LAUSR

Cloud storage security has received widespread attention from industry and academia. When cloud data is damaged and tampered by various types of security attacks, it is one of the most common methods to track accidents through log analysis. In order to support credible forensic analysis of user operation behavior logs in a shared cloud environment allowing multiple users handling data, this paper presents a secure and efficient public auditing scheme for user operation behavior logs. Specifically, a blockchain-based logging strategy was designed to support selective verification of log-data integrity and resist collusion attacks between malicious users and the cloud service provider. Based on the multi-user logging strategy, a public auditing approach was further presented to verify the integrity of log data in the cloud remotely without leaking any log content. We formally prove the security of the presented scheme and evaluate its performance by theoretical analysis and comprehensive experiments. The results indicate that our scheme can achieve secure and effective auditing for logs in the shared cloud storage.