Secure public-auditing cloud storage enabling data dynamics in the standard model

In cloud computing, the paradigm of data outsourcing introduces security challenges, which requires an independent auditing service to check the data integrity in the cloud. Many existing integrity checking protocols cannot be applied to the auditing service because they can only deal with static data, but it is natural for the client to dynamically update their remotely stored data. Thus, an efficient and secure auditing protocol enabling data dynamics is desired to convince the client that the data are correctly stored in the cloud. In this work, we propose a privacy-preserving public auditing cloud storage protocol enabling data dynamics in the standard model. Inspired by a recent homomorphic network coding signature scheme, we employ a data integrity auditing protocol based on the strong RSA assumption, and extend it to enable a third party auditor to audit client's data without learning the data content. Then we further extend our auditing protocol to support the data dynamic operations (modification, insertion and deletion), which achieves high security level in the standard model. At last we prove the security and justify the performance of our proposed protocol through concrete experiments and comparisons with the state of the art.