Toward Assured Data Deletion in Cloud Storage

Outsourcing data to remote cloud servers can significantly reduce the managing overhead and storage burden for individuals and enterprises. When the data stored in cloud are no longer needed, assured data deletion is a fundamental requirement to ensure that the sensitive data on the cloud can be safely deleted. Salient features of cloud storage such as virtualization, multi-tenancy, high availability and the platform complexity pose various challenges to the assured data deletion, which need to be addressed. In this article, we investigate the system model, desirable security properties as well as the potential solutions to the issues of assured deletion. We present the techniques used to achieve verifiable deletion and propose several methods which satisfy the timeliness, fine granularity and the verification of deletion at the same time. We consider various scenarios such as assured deletion with data transfer, fine-grained access control and data storage with multiple copies. Implementation results demonstrate the efficiency of the proposed protocols.