Auditing the Auditor: Secure Delegation of Auditing Operation over Cloud Storage.
Jia Hao Xu · 2011
In cloud storage service, users upload their data together with authentication information to cloud storage server. To ensure the availability and integrity of users ’ data stored in the cloud storage, users need to verify the cloud storage remotely and periodically, with the help of the pre-stored authentication information and without storing a local copy of the data or retrieving back the data during verification. Public verification enables a third party auditor (TPA), on the behalf of the data owner, to verify the integrity of cloud storage with the data owner’s public key. In this paper, we propose a method that allows the data owner to delegate the auditing task to a potentially untrusted third party auditor in a secure manner: (1) The data owner can verify whether the TPA has indeed performed the specified audit task; (2) The data owner can verify whether the TPA did the audit task at the right time specified by the data owner; (3) The confidentiality of the data is protected against the TPA. Our method also enables a TPA to re-outsource the audit task.