Real-time Audit Scheme Based on Multilevel Roles in a Medical Cloud Environment

To support the confidentiality and integrity requirements of electronic health records (EHRs) in the medical cloud storage environment, we propose a multilevel, role-based, real-time auditing scheme. Because of the special and sensitive nature of the data structures of shared EHRs, we adopt real-time auditing and deterministic auditing to improve the audit accuracies. By the use of fine-grained level access controls, we implement hierarchical auditing using different roles to avoid centralized auditing from suffering a single point of failure. The cloud server also supports accountability traceability to achieve nonrepudiation of the audit results. In comparisons with existing schemes, our scheme has lower storage overheads and better scalability than the existing solutions.