CIPPPA: Conditional Identity Privacy-Preserving Public Auditing for Cloud-Based WBANs Against Malicious Auditors

Wireless body area networks (WBANs) rely on powerful cloud storage services to manage massive medical data. As precise medical diagnosis analysis is heavily based on these medical data, any altered medical data may cause severe consequences, the integrity of outsourced medical data has become the most concerning security issue. Up to date, most existing public auditing mechanisms have been proposed to check the data integrity, but they could not achieve conditional identity privacy, any patient would not like others to know his/her real identity corresponding to certain serious disease, and some malicious patients should be revoked timely due to misbehaviors. Additionally, they are vulnerable to malicious auditors, by colluding with the cloud server to cheat patients. In this paper, we propose a conditional identity privacy-preserving public auditing (CIPPPA) mechanism for cloud-based WBANs. CIPPPA is the first public auditing mechanism achieving conditional identity privacy of patients in WBANs, the real identity of a patient is unknown to anyone in cloud-based WBANs other than the private key generator (PKG). We attempt to integrate Ethereum blockchain into CIPPPA, which gives assistance to patients for validating malicious auditing behaviors. Formal security analysis and performance evaluation demonstrate that CIPPPA is practical for cloud-based WBANs.

1 Introduction

Nowadays, wireless body area networks (WBANs) [1], [2], [3] have become increasingly prevalent. WBANs rely on various kinds of medical sensors and wireless communication technologies to collect and transmit medical data, and flexibly realize remote health status monitoring of patients. Due to the sharp increase in the massive medical data of WBANs, these medical data need to be processed promptly, and the feedback messages from doctors also need to be quickly transmitted. However, it is very difficult to achieve these goals only relying on the traditional WBANs, since they have limited calculation and storage capabilities.