Solomon Berhe

A security framework for XML schemas and documents for healthcare

The extensible Markup Language (XML) has wide usage in healthcare to facilitate health information exchange via the Continuity of Care Record (CCR) for storing/managing patient data, diagnoses, medical notes, tests, scans, etc. Health IT products like electronic health record (EHR, e.g., GE Centricity) and personal health record (PHR, e.g., MS Health Vault) use CCR for data representation. To manage patient data in CCR, security as governed by HTPAA must be attained when using XML and its technologies (XACML, XSLT, etc.). Our objective is to have an XML document (CCR instance) appear differently to authorized users at different times based on a users role, constraints, separation of duty, delegation of authority, etc. In this paper, we propose a security framework that targets XML schémas and documents, in general, and CCR schémas and documents, in particular with control capabilities that achieve customizable access to an XML documents elements by applying secure software engineering methodologies and defining new UML XML-focused diagrams for schémas and permissions. This allows us to generate XACML policies, and enforce security at the runtime level on XML instances to insure that correct and required patient data is securely delivered. In a market of rapidly emerging mobile healthcare applications to allow patients to manage their own data (PHRs) and for self-management of chronic diseases, the need for secure access to information and its authorization and transmission to providers (and EHRs) will be critical.

Emerging Trends in Health Care Delivery: Towards Collaborative Security for NIST RBAC

In the next 10 years there will be rapid adoption of health information technology - electronic medical records by providers and personal health records by patients - linked via health information exchange. There is an emergent need to provide secure access to information spread across multiple repositories for health care providers (e.g., physicians, nurses, home health aides, etc.) who collaborate with one another across cyberspace to deliver patient care. Are available security models capable of supporting collaborative access where providers are simultaneously modifying a patients medical record? To address this question, this paper details collaborative security extensions to NIST RBAC.

Leveraging UML for security engineering and enforcement in a collaboration on duty and adaptive workflow model that extends NIST RBAC

To facilitate collaboration in the patient-centered medical home (PCMH), our prior work extended the NIST role-based access control (RBAC) model to yield a formal collaboration on duty and adaptive workflow (COD/AWF) model. The next logical step is to place this work into the context of an integrated software process for security engineering from design through enforcement. Towards this goal, we promote a secure software engineering process that leverages an extended unified modeling language (UML) to visualize COD/AWF policies to achieve a solution that separates concerns while still providing the means to securely engineer dynamic collaborations for applications such as the PCMH. Once defined, these collaboration UML diagrams can be utilized to generate the corresponding aspect oriented policy code upon which the enforcement mechanism can be applied to at runtime.

Integrating Access Control into UML for Secure Software Modeling and Analysis

Access control models are often an orthogonal activity when designing, implementing, and deploying software applications. Role-based access control RBAC which targets privileges based on responsibilities within an application and mandatory access control MAC that emphasizes the protection of information via security tags are two dominant approaches in this regard. The integration of access control into software modeling and analysis is often loose and significantly lacking, particularly when security is such a high-priority concern in applications. This article presents an approach to integrate RBAC and MAC into use-case, class, and sequence diagrams of the unified modeling language UML, providing a cohesive approach to secure software modeling that elevates security to a first-class citizen in the process. To insure that a UML design with security does not violate RBAC or MAC requirements, design-time analysis checks security constraints whenever a new UML element is added or an existing UML element is modified, while post-design analysis checks security constraints across the entire design for conflicts and inconsistencies. These access control extensions and security analyses have been prototyped within a UML tool.