Only you can check my data: certificateless and designed-verifier auditing of multi-cloud storage with faults localization

To improve the data security and integrity of the outsourced data, storing multiple copies of data on multiple cloud servers is a good way. Many public Provable Data Possession (PDP) schemes in multiple cloud servers have been proposed in recent years. However, in some scenarios, the Data Owner (DO) may not want anyone (e.g. a stranger) to check the integrity of their data. Nevertheless, few schemes consider the fault’s location function when the data auditing fails. Another problem is that anyone can make a challenge for the Cloud Server (CS) in the PDP schemes. Some access control strategies are necessary to reduce the waste of computation power resources of the CS. To solve these problems, we propose a certificateless and designed-verifier auditing scheme in multi-cloud storage environments. In our scheme, we utilize certificateless signature combined with a delegation key to achieve designed-verifier auditing. We design a secret Merkle Hash Tree (MHT) to locate the faults of CSs and data blocks. We utilize Zero-Knowledge Proof (ZKP) to achieve access control. Theoretical and experimental evaluation show that the proposed scheme is efficient and practical.