IPAPS: An improved public auditing protocol for secure data storage in cloud‐based medical storage system

Abstract Cloud‐based medical storage system is becoming popular. Cloud server is curious about the private information of stored cases, and the integrity of outsourced data has become increasingly concerned. Numerous public auditing protocols for the outsourced data into the cloud server were proposed. Unfortunately, in the existing protocols, some of them may neglect security to improve efficiency. Recently, Li et al. proposed an efficient privacy‐preserving public auditing protocol for cloud‐based medical storage system (EPPAP), which improved the communication efficiency by storing some of data owner's data in third part auditors, however we find that the protocol is vulnerable to collusion attack and replace attack. In this paper, we analyze the security attacks of the existing protocol, and further propose an improved public auditing protocol for secure data storage in cloud‐based medical storage system (IPAPS). In addition, we give the formal security proof and analyze the performance of our proposed protocol. The security proof shows our protocol takes into account integrity, collusion attack and replace attack at the same time. The simulation experiments in our performance analysis show that the proposed protocol is practical.