PUBLICLY VERIFIABLE SHARED DYNAMIC ELECTRONIC HEALTH RECORD DATABASES

Abstract

Electronic health record (EHR) is a system that collects patients' digital health information and shares it
with other healthcare providers in the cloud. Since EHR contains a large amount of significant and
sensitive information about patients, it is required that the system ensures response correctness and
storage integrity. Meanwhile, with the rise of IoT, more low performance terminals are deployed for
receiving and uploading patient data to the server, which increases the computational and
communication burden of the EHR systems. The verifiable database (VDB), where a user outsources his
large database to a cloud server and makes queries once he needs certain data, is proposed as an
efficient updatable cloud storage model for resource-constrained users. To improve efficiency, most
existing VDB schemes utilize proof reuse and proof updating technique to prove correctness of the
query results. However, it ignores the "real-time" of proof generation, which results in an overhead that
the user has to perform extra process (e.g. auditing schemes) to check storage integrity. In this paper,
we propose a publicly verifiable shared updatable EHR database scheme that supports privacypreserving
and batch integrity checking with minimum user communication cost. We modify the existing
functional commitment (FC) scheme for the VDB design and construct a concrete FC under the
computational l -BDHE assumption. In addition, the use of an efficient verifier-local revocation group
signature scheme makes our scheme support dynamic group member operations, and features, such as
traceability and non-frame ability.