Declarative privacy policy: finite models and attribute-based encryption

Abstract

Regulations and policies regarding Electronic Health Information (EHI) are increasingly complex. Federal and State policy makers have called for both education to increase stakeholder understanding of complex policies and improved systems that impose policy restrictions on access and transmission of EHI. Building on prior work formalizing privacy laws as logic programs, we prove that for any privacy policy that conforms to patterns evident in HIPAA, there exists a finite representative hospital database that illustrates how the law applies in all possible hospitals. This representative illustrative example can support new education, new policy development, and new policy debugging tools. Addressing the need for secure transmission of usable EHI, we show how policy formalized as a logic program can also be used to automatically generate a form of access control policy used in Attribute-Based Encryption (ABE). This approach, testable using our representative hospital model, makes it possible to share policy-encrypted data on untrusted cloud servers, or send strategically encrypted data across potentially insecure networks. As part of our study, we built a prototype to secure Health Information Exchange (HIE), with automatically generated ABE policies, and measure its performance.