Privacy-preserving audit for broker-based health information exchange

Health Information Technology has spurred the development of distributed systems known as Health Information Exchanges (HIEs) to enable the sharing of patient records between different health care organizations. Participants using these exchanges wish to disclose the minimum possible amount of information that is needed due to patient privacy concerns over sensitive medical information. Therefore, broker-based HIEs aim to keep limited information in exchange repositories and to ensure faster and more efficient patient care. It is essential to audit these exchanges carefully to minimize the risk of illegitimate data sharing. This thesis presents a design for auditing broker-based HIEs in a way that controls the information available in audit logs and regulates its release during audit investigations based on the requirements of applicable privacy policy. In our design, we utilized formal rules to verify access to HIE and adopted Hierarchical Identity-Based Encryption (HIBE) to support the staged release of data required for audits and a balance between automated and manual reviews. We test our methodology with a consolidated and centralized audit source that incorporates a standard for auditing HIEs called the Audit Trail and Node Authentication Profile (ATNA) protocol with supplementary audit documentation from HIE participants

PriCL: Creating a Precedent A Framework for Reasoning about Privacy Case Law

We introduce PriCL: the first framework for expressing and automatically reasoning about privacy case law by means of precedent. PriCL is parametric in an underlying logic for expressing world properties, and provides support for court decisions, their justification, the circumstances in which the justification applies as well as court hierarchies. Moreover, the framework offers a tight connection between privacy case law and the notion of norms that underlies existing rule-based privacy research. In terms of automation, we identify the major reasoning tasks for privacy cases such as deducing legal permissions or extracting norms. For solving these tasks, we provide generic algorithms that have particularly efficient realizations within an expressive underlying logic. Finally, we derive a definition of deducibility based on legal concepts and subsequently propose an equivalent characterization in terms of logic satisfiability.Comment: Extended versio

Privacy-preserving audit for broker-based health information exchange

Developments in health information technology have en-couraged the establishment of distributed systems known as Health Information Exchanges (HIEs) to enable the sharing of patient records between institutions. In many cases, the parties running these exchanges wish to limit the amount of information they are responsible for holding because of sensitivities about patient information. Hence, there is an interest in broker-based HIEs that keep limited information in the exchange repositories. However, it is essential to audit these exchanges carefully due to risks of inappropriate data sharing. In this paper, we consider some of the require-ments and present a design for auditing broker-based HIEs in a way that controls the information available in audit logs and regulates their release for investigations. Our approach is based on formal rules for audit and the use of Hierarchical Identity-Based Encryption (HIBE) to support staged release of data needed in audits and a balance between automated and manual reviews. We test our methodology via an exten-sion of a standard for auditing HIEs called the Audit Trail and Node Authentication Profile (ATNA) protocol

Privacy enhancing technologies : protocol verification, implementation and specification

In this thesis, we present novel methods for verifying, implementing and specifying protocols. In particular, we focus properties modeling data protection and the protection of privacy. In the first part of the thesis, the author introduces protocol verification and presents a model for verification that encompasses so-called Zero-Knowledge (ZK) proofs. These ZK proofs are a cryptographic primitive that is particularly suited for hiding information and hence serves the protection of privacy. The here presented model gives a list of criteria which allows the transfer of verification results from the model to the implementation if the criteria are met by the implementation. In particular, the criteria are less demanding than the ones of previous work regarding ZK proofs. The second part of the thesis contributes to the area of protocol implementations. Hereby, ZK proofs are used in order to improve multi-party computations. The third and last part of the thesis explains a novel approach for specifying data protection policies. Instead of relying on policies, this approach relies on actual legislation. The advantage of relying on legislation is that often a fair balancing is introduced which is typically not contained in regulations or policies.In dieser Arbeit werden neue Methoden zur Verifikation, Implementierung und Spezifikation im von Protokollen vorgestellt. Ein besonderer Fokus liegt dabei auf Datenschutz-Eigenschaften und dem Schutz der Privatsph¨are. Im ersten Teil dieser Arbeit geht der Author auf die Protokoll- Verifikation ein und stellt ein Modell zur Verifikation vor, dass sogenannte Zero-Knowledge (ZK) Beweise enth¨alt. Diese ZK Beweise sind ein kryptographisches primitiv, dass insbesondere zum Verstecken von Informationen geeignet ist und somit zum Schutz der Privatsph¨are dient. Das hier vorgestellte Modell gibt eine Liste von Kriterien, welche eine Implementierung der genutzten kryptographischen Primitive erf¨ullen muss, damit die verifikationen im Modell sich auf Implementierungen ¨ubertragen lassen. In Bezug auf ZK Beweise sind diese Kriterien sch¨acher als die vorangegangener Arbeiten. Der zweite Teil der Arbeit wendet sich der Implementierung von Protokollen zu. Hierbei werden dann ZK Beweise verwendet um sichere Mehrparteienberechnungen zu verbessern. Im dritten und letzten Teil der Arbeit wird eine neuartige Art der Spezifikation von Datenschutz-Richtlinien erl¨autert. Diese geht nicht von Richtlinien aus, sondern von der Rechtsprechung. Der Vorteil ist, dass in der Rechtsprechung konkrete Abw¨agungen getroffen werden, die Gesetze und Richtlinien nicht enthalten

Securing Medical Devices and Protecting Patient Privacy in the Technological Age of Healthcare

The healthcare industry has been adopting technology at an astonishing rate. This technology has served to increase the efficiency and decrease the cost of healthcare around the country. While technological adoption has undoubtedly improved the quality of healthcare, it also has brought new security and privacy challenges to the industry that healthcare IT manufacturers are not necessarily fully prepared to address. This dissertation explores some of these challenges in detail and proposes solutions that will make medical devices more secure and medical data more private. Compared to other industries the medical space has some unique challenges that add significant constraints on possible solutions to problems. For example, medical devices must operate reliably even in the face of attack. Similarly, due to the need to access patient records in an emergency, strict enforcement of access controls cannot be used to prevent unauthorized access to patient data. Throughout this work we will explore particular problems in depth and introduce novel technologies to address them. Each chapter in this dissertation explores some aspect of security or privacy in the medical space. We present tools to automatically audit accesses in electronic medical record systems in order to proactively detect privacy violations; to automatically fingerprint network-facing protocols in order to non-invasively determine if particular devices are vulnerable to known attacks; and to authenticate healthcare providers to medical devices without a need for a password in a way that protects against all known attacks present in radio-based authentication technologies. We also present an extension to the widely-used beacon protocol in order to add security in the face of active attackers; and we demonstrate an overhead-free solution to protect embedded medical devices against previously unpreventable attacks that evade existing control- flow integrity enforcement techniques by leveraging insecure built-in features in order to maliciously exploit configuration vulnerabilities in devices