
  • The patient user experience of managing their privacy preferences online can be significantly enhanced by data visualization. A study titled Exploring Visualization Techniques to Enhance Privacy Control UX for User-Managed Access introduced the notion of a "UMA Connection" for helping users visualize the context of a data sharing policy (e.g., contacts, allowed actions, access restrictions, and trusted claims).

In UMA, trusted claims (e.g., information about a requesting healthcare provider such as email, name, role, organization, and NPI) can be conveyed using OpenID Connect. The Google OpenID Connect Demo provides a step by step guide to OpenID Connect and Nat Sakimara's Dummy’s guide for the Difference between OAuth Authentication and OpenID is a good explanation of how OpenID Connect complements OAuth2. A separate specification entitled Binding Obligations on User-Managed Access (UMA) Participants proposes a legal framework that defines the obligations of parties that operate and use UMA-conforming software programs and services.

A recent post by Domenico Catalono entitled UMA Approach to Protect and Control Online Reputation describes a UMA-based approach for supporting privacy based on reputation and trust.  An example in the post is a "global reputation ranking" in the context of an online e-commerce site. In the context of healthcare privacy, when deciding to share their sensitive medical information with a specific healthcare provider, the same concept could be used to display the number and severity of security breaches experienced by the healthcare provider in the past. Section 13402(e)(4) of the HITECH Act actually requires posting a list of breaches of unsecured protected health information affecting 500 or more individuals. The list is available here.

The recently approved XACML 3.0 standard is a powerful mechanism for expressing and evaluating privacy policies. It provides capabilities such as obligation and advice expressions as well as delegation of authorization. In this presentation, Eve Maler discusses possible integration points between UMA and XACML.  The REST Profile of XACML 3.0 and the Request/Response Interface based on JSON and HTTP for XACML 3.0 proposals introduce the notion of "RESTful Authorization-as-a-Service (AZaaS)" which can facilitate the use of XACML in a UMA-based access control environment.

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