Outsourced data tagging via authority and delegable auditing for cloud storage

Cloud storage is now an important development trend in information technology. To ensure the integrity of data storage in cloud storing, researchers have present some provable data possession (PDP) schemes. In some cases, the rank of trust for data owner is low. Verifiers are not willing to check data of the owners. Hence, in this paper, we propose the first double delegable PDP scheme, in which both the ability of tag signing for outsourced data and checking the data integrity can be delegated to proxies. i.e., specifically, we introduce a secure-authority, which is generally trusted by all clients and verifiers. So it is able to generate verification metadata. Moreover, in our scheme the authority does not learn anything about the data to be uploaded to the cloud at all. In addition, the identity of the data owner is not revealed to the cloud servers, and there is no extra storage overhead unlike existing anonymous PDP solutions.